Thread sealant for all our fitting connection
What will be the best to use ???
I used the white Teflon tape but it doesn’t do a good job.
So what would you suggest for normal operation at room temperature and also what to use for high temperature fitting in oven(approx 400F)
Thanks
We just use the white Teflon tape and that works for us both in and out of the autoclave. We have used hydraulic sealant from Loctite but it makes disassembly nearly imposable when the lines get filled with resin.
I agree that the white Teflon tape should work just fine. You can always back it up by covering the connection with sealant tape.
Just for asking when you put the tape on the thread how many time you go around?
I went to the hardware shop to look for a sealant and the guy overthere told me to go approx 10 time around .
^LOLOL 10x Two wraps (clockwise -> direction of thread) is all you need.
10 x two wraps. You mean. 20 time ?
No, sorry - bad post on my part… I was enjoying the 10x wrap suggestion given to you by the hardware store. Thread sealant tape works by jamming or wedging itself into the thread grooves after being CUT by threads during tightening. Wrapping it 10x will not allow the threaded pieces to seat properly. Two layers of tape will do the job. Just make sure it’s wrapped in the same direction as the threads. (i.e. when you screw the connection together it will not try to unwrap the tape but will rather “tighten” it onto the threads - if that makes any sense at all) Try it both ways, you’ll see what I mean. 
Thank you for the fast answer
I did it with about 2 to 3 times around but it was not so good
But I think I have to do it again with more precision
I will try again and let you know. Thanks
They also make some other types of sealant tape in the same section where you probably bought your white teflon tape. I just was recommended I think the pink one, but they make a yellow one as well I think for gas applications and such.
Also forgot to mention that the tape should NOT extend to the very tip of the male connection. Leave 1 to 2 threads clean (with no tape applied). I learned that one in aircraft school; the idea being that a piece of tape could break loose and end up causing havoc downstream. And finally, if you cannot get a good seal with a different tape (as suggested) then the fittings may simply need to be replaced and they might have already been sprung and simply won’t connect well any longer. Don’t over-tighten either.
For tapered threads:
3 times
For parallel threads:
up to 1/4: 5 times
up to 3/4: 7 times
up to 2": 10 times
Not from a book, just from experience.