Wet sanding, Compounding, Polishing...discussion

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MikeyDSlagle

MikeyDSlagle

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I got a PML Callisto and MAC Ethos 2.0 for my birthday and am currently in the cut/polish stage on both. Well I actually finished up the Callisto today. I stumbled onto a few sites that sold pigments and additives to mix my own paint and I used Duplicolor Paint Shop gloss clear for the base to mix with - because I couldn't find just the right color. But so far I am really impressed with these pearls and flakes.

On my Callisto I wasn't thinking and kept getting ahead of myself which resulted in me having to paint the fins twice more than I intended. With 1200 grit I sanded through on the edges of the fins, even with 3 coats of clear. With the multiple layers of paint, different colors are showing around the edges...but I am letting it go. I never did get all of the "wavy/orangepeel" completely out of the fins because I kept cutting through around the edges. Yeah I know it is common to do so. They look okay after polish but not what I wanted. I MAY go back and redo the fins. But for that I will need more clear and pearls.

On my Ethos, I have already polished the nose. The light color made it pretty hard to see the orangepeel as I was cutting. It is super glossy and slick but I can still feel slight orangepeel in places, but I am not worried about that. It looks great.

Next up is cutting/polishing Ethos itself.
My normal routine is 1200 or 1500 - 2500 - swirl remover - polish - then eventually wax and buff.

Now for the discussion.

An issue that has haunted me since high school:
Does sand paper actually wear out? I was using some 1200 and it got to the point it seemed to not be cutting at all. Or is it just clogged? If it is clogged, how do I unclog? It seems unlikely that lacquer paint will wear out sandpaper this quickly.

I do my wet sanding with my hand. I have a few sanding blocks but they have so little surface contact that they are extremely difficult to use, and impossible to use in some places. What do other folks use? Is there some sort of pad?

Is there another option other than wet sanding with 1200 or 1500? Such as a rubbing compound that can be used on a polisher. I have found all sorts of compounds that "removes 1200 grit sanding marks" but I want something to replace 1200 grit sandpaper if that is possible. A rubbing compound on a dual action polisher maybe?

Or some sort of "elbow grease free" option for wet sanding. I know electricity and water don't mix. But surely something is out there, DIY, home projects, something. I find it hard to believe folks wet sand entire vehicles by hand. I have seen pneumatic sanders but they require more of a compressor than I have.

I realize rockets get banged up from travel, recovery and general carelessness but I want to get this Ethos looking good. So please keep "wasting your time" comments out of the discussion. LOL. I am not looking at saving time really, but saving my poor ole elbows and fingers. :D
 
Sandpaper does wear out. It will change color to that of the backing paper.
I sand the tubes by turning in lathe at a reasonable speed. I will fill grooves and paint up to primer before putting on fins. Just use coarse sandpaper to rough up where fillets will be.

M
 
After 1000-1500 (3M films are my preference) Check out 3M Trizact 3000. It is a game changer. It is on a foam backed disc, lasts a long time, and is best used wet. As it has a foam back, and a somewhat porous face, it retains water very well. You could even 'safely' wetsand with this on an electric orbital sander, with caution. I have used this stuff for years, and love it. For doing gloss, there is no substitute, IMO. 3000 Trizact will remove 1200 grit scratches very well, that is what it was designed for. It is almost certain that your local body shop uses it.

Get it 'flat' with 1000, maybe 1500, then hit it with the 3000 Trizact. This can be followed by 3m Trizact liquid compound, or with one or more of the Perfect-it line. I have all of these, and prefer the Trizact liquid. A 2HP or larger buffing jack with 14" -16" wheels with Menzerna dry stick compounds, (pre-polish, fine, and extra fine) are very fast after the Trizact, and can get most of the shape of a rocket. This is by far the fastest, and best way to do the finish polishing, though there is a learning curve. A buffing jack may not be available to most folks, though.
 
