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I cut up some left over floor pans to do a paint/weld test. I have all the plug weld
holes drilled in the pans and I was going to start welding them in this evening. I
got into a conversation this afternoon with one of the experts on these forums and
we both had a different opinion about what all should be coated with epoxy...whether to
coat all of the support or just up close to the plug weld holes.
I re-measured the thickness of the trunk supports and I made two pieces of metal each
for the trunk supports, floor supports and just floor pans. Tomorrow I will flatten these
out good and bead blast them. Then I'll paint three sets with PPG Epoxy and three sets
with 3M Weld-Thru Coating.
So I will have floor pan to floor pan which is .032" thick. Then floor pan to trunk
support and trunk supports are .047" thick. Then floor pan to floor supports which are
.068" thick. I'm really close on the thicknesses because I used a micrometer.
Just another picture. You can kind of see the different thicknesses in the metal. I
talked to PPG last April about brushing on Epoxy. They don't really like to commit
to anything like that but they told me it could possibly be brushed or rolled on.
They said that 2 coats sprayed will give you about 1.5 mils thickness, so that's what
I'll be shooting for with a brush. I'll brush it on carefully up to the screw
holes and the plug weld holes, then I'll put in the sheet metal screws that I used
on the floor pans so the two pieces of metal are tight. Then I'll weld the plug
weld and 2 screw holes...the 2 screw holes will be welded from the bottom and the
plug weld on the top. There will be three sets sprayed with the 3M coating and
3 with Epoxy. I'll let the Epoxy dry overnight at 72 degrees in the shop, the 3M
coating I will give it one coat and let it flash then give it the second coat and
wait about 15 minutes so it's dry to the touch, screw the pieces together and
weld them up. When they're all welded up, I will separate them as carefully as I
can so we can actually see how far the weld burned back into the 3M and the Epoxy.
Once I find that out, I'll coat those floor pans and supports accordingly and
weld them up. I'll give you pictures when I coat them, weld them, and take them
apart. I would have fired up the bead blaster and done it tonight but the vacuum
on the bead blaster is pretty noisy and I have good neighbors and I want to keep
it that way.
The whole idea of this test is to make sure my plug welds are solid and I don't
get any contamination in the weld from the Epoxy or the 3M coating, also if I
know how far back it burns into the coatings, then I can probably eliminate some
of that smoke when I weld it up. This test has no controls except the dimensions I
gave you of the thicknesses and what I coated them with.
Here is the Epoxy and the catalyst.
Here is the 3M coating.
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