MrILO

I own 1982 GSL in very good shape, with very nice leather interiors, in very good conditions, but with some plastic showing signs of aging badly, turning grey and becoming brittle.
I understand from other threads that this is a common issue on the seat belts buckle cover shells, and in the areas that are exposed to sunlight.

I have some experience with plastic materials, so I tried to understand first what plastic the parts are made of. My impression is either polypropylene (PP) or nylon - in both cases, hard to paint.
A method to tell whether it is ABS plastic is to burn a little and smell the fumes. I was convinced that the seat belt cover shells could not be ABS, and I tried my wife's propane torch (mostly used for caramelizing sugar) on the inner side. I did a very quick flame 'touch and go' and noticed that the plastic reacted very well. Not ABS certainly, likely PP.

Now, flaming treatment is common practice for painting PP, so I took the plunge.
A series of quick burst of flames was applied to the seat belt covers. quick, repeated passes, enough to melt a very thin layer of the surface, but not enough to damage the part. Extreme care applied!
Anyway, this is the result, before and after.







Further washing and waxing gave a very pleasant result.
Besides, whereas before the deteriorating area would crumble if scratched, after the heat treatment their surface is hard and scratch resistant.

This encouraged me to try a more difficult part, in direct sight.
This was harder, as I found out that the exposure to flame, while not bad, would restore, on such a large surface in direct view, a darker shade of colour on the greying part than on the part that was still good, despite treating them both. Not unsurprisingly.
So I took the plunge and carefully sandpapered the grey, brittle plastic away, with wet coarse paper. A lot of grey dust came off until I reached a good layer of original plastic.
After the flaming method was applied again, the result was really, in my opinion, brilliant. It almost looks like it's new!




In the meanwhile I have received the carpet from Factory Interiors and the cargo area now has a completely new look.
I'm not sure whether I will have the guts to try this on the last remeining greying part, the two large plastic covers above the wheels...

With the help of the donor of the propane torch (my kind wife, who also happens to like the RX-7 a lot ) I have made a video that details the process as it is applied on the seat belts.
It will take me some time to upload it on youtube as I have a very slow connection.