Compressor best practises and HVLP setup

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mpitfield

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I have a relatively inexpensive hobby compressor that I use for my HVLP spray gun. I use this infrequently, possibly getting used a couple of dozen times in one year at most. Should I leave pressure in the tank, if so how much, or drain it completely and if so should I leave the petcock open on the tank in-between uses?I have a relatively inexpensive hobby compressor that I use for my HVLP spray gun. I use this infrequently, possibly getting used a couple of dozen times in one year at most. Should I leave pressure in the tank, if so how much, or drain it completely and if so should I leave the petcock open on the tank in-between uses?
 
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I have a small compressor I drain after each use. From what I understand you don't want moisture in the tank.

Thanks AB.

I did a bit more Internet digging and you seem to be correct. At least everything I read indicated that you should empty the tank after use and drain. I just dumped 20 gallons @ 150 PSI, then opened the petcock and drained a small amount of water. Interestingly when I tried to close the petcock, it felt like something was grinding in the threads. So I removed it and it would seem that when it was manufactured they forgot to deburr two holes and their sharp edges were catching on the inside. A quick file and it works better than new.

My digging also landed me into videos regarding the air delivery system. This is one area that you can spend quite a bit on setting up for HVLP...a lot more than the few hundred I have spent so far. So I am going to make some changes, which will hopefully improve my results.

Some easy ways to improve the performance of my low-end system is to address the volume of air it delivers. Apparently when it comes to HVLP, the biggest factor is volume of air, at least more than air pressure, which is also a consideration. Sounds obvious in looking at it now, hence the “HV” (High Volume) in HVLP. Strangely enough when I solicited advice before the emphasis was on pressure, as in the “LP” (Low Pressure)…I know, don’t say it! :facepalm:

Besides the guns, which can get quite expensive, I now know that my fittings, connectors and airline are too restrictive for the optimal CFM, and these are relatively inexpensive to swap. So I will be swapping them for 3/8 ID. Also the water/air filter I have is very cheap and likely doing very little except adding to robbing performance, so I will be looking at my options.

One other area I will look at and may or may not do anything about is adding some vertical loops of pipe after the tank with drains at the bottom of the loops to drain any accumulated water. This apparently helps to cool the air before it hits the filter, but I am not convinced at this time that this is something I need to do for hobby purposes

As for the compressor, it looks like what I thought was a big tank, 20 gallons, and a big enough compressor, 1.8HP, it is possibly undersized. The general consensus is a min of a 60-gallon tank, 5HP compressor and a two-stage air compressor. However these numbers seem to be the optimal setup for painting a car, and not a relatively small hobby rocket, so I am not as much concerned with the tank and compressor size at this stage.

I will see how things progress after the airline and fitting change and if anything I will likely upgrade my gun, or add a gun specific for top and clear coat. This is because gun I have is really optimized for primer.
 
Also don't forget to change the oil regularly. I bought some quality compressor oil at Sears. I believe it was synthetic blend. Refer to the manual on the amount you should add. Mine has a clear glass you look through and the level of the oil has to be half way up in the glass window. Every compressor is different so check.
 
Also don't forget to change the oil regularly. I bought some quality compressor oil at Sears. I believe it was synthetic blend. Refer to the manual on the amount you should add. Mine has a clear glass you look through and the level of the oil has to be half way up in the glass window. Every compressor is different so check.

My compressor is oil-free, so that is one last thing I need to worry about.
 
Thanks AB.

I did a bit more Internet digging and you seem to be correct. At least everything I read indicated that you should empty the tank after use and drain. I just dumped 20 gallons @ 150 PSI, then opened the petcock and drained a small amount of water. Interestingly when I tried to close the petcock, it felt like something was grinding in the threads. So I removed it and it would seem that when it was manufactured they forgot to deburr two holes and their sharp edges were catching on the inside. A quick file and it works better than new.

My digging also landed me into videos regarding the air delivery system. This is one area that you can spend quite a bit on setting up for HVLP...a lot more than the few hundred I have spent so far. So I am going to make some changes, which will hopefully improve my results.

Some easy ways to improve the performance of my low-end system is to address the volume of air it delivers. Apparently when it comes to HVLP, the biggest factor is volume of air, at least more than air pressure, which is also a consideration. Sounds obvious in looking at it now, hence the “HV” (High Volume) in HVLP. Strangely enough when I solicited advice before the emphasis was on pressure, as in the “LP” (Low Pressure)…I know, don’t say it! :facepalm:

Besides the guns, which can get quite expensive, I now know that my fittings, connectors and airline are too restrictive for the optimal CFM, and these are relatively inexpensive to swap. So I will be swapping them for 3/8 ID. Also the water/air filter I have is very cheap and likely doing very little except adding to robbing performance, so I will be looking at my options.