Sanding paper will wear out. It will also clog. This is why (the proper) sandpaper is used wet; the water keeps the material being sanded from gumming up the sandpaper.

There are different "grades" of (automotive) polish. Everything from cutting in compound (fairly coarse as polishes go) to buffing compound to final polish. Give the guy at Summit Racing 1-800-230-3030 a call and ask them questions. Even if you tell them it's for a hobby rocket, I doubt they'll laugh. You should see what I put their products to use for...
 
Paging Nathan... Nathan, you are wanted in the "Wet Sanding Compounding Polishing Discussion" thread.
 
Yes people wet sand entire cars by hand with little pieces of sandpaper. I've never heard of using a machine to do wet sanding.
 
a rubbing compound on a DA polisher( something like the porter cable 7424 or rupes big foot) doesnt take the place of sanding. it refines the sanding more. its basically a finer grit.

yes, sandpaper does wear out. when wet sanding a car i will change 1/4 sheets every panel. if the paper gets glogged, i toss it and get another sheet.


best option?
practice spraying techniques to get the color and clear to lay perfect.

or fly nakey!! :)
 
Thanks folks. No reason at all for me to be so busy at work that I am too tired to even turn on my computer in the evenings. HA.

Chris_H said:
After 1000-1500 (3M films are my preference) Check out 3M Trizact 3000. It is a game changer. It is on a foam backed disc, lasts a long time, and is best used wet. As it has a foam back, and a somewhat porous face, it retains water very well. You could even 'safely' wetsand with this on an electric orbital sander, with caution. I have used this stuff for years, and love it. For doing gloss, there is no substitute, IMO. 3000 Trizact will remove 1200 grit scratches very well, that is what it was designed for. It is almost certain that your local body shop uses it.

Get it 'flat' with 1000, maybe 1500, then hit it with the 3000 Trizact. This can be followed by 3m Trizact liquid compound, or with one or more of the Perfect-it line. I have all of these, and prefer the Trizact liquid. A 2HP or larger buffing jack with 14" -16" wheels with Menzerna dry stick compounds, (pre-polish, fine, and extra fine) are very fast after the Trizact, and can get most of the shape of a rocket. This is by far the fastest, and best way to do the finish polishing, though there is a learning curve. A buffing jack may not be available to most folks, though.
Click to expand...

I will look into some of these Trizact products. Yeah the buffing jacks are this folks. LOL I have tried some of the buffing rouge bars for polishing metal but I have yet to get the hang of that.

sooner.boomer said:
Sanding paper will wear out. It will also clog. This is why (the proper) sandpaper is used wet; the water keeps the material being sanded from gumming up the sandpaper.

There are different "grades" of (automotive) polish. Everything from cutting in compound (fairly coarse as polishes go) to buffing compound to final polish. Give the guy at Summit Racing 1-800-230-3030 a call and ask them questions. Even if you tell them it's for a hobby rocket, I doubt they'll laugh. You should see what I put their products to use for...
Click to expand...

The "roughest" compound I have found so far has been to remove 1000 grit sanding scratches. I used 3M wet/dry sandpaper and now I am trying some Gator brand from Lowes and it seems to be working just as well as the 3M. It's much cheaper as well.

tomsteve said:
a rubbing compound on a DA polisher( something like the porter cable 7424 or rupes big foot) doesnt take the place of sanding. it refines the sanding more. its basically a finer grit.

yes, sandpaper does wear out. when wet sanding a car i will change 1/4 sheets every panel. if the paper gets glogged, i toss it and get another sheet.


best option?
practice spraying techniques to get the color and clear to lay perfect.

or fly nakey!! :)
Click to expand...

I can get the color down pretty good but clear still gives me problems. I don't have the best setup for spraying so I am making do with what I have. Once I have a shop up and running I expect to be able to get better results. For the paint job on Ethos I mixed flakes with the clear. And, from what I have read, it is common for the finish to feel rough. Sanding is required to knock down the flakes and clear is needed before sanding. I have 6 coats of clear on Ethos now that is waiting to be sanded.

