twobob,

My furnace is simply made from fire bricks around an 18" length of 1/4" wall thickness steel pipe. The end of the steel pipe in the furnace is around 1" from the fire brick back.

I have two cross bars inside the pipe to sit the barrels on to keep things flat and off the inside of the red hot pipe. When I assemble the furnace I set up the steel pipe so these cross bars are fairly level, perfect is not necessary but they need to be reasonably level.

The heat source is simply an Oxy/LP heating torch placed in the end, blowing onto the side/bottom of the steel tube about 2-3" from the end inside the fire brick structure.
My furnace is simple, easy to dis-assemble and store out of the way and certainly effective.

To operate, the furnace built and the heating torch lit, and the barrels are prepared as required with plenty of flux and plenty of the the silver solder laid on top of the barrels in the grooves formed by the barrel and top extension.

When the steel pipe is a nice and red, the wired together barrels/shoe-lump/top extension, prepared with the flux and silver solder mentioned previously, are slid with the lump down, into the pipe, to almost he back end of the pipe (I forgot to mention I mark the barrels with a marker where the outer end of the steel pipe comes so the barrels don't go in too far, you don't want the naked flame on the barrels etc)

After the bits are in place in the red hot pipe furnace, just keep an eye on it, it won't take overly long and it will be up to the correct temperature and the solder will melt. So long as your joint was well fitted and clinically clean when it was fluxed and wired together, capillary action will draw the molten solder completely and nicely through the whole joint. Watch, and as soon as the solder runs, turn off the heat and let the whole lot cool for half an hour or so.

There is the heat control. As soon as the solder runs it has reached the correct temp of 1205 degrees F, so by turning off the heat, the metal simply cannot over heat. After the half an hour or so, carefully remove the barrels, they will still be very hot, and set them aside on some parallel bars to cool completely.

It sounds like my process is similar to the one on the DVD you mentioned

I used to cut the chambers to about 30 thou short before I joined the barrels/shoe-lump etc, so yes, I did the coat chambers and half-way down the bores with an anti scaling solution.

Best
ALEX