High Pres Line Splice

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marininn
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Joined: Wed Jun 12, 2019 7:50 am

High Pres Line Splice

Post by marininn »

I have aluminum line on the high pressure side and need to attach two tubes together. Can I use the flare fitting parts, which are brass, to connect two aluminum pipes to make one? I use these on copper tubing all the time for propane, but propane is typically very low pressure after the regulator, AC system is much higher so that is my concern. Will the flare fitting be sufficient?
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Cusser
Posts: 595
Joined: Sun Apr 24, 2016 6:29 am

Re: High Pres Line Splice

Post by Cusser »

marininn wrote:I have aluminum line on the high pressure side and need to attach two tubes together. Can I use the flare fitting parts, which are brass, to connect two aluminum pipes to make one? I use these on copper tubing all the time for propane, but propane is typically very low pressure after the regulator, AC system is much higher so that is my concern. Will the flare fitting be sufficient?
I worked in a laboratory over 40 years, and we spliced and connected lines of hydrogen (flammable/explosive) and helium, the smallest molecules. So we used only SwageLok fittings.

I would guess that your aluminum line would be metric, so a metric compression union. https://www.hoseandfittingsetc.com/prod ... arker-0106

If you or someone can flare tubing, that may be a different story.
Dougflas
Posts: 358
Joined: Mon Apr 18, 2016 6:10 pm

Re: High Pres Line Splice

Post by Dougflas »

If memory is correct, the older fittings were flare type but double flared.
marininn
Posts: 9
Joined: Wed Jun 12, 2019 7:50 am

Re: High Pres Line Splice

Post by marininn »

It's not the type of gas, but the pressure that matters. A compression is not as strong as a flare fitting for everything I have ever seen.
I can only do a flare, which is never going to pull apart, I am just asking about holding the pressure.
Auto sells https://shop.advanceautoparts.com/web/S ... d=IR-13696 but will have to be special ordered in, and it is hot and is for old lady's car who rather not wait so long and have to drive uncooled...
It is 3/8th of an inch line, if not exactly, then close enough for a flare to work.
tbirdtbird
Posts: 37
Joined: Sat May 02, 2020 1:48 pm

Re: High Pres Line Splice

Post by tbirdtbird »

You are correct, compression fittings are nearly useless.
Flare fittings are used on copper tubing in residential and commercial HVAC all the time.

Have refitted copper on a commercial freezer box (-40°) using flare, as was the original. Use Nylog on the flare, and be sure they are tight.

However, cannot speak to flareing aluminum tube. Double flare would not be a bad idea so as to strengthen the edge and keep it from splitting
marininn
Posts: 9
Joined: Wed Jun 12, 2019 7:50 am

Re: High Pres Line Splice

Post by marininn »

Thanks for sharing Nylog. I had never heard of it.

https://www.youtube.com/watch?v=vAULfI8-Wwk

I will get some. The vid also shows copper flares used, so if I can flare the aluminum then it should be just as good.
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