The burning question! When I'm watching people make their foundry on YT (I'm trusting it less and less as a source of good information on these topics) they sometimes make two holes it looks like instead of one for their burner holes (tuyere?). Is this because you should have some venting aside from the top, or more likely because they intend on using a dual burner set up instead of a single one. Propane as a fuel source here is what I'd be using. Are there benefits to using a dual burner? Major drawbacks? I'm trying to summon a single example of it and I can't bring many to mind. I'll be using a slightly larger than normal crucible but nothing absolutely massive, I'll probably need to use a Salamander Super A20 (30 KG). It's large, but not enormous. Would using a dual burner use entirely too much fuel for the potentially quicker melt you might get out of it? Again I feel like I don't see many/any examples of a dual burner setup, was curious why that was. And what about that other hole if it wasn't? Does letting more air into the foundry help it in the same way having a fire that has a little air channel beneath it helps it burn? Thank you again!
here is my first hand experience, http://forums.thehomefoundry.org/index.php?threads/ht1s-insane-overpowered-new-furnace-build.1938/ Dont do it V/r HT1
Wow alright haha you definitely went all out on that. Yeah I can see what you mean.. Definitely appears like overkill when you get a chance to see it in action.
I think the main advantage of dual burners is much more even heating if they were sized correctly for the furnace, there's only so much swirl the flames can spiral on the way through the furnace. I have a single burner furnace with A25-AT30 (about the same as A25) crucibles and the only time I had super even heating was with a refractory disc under the crucible that gave a narrow ring air gap against the furnace wall. So two half sized burners would even up the flame distribution in my opinion.
I have dual naturally aspirated household pressure natural gas burners...I don't think I'd be able to get up to temp on one burner alone. http://forums.thehomefoundry.org/index.php?threads/natural-gas-furnace-build.1900/ My furnace has a bit of mass to it, (1" muzzling/2" wool) but I have no cracks, and while the first pour takes a while to get up to temp, subsequent melts are much quicker. If I had to do it over for the amount and type of work I do (mostly prototypes), I'd go lower mass (satanite, etc) so I could get a quicker melt. If I were doing more production, I'd stick with what I have.
