Sheet Metal Coating?

[Guest Hal Davis (MODEL A HAL)]

Being the lazy type, I was trying to find a way around sandblasting the paint/rust off of my A's rear fenders. I figured a knotted wire brush on a right angle grinder would do the trick or at least reduce the amount of sandblasting. When I get down to "bare metal" it is not so bare. There appears to be a transparent yellow coating on the metal. It will come off, but is much harder to remove than the paint. In fact, it seems to only come off when you generate a lot of heat. I did not notice it on the front fenders, but I sandblasted them instead of using the wire brush. What is this stuff? Some sort of protectant that Henry used? Is it residue from the paint that got smeared by the wire brush?

[Rick Hoover]

Well Hal, guess who?<P>I "think" what your finding is old zinc chromate primer (which is yellow) that was applied the last time they were painted. Zinc chromic acid was used to bare metals to prevent corrosion and act as a binder prior to painting. "You" now know it as Trio/Prime self ecthing primer that you just bought, which contains Chromium Zinc Oxide. Both will gag you, if you inhale it. <BR>If your going to continue doing it the hard way with that wire wheel, make sure you have a respirator on. (Only joking about the hard way thing)<P>As for Henry, I was told that Ford used this process of "Bonderizing" and then the fenders were Dip Painted.<P>Rick

[Guest SalG (Sal Grenci)]

FYI, My Model T is done in Zinc Chromate, under the black. My dad worked for Grumman (Luner Module, F-14, space shuttle wings) on Long Island and got some. It has bright yellow color and is not very friendly to people. SalG

[Guest Hal Davis (MODEL A HAL)]

This stuff is transparent. I can see the metal through it. It looks like varnish or something like that. I have not opened the Trio-Prime yet, but assumed it was similar to the zinc chromate that is used on aircraft. <P>This may not be the original paint. The car had some body work done prior to 1966 and it has definitely been repainted (with a brush, it appears, in some places), but I didn't think it had been stripped to bare metal. Anything is possible.

[Rick Hoover]

Have no clue then to what is is. I guess, just keep going the best you can and then lightly dust sandblast it clean. <BR>Trio Prime is dull green looking.<BR>Rick