Originally Posted by
HI-TEK
Hi Gatch,
the whole thing starts at the beginning.
1. If you are using wheel weights plus Tin, does your mix contain any Zinc? If it does, that will answer all questions. The coating does not like Zinc at all and will peel off.
2. If you are sure of "no Zinc", do you use any casting/release lubes in and or around your Molds?
3. With Water quenching, freshly made cast, what is the purpose of doing this? Have you had any increase in hardness, (if that is the aim).Do you dry the water off the quenched cast? Any possibility of contamination coming from your water quench?
4. If you have Zinc in mix, dropping them into water will cause the Zinc on surface to "React" with the water, causing a dry film, that will interfere with bonding of the coating.
5. The next problem may be, simply using too much first coat, and then not drying enough before baking. How do you test if the first coat is dry or not before baking?
Please look at simple things, one item at a time.
As Tazza suggested, have you slugged your bore to measure internal diameter and then match your bore sizing requirements accordingly.