Weekend

Possible problem

From where I sit, it appears you are using teflon tape on your pipe fittings.  You should switch to something like Loctite 592 Thread sealant and vacuum equipment gasket maker with PTFE.  Telfon tape really isn't a very good pipe sealer.  Plus when you disassemble  a joint it leaves shreds of teflon behind that can migrate and mess up things like regulators.

Re: Possible problem

While I don't argue the weakness of using Teflon tape (even though it is in very wide use everywhere in spite of pipe sealant being considered superior), all of my few vacuum chucking problems have been due to clogged filters. I would say that any leakage through a reasonably taped joint is very miniscule compared to the leakage through bowl/chuck interface and even through the pores of the wood itself.

Re: Possible problem

Pipefitters will tell you to use tape (3 wraps) AND dope.  I’ve found that to be very effective—I have never had a threaded joint leak in anything since I’ve adopted the practice.  It’s important to keep the tape and dope away from the first ring of the male threads when applying them.

Jason

Re: Possible problem

When I worked at a steam sterilizer company we had many machines with piping.  We employed a number of pipe fitters.  Every machine would be tested before it left the factory.  One of the biggest rework factors were piping leaks both in the factory and then after delivery to the customer.  I was assigned to find a way to eliminate the leaks.  I tested every pipe sealant, tape and technique known at the time.  What I determined through testing was that Teflon tape would seal, but any realignment would produce a leak.  I found that the best sealant was Loctite Pipe sealant.  Our leaks in the factory went from 8-10 per machine to none.  Our rework in the field was reduced over 90%.  There were other pipe sealants that worked as well as Loctite, but were almost impossible to disassemble once the sealant cured.

Re: Possible problem

For plastic pipes you would want No More Leaks™ Plastic Pipe Thread Sealant.

Re: Possible problem

For threaded plastic pipes you would want No More Leaks™ Plastic Pipe Thread Sealant.

Re: Possible problem

I think the key there is “realignment.”  I’ve never had a problem with a taped and doped joint that has been further tightened, but I would never loosen one without taking it completely apart, cleaning it, and re-taping and re-doping it.

I can’t emphasize enough using both tape and dope (thread sealant, not putty, not thread locker).  I’ve definitely had issues in the past using one or the other.  I’ve not found brand to really matter, but there are some Teflon tape brands that are better than others.  The better ones don’t get as thin when you put some tension on them.

Jason

Re: Possible problem

The local water treatment people use Teflon only but it is the pink, thicker stuff not the white.

Bill