One other area I will look at and may or may not do anything about is adding some vertical loops of pipe after the tank with drains at the bottom of the loops to drain any accumulated water. This apparently helps to cool the air before it hits the filter, but I am not convinced at this time that this is something I need to do for hobby purposes

As for the compressor, it looks like what I thought was a big tank, 20 gallons, and a big enough compressor, 1.8HP, it is possibly undersized. The general consensus is a min of a 60-gallon tank, 5HP compressor and a two-stage air compressor. However these numbers seem to be the optimal setup for painting a car, and not a relatively small hobby rocket, so I am not as much concerned with the tank and compressor size at this stage.

I will see how things progress after the airline and fitting change and if anything I will likely upgrade my gun, or add a gun specific for top and clear coat. This is because gun I have is really optimized for primer.

Can you post a shot of your set-up? I have two data-points from experience to draw from, and I am pretty sure neither are appropriate- in an old job we had a giant compressor tank (I'm remembering it being ~6' long, 3' in diameter, laid down) driven from a huge compressor head. Now, I am the owner of the $99 HomeDepot special 2.5gal pancake compressor. Don't get me wrong, I love the little thing for all my finished carpentry needs, but I am POSITIVE it couldn't drive anything more than a finish nailer. What does it take to cross the threshold from Testor/Badger airbrush (maybe shouldn't lump the two together), to a true HVLP to do large jobs?
 
Can you post a shot of your set-up? I have two data-points from experience to draw from, and I am pretty sure neither are appropriate- in an old job we had a giant compressor tank (I'm remembering it being ~6' long, 3' in diameter, laid down) driven from a huge compressor head. Now, I am the owner of the $99 HomeDepot special 2.5gal pancake compressor. Don't get me wrong, I love the little thing for all my finished carpentry needs, but I am POSITIVE it couldn't drive anything more than a finish nailer. What does it take to cross the threshold from Testor/Badger airbrush (maybe shouldn't lump the two together), to a true HVLP to do large jobs?

I frequently use a Porter Cable pancake compressor to run my Harbor Fright HVLP touch up gun an regular tank style gun, while not ideal sized they will work well enough for the sizes of projects most of us deal with in rocketry. The best compressor is the one that puts out the specified CFM at the suggested pressure for that spray gun.
Its a definitely a good idea to drain the tank after use, and to use a moisture trap/seperator between the hose and compressor during use.
 
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Let the pressure off of the tank, drain any water, store it clean and dry.

I think that most of the stuff that you’ll read on HVLP guns is pretty much ‘baseline’ for spraying large volumes of paint at one time across large areas like auto body applications. For rocketry, even large rockets, I’ve found that you can do pretty good with far less than a full car paint booth. As long as your compressor/tank can maintain pressure and volume at the spray cap during your spray run, you’re golden.

I used this compressor, which everyone said was too small :
https://www.sears.com/craftsman-3-g...p-00915362000P?prdNo=6&blockNo=6&blockType=G6

With this spray gun, which everyone said was total crap and not worth using as a boat anchor : https://www.harborfreight.com/air-tools/paint/20-oz-8-cfm-gravity-feed-spray-gun-67181.html

With these accessories, which everyone said was good money after bad :
https://www.harborfreight.com/air-tools/air-hoses/38-in-x-25-ft-pvc-air-hose-61977.html

https://www.harborfreight.com/Disposable-Inline-Moisture-Filter-68224.html

https://www.harborfreight.com/Inline-Desiccant-DryerFilter-68215.html

With this paint, which everyone said was too expensive and the wrong stuff to use on a cardboard/plywood rocket :
https://duplicolor.com/product/paint-shop-automotive-lacquer-finish-system

And I sprayed the parts in this :
https://www.walmart.com/ip/Honey-Can-Do-36-Wardrobe/17108665


And even after screwing up setting up the gun several times, once I figured it out ( https://www.how-to-build-hotrods.com/set-up-hvlp.html ), I sprayed for several hours (2 coats of primer, both sanded, 2 coats of color, 2 coats of sparkle, and 3 coats of clear) without any problems at all or the compressor running like a scalded dog.

