Engine Bay Prep.

67 newb · 09-12-2009, 07:08 PM

Hey Guys,

I just welded in new fender aprons and a radiator support. Next I'm going to grind down the plug welds a bit til it's flush and clean. Everything is cleaned down to the metal, I just want to be sure of the correct procedure to painting the engine bay.

I was going to etch the metal first with some Du Pont metal prep, then prime.
They also have a self etching primer. Can that be used in a single step before painting?
I have about 3 cans left over of the high heat resistant engine spray paint (black) that I was going to use on the engine bay. Is that ok? Or do I have to have engine compartment paint?
Do I need to seam up certain joints, corners or intersections around the compartment before painting? If so, what kind of sealant?

Any recommendations on what brand primer to use?

Thanks

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Flash70 · 09-12-2009, 09:57 PM

Well I can not comment on a lot of that but I will say that I just used Flat Black paint and rust resistant primer for my bay. It looks good. The paint only withstands 210 degrees but I am thinking it probably will not get that hot in the bay. Anybody can correct me if I am wrong. I have used it before though and it worked fine.

67stangr · 09-14-2009, 05:56 PM

i used a little sandpaper in parts and then i fallowed up with the ceramic engine black and with stands 1500 degrees and turned out better than i thaught.

Adrenolin · 09-14-2009, 06:21 PM

I took the bay down to bare metal and then after the prep with Marine Clean and Metal Ready I shot 2 or 3 coats of POR-15. Durable?? Let me just tell you.. 2 weeks ago I had to drill and then sand the POR around the hole for a ground strap. Using 40 grit paper it wouldn't take it off and I had to get a dremel to lightly grind it off. Fighting brake issues and had brake fluid running down drivers side apron and resting on the frame rail for 3 days before I cleaned it up and not a single mark and the POR is hard as a rock!

That said.. I did topcoat the POR with their chassis black topcoat and the brake fluid did soften that up a bit. With the black POR under it though you don't see it. Also note that POR can be sprayed, brushed, rolled and then topcoated and its dry the next day however for it to fully cure to the hardness I've mentioned above it'll take about a month so just be careful until then.

I've never seen another 'paint' thats brake fluid safe over a 3 day period. I really thought I'd have to repaint but didn't have to. If your looking for a durable and long lasting finish This is what I'd recommend. It's a LOT of work but I know I don't have to worry about painting it for a long time and chemicals will not eat away at the finish.

Jonk67 · 09-14-2009, 09:40 PM

I've paint stripped and wire wheeled down to bear metal, cleaned out most of the seam sealer as it crumbled out and replaced with 3M seam sealer in a caulk tube (2 tubes worth). I have seen other brands mentioned and the 3M is gray, wish I would have picked one that was black as you have to do it first then paint over. I tried to get some paint under the seam sealer so it wouldn't be bare metal in case water gets under the sealer.

I now plan to spray with self etching primer then top coat with Eastwood underhood satin black. Hopefully this will hold up well, I've already done the firewall and it came out nice, not as shiney as semigloss but not flat either.

I know it won't be as tough as POR15 as mentioned above but I've read that it's not the nicest stuff to get off of your skin or anything else it gets on and was more work than I wanted to tackel this go round. I'll probably want to redo it in a few years anyway, maybe paint it body color and can't imagine how you'd get the POR off then? I would consider using the POR on my frame though. I used Eastwood chassis which is nice but the POR would have been better.
Jon

Adrenolin · 09-14-2009, 10:14 PM

Its not that bad getting off your skin. I opened a new quart last week for a repair on dad's car as well as the inside of our front bumper. When opening the can my hand slipped and it spilled out damn near covering my left hand. Grabbed a rag removing most, cleaned up the work area then some Lacquer Thinner on a clean rag removed the rest from me hands.

It's also easily paintable. If dried already simply give it a light sanding to degloss it. I found that the 2k Epoxy primer we used bonded very well to it.