As far as I know the block is cast iron and thus should be fine for that temperature. Are there any machined surfaces which might experience accelerated corrosion?
From the heat? The coating I am chasing will be done for the purpose of aesthetics. So my goal would be to mimic coverage of the black factory finish. I might consider coating the side of the block that mates up to the trans since there is bare metal exposed there, but I think I have
some flexibility.
You would have to be a little careful heating and cooling to avoid thermal stress from one part of the block being significantly hotter than another, either cracking the block, or the coating, mostly don’t warm it or cool it too fast. 500 is hot but nothing out of the ordinary for many industrial processes. That said I’ve seen components crack from thermal shocks.
Though different coatings have slightly different methods when applying, my initial question was asked because one of the coatings required that the part be heated to 500F, removed from the oven, and then the coating is applied when the part is heated (obviously cooling at room temp). This was for Cerakote's Glacier Chrome. After speaking to them, that coating has been discontinued so a moot point right now. I need to venture down another path.
How are you planning to heat it? Do you have a large enough oven or are you planning to make one?
I had some experience with baking a Heresite coating on the inside of a tank for sulphuric acid service, long time ago now. I think we had to get to 950 F and hold for 6 hours, maybe more.
We put rock wool blankets over the outside and a propane burner in the tank. Took at least 12, maybe it was more than 24 hours to get up to temperature and more again to cool down. Think the tank was maybe 15 ft diameter by 20 something tall. All worked successfully.
I wouldn't be anywhere near those temps. The 500F I mentioned earlier was more of an exception anyways. Most curing schedules (granted these were for the powder coats I was initially looking for) were at around 200F. Anything under 500 and I'd be going to craigslist for an old cheap oven. An AHU block will fit in an oven no prob... the block is the size of a large toaster.
Yesterday I came across another vendor that was recommended to me elsewhere, Jet-Hot Ceramic Coatings. This was very promising because they DO have a reflective, almost chrome-like, ceramic coating that was good up to 1250F. But, they would NOT entertain an engine block. It was explained that the block would be difficult for them to handle since their lines are not set up for "large and heavy" parts. Also their prep involves a thermal cleaning and media blast and they did not want to use media on an engine. Understandable, but a bummer.
So I'm back to square one.
I need a high temp chrome-like finish on a cast iron block.
Any takers?
