Hi guys!

I know that this topic has been discussed through 1 zilion times, but I have a stupid question: what if I use zinc plated sheets for floor? What will be the consequences?

Also - the seam seeler should be used before painting, right?
And another - I have Por15 primer and Por chasis black. Is it to OK to prime chasis and leave it for 2 months before final painting? I heard that with normal primers you have to do final painting immediatly.

Thanks!
Janis

Welding Zinc plated steel sheet can produce a nasty yellow-brown smoke from the Zinc plate.

This smoke contains Cyanide based compounds and is naturally BAD for your life expectancy

i.e DON'T WELD ZINC PLATED SHEETS

Lots of good ventilation required or just don't do it.

Ditto on the welding question.

On the seam sealing question I'd say that it depends... I used an self-etch primer (SuperEtch) which is only going to work when in contact with bare metal and produces truly fantastic adhesion which is probably way beyond what the sealer would achieve. It is also possible to run the thin primer into the seams by capillary action which is obviously advantageous.

So I painted on the primer and let it dry thoroughly (important!) before sealing the seams with the proper car body seam sealer (not just bath sealant or framing sealant) before painting with Dulux Weathershield black gloss.

Hope this helps,
Craig.

I'm finally at the painting stage for my mid-engine Mini, after, oh, 8 years or so...

Welding zinc is only okay if you have good ventilation. And note that even though it's zinc coated, the zinc will burn off near the welds and will rust. Riveting OTOH is obviously not a problem.

About the painting, I gave up on brushing it on. I tried some "Rust Bullet," and while it seems like good stuff, using a brush left terrible brush strokes. Sure, spraying it on would work fine but I just don't want to do that at home. So it's going to be powder-coated. Not cheap, but since so much time and work has gone into the thing it would be a shame to give it an ugly paint job.

About the seam sealer, someone from your side of the pond had the following comment. [For those who don't know (I didn't) "intumescent " means the stuff puffs up when exposed to high heat]:

"Here in UK we are obliged to use an intumescent sealant in any areas where fire/gasoline is an issue. The rule of thumb here is that you apply it to any seams (alloy joints to space frame) where you could expect a source of fire to try and enter the driver compartment. It's mandatory on the bulkhead behind the driver for single seater race cars here in UK - where the engine sits behind the drivers head. In saloon cars where the tank is in the rear then the bulkhead between the boot/trunk and the interior is usually sealed with alloy sheet and intumescent sealer."

Also, I wouldn't apply the sealer before painting it, but that's just me.

Lastly, be aware high-gloss paint will only look nice when it's perfectly clean. Depending where the surface is visible in the car, the high-gloss will cause annoying reflections of the sunlight.

[Edited on 11/12/04 by kb58]

This is used when connecting buildings by plastic pipes or ventilation systems. It expands rapidly when exposed to fire blocking the aperture where the pipe has melted. It's probably a good idea but it's not mandatory if you have a firewall. The mig brazing mentioned a while ago is designed to join the sheets without destroying the zinc coating

I agree about the brazing, but I thought the context above was welding.

I thought it was established that welding zinc coated plate wasn't a good idea, what with the poisonous fumes and weld contamination, just putting forward alternatives, although expensive ones, for consideration.

There is a weldable coated steel plate which I believe is called 'Zinc Bright'

I used it for my floor panels and although the weld area is affected the main plate stays coated. I put one coat of paint on it and it's been the best anti-rust I could have used.

Welcome back Rob