A few questions

[Alan O'Connell]

1. How do you keep an aluminum manifold from darkening up again after sandblasting?
2. How do you keep sandblasted exhaust manifolds from rusting?
3. Has anyone used stainless steel head nuts?

[19Fordy]

Some ideas for:
#1. Clear powder coat
#2. Clear ceramic coating
#3. Stainless steel head bolts can't be used. Not strong enough and they gall. IMO.
But...........ARP makes them.

[Kurt in NJ]

There is another question you should ask too---how do you clean all the sandblast media out of the internal manifold passages so it doesn't get sucked into the engine

for the exhaust manifolds there is paint that is applied and baked in a oven, it can be in different colors

[4t8v8]

Originally Posted by Kurt in NJ

There is another question you should ask too---how do you clean all the sandblast media out of the internal manifold passages so it doesn't get sucked into the engine

for the exhaust manifolds there is paint that is applied and baked in a oven, it can be in different colors

1. Don't sandblast an intake manifold!!!! Don't ask me how I know this.
2. I tried the paint/bake thing a few times but couldn't make it stay very long. l Had them Jet Hot ceramic coated 4 years ago. They still look new.
3. Stainless Steel nuts and bolts are too soft and maleable. They stretch too easily to hold under that much heat.

[Kube]

Originally Posted by Alan O'Connell

1. How do you keep an aluminum manifold from darkening up again after sandblasting?
2. How do you keep sandblasted exhaust manifolds from rusting?
3. Has anyone used stainless steel head nuts?

Alan, I glass bead the manifolds and have found that a much better "road" to take than utilizing sand. In my opinion, sand is too aggressive. I spray the cleaned manifold with a clear coat I bought from Eastwood. I do not recall the product name but will get it for you if desired. It has proven to hold up for a long time.
I have never had an issue cleaning them thoroughly after stripping. As you know quite well, patience, patience, patience...

I powder coat my exhaust manifolds after sand (yes, sand) blasting. Holds up seemingly forever.

I have not used stainless head nuts as I prefer to restore my cars to original appearance. I do not believe galling would be an issue as a previous post has allowed if the stud (threads) were clean.

[rotorwrench]

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Stainless fasteners should always have a good coating of anti-seize or thread lube if they are utilized. The galling problem is a real problem depending on the metals involved on both sides of the fastening equation. The high nickel steels are softer than plain steels. Sometimes they work OK but I've seen more than a few stainless nut and bolt combinations that fuse together. With dis-similar metals it may be OK but it is still a gamble without some thing to protect the threads.

In aviation we generally only use stainless hardware in very high heat situations. The fasteners that work the best are silver plated but they are a one use item in extremely high temp applications and should be replaced after removal. Most plain stainless fasteners used in very high temp applications have to be destroyed to remove them. I got really good at drilling the bolts out of the aft end of the T-53 Huey engines when doing hot section inspections. We used a lot of bees wax and cobalt drills. I also got good a sharpening the dull bits. PITA for sure.