I've been playing with the Plastex stuff now for about a week. It works pretty good, and on the whole I'm pleased. The stuff is stupid strong, and even if I were worried about it you can imbed fiberglass mat in it for extra strength. It bonds quite well to the ABS that the bodywork is made out of. It also sands easily and seems to be exactly the same stuff as the ABS once it has cured.
Good things: Bonds quickly and can be used to mold tabs and/or protrusions. The molding bar that comes with the kit is simply great. Heat it up to 150º F and you can mold it like clay, then when it cools it hardens until it's about like tire rubber. The Plastex stuff won't stick to it at all. Great for re-creating those little tabs you've broken off. Also, the Plastex fills cracks neatly and can be dammed with regular packing tape or electrical tape. This produces a nice smooth finish that requires little sanding. Because of the fast set time you can do a lot of work in a short amount of time. However, be sure to give it a couple of hours before sanding.
Bad things: The Plastex bonds quickly, and partially sets up in about 10 seconds. This can make it difficult to move it to where you want it. At the same time it can flow down into areas where you don't want it to be unless you are careful. The raw liquid doesn't stick very well to painted parts, so you really need to remove any paint from where you need the repair. I found the substance to be difficult to use as a body filler due to it's short working time and it's tendency to hump up like a weld. For finish work I would still use some kind of epoxy filler.
Basic techniques: The included video shows the guy putting a couple of drops in a cup full of the powder and lifting that up with the eyedropper to use like a welder. I was unable to make this technique work very well. I found it was easier to fill the gap with a generous amount of powder and then use drops of the liquid to spread it out into a weld like seam. This works well when filling molds too. With any crack it is best to V out the crack quite a bit and scrape all the paint off both sides. Then use packing tape (the clear plastic stuff) to cover the cracks on the "good" side.
Anyway, so far so good. I'm liking the stuff and I'm seeing good results so far. Can't wait to see how it paints.
