help needed on painting resin

[darthgarth]

ok guys, i call upon the gods of stormtrooper once again. I have some resin hovi tips for a an fx lid i am painting up for a present for a friend. I washed the raw casts, primed them and sprayed with humbrol matt black paint. i have sprayed on several coats but the paint keeps cracking and when scratched with a fingernail keeps cracking off. It is seems obvious the paint has not bonded to the resin and has shrunk during drying. Any tips? i have ten days to complete.

 

thanks in advance

 

garreth

[pandatrooper[TK]]

For resin, I usually:

 

- sand lightly (scuff the surface, but try not to remove detail. I use 400 grit or a scotchbrite pad

- wash with detergent and dry. Its important to remove any residue / mold release, etc.

- apply a couple light coats of primer (lacquer based), let it dry

- apply your top coat (I use Krylon or Rustoleum or sometime Tamiya or Testors). I discovered that Humbrol changed their formulas and their paints have been thin, runny and more transparent than in the past.

[darthgarth]

i didnt sand, even as i sprayed the primer i was thinking should i sand. thanks terry, back to the painting board i guess

[pandatrooper[TK]]

I noticed that when people sell cast stuff (even when I cast my own stuff) that the way the resin settles within the silicone – even if the original sculpture was sanded before molding – the “sand” marks cast into the resin do nothing for paint adhesion. In fact, sometimes they still end up with a slick finish for whatever reason. Some people use mold release depending on their mold material, you can even use baby powder as a release agent.

 

Regardless, I would always do a light sanding then thoroughly wash it with detergent to remove any agents. Abrasion on the surface creates something for the paint to stick to.

[TK bondservnt[501st]]

baby powder leaves a mark.

 

proper prep would be to use a common houshold degreaser.

let soak immersed for about 5 minutes. rinse and dry.

 

your finger oils have just been removed along with mould release.

 

painting with a primer matched to your paint is very important.

different types of paint need different primers.

 

applying paint in the correct temperature and humidity conditions is

also very important.

 

some people, when paint is cured, apply rubbing compound and polish the paint.

then the proper clear automotive wax usually works well.

 

leaving paint in the raw and scratching it before it cures will always take paint off.

you need to let it completely cure. primer and paint don't cure as soon as they are dry.

[sskunky]

Also apply very light coats and leave for ten to fifteen minutes before each coat.

[Smitty]

What kind of primer are you using? I dont sand any resin castings if I can help it. Sounds like your primer isn't bonding to the surface. When the paint flakes off, do you see resin or primer exposed?

[darthgarth]

What kind of primer are you using? I dont sand any resin castings if I can help it. Sounds like your primer isn't bonding to the surface. When the paint flakes off, do you see resin or primer exposed?

 

 

Im using halfords own brand grey primer. (basically car spray paint from an auto store) then humbrol modelling spray black. i used it on that hasbro you helped me out with and that was fine. Its the hovis you sent me im trying to paint and its the resin i see underneath. Most of it is fine, its just cracking in a couple of places. If i try to sand it all off then ill lose detail i reackon so maybe ill try to paint with brush/ humbrol?

 

I think i probably didnt wash them properly (i help them under a hot tap and used washing up detergent)

I certainly didnt rough the surface up.

 

In all fairness most of it is fine, its a couple of places around the top and a couple of the ridges on the side and it probably wouldnt notice, but i would know it was there.

 

Garreth

[BananoPower22[TK]]

Sorry to bump into this thread, but I'm having difficulties painting resin pieces too. I use Rustoleum Metallic (silver) as a primer, but the paint doesn't bonds well and leaves bubbles

[darthgarth]

ive never used rustoleum but I have found that washing the resin properly is the key, then a primer before any colour. sanding lightly before priming doesnt hurt. Basically the advice above is all sound, just follow the steps above.