Prepare PE for painting

[cog]

I'm going to start a plastic kit with quite some PE parts. I do not see any problems with bending etc, but how can I prepare the finished (bent/shaped) PE parts for painting. Is it merely a matter of cleaning with vinegar, turpentine, alcohol or do I need to take other steps. I can't imagine me sanding those tiny items ...

Edited June 14, 2016 by cog

[grsjax]

What I do is clean with acetone or alcohol to remove grease, oil, etc.  Dip in vinegar to etch and then use blacken-it or similar product.  The blackening gives a good surface for paint adhesion but can darken light colors.  If you don't want to blacken the parts leave in the vinegar longer to give a good etch to the surface.  Rinse with clean water and either use acetone for fast drying or lay on a paper towel to air dry before painting.

[cog]

Thanks grsjax!

 

I'll have a go at that

[allanyed]

Hi Carl,

 

You mentioned a plastic kit so am I correct to assume PE is polyethylene?  If that is the case, using Blackin It on plastic is a new one for me.  Never knew that worked on anything other than brass, copper and bronze.    Always something new and interesting here :D 

Both HDPE and LDPE rate in the mid range for resistance to acetone.  No problem with resistance to acetic acid or alchol, but  I have doubts that vinegar, which is usually 5 to 18 percent acetic acid will etch polyethylene.  

 

Allan

Edited June 16, 2016 by allanyed

[GuntherMT]

PE is "Photo Etched" parts, usually brass.

[allanyed]

Ahhhhhh,  now I get it

 

Glad it's Friday.......

 

Allan

[Guest]

Honest truth, the Tiger tank I did a couple years ago with (what felt like ) a ton of PE on it....I didn't do anything at all to prep it per sé...and primer adhered just fine, even on the larger flat pieces like the fenders (you can see it by clicking on my signature...board wouldn't let me use the img tag).

 

Unless a part is overtly contaminated, today's model paints do a pretty good job holding on, though if something will be subject to a lot of handling after being painted then more care could be wise.

[cog]

Thanks,

 

I might give some part of a PE sheet a whiff of paint, have a look what that will do ...

 

Your tank looks good!

[jim_smits]

I like the blacken-it tip. Be almost like a layer of primer for the brass and I will have many tiny parts on my Hood build.

[bluenose2]

Hello Les here. Here's what I do. Before you detach any parts from the sheet I use a fine grit foam backed sanding paper available from any good paint store. Scuff it up lightly both sides.Then you can attach and prime or paint. No vinegar or anything else required.

[cog]

Thanks Les

[Jaxboat]

I think you could use a solvent based paint with no issues. Paint adheres to a surface through one of two mechanisms: mechanical adhesion or chemical adhesion. To get good chemical adhesion you need excellent surface wetting which a solvent based paint provides. If you use a water based paint on brass that has fingerprints on it, the water based paint will not adhere properly because it can't "wet" the surface properly. I like the alcohol vinegar combo before applying water base paint and I will try that. Sanding would provide for mechanical adhesion in all cases but some parts are so small that it would be tedious or impossible. IMHO

Best

Jaxboat