Off Gassing Intake Manifold

[Guest]

Got an intake manifold in the oven that has been off-gassing for over an hour at 400 degrees part temp. There's still some smoke coming off it every time I open the door and some areas are turning bronze/gold. What is this? Is this oil on the surface or are those areas clean and just 'burnt'?

Should I be OK just pulling it out, cooling it, and coating it? Anything else I need to do? Thank you!

Juan

[Guest]

Re: Off Gassing Intake Manifold

Well after over 2 hours in the oven at 400 degrees it finally ceased to smoke. I took a picture that I will share tomorrow but it basically looks like what I described. Certain areas just have a bronze/gold finish on them. I don't know what it is, looks like oil that came to the surface during off-gassing and created a layer of junk.

[CRAVED]

Re: Off Gassing Intake Manifold

i'd be blasting it again now, then blow off and coat

[Guest]

Re: Off Gassing Intake Manifold

i'd be blasting it again now, then blow off and coat

Sounds like a good plan. The stuff looks like it would easily blast off. Also, it's only in areas that didn't get an intense blasting coverage or didn't get sanded with the DA. Those 2 areas seem fine, it's everything else that turned this weird color. Is there something else I can do in the future to avoid this? Different degreaser? Anything?

[banditpowdercoat]

Re: Off Gassing Intake Manifold

ive found metal will turn colors when subjeceted to prolonged heat. Ive usually just powdered over them with no ill effects

[CRAVED]

Re: Off Gassing Intake Manifold

most likely this would be cast alloy, which i havent seen to change colour.

simple green works for me, but expensive here in Australia - so i dont think this will change with degreaser, if its in the metal then outgassing is fine to remove, thats why i follow the blast after outgas process - cleans the alloy and makes the stuff your blasting off come off easier

[Guest]

Re: Off Gassing Intake Manifold

The composite intakes from GM LS series motors need to bake in the oven for a LONG time before they stop smoking. I baked the last one 6 hours to be sure it was ready to shoot. They are very pourus though and take a long time to leach the oil to the top and burn off.

[Guest]

Re: Off Gassing Intake Manifold

Here's what it looked like last night.



I was able to just go over it today and blast most of it off. I don't know if it was the oil just sitting on the surface or the metal turning that color, so I'm not sure if it would have been an issue or not. If it was the oil, shouldn't it have burnt off after almost 3 hours in the oven?

I washed it down again and it's back in the oven, gonna leave it in there for another hour then tape it all off and coat it. Wish me luck.

[Guest]

Re: Off Gassing Intake Manifold

I'll assume that's cast aluminum. Must be oil, aluminum won't change color with heat the way steel does.

I'm sure it's cast aluminum. What do I need to do to ensure a good clean surface on this manifold?

[Guest]

Re: Off Gassing Intake Manifold

Sounds good Jeff. I rinsed it down, degreased it again, blasted it, cleaned it, and stuck in back in the oven for another hour. Shot 3 coats of bumper black on it and it's now cooling down in the oven. I will post some picture of it tonight or tomorrow.

Thanks for all the help.