To me once a rocket flies...it is finished. No further work is needed. So I like to have them in the condition I want to fly them. And the next launch is after the crops are cut sometime in September maybe so to get my rocket fix, I "finish" my rockets. I have flown one nakey and it hasn't flown since. It was just ho-hum. I started working on it again but put it on hold for other projects.

I have found several pneumatic wet sanding tools but they require a good sized compressor - something that is not in my near future. Looks like I will be hand sanding for now. I do good on the body tubes but have more trouble on the fins, cutting through on the edges.

So now the question. When you folks hand sand, do you use a block of some sort, a sponge or just hand and fingers? A block works better but like I mentioned, with so little surface contact (on the body tube), it is really difficult. And I really cut through the edges on the fins with a block, but that is just technique
 
MikeyDSlagle said:
So now the question. When you folks hand sand, do you use a block of some sort, a sponge or just hand and fingers? A block works better but like I mentioned, with so little surface contact (on the body tube), it is really difficult. And I really cut through the edges on the fins with a block, but that is just technique
Click to expand...

I collect chunks of flexible foam and/or sponges of various stiffness-es. Select the right stiffness, cut to size, wrap sandpaper around it, wet down rocket, dip foam&paper in a bucket with a little Dawn (few drops), hand sand sand sand. Lotsa elbow grease.

The foam that is in some surplus ammo boxes is very stiff and is great for large airframes. Cut a roughly-rounded edge on a soft sponge, use for fillets.

Best -- Terry
 
prfesser said:
I collect chunks of flexible foam and/or sponges of various stiffness-es. Select the right stiffness, cut to size, wrap sandpaper around it, wet down rocket, dip foam&paper in a bucket with a little Dawn (few drops), hand sand sand sand. Lotsa elbow grease.

The foam that is in some surplus ammo boxes is very stiff and is great for large airframes. Cut a roughly-rounded edge on a soft sponge, use for fillets.

Best -- Terry
Click to expand...

I had liberated some foam from work before it made it to the dumpster that works great. Some sort open cell I am guessing, used to ship some of our larger batteries. Need to get me some that is a bit on the stiffer side but for now this will work.
 
MikeyDSlagle said:
So now the question. When you folks hand sand, do you use a block of some sort, a sponge or just hand and fingers?
Click to expand...

Hand and fingers only when I am wet sanding clear coat. I feel like I have better control that way. And to avoid sanding too deep, especially near edges, you need to be able to feel what the sandpaper is doing.
 
For me it seemed to go better with the foam block. I still had issues around the fin edges, but that's just something I need to work on, as well as getting the clear to lay right so most of this can be avoided. I know I will still have to cut and polish, but it'll be much easier if the clear acts right.
 
Next up is cutting/polishing Ethos itself.
My normal routine is 1200 or 1500 - 2500 - swirl remover - polish - then eventually wax and buff.

Auto finishers typically start with 800 wet, unless they are using a DA sander for the initial cut. Starting with 1200 may not be providing the leveling you are after. Also be sure to use a backing pad behind your paper. Norton and 3M make them and they can be cut to size. Three coats of paint shop clear is a fairly thin mil layer. It is an old school single stage (similar to the old lacquers) and has a lot of shrinkage. You can easily double that. Change your paper as needed. If you can't feel the 800 cutting you are likely burnishing the finish instead of leveling. Your paper should not clog if you have provided at least 48 hours to dry... more days, the better for lacquers. They continue to shrink for some time.
 
MikeyDSlagle said:
So now the question. When you folks hand sand, do you use a block of some sort, a sponge or just hand and fingers? A block works better but like I mentioned, with so little surface contact (on the body tube), it is really difficult. And I really cut through the edges on the fins with a block, but that is just technique
Click to expand...

I have a set of these, but they're pretty expensive for what you get. 1500-12000 range.
 
