I am currently building a new gas forge and after looking at a lot of custom forges I am wondering why I have not seen any soldered copper piping on them? All the connections are threaded elbows and tees. I would think that every threaded point is a potential leak hazard and soldering would prevent that but I must be missing something. Maybe the soldered areas would get to hot next to the forge and melt? any thoughts?

Thanks,

IAF

Lack of confidence in wicking solder completely into a joint. And you don't have to sand /de-oxidize when things are threaded. Disassembly ease is a legitimate reason for use of non-soldered joints, so it is not all attributable to my initial remark. I like to weld and silver solder(really silver braze) and use pipe /plumbers' solder. Some do not enjoy those processes so threaded with good Loctite thread sealant is quite sufficient.mike( I use teflon tape too, but the Loctite inspires more confidence for me.)Sorry- it is necessary to acknowledge that black iron threaded -joint pipe with sealant is the prevailing gas distribution material/system in the American home and it is safe and works well.-Without this amendment, my post seems pretty disrespectful or critical in a mean spirited way- that is not me)SORRY

Edited July 24, 200817 yr by racer3j

Many propane fittings have pipe threads, so you kind of start out with that standard. Also, some forge designs are based on iron pipe (for example, a piece of 1/8" schedule 80threaded inside to 1/4-28 to accept a MIG nozzle). Many forges have very few fittings between a propane hose and the tube that holds the orifice, so it wouldn't really be worth the trouble switch from threaded to sweated and back. And have you seen the price of copper lately? :)

Solder can melt at the temperature that most forge bits are subjected to, especially after shut down. Threads, when properly sealed with teflon tape or pipe compound, are a much safer alternative. Making it a little easier or faster to put together might not be the best trade off when the potential penalty might be an uncontrolable property eating fireball in your garage or where ever you chose to do your work.

Copper is a theft magnet these days too!

I would be too worried about the solder getting too hot, can you imagine the catastrophie if a solderjoint got hot a came apart, that would be a fireball second to none.
I don't think that it would happen, but just because there is a posibility or a thought of it happening, whith threaded pipe there is no chance of it coming apart.

welder19

I wouldn't even consider a soldered joint on a forge... Too much danger if it is melted out or it fails.

Copper would probably be safe enough if you silver soldered it, but I still don't see any real advantage. Last forge I made, I mitered and TIG welded black pipe to save money on fittings. Of course, my TIG welding's kind of slow, so I probably blew all my savings (and then some) on argon. But I guess that just shows I needed the practice . . . .

I would use steel pipe with threaded connections, you can get various lengths at Home Depot. Or have a muffler shop bend it up for you, I work at a company that makes exhuast for big trucks so I lucked out on mine. I don't know if you could get copper big enough to flow the volume of air needed. Mine is 2 1/4 inch.

Edited July 26, 200817 yr by unkle spike