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nbachert

Well Known Member
Patron
I hung my engine today and I'm continuing on but I'm not sure if I put permatex 2 on the oil hoses themselves. I did on the fittings I installed on the engines but the directions don't say anything about the hoses other than you'll need to loosen the pressure hose during the initial start to bleed the air out. That leads me to believe the answer is no because I would break the gasket made by it. Also, with the fuel lines should I put fuel lube on them? Any help is appreciated, thanks,

Nick
 
Mel said:
Do not use sealant on flare fittings. Flare or threads.
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Mel,
I have heard both sides of using sealant on flare fittings - both from people I trust. With your experience in airplane construction, I would like to know why you say to not use sealant. Is it bad or just not needed? I have one friend who does medical gas and hydraulic plumbing and does not use sealant and one that builds race cars for the Ferrari circuit who does.

Is it just not needed or can it cause problems if used? Thanks
 
rockwoodrv9 said:
Mel,
I have heard both sides of using sealant on flare fittings - both from people I trust. With your experience in airplane construction, I would like to know why you say to not use sealant. Is it bad or just not needed? I have one friend who does medical gas and hydraulic plumbing and does not use sealant and one that builds race cars for the Ferrari circuit who does.
Is it just not needed or can it cause problems if used? Thanks
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It is not needed and can cause problems. A few people will use just a tiny drop of blue loctite on flare fittings. I have done this without problems but it should not be necessary.
 
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Mel is correct, the flare seals against the fitting to create the seal, any sealant used on the flare will likely find its way into the the fuel/oil system. Fuel lube for example (and many other sealants) will not desolve in fuel/oil so it has the potential tp clog filters, injectors etc..

If your flares leak without sealant then you have problems with your flaring process.
 
Where is that "Tite Seal" you recommend used then? I used it on my brake line hose and, at the very least, didn't cause problems. :confused:
 
tkatc said:
Where is that "Tite Seal" you recommend used then? I used it on my brake line hose and, at the very least, didn't cause problems. :confused:
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Sealants such as tite-seal are used on pipe threads and gaskets.
 
Don't use anything on flare fittings. The contact surfaces are designed to seal naked, I've used them on high pressure air up to 15,000 psi for quite a few years with no issues.
 
Sealant only on tapered threads, like NPT threads on AN fittings. Nothing on the flare side.
You would be surprised (maybe not) on what we've seen!
Tom
 
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