How to clean and/or whiten soft plastic parts?

[AlanMintaka]

Hi Everyone,
I have a number of the soft plastic door and window parts that came with the old American Plastic Bricks sets. I don't know what kind of plastic was used - it's somewhat soft to the touch and bends easily.

The original color was white. Now most of them are a kind of dingy yellowish brown. Some of the coloring responds to dish soap and warm water, but mostly the dingy coloring remains after washing. I tried scrubbing with a toothbrush and nylon dish pad in the soapy water. This has had no effect.

Does anyone know of a way I can clean this stuff without damaging it? Bleach cleanser works pretty good with some elbow grease but I worry that this would cause the material to break down over time. On the other hand, I don't know what I'm talking about, which is why I'm posting here.

I did search for this topic in the forums but was unable to come up with a good match for what I'm trying to do...

Thanks for your time,

[Rogviler]

Hmm, I was under the impression that the soft plastic doors and windows were strictly for the Canadian market (while hard plastic ones were sold in the U.S.), and if so, I believe they were originally yellow, while the U.S. ones were white...

I could be wrong though, and there's not a lot on info on the web. Any chance you could take a picture?

-Rog

EDIT: Also, if it truly is yellowed from UV exposure or similar, there's really nothing that can be done to make it white again. I've heard lots of tips, like whitening toothpaste, Borax, Comet, and bleach of course, but those are mainly either going to abrade the surface away to get it down to white plastic again, or they're going to damage the plastic, similar to what happens if you put too much bleach on a piece of clothing, where it eats a hole in it. Best bet seems to be to paint over it or leave it as it is.

[AlanMintaka]

Hmm, I was under the impression that the soft plastic doors and windows were strictly for the Canadian market (while hard plastic ones were sold in the U.S.), and if so, I believe they were originally yellow, while the U.S. ones were white...

Hi Rogviler,
The sets I always had when I was a kid circa 1955 - 1965 all had the soft white plastic doors and windows, except of course for the clear jalousies. The white bricks were hard plastic but the doors and windows were definitely made of different, softer stuff - kind of rubbery actually.

The sets I've been collecting on eBay are made of the same materials and have Chicago Illinois labels on the cans and manuals. The only difference I noticed is that there are a few windows of a style different than the ones I had years ago. They have diagonal crisscross panes, a kind of Scandinavian style. There aren't many and I really don't know which set(s) they came from.

Aside from those few windows, everything else is the way I remember it. Are you sure you don't have the materials backwards, i.e. the soft stuff in the US and the hard stuff in Canada?

Either way, the ones I have are supposed to be white, not yellow. I can see that by the clean ones.

I'm working on the pictures. Right now it's time to collapse. I've been up the better part of the night scanning the manuals for the 70-72, 725, and 735 sets.

It beats watching my 401K's tank, but I'm not sure it beats booze.

Later,

[Rogviler]

The white bricks were hard plastic but the doors and windows were definitely made of different, softer stuff - kind of rubbery actually.

Aside from those few windows, everything else is the way I remember it. Are you sure you don't have the materials backwards, i.e. the soft stuff in the US and the hard stuff in Canada?

Okay, that clears it up a bit. I think the doors and windows in Canada were yellow, and also a slightly different size due to changing to the metric system (which would probably be the easiest way to tell). I had just thought I read something about the Canadian versions being soft and lots of kids being miffed over bent windows and doors out of the package... But maybe that was a universal thing.

I only asked because if they are soft and not supposed to be I would have suspected a type of plastic that's going to keep breaking down over time, like certain types of vinyl or even something rubber based.

So you might try some of those suggestions. I suspect that the reason some were able to be whitened from scrubbing is by taking off the yellowed plastic. Toothpaste would probably be the most gentle, followed by a plastic polish like the kind made for polishing model airplane canopies. Borax and Comet are going to be more abrasive. You might test on one piece and work your way from mild to harsh.

There's really no way to just "bleach" the yellow out without ruining it, in my opinion.

-Rog

[srspicer]

Hi Alan,

The only way to remove the yellowing is to remove the yellowed layer of the plastic. I work with styrene, ABS, and other plastics all the time. As has been suggested, carefully sanding down the top layer is the best way. You will loose any shine the surface has, but you can buff the plastic back to shiny again. If you use square sanding sticks and the like, you will be able to get them white again. Just go slow and carefully so as not to gouge the surfaces.
Bleach will make the plastic brittle, and it will crack over time.

I hope this was helpful. Good luck.

Scott

[AlanMintaka]

Best bet seems to be to paint over it or leave it as it is.

There's really no way to just "bleach" the yellow out without ruining it, in my opinion.

Just go slow and carefully so as not to gouge the surfaces.

Bleach will make the plastic brittle, and it will crack over time.

Thanks Rogviler and srspicer,

That's what I wanted to know about cleaning materials with some kind of bleach in them.

Since posting my message I've been experimenting with soaking the parts in dish soap (not the automatic washer soap, just the stuff in bottles for hand washing). It doesn't restore the original white color, of course, but soaking goes a long way towards removing a lot of the crud.

"Gouge" is the keyword in srspicer's response. I stink at detail work. If any kind of fine detail cleaning is to be done, I'm going to stick with a toothbrush and that soapy water mix.

There is one other thing I'm going to try with a few test pieces. I'm going to run a few of them through the dishwasher in the silverware bay just to see what happens. What I don't know is what effect the dishwasher soap will have over time, even after only one washing. I'll be using Cascade most likely. Anyone know what that stuff does to soft plastic?

Also, there is that option to paint them somehow. What kind of paint would be best for this sort of plastic? I have a lot of model enamel around here for painting HO structures and hard plastic models. I can easily test this on a few pieces past their prime too, but I wouldn't know about long term effects. Is model enamel the way to go with soft plastic like this, or is some other paint a better bet?

Thanks once again for these responses and all the time you folks have been spending on my questions. It's great to able to ask these sorts of things without being flamed for the usual internet reasons.

"Round up the usual suspects."
-- Captain Louis "Frenchie" Renault (Claude Rains) , in "Casablanca"

Have a good one,

[srspicer]

You may end up melting or distorting your parts. The water can get very hot, even on the 'normal' selection or low heat. Fore-warned is fore-armed

Scott

[Rogviler]

I would try either Krylon Fusion or the same paints you'd use on vinyl kits, i.e. acrylic enamel.

-Rog

[Chacal]

Sacrifice one of the bricks, sanding it down in one tiny area (making a dimple in the plastic, if possible). This way you can see if the yellowing is superficial or it goes deeper. If it goes deeper, it is likely that the plastic has discolored from UV exposure, as Rogviller said. Then there's not much that can be done, as with the UV discoloration comes weakening of the plastic itself.