Does repeated stripping hurt a body?

[MrBuick]

I've got a few car bodies that I'm planning on using to hone my painting skills and maybe just use for color testing. My question is, does repetitive paint stripping weaken the body in any way? In the end, it's not a big deal because they're junk bodies, but if it'll do something to the plastic that will make paint results less than desirable I'd like to know. I use break fluid as stripper. 

[Ace-Garageguy]

Break fluid? Brake fluid might work better. 

I've had some embrittlement issues, particularly on older styrene, after a prolonged brake-fluid soak, and I believe I've noticed some of the same thing happening with the oven cleaner / lye based products. I think it's probably the plasticizers being leached out.

None of this has seemed to interfere with the stripped plastic accepting fresh primer and paint...however I DO recommend a Comet / hot water scrub after stripping, followed by a 70% isopropyl alcohol bath.

[Mark]

It probably depends to some extent on the paint that has been used.  One guy I used to know used mostly automotive paints.  If he didn't like the looks of a paint job, into the strip tank it went, sometimes while the paint was still wet.  Somewhere around here I've got what is left of a Jo-Han '68 4-4-2 kit body that he absolutely ruined with that procedure.  (I bought all of his stuff when he quit building some time ago.)  All of the detail is soft now, windshield pillars became brittle, vent posts disappeared entirely.  Someone told him that I had a '68 kit, and for the longest time he was pestering me to sell it to him.  I didn't, partly because I knew I'd never find another one, partly because I knew that it might have wound up like the first one.

I've also got a Jo-Han '66 Chrysler hardtop that was apparently stripped and rebuilt in the past.  When I took it apart I saw signs of a previous rebuild.  I didn't like the paint job that was on it; into the soup it went, and it's now really brittle.  I could probably crush the body with one hand now.  The trim detail was normal when I bought it, a little soft now.  This one will probably get rebuilt with the custom parts left over from another one.

[Snake45]

"Back in the day," the recommended stripping method was soaking in model airplane fuel (nitromethane and castor oil, mostly). It worked, but it would "embrittle" the body, at least for a period until it dried out thoroughly. (Naphtha--lighter fluid--will do the same thing.)

I've only ever soaked one body in brake fluid, and it didn't seem to hurt it at all. On the other hand, I've stripped dozens of bodies with oven cleaner, some of them two or three times till I got the finish I wanted, and never noticed any change whatsoever to the plastic.

So I guess if a chemical doesn't hurt a body once, it won't hurt it on repeated use.

[Longbox55]

For doing color testing, many builders use white plastic spoons. They are made of the same type plastic that model kits are made of, are very cheap, and once finished, give you a permanent record of what a given color looks like. It can also give you the chance to test different paint/primer/basecoat combinations before you commit to a body without using much in the line of materials. It actually can become somewhat addicting.