MAPP Gas

Turfman · Aug 9, 2003

I have a galvanized pipe that is pretty corroded. I have a propane torch, but I am thinking of investing in a MAPP gas torch to do this project. What are the benefits of MAPP gas? The cost is considerably higher than propane and I am wondering if I'll see any benefit over the increased cost.

RoyJackson · Aug 9, 2003

MAPP gas burns hotter so you can do some jobs you cannot with propane.

But what were you planning to do with the corroded pipe...is it sweat soldered or brazed in place?

Mrwurm · Aug 9, 2003

Turfman, I have purchased small Mapp gas tanks that are designed to replace a disposable propane tank. This type of setup will produce a somewhat hotter flame but you are limited by the venturi type air introduction. Or, are you talking about buying a small welding nozzle with a separate disposable tank for oxygen? That kind of setup will burn hotter than propane, but small disposable oxygen tanks are quite expensive and you will go through them much quicker than the Mapp gas.
Now that I think of it, you can get small disposable acetylene tanks for your torch nozzle as well.

Bird · Aug 9, 2003

My first experience with welding was MAPP gas. I intended to buy an Oxy/Acetylene rig, but the guy at the welding supply shop recommended the MAPP gas instead, for safety reasons, because I was going to keep it in an attached garage at the house. He said if the acetylene leaks, it could become explosive before you knew it, but the MAPP gas would smell so bad that you'd know it was leaking long before it became explosive. So I bought the little portable welding rig; hoses, regulator, torch, molded "plastic" carrying case, refillable 20 cu. ft. oxygen bottle, disposable MAPP gas bottles. I took it home, read the manual, tried welding two pieces of metal together, no luck, took it back, and that salesman took me out in their shop and welded with it, laying down as pretty a bead as I've ever seen done with a welder. /forums/images/graemlins/blush.gif So I went home and learned to use it. /forums/images/graemlins/laugh.gif Turned out to be good for welding, cutting, brazing, etc.; very nice little rig.

Phred · Aug 9, 2003

I use it to sweat copper.
Faster, and the mapp torches (the little hand held ones) are higher quality than the propane ones.
The propane ones do not last IMHO.

Fred

OkeeDon · Aug 9, 2003

OK, I assume what you have is one of the little propane torches that fits on the end of a disposable propane tank, and what you are thinking of is the Mapp Gas disposable cylinders, instead. First, Jerry is right - the Mapp gas will work on your present torch, but the venturis are the wrong size, and it won't be much better. Second, you can get a complete Mapp gas torch outfit pretty cheap. It's worth doing - the Mapp gas is a lot hotter with the right torch. For example, when sweat soldering copper, if there's any water in the line, it just won't heat with propane, but Mapp gas is hot enough to boil it away and let you get on with soldering.

Next, I assume what you want to do with the galvanized pipe is heat the threaded joint enough that it will come apart easier. That may work, but it may require a bunch of heat - pipe is a pretty good heat sink and will just soak it up. If it is a threaded joint, I would first try a bigger pipe wrench. I'd jar it a bit with a hammer to loosen the corrosion. Heat won't hurt. But, be careful - don't get it so hot that the galvanize burns, the fumes are no fun.

They won't kill you but they will give you a headache and make you a little sick. If you have to use heat on galvanize, set up a big fan to blow the fumes away from you, and you'll be OK for a short time. You'll know they are there - they are yellow.

Turfman · Aug 9, 2003

That's exactly what I'm planning to do. I just need to heat it up some and get a nipple in the bronze gate valve out. It's been in the ground for about 50 years. I appreciate your caution on the galvanizing, but in this case, I don't think it should be a problem with all the rust covering it.

The plan is to give it another session with the PB Blaster, tap it a bit and hook up my biggest pipe wrenches and add a 3 foot piece of pipe to the handle (cheater bar) of one of them and give it a twist. I'm hoping a new MAPP torch and MAPP gas will give me the edge I need on heating it up and breaking it loose. The option is to wait until the secondary water is shut off for the year (mid-October) and cut the old gate valve off, rethead the 1.5 inch pipe in the hole and put on a new ball valve. Not a pretty operation, if I can find a 1.5 inch pipe threader. /forums/images/graemlins/frown.gif

OkeeDon · Aug 10, 2003

Here's links to some Harbor Freight pipe threaders. They're so inexpensive it's not worth trying to rent one; almost not worth the trip to try and borrow one from someone. I needed to do a lot of 3/8 and 1/2 stuff for LP gas hookups, so I bought the most expensive one. I also bought a pipe vise pretty cheap, and a pipe cutter (like a large tubing cutter). The cast iron is not as high a quality as more expesive threaders and vises, but, with care and lubrication, we have made many threaded joints without problems.

pipe threader 69.99
pipe threader 39.99
pipe threader 39.99