I got one of the best paint jobs that I’ve ever done, and certainly one of the top in my local area (but still well short of Nathan’s legendary paint!). The clubs that I launch with like what I do with rattle bombs and some prep work, and they’ve absolutely pooped their pants on my DX3 paint job.

Since going HVLP, I use less paint, get better coverage, get better surfaces, get all the colors I’ve ever wanted, and there is almost NO overspray whatsoever. It’s an investment initially, but I’ve found it to enhance greatly my MP/HP rocket finishes.

Bottom line is, test YOUR set up. If it does what YOU want it to do, go for it (and to heck with the haters that say you have to have a jumbo tank and a ‘professional’ quality gun).

13001075_860905604036331_7720497381872148221_n.jpg
13015463_860904800703078_3262017433624562258_n.jpg
 
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I frequently use a Porter Cable pancake compressor to run my Harbor Fright HVLP touch up gun an regular tank style gun, while not ideal sized they will work well enough for the sizes of projects most of us deal with in rocketry. The best compressor is the one that puts out the specified CFM at the suggested pressure for that spray gun.
Its a definitely a good idea to drain the tank after use, and to use a moisture trap/seperator between the hose and compressor during use.

Wow, I guess I need to get to HF and look at some guns!
 
Bottom line is, test YOUR set up. If it does what YOU want it to do, go for it (and to heck with the haters that say you have to have a jumbo tank and a ‘professional’ quality gun).

13001075_860905604036331_7720497381872148221_n.jpg
13015463_860904800703078_3262017433624562258_n.jpg

Beauty! I really like the idea you had for a spraybooth- I have a 3" FG Adventurer 3 from Rocketry Warehouse, a 4" AGM-Pike from MadCow and a 2" Nuke Pro Max naked, ready for some clothes- might have to get into HVLP!
 
Can you post a shot of your set-up?

Here are some pics of part of my setup. For a paint booth I built it using PVC pipe and clear plastic drop sheets. It is about two years old and has a lot of paint on but still going strong. It is made up with three sections, a back and two sides that come apart with two wing nuts at the top and two at the bottom. The sections are about 6' by 3'. I lay down a drop sheet down under my the lazy Suzanne I built to rotate what ever I am painting.



Here is a pic of the pressure gauge that was installed at the gun. After a bit more reading, I assumed this was also a chocking point for my air delivery system, as it is 1/4" instead of 3/8" however there doesn't seem to be a 3/8" option for this. There seem to be some contradictions in this technology. One being the consistent recommendation of 3/8" over 1/4" for the air delivery system, but there only seem to be 1/4" options for this regulator/gauge. The other confusing norm is that the gun manufacturers make air pressure recommendations based on the air pressure of the tip of the gun. However there is no way of measuring the tip while spraying so the industry seems to just make an adjustment to the number and use the pressure at the gun. I may replace the one I have with a digital one as I find it difficult to read the analog display and I want something a bit more accurate so I can duplicate results.



Here is a pic of the water filter, which is a very basic water/particulate filter and something that I am going to look at changing to something with more stages.



Here is another shot of the water filter but showing the 1/4" fittings, which I could swap out for 3/8" and still use but I am still doing a bit of research. I may go with a wall mount filtration, water separator/air dryer system. And I know I said in a previous post that I felt the longer cooling pipe wasn't necessary, well I may install some after all as the more you read the more this topic comes up, even for a small home shop. This is typically either a copper or cast iron manifold that just loops up and down with ball valves at the base of each loop to drain the water. This allows the air to cool and water condense as it comes off the compressor.



Here is a shot of the compressor with the filter and hose, again the hose is a 1/4 so I will have to pick up a 3/8.



And finally here is a pic of the 1/4 fittings and the new 3/8 ones I picked up today, quite a bit of difference and I had to change the connection point on the compressor itself which was relatively easy.



The best compressor is the one that puts out the specified CFM at the suggested pressure for that spray gun.

Yes I am just realizing how important it is to match your compressor and gun setup. My compressor says it puts out 5 SCFM @ 40PSI, which is perfect for my gun even with a bit of room. Hopefully the larger diameter fittings and hose will help deliver this.

I think that most of the stuff that you’ll read on HVLP guns is pretty much ‘baseline’ for spraying large volumes of paint at one time across large areas like auto body applications. For rocketry, even large rockets, I’ve found that you can do pretty good with far less than a full car paint booth. As long as your compressor/tank can maintain pressure and volume at the spray cap during your spray run, you’re golden.

