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Air Hoses safe to use at high pressure?

Posted: Sat Dec 22, 2012 3:27 am
by Binary Blue
Are air hoses like this:

http://www.harborfreight.com/1-4-quarte ... 97447.html

safe to use at high pressures? I know they say 200PSI max pressure, but from what I've gathered form this forum, those numbers reflect a considerable safety margin.

I'm talking abut between 100-300 PSI.

Also, would Ace Hardware or Harbor Freight sell shorter lengths of air hose? I only need a few inches, not 25 feet.

I've heard form other forums that they do, but those lengths are not listed on the Harbor Freight website and the Ace website lists nothing like that. For that matter other people have posted that Ace lets you cut and crimp your own lengths of hose.

Posted: Sat Dec 22, 2012 4:50 am
by mattyzip77
I think you have to buy it by the foot so buy a foot and have a spare piece... :roll:

Posted: Sat Dec 22, 2012 7:17 am
by Zeus
Look in the plumbing section for lengths of steel braid hose with fittings on both ends, it starts from 4" and goes up to 2'.

Posted: Sat Dec 22, 2012 11:23 am
by Fnord
First off, look for what Zeus suggested.

If you're using it to connect a pilot valve, buy a high-pressure rated length and do not exceed the rating. Hoses are not very dangerous when they burst, but you'll cause the gun to fire if it dumps the pilot volume when bursting. In many cases, metal tubing is preferable for pilot lines.

If it's a 'normal' air line where the dangers are minimal, a possible DIY solution would be to buy the best hose you can find, then wrap it in a layer of wire and apply heat-shrink tubing over that.

Posted: Sat Dec 22, 2012 1:29 pm
by D_Hall
High pressure rated lines are not expensive... Even when built to custom lengths. Why in the world don't you (OP) just guy buy the right part for the job?

Posted: Sat Dec 22, 2012 4:24 pm
by Binary Blue
Thanks for all the help guys!

D_Hall wrote:High pressure rated lines are not expensive... Even when built to custom lengths. Why in the world don't you (OP) just guy buy the right part for the job?

I wasn't planning to use the hose in the pilot area. I was planning on using it as a way of connecting the exhaust end of the QEV to the barrel, or just about anywhere other than the pilot end.
Brigadier General wrote: Look in the plumbing section for lengths of steel braid hose with fittings on both ends, it starts from 4" and goes up to 2'.
Do they have NPT threads on the end?

Posted: Sat Dec 22, 2012 5:16 pm
by POLAND_SPUD
Just to remind you - try push to connect fittings and tubing >
Image
Image
Awesome stuff!!

The only problem is that most of them are rated @10bar, though there is both tubing & fittings rated to 50bar

Posted: Sat Dec 22, 2012 6:38 pm
by D_Hall
Binary Blue wrote:I wasn't planning to use the hose in the pilot area. I was planning on using it as a way of connecting the exhaust end of the QEV to the barrel, or just about anywhere other than the pilot end.
So? Again, high pressure hose assemblies aren't that darned expensive. Just buy the right part for the job!
Do they have NPT threads on the end?
And they can be purchased with any fitting you want.

Posted: Sat Dec 22, 2012 10:04 pm
by Binary Blue
D_Hall wrote:
Binary Blue wrote:I wasn't planning to use the hose in the pilot area. I was planning on using it as a way of connecting the exhaust end of the QEV to the barrel, or just about anywhere other than the pilot end.
So? Again, high pressure hose assemblies aren't that darned expensive. Just buy the right part for the job!
Do they have NPT threads on the end?
And they can be purchased with any fitting you want.
I'll keep that in mind.


Just a quick update to the thread:

I went to Home Depot today and looked for short hose lengths. They only sell long lengths (10-25 ft usually).

Posted: Sat Dec 22, 2012 10:20 pm
by PaperNinja
cut the hose...

Posted: Sat Dec 22, 2012 10:48 pm
by Binary Blue
PaperNinja wrote:cut the hose...
But how do you attach the fitting to the cut end?

Sorry for all these noob questions.

Posted: Sun Dec 23, 2012 7:11 am
by jrrdw
The ends have hose barbs on them. Cut the crimp off and what ever hose is in the crimp then use a screw clamp to hold it in the new length of hose you made. It's about one of the easiest things there is to do...

Posted: Sun Dec 23, 2012 1:04 pm
by Technician1002
Refrigeration service gauge hoses are rated for typical pressure you would find servicing an air conditioner.

They even come with proper crimped connectors so you don't have to use DYI hose clamps that are not built to hold the high pressure.
Image

Typical high side gauge is 0-800 PSI and the low side gauge is 0-300 PSI.

Posted: Sun Dec 23, 2012 2:41 pm
by c11man
what type of threads/connectors do those HVAC hoses have on them?

Posted: Sun Dec 23, 2012 7:32 pm
by Technician1002
AC hoses fit a flair fitting. Not sure of the size. The service fitting they fit have a standard tire valve core in it, but the stem is larger diameter so a standard air chuck won't fit it.