View Full Version : Acetylene
06-14-2011, 06:26 AM
The drum beats are starting to get louder about a coming shortage of acetylene, due to explosion at the factory a while back. Anyone having trouble getting your bottles filled? I have heard via the rumor mill that some places are holding back stock, only sell to their prime customers. ????
I guess that may force people to use Mapp Gas, or Propane and use Acetylene only when absolutely necessary.
That kind of sucks.
It is all getting too expensive.
06-14-2011, 10:23 AM
Can you silbraze with MAPP? Does it come in MC and B tank sizes?
I have used MAPP exclusively for at least the past decade. My acetylene hoses have rotted from lack of use, although I still have the "B" tanks, but would like to get rid of them.
Mapp gas is good for most applications, but it is not recommended for welding high iron content metal.
I think it is about 200 degrees F less temp than acetylene, but silbraze should work with Mapp.
I would not use it to build a race car, but for copper it works good.
06-15-2011, 05:13 AM
While you can silbraze with Mapp, you are limited on the size of tubing. I brazed up the lineset for my heatpump with silphos 15 and found that on a 7/8" fitting (3/4" in plumbing trade), a standard Mapp torch had a hard time getting the job done (especially at the service valves). On some of these joints, I found having the wife holding the propane torch while I hit it with the Mapp torch got the job done quickly and cleanly.
I know some HVAC guys will use a air-acetylene and others use oxy-acetylene. In the HVAC trade, it seems like Mapp isn't used much as these guys want to heat the joint fast (to protect service valves, reversing valves, etc.) and the acetylene torches are also able to get the job done if working on big chillers and refrigeration units.
A lot of it too is in the size of the torch (BTUs). The Mapp flame is hot enough, but may not have enough BTUs in your standard hand-held torch. Acetylene is used so much that you have a wide range of torch tips to choose from and can easily change out to get the right flame for the job.