PDA

View Full Version : How do I bleach plastic parts to turn them white?


Rack 'n Ruin
2015-02-09, 12:42 PM
Hello!

I have a number of plastic Kreon parts (helmets, guns, etc) in a variety of colours (red, grey, black) that I'd like to turn white. I think it is possible to do this using bleach. Is this true? If so, can anyone recommend a technique please?

The bleach I have available is a thick, blue bleach, which I plan to dilute with water as required. Amusingly, the brand name is Vortex. :D

Tetsuro
2015-02-09, 01:23 PM
I kinda doubt that's possible, especially if they're cast in that colour. It's not like fixing discolouration which is only surface deep.

Wouldn't it be easier to just, y'know, paint them?

Rack 'n Ruin
2015-02-09, 01:27 PM
Nah, I can never get white paint to look smooth enough or (odd thing to say) white enough. I was hoping for an even "pure" white maintaining the smooth plastic finish the parts already have. I know Clay has made a white custom Alt Shockwave (it's in his avatar), and I had a feeling bleach may have been involved.

Tetsuro
2015-02-09, 01:28 PM
You can get white paint to look reasonably smooth by spraying it. At least you'll avoid obvious brushstroke marks.

Denyer
2015-02-09, 06:53 PM
What you're probably thinking of is hydrogen peroxide to "reverse" yellowing -- http://tfarchive.com/community/showthread.php?t=38279

Don't know whether I've still got the magazine to scan again, but there's various articles online that have their own preferred take on how to do it. Some submerge the parts, some prefer to use cream.

Very doubtful you'll achieve any worthwhile result with other colours of plastic.

Duplicate the parts by casting in resin as this creative bod does --
https://www.facebook.com/MotUcheads?ref=profile

Practising use of spray cans (light, even coats, basically) and picking a type of paint that doesn't react with the plastic is also worth a try first. Clean undercoat (Citadel white is worth a shot) and then either paint over or seal it if you want glossy.

If you want designs possibly try talking to small stores that do their own printed LEGO minifigs.

Clay
2015-02-09, 10:28 PM
Nah, I can never get white paint to look smooth enough or (odd thing to say) white enough. I was hoping for an even "pure" white maintaining the smooth plastic finish the parts already have. I know Clay has made a white custom Alt Shockwave (it's in his avatar), and I had a feeling bleach may have been involved.

Nope, the police Shockers has a head that's painted white.

I think you're conflating dyes with the de-yellowing effect of peroxide as Denyer noted. While peroxide will remove the yellowing from white plastic due to sun exposure, it won't change it to another color that it wasn't to begin with. While you can use dyes on plastics (a process which I never personally got the hang of), I don't think that such a thing as white dye exists. And bleach would only fade the color.

I'm sorry to say that you're best bet, aside from getting said parts cast in white plastic to begin with, is to use paint. But it's really not difficult... it just takes many, many thin coats with an airbrush or spray can as opposed to just glopping on darker paints. But it's worth it!

Best advice I can give is to not be afraid to fail and ruin a part or two. First white repaint I tried to do, I used white out/liquid eraser. Don't do that. But eventually I managed to pull this off:

http://i50.photobucket.com/albums/f303/claywyatt1982/kitbash/halfshell/th_halfshell025.jpg (http://s50.photobucket.com/user/claywyatt1982/media/kitbash/halfshell/halfshell025.jpg.html)

so perseverance pays off.


Duplicate the parts by casting in resin as this creative bod does --
https://www.facebook.com/MotUcheads?ref=profile


Hmm, I'm not sure. With my experience in making molds and casting resin, you essentially only get five out the six sides of a cube - the bottom is sacrificed so that you have somewhere to pour the resin into the mold. Also the molding gel doesn't really like hollow spaces in the piece you're making a mold of. You tend to break off any internal details when you remove the piece and the resulting resin copies are completely solid. While it works great for making copies of head sculpts, it wouldn't be an apropos process for Kreon parts.

Isn't that annoying? We have 3d printing, molding, and cold cast resins in our homes now and they don't quite work how we want them to.

Thunderwave
2015-02-09, 11:49 PM
In my experience, as a table top wargamer, you'd want either an airbrush or something like a white primer and white paint. I recommend the P3 brand from Privateer Press if you're going to go the paint on route. Their paints go on smooth and give very nice color coverage with a single coat.

Rack 'n Ruin
2015-02-10, 12:57 PM
Ah. Cheers, all. Looks like I got the wrong end of the stick.

Thanks for the painting tips. Unfortunately free time is at a premium for me, so I doubt I'll have time to paint anything. I was hoping I could just dump some parts in a solution and let it do its stuff. I think I'll just abandon my plans to re-colour the parts. Life's too short to worry too much about the colour of a Kreon's helmet or gun(!).

Thanks again for the words of advice, though. Much appreciated.