I would like to run some large copper pipe in my garage for air lines.
What is the largest diameter copper pipe that I can solder with a standard hand held propane torch?
Just make sure you use type L or type K copper.
M= light duty
L= medium duty (yes L, no type o)
K= heavy duty
...In the spring of 2008, true MAPP gas production ended in North America when production was discontinued at the only remaining plant making it. Current products labeled "MAPP" are in fact MAPP substitutes. These versions are stabilized liquefied petroleum gas (LPG) with high levels of propylene.
I have soldered 3" copper with a small hand held torch. Before assembling, I tinned the male parts and all went together with no leaks.
Just make sure you use type L or type K copper.
M= light duty
L= medium duty (yes L, no type o)
K= heavy duty
No reason one would need anything more than type m.
True Mapp gas is getting hard to come by anymore.
Agreed , there was a big discussion about type M being used for compressed air awhile ago.
A couple of people highly disagreed with this opinion.
M for air pipe is fine, this is from my brother who is a pipe fitter
I was wrong in my earlier post when I stated the copper sewer pipe in my house is 4". It's actually 3". The smaller piping is 1 1/2".
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Everything in the pictures was done with a hand held propane torch and there is far more copper plumbing than pictured. As you see, the bigger pipe can be done, so you can easily do the size pipe you need. The top picture is sideways.
Lovely workmanship.
Al.
I was wrong in my earlier post when I stated the copper sewer pipe in my house is 4". It's actually 3". The smaller piping is 1 1/2".
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Everything in the pictures was done with a hand held propane torch and there is far more copper plumbing than pictured. As you see, the bigger pipe can be done, so you can easily do the size pipe you need. The top picture is sideways.
M is for heating
L is for potable
K is for hvac lines and underground water lines
Aside from strength corrosion is also a factor. M is thinner and will have a shorter service life if the potable water is corrosive. In a boiler little fresh water enters the system so once the initial fill reacts and goes neutral corrosion is a mute point. You can also add corrosion inhibitors. Most underground water lines are no longer run in copper, at least around here it's PP or PE with insert adapters or fusionweld.
For the price you could probably buy a 120$ hand crimper, plastic fittings, and twice as much pipe if you did pex instead of copper. So you could run a medium sized line from the source to each appliance with the only real restriction being your manifold which you could probably afford to do in brass fittings if corrosion is a concern. Other wise for the cost if supply size is most important go with black iron and rent a threader, threading pipe is easier than soldering and much more consistent if you have good dies.
One thing to keep in mind is that plastic pipe won't dissipate as much heat and you may end up with moister air so if you use it to paint you may want a buffer tank with a drain before the spray gun to cool and condense any humidity and help particles to fall out.
DO NOT USE GALVANIZED PIPE.
Sorry for the necro post but this is a common situation and this thread shows up a lot in related google searches.
I agree, first thing should have been to determine what size he needs before wondering how big can be soldered, backasswards. Then we got to type before we determined demand and proper size, on page 2 and still havnt got to it yet?

This post seems to be crossing logic between the suitability of materials regrading potable water, boiler systems and compressed air systems - three different animals. The OP's question was specific to compressed air in his shop, it's not helpful to mix commentary on other systems.
A buffer tank with a drain does very little to help remove moisture in a compressed air system. It does even less to "help particles fall out". Moisture traps and filters accompanied by radiators or coolers are far more effective.
Apologies, but it seems like some serious copy and paste from the internet netherworld for your post.
This post started 33 months ago. I would hope the airline have been finished by now.![]()
This post started 33 months ago. I would hope the airline have been finished by now.![]()


