Why is My Spray Paint Going On with a "Grainy, Sandy" Texture?

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brockrwood

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Dang. We need a heated “painting shed”.
Idea for cheap painting shed: Buy an old minivan with a shot transmission but working engine and heater for $200. Tow it into driveway. Take out the back seats. Whenever you want to paint rocket, go into minivan and turn on engine and heater. Don’t worry about paint spray getting all over inside of mini-van. That is what it is for. Heck, if you have an extension cord and space heater, you can dispense with the working engine and heater.
 

brockrwood

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Nah, I've painted below freezing before with great results.
Someone somewhere said it is the temperature of the rocket and the temperature of the paint can that matters. Make sure rocket and paint are warmed up. Go outside into thecold. Paint the rocket. Go back inside. I need to try that method. From November through February, it won’t hit 70 degrees in Boulder, Colorado.
 

manixFan

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Someone somewhere said it is the temperature of the rocket and the temperature of the paint can that matters. Make sure rocket and paint are warmed up. Go outside into thecold. Paint the rocket. Go back inside. I need to try that method. From November through February, it won’t hit 70 degrees in Boulder, Colorado.
Thats true to a degree (har har). But at some point the ambient temperature and humidity does matter. If it’s super dry the solvent can evaporate so quickly the paint is basically dry by the time it hits the surface. Cold air is very dry air (just physics) so the colder it is the more likely that may happen. But if you have kept the paint warm that can mitigate it somewhat. I’ve painted in the 40’s but colder than that would be a real challenge it would seem. I’ll have to try below freezing and see how it works.

Tony
 

bobbyg23

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Someone somewhere said it is the temperature of the rocket and the temperature of the paint can that matters. Make sure rocket and paint are warmed up. Go outside into thecold. Paint the rocket. Go back inside. I need to try that method. From November through February, it won’t hit 70 degrees in Boulder, Colorado.
Exactly
 

gna

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Maybe not a do over, you could try a light wet sand with 800 or 1000+ grit to knock the knobs off and see how it looks. Bad results worst case you can hit it with another light coat of bumpy paint... :dontknow:
I wet sand with 600 or 800 and put another coat on. Usually looks fine.
 

BSNW

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It is not the wind, temp, or humidity.

The bubbles are coming from a gas out reaction with the primer. This coupled with using an old topcoat that has not been shaken long enough. Seen this many times. Incompatible primer with a solvent heavy top coat. Wait until dry, then sand with 220. Then let it gas out for a couple days. Then sand with 400. Tack-cloth and shoot with a fresh can that has been shaken for 10min and warmed in a sink of hot tap water. It will come out like glass. Do NOT re-prime before new topcoat.
Hope this helps
Andrew
 

DeltaVee

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I've had great results with rusto 2x. I've also got very pebble finishes... tiny bubbles etc. The pebbles have always occurred on windy days. The bubbles came when I tried to spray at a somewhat upward angle... and is not hard to understand why... paint pooling on the nozzle. These paint + primer product is pure gimmick from marketroids... and from my experience with them, is a nonfactor in terms of results. Technique is huge here with rusto. Get the distance right... never reverse direction when the spray is ON the rocket, only after you've gone past the end. Suspend the subject horizontally so gravity will work to spread a potential run out rather than enhance it. If it's windy use the garage... I put the subject a few feet in and spray out towards the open garage door.... it does depend on wind direction to pull that off... oh and wait until the wife's not home!! These sorts of ideas really seem to work for me...

I just finished my Cherokee-G with 2x white and got a fine gloss on it. And yes it took two coats with a good sanding of the first one, and yes it was on top of 2x gray primer. The rusto needs DAYS to cure properly (the primer too!) but the reward was being able to sand even the gloss first coat without gumming up the sand paper! As usual patience has a payoff.

