Body fillers-primers-sanding grits and other sundry items

[rustybronco]

Some good reading material here.

http://www.roadsters.com/filler/

[azr]

Thanks Dale...

[posplayr]

takes a while to digest, as there is a lot of info there to absorb. Fortunately in SB applying paint/bondo the temperature is not nearly as much of a concern. But in ND and the winter you gotta know what you are doing. Kinda funny/kinda sad story about the corvette with the new front end.

It was good to read about the bondo work. He generally always applies to bare metal. I sand off all the paint and then just before applying sand it smooth and wipe off with a wet rag, but immediately blow it off and set in the sun to dry. Then I take some 40-60 grit and cross hatch to scratch the metal being careful to also get inside of the low spots and anyplace where I will be feathering the bondo. You can usually just blow this off (rather than get it wet again) as the deep scratches don't really sand they just scratch(i.e. no dust)

[rustybronco]

But in ND and the winter you gotta know what you are doing. Kinda funny/kinda sad story about the corvette with the new front end.

If it was winter in ND, I'd be applying it in the house.

What I found best was not to use cardboard for mixing filler on. I never thought about it drawing the solvents of of the resin. That, and moisture on the metals surfaces; I wonder if could could be one of the reasons tank liners fail? The liner in my fuel tank was flaking off and it had a light coating of rust on it and the tanks surface. ??

[posplayr]

If it was winter in ND, I'd be applying it in the house.

What I found best was not to use cardboard for mixing filler on. I never thought about it drawing the solvents of of the resin. That, and moisture on the metals surfaces; I wonder if could could be one of the reasons tank liners fail? The liner in my fuel tank was flaking off and it had a light coating of rust on it and the tanks surface. ??

Yea the cardboard does make sense, but I think I instinctively look for some wax impregnated, clean board or cut the side of a piece of plastic bottle and not just anything.

If you have ever used Por-15 rust inhibitor paint you learn quickly what is dry and what is still wet in the pores. The stuff bubbles so as a general rule with that stuff wash today spray tommorow.

I have to say, with the modern water proof bondos and two part primers, body work has never been easier. Especially with how easy the clears are to work with.

[rustybronco]

I wouldn't use wax impregnated anything when it comes body and paint work. Either mix it on a piece of Lexan, some small plastic cutting board or what what some of the body shops like to use, a piece of 1/8" aluminum sheet stock. If the filler gets a bit crusty on it, you just hit it with the DA.

[hikermikem]

If the filler gets a bit crusty on it, you just hit it with the DA.

OK, what's DA?

[rustybronco]

Dual action sander.

Jim, a correction to what I said earlier. Wax is used as a parting or mold release agent for fiberglass work.

[posplayr]

Dual action sander.

Jim, a correction to what I said earlier. Wax is used as a parting or mold release agent for fiberglass work.

Dale, point taken i will watch out a little more in the future but I'm thinking my previous caution has not resulted in any adhesion problems.
Jim

[SVSooke]

Back in the day of lacquer paint finishes on custom cars, painters would color-sand the paint after it dried and repaint to get all the sand scratch shrinkage out. This process was repeated until the paint didn't show the sanding marks. They used to say, "This car has 20 coats of hand-rubbed lacquer." "Hand-rubbed" was the term in some areas for color-sanding by hand. The thinner in the paint was stronger, and took longer to evaporate than the thinner used in the primer. When you painted lacquer paint, the thinner would soak into the primer and cause it to shrink back into the scratches in the body work. That is why the process was repeated until scratches didn't show in the final coat.

I believe this is the answer to the question you asked me a while ago Dale.I wasn't sure why you sanded lacquer down,now we both know.