Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Restoration of cast iron automotive parts
Q. I would like some advice on cast iron exhaust manifold restoration.They can get pretty ratty. I've ground a lot of the pits out with a flap-wheel on a hand-held grinder but what to finish with? A mechanic scoffed at me saying "never seen paint yet that would stick". Is metal-enameling (porcelain) within reach of a do-it-yourselfer. The information on the process is impossible to find or are some of the claims by some exhaust paint mfrs. within reason that their products don't burn off. I'm willing to grind to bare metal.
Thanks,
hobbyist - Moncton, N.B., Canada
2007
A. There is at least one supplier who can coat your manifolds with ceramic in white, black or silver. We can't recommend by trade name on this forum, but you'll find them in an internet search. No, sorry, it's not a process you can do at home. Some of the "high" temperature paints will last for a little while.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
2007
A. Hi Pete. Porcelain is more like spraying with molten glass than like dipping in paint. The temperature is so high that the ceramic frit melts and fuses together into a glass-like coating. Beware of "ceramic" paints, as that only means there are particles of ceramic frit mixed into a paint, not that the particles are melted and fused together.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 2013
Restoration of cast iron brake calipers, steering box, etc.
Q. I have been a follower of the Finishing.com forum for some time and have done research on the site and other relevant sites trying to find a solution to restoring automotive cast iron. I need to restore several cast iron automotive parts (steering box, brake calipers, etc.) to a fresh cast color (grey-brown), gloss (flat) and texture (semi-rough) "like they were installed at the factory". I am not interested in a cast blast, ceramic or other coatings or finishes which will not pass show judging.
I have tried several techniques:
1. Evaporust (and similar products): wonderful product for removing rust from ferrous metals including cast iron however the resulting finish is too light grey.
2. Electrolysis: also a good contender and effective at removing rust and reviving a cast finish however like Evaporust produces a light grey finish that is not like a fresh-casting.
3. Electrolysis & Seasoning: Following the electrolysis process I have done heat seasoning with Crisco and separately with coconut oil at temperatures and time varying from 30 mins to 45 mins at 300 °F to 375 °F and using single application and multiple coat applications of these products. The best result I have achieved is with a light, single application of coconut oil baked at 300 °F for about 40 mins. This produces a finish that is "close" to fresh cast iron however somewhat brown (vs grey) with a semi-gloss rather than flat finish. I welcome any other thoughts and ideas.
Car Restorer - Hobbyist - Vancouver, Canada
October 19, 2015
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