# Brazing with propane



## TimT (Jan 1, 2004)

Considering making the switch from acetylene to propane for my brazing. Looking for any pros and cons, feed back, tips and tricks.

Tim


----------



## mchimonas (Dec 19, 2008)

I braze with oxy-propane. I use one of these pre-set smith regulators (http://store.cyberweld.com/smlitoreford.html) for the propane with a standard oxygen regulator for the oxygen. It is set to a max of 18psi, so for brazing you only need to open it a little for 5-12 psi. Propane is very cheap, $2 a bottle and can be stored as a liquid so a single blue canister lasts surprisingly long. A draw back of the smith regulator is that the setting tends to drift, so you make your neutral flame and mid way through brazing you notice your flame is now a carburzing flame. It is easy enough to adjust, and I am sure there are better propane regulators out there. The oxy-propane flame is hot enough for any bicycle brazing task I can think of. The propane-air flame is probably too cold for brazing.


----------



## dbohemian (Mar 25, 2007)

TimT said:


> Considering making the switch from acetylene to propane for my brazing. Looking for any pros and cons, feed back, tips and tricks.
> 
> Tim


May I ask why? I would never switch. I would absolutely consider an addition in the form of an oxy/propane setup but many things are just done better with acetylene. The only process that is better served by propane is lug brazing. Is anyone other than my weird ass lug brazing on this list?


----------



## TimT (Jan 1, 2004)

No real reason other then I like to experament. And yes I do lug work. Just finished welding a lugged road bike. Going to the powder coater this week.

Tim


----------



## dbohemian (Mar 25, 2007)

TimT said:


> No real reason other then I like to experament. And yes I do lug work. Just finished welding a lugged road bike. Going to the powder coater this week.
> 
> Tim


Tim....You "brazed" a lug frame. You did not weld it.

And you are going to take you lugged frame and cover up all those lugs with a thick yucky powder coat? I like powder all except for lugs. Seems like such a waste to do all that work and then completely blow it out with a orange peel mess of a powder. No, don't tell me it's any good (cosmetically) cause it ain't.

So, back to the original question. If you want a lug only rig, go for propane. Shouldn't cost too much but I wouldn't give up my acetylene for fillet work or tiny braze on applications.


----------



## TimT (Jan 1, 2004)

Dave the "English major" I stand corrected. For the record its a utility/commuter frame not to be entered at any bike shows and not to hang on the wall. It was cheaper to have it powder coated by far.

So back to it. Why is acetylene better than propane or MAPP . Do you have more flame control? I do more fillet work. 

Tim


----------



## dbohemian (Mar 25, 2007)

Actually more like the "Engineering Major" 

Acetylene is not necessarily better than Propane. In fact the by products of each reaction are identical in that CO2 and H20 are produced. It's just that propane has a much larger envelope when welding, which although awesome for lug brazing is more difficult for me to use when fillet brazing or doing very small work.

The acetylene flame can be adjusted to different types of work and for that reason it is more useful overall. You have to weigh the safety factors (propane is safer) vs costs etc, but the reason Acetylene is so prevalent is that it is useful for all sorts of welding/brazing and cutting where propane is really only great on general heating and brazing. For fillets acetylene really is the preferred fuel and since you have it already it seems like a no brainer.

As far as the utility thing. Not buying it I/you could have brazed your commuter together with one dollar of bronze and saved even more money. The use of lugs costs a lot and for that reason alone deserves more respect than just covering it with any ol thing. You could have in fact bought a new mass produced frame for 100 dollars thus saving yourself more dough. Building your own frames as a hobby makes no actual financial sense so IMHO it should be done right, the craft deserves that much at least.


----------

