Assembling my HI booster kit

cramerdn · 25th September 2007, 04:13

So I have my whips and an HI booster and lots of adapters. Time to get it all assembled into a working booster.

Heres my question.

A bunch of the fittings are 1/4" NPT or NPTF standard. Is there a standard tourque for these fittings or a standard number of threads I should screw them into each other?

I am especially concerned about drive gas hole in the booster. I certainly don't want to screw up the threads on the unit.

Jimmer · 25th September 2007, 04:49

NPT threads are very much a "feel" sort of thing. You can't really go by torque or threads, because the depth of cut of the tap, the quality of the thread on the male end, or even the amount of teflon tape or pipe sealant will change how tightly the threads engage. A general rule in my experience with taper threads, is "snug, plus an 1/8th". Rather vague lol. One way to go about it would be to tighten it and put some O2 or O2 safe air into the system and check for leaks. If there is a leak, tighten that joint a little more. That's the thing with tapered threads for high pressure, a little bit more tension on the thread and the joint is sealed tighter.

I hope that helps,
Jim

diverrob · 25th September 2007, 05:09

I just finished putting my system together and as was stated in the previous post the NPT threads should be tightened by feel (you really have to come on to them to do any harm). As for the other fittings they are "O" ring sealed and you don't need too much torque to seal them, just enough to ensure they don't back off with use. The only NPT thread is the drive gas and it is only LP gas (150psi max) so getting it to seal won't be a problem. Have fun with your new toy

Rob

cramerdn · 25th September 2007, 06:03

Quote: (Originally Posted by diverrob)

I just finished putting my system together and as was stated in the previous post the NPT threads should be tightened by feel (you really have to come on to them to do any harm). As for the other fittings they are "O" ring sealed and you don't need too much torque to seal them, just enough to ensure they don't back off with use. The only NPT thread is the drive gas and it is only LP gas (150psi max) so getting it to seal won't be a problem. Have fun with your new toy

Rob

I have adapters for the supply gas and out-put ports. I am using 9/16" x 18 1/4" NPT male to male adapter, then a 90 degree male/female elbow 1/4" NPTF, then a 1/4" NPT to quick disconnect.

I wanted the elbows in there so that the whip hoses did'nt come out sideways but rather toward the end of the booster. That way it can stay in the pelican case when in use.

robinfante · 25th September 2007, 14:46

Quote:

I wanted the elbows in there so that the whip hoses did'nt come out sideways but rather toward the end of the booster. That way it can stay in the pelican case when in use.

Which is exactly what I did, and for exactly the same reason. Works a charm. Then I went and put a handle attachment on, thereby making it too large for said case...D'OH!

I'm trying to think of any advice to give to make it easier, but I'm coming up blank. Now that HII has resolved the design issues (granted, much heartache in those 8 words) its pretty much plug and play.

**kevin stone** · 25th September 2007, 18:57

Hi Rob
got any pics????????????
thanks
Kevin

25th September 2007, 04:13	#1 (permalink)
cramerdn Obey my dog! Current Rebreather/s: Evolution Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2006 Location: Townsville QLD Posts: 626	Assembling my HI booster kit So I have my whips and an HI booster and lots of adapters. Time to get it all assembled into a working booster. Heres my question. A bunch of the fittings are 1/4" NPT or NPTF standard. Is there a standard tourque for these fittings or a standard number of threads I should screw them into each other? I am especially concerned about drive gas hole in the booster. I certainly don't want to screw up the threads on the unit. __________________ "Its better to live one day as a tiger than an entire life as a worm." "But who's ever heard of a worm skin rug?"
(Online)

25th September 2007, 04:49	#2 (permalink)
Jimmer New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Dec 2006 Location: Ontario, Canada Posts: 72	Re: Assembling my HI booster kit NPT threads are very much a "feel" sort of thing. You can't really go by torque or threads, because the depth of cut of the tap, the quality of the thread on the male end, or even the amount of teflon tape or pipe sealant will change how tightly the threads engage. A general rule in my experience with taper threads, is "snug, plus an 1/8th". Rather vague lol. One way to go about it would be to tighten it and put some O2 or O2 safe air into the system and check for leaks. If there is a leak, tighten that joint a little more. That's the thing with tapered threads for high pressure, a little bit more tension on the thread and the joint is sealed tighter. I hope that helps, Jim
(Offline)

25th September 2007, 05:09	#3 (permalink)
diverrob The Evolution of Diving Current Rebreather/s: Evolution Other SCR Other Rebreather/s: Not Bought Yet Other SCR Join Date: May 2005 Location: Victoria BC Canada Posts: 336	Re: Assembling my HI booster kit I just finished putting my system together and as was stated in the previous post the NPT threads should be tightened by feel (you really have to come on to them to do any harm). As for the other fittings they are "O" ring sealed and you don't need too much torque to seal them, just enough to ensure they don't back off with use. The only NPT thread is the drive gas and it is only LP gas (150psi max) so getting it to seal won't be a problem. Have fun with your new toy Rob
(Offline)

25th September 2007, 06:03	#4 (permalink)
cramerdn Obey my dog! Current Rebreather/s: Evolution Dolphin Other Rebreather/s: Dolphin Join Date: Dec 2006 Location: Townsville QLD Posts: 626	Re: Assembling my HI booster kit Quote: (Originally Posted by diverrob) I just finished putting my system together and as was stated in the previous post the NPT threads should be tightened by feel (you really have to come on to them to do any harm). As for the other fittings they are "O" ring sealed and you don't need too much torque to seal them, just enough to ensure they don't back off with use. The only NPT thread is the drive gas and it is only LP gas (150psi max) so getting it to seal won't be a problem. Have fun with your new toy Rob I have adapters for the supply gas and out-put ports. I am using 9/16" x 18 1/4" NPT male to male adapter, then a 90 degree male/female elbow 1/4" NPTF, then a 1/4" NPT to quick disconnect. I wanted the elbows in there so that the whip hoses did'nt come out sideways but rather toward the end of the booster. That way it can stay in the pelican case when in use. __________________ "Its better to live one day as a tiger than an entire life as a worm." "But who's ever heard of a worm skin rug?"
(Online)

25th September 2007, 14:46	#5 (permalink)
robinfante I have a smoking gun Current Rebreather/s: Megalodon Prism Topaz MK 15.X Other Rebreather/s: Sport Kiss Join Date: Nov 2005 Location: mountain lakes nj Posts: 148	Re: Assembling my HI booster kit Quote: I wanted the elbows in there so that the whip hoses did'nt come out sideways but rather toward the end of the booster. That way it can stay in the pelican case when in use. Which is exactly what I did, and for exactly the same reason. Works a charm. Then I went and put a handle attachment on, thereby making it too large for said case...D'OH! I'm trying to think of any advice to give to make it easier, but I'm coming up blank. Now that HII has resolved the design issues (granted, much heartache in those 8 words) its pretty much plug and play. __________________ Homer to Bart: “When a woman says nothing’s wrong, everything is wrong. And when a woman says everything’s wrong, EVERYTHING is wrong. And when a woman says something’s not funny, you better not laugh your ass off!” Check out www.robinfante.blogspot.com for trip reports and pics.
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25th September 2007, 18:57	#6 (permalink)
kevin stone Supporting Member Current Rebreather/s: Sport Kiss Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: us ct. Posts: 212	Re: Assembling my HI booster kit Hi Rob got any pics???????????? thanks Kevin
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