Bottom line is, test YOUR set up. If it does what YOU want it to do, go for it (and to heck with the haters that say you have to have a jumbo tank and a ‘professional’ quality gun).

13001075_860905604036331_7720497381872148221_n.jpg
13015463_860904800703078_3262017433624562258_n.jpg

Very nice looking finish, I remember seeing your original post on this. You have a very similar setup as me, same paint as well. I like it but I wish there was a better selection of colours, have you tried to blend them at all? Re the haters, they will always be there and I just consider it background noise.
 
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Instead of blending colors in the Duplicolor line, to get other colors, I buy from here: https://www.tcpglobal.com/Automotive-Paint/Restoration-Shop/

A quart of color plus a quart of reducer costs the same as 2 quarts of the duplicolor, so you'd better be committed to that color! Choices for enamel, too. Stay away from the urethane unless you have ALL the right safety equipment.
 
reads like youre on the right track. one thing to consider is with oilless compressors- the produce a lot of hot compressed air, which can cause more moisture. one simple way to cool the air is to coil an air hose in a bucket of ice water, then after that have your moisture trap. something i do(i did it with my lil pancake compressor and also do it with my 60 gallon one) is crack the drain valve slighly when spraying. helps moisture leave the tank and not enter the lines. when i was set up for spraying cars(i got into that as a hobby and have sprayed about 20 cars,trucks, and bike parts) i had 3/4 copper pipe in 4 vertical rows each 4' long with drains at the bottom, then through my moisture trap. i never experienced a problem with moisture in the paint.
i also keep one hose dedicated to spraying only.



the link Banzai88 has- ive sprayed a couple of their house brand paints. theyre a pretty nice paint to spray and coverage is good.
an old friend of mine had me do a major restoration on a ( believe it or not) 1977 pacer. sprayed in the color
https://www.tcpglobal.com/Automotive-Paint/Restoration-Shop-2917/
im going to be using that color on a rocket some day.
and their prices are very good.
image_3280_zpsjrmr97ov.jpg
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Instead of blending colors in the Duplicolor line, to get other colors, I buy from here: https://www.tcpglobal.com/Automotive-Paint/Restoration-Shop/

A quart of color plus a quart of reducer costs the same as 2 quarts of the duplicolor, so you'd better be committed to that color! Choices for enamel, too. Stay away from the urethane unless you have ALL the right safety equipment.

Thanks for that link...BTW what tip size/s are you using on your HVLP gun/s?

My HVLP came with a 1.5, which I find okay for prime and base but a bit big for my top coat, at least gloss. I have been looking around and it seems like 1.8-2.2 is recommended for prime, base 1.4 and top 1.2-1.3.

These numbers seem about right from my very limited experience, and so I would like to get a dedicated HVLP for prime. Because 1.5 is doable for me I would probably go with the low end @ 1.8, which I know can be picked up inexpensively. I would also like to grab a dedicated topcoat gun, maybe a 1.3, but I know this gun would be a bit more money. Then I would just use my current gun for base which although I may get better results with a 1.4, I am okay with 1.5. Ideally I would just get a matched cap, tip and needle @ 1.4 for this gun however I cannot find options for the Porter Cable HVLP I have.

Also have you used the matte clear, if so do you find it needs a bigger tip? I have used both the gloss and matte with my 1.5, and I find 1.5 too big for the gloss but I found it was easier with the matte, still not optimal but easier. Does matte generally take a bigger tip?
 
p.s.
imo, your compressor is big enough to spray rockets. you wont have the trigger pulled for the length of time it is when spraying big jobs. just keep an eye on the pressure gage on the tank and youll learn how long you can spray for
 
reads like youre on the right track. one thing to consider is with oilless compressors- the produce a lot of hot compressed air, which can cause more moisture. one simple way to cool the air is to coil an air hose in a bucket of ice water, then after that have your moisture trap. something i do(i did it with my lil pancake compressor and also do it with my 60 gallon one) is crack the drain valve slighly when spraying. helps moisture leave the tank and not enter the lines. when i was set up for spraying cars(i got into that as a hobby and have sprayed about 20 cars,trucks, and bike parts) i had 3/4 copper pipe in 4 vertical rows each 4' long with drains at the bottom, then through my moisture trap. i never experienced a problem with moisture in the paint.
i also keep one hose dedicated to spraying only.

the link Banzai88 has- ive sprayed a couple of their house brand paints. theyre a pretty nice paint to spray and coverage is good. an old friend of mine had me do a major restoration on a ( believe it or not) 1977 pacer. sprayed in the color https://www.tcpglobal.com/Automotive-Paint/Restoration-Shop-2917/ im going to be using that color on a rocket some day. and their prices are very good.

