The best material available for this type of repair is BELZONA (1111)
Super metal.
The Belzona technical consultants are very helpful.
The Belzona website is www.belzona.com
I once sealed a 90' long pourous welded seam on an unleaded gasoline
storage tank at a refinery with Belzona. Caterpiller specs Belzona
for repairs to engines. I have seen several aircraft engines repaired
with Belzona.
Degrease the area to be repaired with MEK. Use a propane torch to
lightly heat the surface. This will bring oils to the surface.
Degrease the area again. Roughen the surface. Ideally, grit blast
with black beauty, to produce a near white 3 mil finish. Degrease.
Apply Belzona Super Metal. Enjoy a dry engine.
This stuff works very well when repairing fuel tank leaks. DO NOT USE
FLAME ON FUEL TANKS, unless you want to make the Darwin list.

(Paul Lee) wrote in message . com...
The Franklin engine I rebuilt came with an odd ball cast aluminum oil
pan with a big shaft access hole in back. May have been a helicopter
engine oil pan. I put a disc there and welded it shut (from outside).
But the weld is dripping some oil especially when hot. I
am planing to take out the oil pan and fill the inside groove between
the disc and oil pan with either JB weld or Hi Temp RTV silicone.
The RTV works great as gasket to seal out other holes with plates
bolted on them. But there would be no pressure plate to hold it in the
groove in this case. Which one is better choice? Another sealer?

I don't want to get another oil pan since I adapted this shape
for other uses.

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SQ2000 canard: http://www.abri.com/sq2000