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MikeyDSlagle said:
I do my wet sanding with my hand. I have a few sanding blocks but they have so little surface contact that they are extremely difficult to use, and impossible to use in some places. What do other folks use? Is there some sort of pad?
Click to expand...
I don't have any pictures on my computer currently, but I normally 3D print a few sanding tools for each project. Sanding blocks are great for things that need to be flat, but I've printed sanding tools to help sand fillets even, to sand a radius in fins to give better adhesion to motor tubes or blocks with a radius to sand tubes down. I normally CA sandpaper to the tools as I consider them to be disposable in most cases. Really, you can make the same things with wooden blocks. I find it makes things a little easier and ends up with less waviness on parts than just hand sanding with paper.
 
KC3KNM said:
I don't have any pictures on my computer currently, but I normally 3D print a few sanding tools for each project. Sanding blocks are great for things that need to be flat, but I've printed sanding tools to help sand fillets even, to sand a radius in fins to give better adhesion to motor tubes or blocks with a radius to sand tubes down. I normally CA sandpaper to the tools as I consider them to be disposable in most cases. Really, you can make the same things with wooden blocks. I find it makes things a little easier and ends up with less waviness on parts than just hand sanding with paper.
Click to expand...

There are these printable sanding shape tools on Thingiverse - includes an assortment of round convex and concave sizes, plus a few angles. Those max out at 1" dia - I suppose I should add some larger, at least in common tube sizes. There are lots of other various sanding blocks elsewhere on TV too.
 
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Jozef said:
Next up is cutting/polishing Ethos itself.
My normal routine is 1200 or 1500 - 2500 - swirl remover - polish - then eventually wax and buff.

Auto finishers typically start with 800 wet, unless they are using a DA sander for the initial cut. Starting with 1200 may not be providing the leveling you are after. Also be sure to use a backing pad behind your paper. Norton and 3M make them and they can be cut to size. Three coats of paint shop clear is a fairly thin mil layer. It is an old school single stage (similar to the old lacquers) and has a lot of shrinkage. You can easily double that. Change your paper as needed. If you can't feel the 800 cutting you are likely burnishing the finish instead of leveling. Your paper should not clog if you have provided at least 48 hours to dry... more days, the better for lacquers. They continue to shrink for some time.
Click to expand...
This time I started with 600, thought I had picked up 800 but it was 600 when I got home. Went a lot faster this time. I thought 3 coats would've been sufficient, next time I'll take a different route. Either more coats or a different system.
 
vcp said:
I have a set of these, but they're pretty expensive for what you get. 1500-12000 range.
Click to expand...
I have eyed those several times, but just can't put down the cash for em. I'll come up with backing sponges and rubber.

I don't have a 3d printer, so getting stuff printed would be an extra hassle.
 
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MikeyDSlagle said:
I have eyed those several times, but just can't put down the cash for em. I'll come up with backing sponges and rubber.

I don't have a 3d printer, so getting stuff printed would be an extra hassle.
Click to expand...

I get that, just throwing some ideas out there. If you've got a few blocks of wood, it's easy to apply the same idea and make your own tools if you can't find what you need on the market.

vcp said:
There are these printable sanding shape tools on Thingiverse - includes an assortment of round convex and concave sizes, plus a few angles. Those max out at 1" dia - I suppose I should add some larger, at least in common tube sizes. There are lots of other various sanding blocks elsewhere on TV too.
Click to expand...

I like that, saves time of designing your own. Here's a sanding jig I just printed up. Should save a good amount of frustration. :D
 

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MikeyDSlagle said:
For the paint job on Ethos I mixed flakes with the clear. And, from what I have read, it is common for the finish to feel rough. Sanding is required to knock down the flakes and clear is needed before sanding. I have 6 coats of clear on Ethos now that is waiting to be sanded.
Click to expand...

does that 6 coats have a few coats of straight clear on top of the clear with flake? reason i ask is because if the topcoat of clear has flake in it you will be sanding on the flake and it might not look that nice after buffing.
 