Yes once you start looking into HVLP the moisture trap discussion is coming up over and over again, and the system with the drains you mentioned is quite popular because it is simple and inexpensive, so this is what I am looking into now. Love the Pacer BTW...man I hated that car when it came out, that and the Gremlin...wasn't one of those cars considered a death trap with the exploding gas tank if hit in the rear?
 
p.s.
imo, your compressor is big enough to spray rockets. you wont have the trigger pulled for the length of time it is when spraying big jobs. just keep an eye on the pressure gage on the tank and youll learn how long you can spray for

Yes I think it is just about right, although when matching guns and compressors, this compressor limits the HVLP guns you can use. However their are still options for this setup and once I fix my diameter size on the fixtures and hose I should be okay. Then I just need to address the air quality/moisture trap issue.
 
Thanks for that link...BTW what tip size/s are you using on your HVLP gun/s?

My HVLP came with a 1.5, which I find okay for prime and base but a bit big for my top coat, at least gloss. I have been looking around and it seems like 1.8-2.2 is recommended for prime, base 1.4 and top 1.2-1.3.

These numbers seem about right from my very limited experience, and so I would like to get a dedicated HVLP for prime. Because 1.5 is doable for me I would probably go with the low end @ 1.8, which I know can be picked up inexpensively. I would also like to grab a dedicated topcoat gun, maybe a 1.3, but I know this gun would be a bit more money. Then I would just use my current gun for base which although I may get better results with a 1.4, I am okay with 1.5. Ideally I would just get a matched cap, tip and needle @ 1.4 for this gun however I cannot find options for the Porter Cable HVLP I have.

Also have you used the matte clear, if so do you find it needs a bigger tip? I have used both the gloss and matte with my 1.5, and I find 1.5 too big for the gloss but I found it was easier with the matte, still not optimal but easier. Does matte generally take a bigger tip?



getting into guns can get quite complicated. you have a good plan in going less expensive for a primer gun with a 1.8 tip. typically, any bigger tip is necessary when polyester primers like evercoats featherfill and quicksand. but for most primers a 1.8 tip is good. even with products like the featherfill and quicksand they can be thinned to spray with a 1.8 tip.
personally for me, on basecoats, single stage, and clears, i have a devilbiss tekna with a 1.3 tip. of course, i got that gun because of the auto painting. their finishline 3 and 4 guns are really good. theres other guns that are less expensive and produce good finishes,too- iwata makes great guns and ive read the sharp finex is a good gun,too.
imo, 1.3-1.5 tips are good for most basecoats, clears, and single stage. even with the 1.3 tip in my tekna i can have to change up spraying technique a bit between different brands/types of paint as the viscosity can vary a bit between them.
and most brands of paint can be reduced to make atomization better
 
Love the Pacer BTW...man I hated that car when it came out, that and the Gremlin...wasn't one of those cars considered a death trap with the exploding gas tank if hit in the rear?

yes, it is considered a deathtrap. the engines and trans were actually a good design and in use for many years. i was surprised when i did a compression test on that motor withb125,000 miles onmit it had 125 psi on all cylinders. a tune up and carb rebuild she purred.
it was one i got a little over my head with. the body line on the door- follow that around the back to the other door- 95% of the steel below that line was rotted out and had to be replaced. theres no aftermarket panels for pacers( it cant be!!!LOOL) so i had some metal shaping happening- hardest,most tedious was the rear corners below the taillights. its not easy shaping metal like a fishbowl!!!

one other paint line you may want to look into is kirker. they arent well known, but have been in business for a long time. ive shot a few of their basecoats,too, and they are nice. the products i like from them are there primers. their perfect prime has a good build and sands nice.

one ive been lookin at rather new is tamco paints. their clears are relatively inexpensive.
one thing i like about spraying clears is i can add some flake to it. i can add as little or as much as i want. when i did mymotorcycle tins i started with black base, then clear with a dark blue flake. 3 coats, then 3 coats of straight clear. they look black in the shade but once the light hits em they look blue and sparkle. pretty sweet effect.
 
getting into guns can get quite complicated

Understatement of the thread! Between needle size, nozzle material, and number/size/distribution pattern of atomization holes you can drive yourself crazy comparing apples to apples to apples and STILL not have a full feel for how a piece is going to perform with your chosen materials.

