On Tue, 12 Jul 2016 08:17:12 -0400, Ed Pawlowski wrote:

On 7/12/2016 1:09 AM, Deodiaus wrote:
see http://memphis.craigslist.org/grd/5678750036.html
I was thinking of building a backcast out of plaster on the outside or just sand to keep it from melting away in case I get too hot. Then just heat it up from the inside to reseal the hole.


Sure, go for it. Be sure to report back with the results.
The plaster will blow away before you get hot enough to melt. A sand
backing MIGHT work if you use refractory sand and keep it DRY,(use
binder, but not water!) Tou will need a LOT of BTIs because the whole
crankcase will act as a heat sink - sucking away all the heat you can
give it. Even to Tif weld it I'd heat the whole thing with a big
propane weed-burner or rose-bud tip torch before attempting to weld it
or you really need to "pour the coals to it" with the TIG.

Using aluminum "brazing" rods you really need to heat the whole case
pretty good too.