Brake Fluid Question

[acorn 0]

Hi All,

Has any one experienced old plastic parts 'mysteriously' breaking, as if they had gone brittle, after a soaking in break fluid.

I have never seen this on a body shell, but it appears to affect the ABS(I think, the old black stuff anyway!!) plastic. (Actually, aren't the old hard body shells ABS too? mmmm confused!!!)

Anyway

Case in point: A hotshot rear arm, and a shock absorber end.

The rear arm actually looked like it was already broken or at least cracked, no evidence of glue though; and the shock end just looked like a fresh break!!!

A simular thing happened with a sand rover front wheel. This just fell appart, like it shattered, after a short(hours, not days) soak.

I origionally thought the break fluid was killing glued up parts, but they worked fine, with out breaking, before the brake fliud. And there is no evidence of glue.

The only thing I can think of, is the break fluid getting in to existing micro cracks, and some how expanding them causing the shatter effect.

If so then should we keep old ABS away from brake fluid? Id so, what safe alternative is there to brake fluid on ABS???

Any ideas?

[jims hobby shop 0]

hi

not sure about the plastic's in particular.

but the models from the 1960's some will evaporate from the brake fluid propertie's.

certian styrene whether it be delrin or abs among a few , react totaly different to petro based brake fluid.

hopefully someone else can start a topic on the effects of the B.F. on plastic.

jim

[oldWilly 0]

Hey there!

I stay away from the brake fluid all together as it is hard on the skin and to hard to dispose of, you should not be pouring it down the drain! It's bad for us all! I use Easy Off oven cleaner ( cheaper too) and sometimes a hobby shop product called Easy Lift Off or ELO. I do know what you are talking about though. I think the brake fluid reacts and srinks some plastics on the surface. This sets up internal stresses in the part that cause it to crack and crumble right before your eyes. Most containers of it have a caution about spilling it on painted or plastic parts of your car perhaps this is why. Try the oven cleaner method. Just brush it on and wait untill the paint softens. Then use some liquid soap and a brush to scrub the paint loose then just wash it all off with water and your done. Don't go straight for the water as it neutralizes the chemicals and you end up with a big sticky mess of old paint, the soap holds the old paint in suspention so the water can wash it away. Same goes for the ELO. BTW the old body shells are styrene plastic like a model kit. The suspentions are ABS plastic, that's why you can't glue it back together with model glue.

[DJTheo 2]

Somehow I have the feeling that chassis and suspension parts are from a different plastic then ABS bodies, as they are more elastic, more nylon, so that might be the reason? [?]

Cheers

[GRIGGY 0]

Originally posted by acorn

Hi All,

Has any one experienced old plastic parts 'mysteriously' breaking, as if they had gone brittle, after a soaking in break fluid.

I have never seen this on a body shell, but it appears to affect the ABS(I think, the old black stuff anyway!!) plastic. (Actually, aren't the old hard body shells ABS too? mmmm confused!!!)

Anyway

Case in point: A hotshot rear arm, and a shock absorber end.

The rear arm actually looked like it was already broken or at least cracked, no evidence of glue though; and the shock end just looked like a fresh break!!!

A simular thing happened with a sand rover front wheel. This just fell appart, like it shattered, after a short(hours, not days) soak.

I origionally thought the break fluid was killing glued up parts, but they worked fine, with out breaking, before the brake fliud. And there is no evidence of glue.

The only thing I can think of, is the break fluid getting in to existing micro cracks, and some how expanding them causing the shatter effect.

If so then should we keep old ABS away from brake fluid? Id so, what safe alternative is there to brake fluid on ABS???

Any ideas

The same thing happened to me just the other day. I put a Sand Rover shell in brake fluid to remove the thick black paint that been hand painted on. The car was an Ebay win which was complete with box and extras. The shell was in great condition but was the wrong colour. After soaking in brake fliud for a day the paint had mostly lifted and I was able to brush it off. As i did so the plastic started fall apart in my hands. There is no evidence of glue or impact damage. I now have a shell with a split running down the length of the bonnet, the nearside front mudguard has broken off and there is a whopping split near one of the rear lights. An easy retoration has now turned into a near impossible mission but I'm gonna see what I can do. I have soaked loads of parts and some shells in brake fluid before with no problems so why did my Sand Rover shell break up? Maybe it is made of a more brittle plastic??? Has anyone else had this problem?

[T.C~Tamiya 2]

I think the Sand Rover shell is made of polypropylene and not the usual styrene.

[DJTheo 2]

I don't think SR body is different plastic then others, only Holiday Buggy is. I also had a Bruiser body getting pretty brittle after stripping paint, guess it has to do with how long you leave it, how strong is the fluid concentration, environment temperature and condition of the plastic, too many unknown factors, so unfortunately its hit or miss till someones systematically analyzes the mechanisms which cause the damage [] Any chemist or chemical engineer around???

Cheers