I can have to change up spraying technique a bit between different brands/types of paint as the viscosity can vary a bit between them.
and most brands of paint can be reduced to make atomization better

That's what I've found. I actually got lucky and have the nicer HF tip on the gun that I bought, it's a 1.4, and it does VERY well with lacquers, although I find it a bit much for the clears. I have to change technique a little for enamels, and pay more attention to viscosity, but it does produce a fine finish.

Bottom line is, regardless of equipment, within limits, the gun (air/fan/fluid), along with air pressure and fluid viscosity, can be tuned to work together to get pretty good results with minimal investment in a spread of equipment. Me? I like it all well enough that I have ordered a gun which I intend to dedicate to clear coat only to make process flow a little easier. I've sprayed a number of rockets, some lacquer and some enamel, and so far there's really nothing that I don't think can't really be done well with some prep and attention to detail. Heck, even some of my 'bad' stuff was saved with a buff/polish cycle.

Think through your paint process, prep, and keep everything clean! I did lots of practice on paper towel and wrapping paper rolls. Paper/cardboard/plastic/plywood takes some quality prep, but it's worth it in the end. Painting on fiberglass with lacquers = awesome finish!

Even the best paint and most expensive spray guns and all the training/experience in the world won't save a paint finish with oil and/or water in the line. Budget wise, if I had to make a choice between a mediocre gun and excellent filtration or a great gun and so-so filtration, I'd go with the better filtration any day.
 
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yes, it is considered a deathtrap. the engines and trans were actually a good design and in use for many years. i was surprised when i did a compression test on that motor withb125,000 miles onmit it had 125 psi on all cylinders. a tune up and carb rebuild she purred.
it was one i got a little over my head with. the body line on the door- follow that around the back to the other door- 95% of the steel below that line was rotted out and had to be replaced. theres no aftermarket panels for pacers( it cant be!!!LOOL) so i had some metal shaping happening- hardest,most tedious was the rear corners below the taillights. its not easy shaping metal like a fishbowl!!!

one other paint line you may want to look into is kirker. they arent well known, but have been in business for a long time. ive shot a few of their basecoats,too, and they are nice. the products i like from them are there primers. their perfect prime has a good build and sands nice.

one ive been lookin at rather new is tamco paints. their clears are relatively inexpensive.
one thing i like about spraying clears is i can add some flake to it. i can add as little or as much as i want. when i did mymotorcycle tins i started with black base, then clear with a dark blue flake. 3 coats, then 3 coats of straight clear. they look black in the shade but once the light hits em they look blue and sparkle. pretty sweet effect.

Thanks for the info on the paints and now hearing how much work you put into that pacer it really does look good, as a matter of fact I don't remember them looking that good from the factory.

When I was a kid a tinkered with a friends late model BMW and used to watch another friend and his cousin work on his Corvette but I never got the car or anything with an engine bug, except my gas/electric RC days, which is just a memory at this stage. I do love watching the TV shows when they restore and or build them though. I just watched a recorded episode of the new show "American Restoration" and they restored two nice unique bikes heritage motorcycles, and the other guys took a 67 Mustang and turned it into quite an incredible looking and sounding car for some musician


Budget wise, if I had to make a choice between a mediocre gun and excellent filtration or a great gun and so-so filtration, I'd go with the better filtration any day.

I was surprised to hear this statement the first time, but filtration, water removal, and air volume seem to what is discussed the most in the HVLP forums, discussion threads, on how-to videos by the pros, etc.

All of my equipment is definitely at the bottom end of that spectrum and the price differences when you look at the high end guns is big, not likely something I will pick up, but I will keep my eye out for a mediocre clear and low end primer gun, that works in the CFM range of my setup.

Right now I am in the process of making an Excel job cost for about a 25'-50' air cooling system in both copper and high pressure steel pipe, as well as figuring out which filtration system I want. I found a decent one for a reasonable price, a bit more than I wanted to spend, but after reading up on it the lower end ones seem to have too many comments about the entry systems being too limited and hitting the wall on capacity fast. So I upped the budget slightly. Realistically the budget is still a joke compared to what these setups can cost but for my hobby purposes it should do well.
 
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All of my equipment is definitely at the bottom end of that spectrum and the price differences when you look at the high end guns is big, not likely something I will pick up, but I will keep my eye out for a mediocre clear and low end primer gun, that works in the CFM range of my setup.

