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Threading Copper??? (or pvc)
Posted: Fri Mar 05, 2010 3:40 pm
by bobgengeskahn
So I have searched the How-to section and the rest of the forum and have not found anything, so if I have missed something a link would be fine.
My question is, how do you thread into the side of a copper tube for an air in?? I was thinking of using a "T" fitting and threading into that, but I'm not sure if it wold still be too thin (I'm threading 1/8" NPTF). My other construction material choice would be PVC/ABS since I'm operating at low pressure, but I've read that threading into plastic doesnt last.
Any help would be greatly appreciated
Posted: Fri Mar 05, 2010 3:45 pm
by psycix
Copper is thin, if you would tap or cut threads in/on copper pipe you will make it too thin or even go through.
Air into the side of a copper tube? Unless its a simple venthole use a T-piece like this:
pipe-Tpiece-pipe
You can thread into PVC. Make sure to do so at a fitting so that you've got twice the thickness.
Tap threads with a tap and then thread the fitting in. Do not do this a lot, the threads will wear down fast. Just thread it in ONCE and thats it.
Posted: Fri Mar 05, 2010 3:47 pm
by Hubb
Threading into PVC will probably last you longer than threading into copper pipe. If you thread through PVC, try to do so in two layers (one layer being some sort of fitting and the second being the actual pipe). If you want to tap into copper, I suggest brazing or at least epoxying the fitting in place when done. Also try the double layer method with the copper too.
Posted: Fri Mar 05, 2010 3:48 pm
by deathbyDWV
Threading into plastic is just fine. Just try to do it through two layers.(at a joint) For copper I wouldn't thread through the pipe because you might not get a good enough seal due to the thin walls. What I would suggest for copper is using a tee with a bushing that has 1/8 inch threads. Or just epoxy the fitting in. Epoxy works great.
Edit...Darn hubb... Beat me to it... You win this round...
edit... And psysix? Wow I type really slow...
Posted: Fri Mar 05, 2010 3:59 pm
by metalmeltr
Maybe you can find or make a copper bung that could be soldered or brazed to the side of the pipe then have your threads in the bung.
Posted: Fri Mar 05, 2010 7:42 pm
by Gippeto
metalmeltr wrote:Maybe you can find or make a copper bung that could be soldered or brazed to the side of the pipe then have your threads in the bung.
We have a WINNER!!
Go to a plumbing supply store and ask for a 1/2" male sweat to 1/8" nptf bushing.
These guys call it a flush bushing.
http://www.plumbingsupply.com/images/co ... ushing.jpg