Oh yeah, it had 5 or 6 coats on top of the flakes. I did 3 coats then about a week later, after wet sanding Callisto, I went back and did a few more.

Alot of the work ended up being a waste..somehow I ended up with a bit of CA glue near a rail button. Rubbing alcohol is not what I should've used, Rem Oil works great for removing CA however, should've remembered that because I use it to remove glue residue from my beer bottles.
I should've went back and put a bit of clear on the bad spots, but it sanded and polished out okay. Little mistakes like that are so frustrating. Live and learn.
 
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vcp said:
I have a set of these, but they're pretty expensive for what you get. 1500-12000 range.
Click to expand...

I have those too but I only use them for final sanding when turning pens on the lathe. There is no reason to use such fine sandpaper on rockets. And they wouldn't last long.
 
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Nathan said:
Yes people wet sand entire cars by hand with little pieces of sandpaper. I've never heard of using a machine to do wet sanding.
Click to expand...


I wet sand with a DA all the time, as beyond 1000, if it is not wet, most finishes will clog the abrasive immediately. And a DA will do a far better job than a hand block, or hand paper. All are necessary, though, each in their own place.

When wet sanding with an electric sander, heads up, as electricity and water can be dangerous together. I use pneumatic sanders.
 
MikeyDSlagle said:
So now the question. When you folks hand sand, do you use a block of some sort, a sponge or just hand and fingers? A block works better but like I mentioned, with so little surface contact (on the body tube), it is really difficult. And I really cut through the edges on the fins with a block, but that is just technique
Click to expand...
 
At the auto paint stores, there are flexible sanding sponges that can be used for tubes.

For the fins, use a foam block on the flats, and folded paper by hand for the scary parts. If you are good, you can use a block for most surfaces. Every stroke is a cut. When you find your mind wandering, and not paying close attention, that is when you will burn through.

Speaking in theory, if you want an ultra polish, at some point early on, there needs to be an abrasive that 'cuts flat' the surface, levelling orange peel, runs, sags, any other imperfections. Then, as things progress, the surface needs to be keep flat, and what is necessary here will all depend on what is being sprayed, or applied, and how smooth it is. If you can keep things flat, then less agressive abrasives are necessary. I like to flatten early and keep things flat, as opposed to flattening more towards the end.

If a layer beneath the final finish is not completely smooth, and then you try to level a top coat, there is greater danger of burning through.

For sponges, those are mainly sponge backed abrasives, and they do not level well. A block will level best. With curves, the block needs to become flexible. Papaer in hapd, wet, is used for the edges, and the details. If you try to sand a broad expanse by hand, it may look good to most, but it will not be as flat as if done with a block.

In my experience, it is not really a 'cut and dried' thing, what methods and sequence to use in acquiring a finish. It is more of a 'language', where you have your tools, and use them appropriately as per what your finish is presenting. If you have developed a recipe for a particular finish, then good. Sponges will not level orange peel or defects, blocks can be dangerous if there may be high spots, and blocks must be matched to potential contours. Uneven pressure will burn through. Hand sanding is good, especially for details and edges. Properly selected abrasives on a DA, all the way through 5000 grit, will always yield a better finish than had sanding, where the use of a DA is appropriate ( bigger expanses) I will use a DA on tubing, fins, nose cone. For cutting back on round surfaces, I have some flexible but fairly stiff blocks that are 3/8" and 1/2" thick. I will use a DA first, with 600 or 1000, to cut through the orange peel. If you are new to using a DA, heads up, as you can cut through your finish quickly.

Using 1000 on a flexible block, say 1/2" thick, until 'uniform dull grey, then getting some 3000 foam backed trizact on your orbital (minimal water is necessary here, and the Trizact will cut like a zombie on steroids compared with hand sanding, both in terms of speed, and in minimizing scratches / quality of finish left. After the Trizact, liquid compounds can be used.

I am a professional finisher, and have used these tools for many years.