Right now I am in the process of making an Excel job cost for about a 25'-50' air cooling system in both copper and high pressure steel pipe, as well as figuring out which filtration system I want. I found a decent one for a reasonable price, a bit more than I wanted to spend, but after reading up on it the lower end ones seem to have too many comments about the entry systems being too limited and hitting the wall on capacity fast. So I upped the budget slightly. Realistically the budget is still a joke compared to what these setups can cost but for my hobby purposes it should do well.

nnnnaaaaaaa, yer far from the bottom of the spectrum. i started with a pancake compressor and this gun from HD

https://www.homedepot.com/p/Husky-Siphon-Feed-Detail-Spray-Gun-H4910DSG/203468550

now that was funny! i made some purdy drip patterns!


filtration can get just as complicated as gun choices.
simply put, its about cooling the air,which the copper pipe will do, and removing any contaminates- water,oil,etc. the drains at the bottom of copper runs will help with. my final filter is a devilbiss startingline, but theres others that are good. my sons stepdad has been in autobody for many years znd uses a simple motorgard filter
https://www.amazon.com/dp/B000WZYKAE/?tag=skimlinks_replacement-20

he likes it because the filter elements are inexpensive,easy to replace, and last a long time.

you could also use the disposable filters that go at the gun
https://www.amazon.com/dp/B000N2VUSQ/?tag=skimlinks_replacement-20



i will use them when i have something big that they wont get in the way of gun movement. as i use a regulator right at my gun, adding that can make it a little bulky.

i dont know if i mentioned it yet, but i crack the drain on my compressor a bit when im spraying. just a little extra help removing moisture.
 
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nnnnaaaaaaa, yer far from the bottom of the spectrum. i started with a pancake compressor and this gun from HD

https://www.homedepot.com/p/Husky-Siphon-Feed-Detail-Spray-Gun-H4910DSG/203468550

now that was funny! i made some purdy drip patterns!

I started with a siphon fed gun, which came in a kit with second gravity fed gun that had a pretty a small bowl. I couldn't get either to work very well except for with primer in the siphon gun but then again primer seems to be the easiest to work with, and clear the hardest, at least for me. Of course not knowing anything about this stuff it was the price (wow a complete kit including a coiled air hose, 2 guns, strainers, cleaning brushes, air hose couplers blowing attachments, all in a carrying case for $90) that attracted me. However it ended up being a pain to use and clean. After the first use I cleaned the gun with lacquer thinner, there is a ring that screws the horns onto the tip that is attached to the horn assembly and was painted a nice attractive blue. After the cleaning all of the pretty blue coating was bubbling off. I guess the paint gun was not designed to be cleaned...that was the first sign that I wasted $90. I still have the kit if anyone wants it!

I then moved to this one, which has worked well enough except for the airflow/quality issues that I am addressing now. As I mentioned I may pick up an inexpensive dedicated topcoat gun with a 1.3 tip.

https://www.homedepot.ca/en/home/p.gravity-feed-spray-gun.1000714352.html

filtration can get just as complicated as gun choices.
simply put, its about cooling the air,which the copper pipe will do, and removing any contaminates- water,oil,etc. the drains at the bottom of copper runs will help with. my final filter is a devilbiss startingline, but theres others that are good. my sons stepdad has been in autobody for many years znd uses a simple motorgard filter
https://www.amazon.com/dp/B000WZYKAE/?tag=skimlinks_replacement-20

he likes it because the filter elements are inexpensive,easy to replace, and last a long time.

Here is a link to the filter, water remover, regulator combo that is a relatively inexpensive solution and should meet all of my infrequent hobby needs and foreseeable growth, if any.
https://www.tptools.com/Filter-Regulator-System,7445.html?b=d*8088

The link below is to the style of cooling system that seems to be the cheap and cheerful easy solution. The one I am looking at will possibly be 1/2 and have drains at the bottom of each run like the second example on this page, also with a slightly longer reservoir connected to the tee before the valves. The compressor will be connected directly to this via a 6' 300 working PSI flex pipe with a 3/8 quick connect on the compressor side and on the other end will be the filter system. I was thinking of gong with 1/2 over 3/8 becasue the price difference is negligible and there seem to be more options (economy of scale), plus I don't want to introduce anything that would contribute chocking the volume. Also looking down the road, if I upgrade my compressor I may need the bigger diameter and I don't want to do this twice. It will also be a min length of 25' and up to 50' which 25' seems to be the standard min with more being better. Depending on the pipe lengths I go with, it will just be a multiple of that, rounded up. So if 8' lengths, keeping 25' min as my goal I would just go with 4 of them, which would result in 40' plus feet once you add in the bends, etc.
https://www.garagejournal.com/forum/showthread.php?t=141247

you could also use the disposable filters that go at the gun
https://www.amazon.com/dp/B000N2VUSQ/?tag=skimlinks_replacement-20



i will use them when i have something big that they wont get in the way of gun movement. as i use a regulator right at my gun, adding that can make it a little bulky.

