If it's a multiple pontic case, I try to keep the cut and solder joint 1 pontic (if you can) from an abutment.
The gap of the cut should be as thin as possible, without the sections binding on each other. Lute it together
with a strong dead wax like Ivoclars pontic wax (it's the light blue/green stuff) or use zap it to lute them
together. Keep pressure on both abutment ends as you let the wax cool, or the zap it totally cure.
Then I like to put some wax under the pontic area and even more to the mesial and distal area so that it won't be in contact with the investment
and will heat more evenly. With the investment I'll put some in the abutments, and make a patty on a piece of plastic or whatever, build up little
mounds where the abutments will seat, let the investment get a little firm (can even use a tissue to draw a little moisture out) and set the bridge
on the patty with the little build ups. Those help keep the bridge from sinking to far into the investment, keeping it up a bit. Then I take a bit of
water to some investment I left in the bowl to thin the investment out just a bit, and cover the abutment units to help keep those more stable during heating.
After it has set, trim any extra investment away so you're not heating up a cow patty (Yippee yay a Cow Patty) burn it out in a oven as per Laservest
investment IFU. Then with the torch heat the solder area hot enough to receive the solder, ideally after it's heated you should be able to hold your
torch on one side and feed the solder in from the other side and it should flow towards the heat, torch side.
Sorry I didn't have to much to say about this subject, as I've just recently joined Brevity Anonymous and am trying to keep it simple....
Yippee yay a Cow Patty