Painting A Robot

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TikaC
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Painting A Robot

I know there were a couple other threads talking about painting your robot. I'm doing this with my RS Media using Rust-Oleum products I got at AutoZone. Thought I'd share my experiences.

I'm starting my test with the battery plate from the remote. This way I can practice a bit. So far, it seems that using primer either makes the primer and paint crack or is too grainy. So I don't know if I'm going to want to use primer. I have health issues which prevent me from doing any large amount of sanding, so I'm trying to find ways to not have to sand.

One thing is to spray a LIGHT coat over the area from about 12" (at LEAST) above the item you're spraying. Otherwise you get runs and stuff.

Also use THIN coats, don't put on a lot of paint at once. Figure you're going to need two or three coats (at least two).

Also I am going to try using a clear top coat. We'll see how it goes. I'll post pictures and stuff here as I go along.

RebelTaz
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I would suggest using the Krylon Fusion spray paint. It is specially formulated to adhere to plastic where other paint only sticks to the surface (and not very well after a period of time).

TikaC
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Dang, and I already got the Rust-Oleum and no money to buy other paint. :( Well, I also picked up some clear coat too, so hopefully it'll help.

A friend of mine said to sand the parts with a very fine sandpaper going in different directions. It shouldn't show any scratch marks, just make the surface dull so that the primer and stuff will spread better and adhere. So the steps would be:

1. Sand down all parts to a dull finish using a very find grain sandpaper (not sure what yet, maybe 1000 or 600 or something), going in random directions but not so that you see scratch marks.

2. One light coat of primer.

3. Two light coats of paint (or more coats as needed, but light coats).

4. One light coat of clear coat.

5. Sand the clear coat to buff it a little (should be dull, and not take off paint or leave scratch marks) so that the last coat of clear coat will spread and blend in with it.

6. Apply last coat of clear coat.

Of course, everything must dry very well (up to 24 hours in the case of the paint and clear coats, I think) before you go on to the next step.

So that's the plan at the moment.

Darn I wish I had known about the Krylon stuff sooner. :(

Rudolph
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"it seems that using primer either makes the primer and paint crack"
That's "crazing", there are a couple potential causes. 1) The primer coat needed to dry longer before putting paint on top. 2) The primer was plenty dry, but the new coat of paint on top caused it to soften again. This one is often due to incompatible paint products.

I've had plenty of car paint craze on me, to the point that I just pay someone else to paint my cars now. So, sorry, I don't have an answer for how to prevent it.

"or is too grainy"
You could try a light sanding after a primer coat, then probably a second coat of primer on that. Another possible cause of grainy primer is that it's drying too fast, sometimes due to spraying too light of a coat (it starts drying before it hits the part).

Truly, don't take my advice on how to cure it though. Like I said, I pay other people to put nice paint jobs on stuff now. I studied up on why my paint jobs failed but never was able to get them any better. My talents definitely do not include painting!

TikaC
TikaC's picture

Well, the "Crazing" was I found due to not shaking the can good enough and I didn't really get much primer on but more a liquidy stuff. The graininess my friend advised the random sand method before I prime, to give it some ways to spread. So we'll see on the next go-round.

Right now the black parts of the remote are looking smooth and shiny for the most part. Not touching it until it dries overnight, though.

RebelTaz
RebelTaz's picture

 

TikaC said: Dang, and I already got the Rust-Oleum and no money to buy other paint. :( Well, I also picked up some clear coat too, so hopefully it'll help. A friend of mine said to sand the parts with a very fine sandpaper going in different directions. It shouldn't show any scratch marks, just make the surface dull so that the primer and stuff will spread better and adhere. So the steps would be: 1. Sand down all parts to a dull finish using a very find grain sandpaper (not sure what yet, maybe 1000 or 600 or something), going in random directions but not so that you see scratch marks. 2. One light coat of primer. 3. Two light coats of paint (or more coats as needed, but light coats). 4. One light coat of clear coat. 5. Sand the clear coat to buff it a little (should be dull, and not take off paint or leave scratch marks) so that the last coat of clear coat will spread and blend in with it. 6. Apply last coat of clear coat. Of course, everything must dry very well (up to 24 hours in the case of the paint and clear coats, I think) before you go on to the next step. So that's the plan at the moment. Darn I wish I had known about the Krylon stuff sooner. :(

 

Most stores should take the paint back and at least least let you swap it for something else. Even if you have used a little of it, just tell them it didn't work on the surface you were painting. I've never had a problem at either Lowes or Ace Hardware in that respect...

The clear coat probably won't help keep the paint from lifting. It will protect the paint, though.

One step I would add to your outline... and I do two or three light coats of primer - you'll find that one light coat probably isn't going to be enough. But Step 2B - after you spray the primer coats, take a regular sheet of copier paper (maybe cut it into quarters) and lightly sand the entire robot with that. Believe it or not, regular paper is essentially super-fine sandpaper and it will smooth the primer coat down to a super smooth shine. That usually takes care of the 'grainy' effect I get with spray primer. Sometimes I spray a couple of coats of primer, plain-paper sand it, spray another coat primer and plain-paper sand that again one more time. That helps to give the top gloss pain coat a fantastic shine. I have done this on many model rockets and they turn out great.

Remember, your final finish will only be as good as the base you start out with.

TikaC
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Thanks for the tips. :) I got my paint at AutoZone. They don't have Krylon, which is what I was looking for and they I don't think take back paint like that. I think I'll take my chances with this stuff. I'll try the paper-sand thing, too.