i dont know if i mentioned it yet, but i crack the drain on my compressor a bit when im spraying. just a little extra help removing moisture.

I have my eye on the DeKkups system. Someone on TRF turned me onto it last year, but I want to address the air volume and quality first. Plus it is hard to justify all of the costs, which can add up quick. Based on how infrequently I use my sprayer, I am addressing things that cause me the biggest pain first. Even then I live with it for a bit until I realize that I am kidding myself in that it is not worth it becasue I have to sand, touch-up and or repaint due to moisture. Something you don't really have to deal with, and or think about, when using rattle cans.

As for the regulator. My current plan is to keep the regulator on the compressor wide open, then throttle it back on the regulator that is integrated in the filter system, to possibly 90PSI give or take. Then I will cheek it down at the gun with a second regulator as you described. This plan may change slightly as I learn more about this, but this seems to be the common setup that I have seen over and over again. We will see, after all this is the internet which as we all know always provides accurate information and advice :wink:
 
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yer settin up good! that filter is pretty much the same style as the motorgard. i have the dekups system myself, but i got it because getting down spraying rocker panels and going around wheel wells required turning the gun at different angles. painting rockets i found just turning cap on the gun so the spray pattern is horizontal works good for me.

yup, it does get pricey setting up for spraying, even when doing it economically!
 
Small update,

Last week I received two new hoses, one is 3/8 3' which goes on the output side of the cooling rack and connects to the filter. The other is a 1/2 6' lead-in hose which will connect the compressor to the input side of the cooling rack. Today I received my new 50' 3/8 auto-retracting hose. This will replace my existing 50' 1/4" hose, which was just coiled up on the back of the tank and a pain to roll up...no more. Hopefully I will pick up the pipe to make the cooling rack this weekend and receive the filter system next week, then I am back to paining.

 
I have a relatively inexpensive hobby compressor that I use for my HVLP spray gun. I use this infrequently, possibly getting used a couple of dozen times in one year at most. Should I leave pressure in the tank, if so how much, or drain it completely and if so should I leave the petcock open on the tank in-between uses?I have a relatively inexpensive hobby compressor that I use for my HVLP spray gun. I use this infrequently, possibly getting used a couple of dozen times in one year at most. Should I leave pressure in the tank, if so how much, or drain it completely and if so should I leave the petcock open on the tank in-between uses?

24 times a year is infrequent. I paint maybe 6-8 times a year and I thought that was lot.
 
Another package arrived today.

This is the two stage water separator coalescing air filter with a regulator in between them. The construction is all metal and appears to be a good quality unit. I also picked up a new regulator to fit onto my HVLP, also pictured below right however I need an adapter to attach it. I also took pencil to paper and designed my cooling rack, then assembled a parts list and priced all of the pieces out. I will try to pick that up this weekend. However I went to use my corded hammer drill today but it seems that one of my employees burnt it out, so I now need to get it fixed as I will need it to affix it to the concrete wall.

 
Another package arrived today.

This is the two stage water separator coalescing air filter with a regulator in between them. The construction is all metal and appears to be a good quality unit. I also picked up a new regulator to fit onto my HVLP, also pictured below right however I need an adapter to attach it. I also took pencil to paper and designed my cooling rack, then assembled a parts list and priced all of the pieces out. I will try to pick that up this weekend. However I went to use my corded hammer drill today but it seems that one of my employees burnt it out, so I now need to get it fixed as I will need it to affix it to the concrete wall.


This is the first I had noticed this thread, lots of useful information. That is a serious looking water separator. I just have a small water separator attached to my gun below the regulator. I guess it's doing the job because I haven't had any problems with water. There is always a small amount, like about a teaspoon, of water to drain from my compressor tank after I use it. What would it look like if there was water getting past the water separator? I am guessing it would cause bubbles in the finish.
 
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