Securing fittings?

[SkiFletch]

hey guys, i'm just wondering what you guys use to secure your fittings, especially if you end up needing to switch npt fittings at radiators or pumps? do you guys advise using marine goop, or perhaps teflon tape, or perhaps both? also, what care needs to be taken mating different materials like plastic, brass, or alluminum? your expertise is appreciated

[---X---]

Marine goops works, though personally for fittings I knew to be permanent I used this epoxy putty stuff I got a home depot...as for joining two surfaces usually I just wipe with isopropyl alcohol and dry, but I havent done much with this type of stuff so there's probably a better way...

[SkiFletch]

oh, i didnt mean about joining surfaces, I meant are there problems using say a male brass npt in a female plastic npt? or switch the materials with alluminum, or something else? are there some npt material combos that suck?

[Bender]

You will have no problems if you use a little teflon tape. For actually securing things together I like JB Weld. Its very strong and waterproof unlike most epoxies.

[Inept]

I have a 3/8" NPT-18 tap that I use for securing my 1/2" fittings (don't be thrown off by the 3/8" NPT business... the NPT measures are all weird and I have no idea why they're like that).

I thread a 9/16" hole with the tap, then I clean it out and apply a gasketing compound to both sets of threads and hand tighten my fittings. Works 100% of the time, and makes reliable joints in almost all matierals including lexan, copper, aluminum, etc...

[SkiFletch]

anybody else?

[DodgeViper]

Personally I perfer using plastic to plastic, but no problem as what bender told you though. You can use brass to plastic without any problems. As far as at the raditaor I would solder the barb fittings. Check out my article on how I did mine. The article is on the fan/shoud construction guide.

CLICK (http://www.phlux.co.uk/articles.php?aid=7&page=1)

[SkiFletch]

well, I will be getting a radiator that has npt thread on it, but the soldering idea is good anyways, always nice to have that extra bit of safety. now for my pump (plastic) If I use brass barbs, I should use teflon tape and JB weld?

[Inept]

I find that teflon tape doesn't really work at all, except in a few unusual situations. In general you're way better off with an epoxy, like JB Weld or a specialized gasket compound or thread sealer like LocTite.

Since your pump more than likely has NPT threads, they lock up pretty tight on their own, but I still suggest using the non permanent version of LocTite to ensure that there's no leaks from the threads. You could try the teflon tape too, I suspect this is one of the places where it will work well. Don't use multiple sealing methods though, like don't put the teflon tape and the epoxy.

[DKYoda]

On my via 1300 .. I used brass barbs ..
Coated the threads with RTV and screwed it in by hand ...
Works well ..

[SkiFletch]

thanks yoda. so I got some marine goop, hows it sound if I just coat both surfaces, dry, and screw it in?

[DKYoda]

Never messed with Marine Goop ... But it sounds like its really good stuff from what I read on these forums ..