While these items have generally worked for me, nothing beats the ease of the old krylon 5 ball paint from the 90's... a fairly reasonable finish but rusto has a far higher gloss when things work out... I just didn't have to be as careful.
 

icyclops

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Paint can be both acrylic and enamel. Almost all rattlecan enamel paint is acrylic enamel.
Yes and maybe that is why paint today is many times crap…..acrylic used to be strictly resins and enamel was an oil based product…now mix everything together and you have the jack of all trades and master of none. You really have to be careful of how you layer your paints now from primers to topcoats. That is why I think so many people have problems with painting now days….besides humidity and other factors. It was so much easier years ago when paint was more stable and simpler made…besides the lead. :)

And not all is both….still many products out there that are specific…..anyway, I mostly airbrush so don’t have to deal with the “Jacks” And have a better selection. Just my 2 cents….
 

icyclops

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Idea for cheap painting shed: Buy an old minivan with a shot transmission but working engine and heater for $200. Tow it into driveway. Take out the back seats. Whenever you want to paint rocket, go into minivan and turn on engine and heater. Don’t worry about paint spray getting all over inside of mini-van. That is what it is for. Heck, if you have an extension cord and space heater, you can dispense with the working engine and heater.
I think I saw one of those parked in a Wallyworld parking lot…. :) Don’t really know if they were painting rockets or sniffing.
 

Lugnut56

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As others have stated, painting can be one of the more frustrating tasks when building rockets, especially if appearance is important to you. You can use the same products, same prep procedures and 4 out of 5 times it comes out good. But on the 5th time, the SHTF (Spots Hit The Finish). I generally use Krylon Filler/Primer, followed by Krylon paint (mainly because the local WM carried 95% Krylon paints, then switched over to 90% Rustoleum paints, and now doesn't seem to be carrying either one--lots of empty shelfs). Depending on the outside temp, I warm up the part to be painted in front of a small heater to. As far as the paint itself, since it's currently storied in an unheated room, I put in my paint shaker for a couple minutes, then in warm water for 5-10 mins, then back in the shaker for another couple mins. This has usually given me good results, but I still can get bumpy/rough finish occasionally. Depending on how bad it is, I will wait a couple days for the paint to dry, then wet sand with FINE sandpaper (start out with 320/ 400 grit and work up to 2000 grit). Then I use a buffing pad in a drill and use course rubbing compound, then fine rubbing compound and finish off with polish. Do this before putting on the decals. It sounds like a lot of work, but it's not. I generally don't use clear gloss over my rockets because on some of the earlier ones it fogged/glazed and really distracted from the paint job. Attached is a picture of the paint shaker I use (not necessary but darn nice to have) and the fins on my HI-Flyer XL that have received the rubbing compound/polishing treatment.

Paint shaker.jpg
Hi Flyer XL fins.jpg
 

Aeronerd

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Thats true to a degree (har har). But at some point the ambient temperature and humidity does matter. If it’s super dry the solvent can evaporate so quickly the paint is basically dry by the time it hits the surface. Cold air is very dry air (just physics) so the colder it is the more likely that may happen. But if you have kept the paint warm that can mitigate it somewhat. I’ve painted in the 40’s but colder than that would be a real challenge it would seem. I’ll have to try below freezing and see how it works.

Tony
Totally agree. I've had this happen to me with cold temperatures and low humidity. the paint dries before it hits my rocket and it comes out looking like yours. Now I stick to the recommendations for temperature and humidity on the back of the spray can and no problems since. Also learned my lesson about spraying outdoors because I get a lot of pollen and dust stuck in the paint job.
 

brockrwood

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I've had similar issues when the temp is below 70. I ran into this in the past few weeks trying to rush to get paint on some LPR builds I am working on. All 3 colors of paint did this to me. I paint in the open, so there is always a slight breeze, but I would say it was rather calm this night.

View attachment 485528
There is a “maker space” in Boulder, Colorado. There is a maker space in Denver, Colorado. Each has lots of cool rooms and tools. What neither has is a “spray painting” room. I need to suggest that.
 

