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Threaded pipe question.
Posted: Thu Feb 25, 2010 5:45 pm
by timebmb757
Never having used threaded pipe for any sort of pressure-holding project, I have a question:
Should I simply put thread tape on the fittings and screw them together, or is there a adhesive of some sort that I should use like with slip-on fittings?
Posted: Thu Feb 25, 2010 5:50 pm
by kjjohn
You can use threadlockers, which are basically an adhesive sealant which makes the thread air tight, but it is not required, and I have never used it myself. Thread tape will work. Also, if those are large diameter pipes (>2"), make sure you have a pipe vise and a mighty big pipe wrench. I've found that large pipes, especially metal ones, are quite stubborn when it comes to tightening them.
Posted: Thu Feb 25, 2010 5:57 pm
by theBOOM
Use teflon tape the yellow type of teflon tape I find the white teflon tape to be to thin and the pink one to thick... so the yellow suits the best...Just thread them in with a pipe wrench and pull off the teflon tape left over tails or w.e.
Posted: Thu Feb 25, 2010 6:26 pm
by Moonbogg
My cannon uses 4" pipe. I spread a good film of anti-seize thread lubricant on the threads, then used teflon tape for sealing. If the threads cut through the teflon tape, you can experience galling and then you can just throw the thing away if you ever need to take it apart again.
Posted: Thu Feb 25, 2010 8:26 pm
by timebmb757
Moonbogg wrote: If the threads cut through the teflon tape, you can experience galling and then you can just throw the thing away if you ever need to take it apart again.
What exactly do you mean by this? IE: What do you mean by "galling"
Posted: Thu Feb 25, 2010 11:52 pm
by DR
timebmb757 wrote:Moonbogg wrote: If the threads cut through the teflon tape, you can experience galling and then you can just throw the thing away if you ever need to take it apart again.
What exactly do you mean by this? IE: What do you mean by "galling"
http://en.wikipedia.org/wiki/Galling
Posted: Fri Feb 26, 2010 2:49 am
by Moonbogg
DR linked it, but I will explain simply what happens. Sometimes the threads bind together permanently due to friction and other factors. It doesn't always happen, but it happens often enough so that you should prevent it if you have any money invested in the parts. They can get stuck together and nothing can free them. No amount of force will loosen the threads. The harder you try, the worse it gets. You become screwed. Get it? GET IT?!?!