Seal the thread

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
Tobin
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Thu Apr 14, 2011 3:16 pm

Im building a +30 bar pneumatic and im thinking about how to seal th threads. I decided to use epoxy to seal the threads so its not really a problem for me. But anyway im just wondering if thread tape works god at this high preassures. Anyone that use it?
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saefroch
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Thu Apr 14, 2011 3:19 pm

PTFE thread seal tape is good at all pressures, if applied correctly.
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jrrdw
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Thu Apr 14, 2011 4:05 pm

saefroch wrote:PTFE thread seal tape is good at all pressures, if applied correctly.
Yup. If you use epoxy you wont be able to get the threaded parts unscrewed again.
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jhalek90
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Thu Apr 14, 2011 4:23 pm

jrrdw wrote: Yup. If you use epoxy you wont be able to get the threaded parts unscrewed again.
if the parts are metal, simply heat with a propane torch and voila! no more epoxy. (sorry to make you cringe jack)
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SpudFarm
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Thu Apr 14, 2011 5:24 pm

For extreme pressure applications I think copper seals are best, have to tighten the threads really good though.

Nothing stopping you from unscrewing or adding friction to the thread witch can be extremely frustrating when you have a bug and have to take it apart often.
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seeyouinhell2mf
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Thu Apr 14, 2011 5:27 pm

non-hardening thread sealing goo?
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SpudFarm
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Thu Apr 14, 2011 5:28 pm

seeyouinhell2mf wrote:non-hardening thread sealing goo?
I don't know about that in high pressure situations..
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seeyouinhell2mf
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Thu Apr 14, 2011 5:34 pm

well seeing as I have very little knowledge in spud cannon terms I don't really know what pressures we are talking about give me an idea in terms of PSI
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Thu Apr 14, 2011 6:41 pm

Thread sealant goop (pipe dope) was used on the hybrid chamber I tested to 11x. I took it to pneumatic pressures of 900 psi while still wet, so yes, it works well.

(Use BAR multiplied by ~15 for psi, 2mf)
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seeyouinhell2mf
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Thu Apr 14, 2011 6:59 pm

ok thanks, I was curious what BAR was,also, I would say when making a cannon never make things permanent until you get to a state in which you know no more work will e needed to be done to it aside from routine maintenance
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jackssmirkingrevenge
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Fri Apr 15, 2011 2:27 am

jhalek90 wrote:if the parts are metal, simply heat with a propane torch and voila! no more epoxy. (sorry to make you cringe jack)
I use Araldite for semi-permanent threaded connections, airtight but with a bit of effort they will come apart when forced.
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Tobin
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Fri Apr 15, 2011 3:08 am

The problem is that i want all parts lined up thats so i , thats why a want to use epoxy so they cant twist if i arent allowed to screw the parts and tight them to the bottom. Of course i wont glue anything until everything works at 100% That would been stupid. So i shall use thread tape untill then.

Will check out araldite
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Crna Legija
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Fri Apr 15, 2011 3:32 am

lock tight black is what i use. no need to wait 24hr for it to cure its only like 10min.
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Zeus
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Fri Apr 15, 2011 4:37 am

Presuming you don't have excessively long pipes held up only by the threads, PTFE tape will do just fine.

Remember, you can never use too much PTFE tape. Your problem might be doing them up tight enough if you aren't the all beef type. Leverage is your friend in such a circumstance.
/sarcasm, /hyperbole
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