Ray - I am in the foundry & machine shop business. We have quite a bit of experience in porcelainizing (glassing). We did a lot of research when doing a large job for burner venturi "caps" for kitchen ranges.<P>If there is any major tip I can give you from the "range" project, is, make sure every and all nibs of the cast iron granular texture are sanded down. What happens is the part will look good at all even areas, but, the nibs will not get coated well and look rough. Also, make sure the parting line (seam) is ground down flush with the casting surface as this to will not glass well, and, will flake in that area.<P>Basically, any sharp granular areas act like a mini volcano. To porcelain, the part is pre-heated to about 1500 degrees. We pour cast iron in electric furnaces at 2650 degrees. Metallurgically, at 1500 degrees the molecular structure starts to loosen up.<BR>The nibs/protrusions will then out-gas like a mini volcano. Then when glassing, you have a sharp / rough area.<P>The other mandatory tip is make sure the vendor sand blasts the part real well (or even Wheelabrate it with steel shot).<P>My company used:<P> Prizer-Painter Co.<BR> 600 Arlington St.<BR> Reading, PA<BR> (610-376-7479)<P>I have seen them doing many manifolds. By the way, I get down your way quite a bit. If you like, I offer to meet you and hand deliver them if you opt to go this route.<P>Regards,<P>Peter J.<p>[ 10-20-2001: Message edited by: Peter J Heizmann ]