Pete.D

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Idea for cheap painting shed: Buy an old minivan with a shot transmission but working engine and heater for $200. Tow it into driveway. Take out the back seats. Whenever you want to paint rocket, go into minivan and turn on engine and heater. Don’t worry about paint spray getting all over inside of mini-van. That is what it is for. Heck, if you have an extension cord and space heater, you can dispense with the working engine and heater.
Great idea!

I already have an old campervan with a bum transmission, leaking roof, rusting everywhere, and worn-out engine too! I was debating whether to fix it up for going to away rocket events, but it will likely never happen. Now if I can only get it to start, but have extension and heater too if I can't. Only problem is it's a bit musty inside from leaking roof. But it has a high roof and would seem to be a great place for painting.

No more paint fumes in the house!
 

bjphoenix

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This happened to me this weekend with a can of Rusto. I did a couple of quick sprays in the air and it looked good so I started painting. Paint went on good for a couple of seconds then I got a stripe of the sandy looking paint, then the rest went on well. I'm going to sand the rough part down and spray over it. I don't know how long the Rusto has to cure before it can be easily sanded.
 

John_lennon

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See pictures. The spray paint is going on with a "sandy" sort of texture instead of nice and smooth. I put the can of spray paint in hot water for about 5 minutes before I started painting.

I am using Rust-Oleum American Accents 2X "gloss" "key lime".

Wind speed is 10 MPH with gusts to 18 MPH.

Painting outside. Trying to spray between gusts of wind.

Humidity is low (21 percent).

Temperature is about 65 degrees fahrenheit.

View attachment 485100

View attachment 485101

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I had this very thing happen to me with my first build recently. It was my first attempt at priming I had the same Gritty Sandy look and feel. I wasn't very happy it felt like a punch in the gut making me wonder maybe this is all just too tough for me to try and tackle with my grandson. I reached out on the forum and they speculated as to why it might be happening. Needless to say I sanded the grit away and mostly anything resembling the color white off the rocket. Went to a couple different retailers grabbing different types of primer and tried again. I then had success. I know I'd had the original paint for a few months when I first decided on the project over the course of a week or two grabbed all the stuff I thought I might need to complete the project. So I know the paint sat for awhile before I used it. But I shook the can and only painted within the recommended temperature and humidity as to not hinder me any more than already being at a super disadvantage. I didn't try the warm water method which was advised by the group. Maybe it would've worked out had I gone down that road. I do know that when I went out and shook the new can I had purchased and decided to try out it sounded totally different than the 1st can I tried. The balls seemed to be moving more freely throughout the can and it did seem the noise appeared louder too. I'm sure this will happen again. But now I know to try shaking the can in the store to hopefully hear the noise of them moving really freely. Hopefully this will help. Also I learned to bring a scrap of cardboard out to do a test on to see how it applies before I ruin another rocket that I've been working diligently on. Hopefully you can see the fuzzy little bits in my photo once zoomed in on. I know it's not the best of photos.
 

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DeltaVee

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This happened to me this weekend with a can of Rusto. I did a couple of quick sprays in the air and it looked good so I started painting. Paint went on good for a couple of seconds then I got a stripe of the sandy looking paint, then the rest went on well. I'm going to sand the rough part down and spray over it. I don't know how long the Rusto has to cure before it can be easily sanded.
At LEAST three days...
 

bjphoenix

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At LEAST three days...
I did some sanding yesterday and got it reasonably smooth then sprayed over it. This was an old rocket I was repainting so I didn't require it to be perfect. I can't remember if I sprayed it Saturday or Sunday so that would be sanding 2 days after paint or 3 days after paint. The paint came off partly as dust but also wanted to gum up a little bit so I agree, more than 3 days would be better.
 

gldknght

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I quit using Rusto 2x paint about a year ago. It's just too hard to get a good consistent finish with it. Even when sprayed under ideal conditions in my basement over other Rusto paint, I get "crinkle paint" more often then not.
 
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