Polished finishes are an artform.

If you are doing polished finishes, and are not using Trizact (3000), you either have a big buffing jack (instrument finisher) , or you are wasting time. The surface needs to be cut completely flat to 1000, at least, before using Trizact. Often, I will do my cutting within 24 hours of the final coat, with 2000 grit, and then use the Trizact 3000. I can do a pretty good size area, all the way from freshly sprayed, to full polish, in a few hours, on some pretty good size areas. An average 4-6" rocket no problem. As time passes, the finish hardens quickly, and the amount of effort required increases exponentially. After a few days, the number of hours required become crazy long. With nitro based lacquers, I will do an initial 'cut' to 1000, maybe 2000, after about 24 hours, then bring it to full polish after a couple of weeks.

Find a system that works, and stick with it. And if you are trying to do nice finishes, Personally, I would forget about rattle cans first thing.

Learn to spray 'glass'. That will save lots of effort. 'Dry' coats are not what you are looking for, you want it all to flow together, right to the point of wanting to sag, but not quite. No amount of 'dry' coats are okay.
 
Awesome write up. Thanks. I am trying to get away from rattle cans altogether and I hope once I have a better setup, in a shop and not under a pine tree, my work will improve.

Using your DA with 1000 grit...is that a pad, paper, or a compound? Just want to know what to look for.

Thanks again for the detailed write up.
 
Chris_H said:
I wet sand with a DA all the time, as beyond 1000, if it is not wet, most finishes will clog the abrasive immediately. And a DA will do a far better job than a hand block, or hand paper. All are necessary, though, each in their own place.

When wet sanding with an electric sander, heads up, as electricity and water can be dangerous together. I use pneumatic sanders.
Click to expand...

That's news to me but all I know is what I read on the Google machine. Seems to me though that a DA sander might work well for sanding relatively flat surfaces but not so well on tubes and nose cones.
 
You are welcome. I realize that some of those words might be difficult to interpret.


I use 3m papers almost exclusively. For the 1000 grit, for the DA, I use the '260l' films. (discs) These are used wet, mostly. You can get away pretty well with the 1000 grit, or start with 2000 grit, if your finish is up to it, by hand, with a flexible foam or rubber block. Wet. Any high spots, or tiny imperfections must be levelled prior to finishing, (spraying the first coat of primer) or they will immediately burn through any layers.

After 1000, if you have an orbital sander, it is well worth getting some Trizact discs in 3000. Even by hand, this is a superior abrasive. Paint stores often sell them individually, though I always buy them in boxes. They are not cheap, but if you are using them correctly, they last a long time, easily 1 disc to 1 rocket for a urethane or lacquer based finish. They are used wet, but the amount of water necessary is minimal, so I am definitely not scared to use these on an electric sander, though it has been years since I have touched an electric sander. A spray bottle with a little water, and a drop of soap is plenty to keep these discs wet. You may find an interface pad to be valuable on your sander, but maybe not. I probably would not use one, but that is me.
The compounds start after the Trizact 3000. The Trizact 5000 is also a time saver.

3m Sells sleeves of 1000, 1500, and 2000 paper. I think I pay about $35 for a sleeve of 50 sheets. Part #'s 02044, 02023, and 02021. That is a ton of paper, and it may be more economical to buy it is smaller and more expensive per sheet packages. Auto paint stores sell it by the sheet, also.

For a compressor, some of the 5hp contractor compressors will run a real spray gun quite well. For pneumatic sanders, compressed air is expensive, not really suited for less than professional use.

I use compounds after 3000. My favorite all around liquid compound is the 3m Trixact liquid compound. I also have all three of the Perfect-it series liquids, but I reach for the Trizact liquid first, and most often, and often do not even touch the Perfect-it.
 
Nathan said:
That's news to me but all I know is what I read on the Google machine. Seems to me though that a DA sander might work well for sanding relatively flat surfaces but not so well on tubes and nose cones.
Click to expand...
 

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