There is certainly alot of bondo type products out there. Eastwood and Autobody Mart has a ton of them. So many, it can get confusing. I don't see any bondo in my future, but if I did, I don't think I would use "Bondo" per se. I think there probably has been much improvement in those type of products since I first used them, Carmine.
I have used a Glazing Putty called "U-Pol" and it works pretty well and does not develop pin holes at all. It is really hard once it sets and it sands and feathers well. I guess it is just a version of plastic filler but much thinner. Comes in a bag and pours out onto mixing palate. Uses VERY little catalyst. If you put just a little too much, it will set up before you can spread it.
"Green Stuff" was a Lacquer Putty product commonly used in the 60's-70's to fill pin holes in bondo.
Bondo is not necessarily a great product, but if it is applied correctly over the top of epoxy primer, and then sealed with more epoxy on top of it, it will stay on the car and last a long time. It cannot be put on there 1/2" thick and be expected to hold up.
Last edited by Wayne Meuir; 05-14-2019 at 05:42 PM..
Lead was always used on joints from the factory. The only exception that I know of is the roof seam under a vinyl top which a plastic filler was sometimes used. Modern vehicles don't use lead because the joints have been redesigned to avoid and need for filler.
The problem with Bondo is that it is not water proof and will bulge in areas if moisture gets behind it.