# New and improved DIY sidearm



## kabbott (Oct 29, 2008)

This is my first thread and first pics so I hope they look OK.
This sidearm works very well so I thought I would Share.

It is made from 3/4" and 1 1/2" L copper with 3" long sections of 1/2 copper welded to the 3/4 center pipe for more surface area.
I split the 1/2" pipe in half with a band saw and welded about 1" on each end.
The ends are made of flat copper washers that I cut out of a 3" scrap pipe with a hole saw. Then flattened and drilled the 7/8 hole in them with a step bit.
Only fittings are 3/4" female adapters on each end.
Whole mess pasted together with Silfos and a TIG torch but you could also use a acetylene torch.


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## Nofossil (Oct 29, 2008)

Nice! I've never tried welding copper - guess I'll have to see if I can add that to my bag of tricks.


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## deerefanatic (Oct 29, 2008)

Its basically copper brazing....... Brazing with copper rod....... You could also brass braze it if you were unsure of yourself and didn't want to completely melt the pipes...


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## steam man (Oct 29, 2008)

I've tried brazing copper fittings while doing my solar system to get some higher temp protection for the evacuated tubes-(over 850 deg-typically 1000-1100 or so), can weaken the pipe so it may not hold at pressure. There wasn't anything definitive about how much it does weaken the copper. I don't see typical boiler pressures and temps needing brazing. Nice job though.

Mike


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## deerefanatic (Oct 29, 2008)

I can't imagine that brazing weakens the copper.... That's what A/C systems are all done as......... Copper brazed (or welded if you will) in order to hold the extreme heat/pressure that refrigeration equipment experiences.....


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## kabbott (Oct 29, 2008)

Yeah technically its brazed, but you can weld it with copper filler, Its very easy to weld.I just didn't have any deoxidized copper filler on hand.


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## DaveBP (Oct 29, 2008)

The tricky part of welded/brazed copper (or brass for that matter) is that the welds are hardened and therefore brittle if they cool slowly. It used to be an accepted method for attaching ground conductors to ground rods for electrical systems but the welds are prone to breaking if they get flexed a few times. Copper welds are prone to cracking from fatigue if they vibrate a lot (like from an air compressor).
It might be prudent to mount the sidearm assembly to minimize vibration and possible flexing at the welds from thermal expansion and contraction. Rubber pipe insulation sleeves inside oversized pipehangers or something like that.
Nice looking work. Clever fins on the exchanger tube.


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## BrownianHeatingTech (Oct 29, 2008)

deerefanatic said:
			
		

> I can't imagine that brazing weakens the copper.... That's what A/C systems are all done as......... Copper brazed (or welded if you will) in order to hold the extreme heat/pressure that refrigeration equipment experiences.....



No, it does weaken the copper.

We have to account for that when selecting tube to use.

Stronger joint, but weaker pipe.  It's a balancing act.

Joe


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## chiefburritt (Oct 29, 2008)

Sorry a steam guy here!!  What is the sidearm for?  Looks like nice work..


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## steam man (Oct 29, 2008)

BrownianHeatingTech said:
			
		

> deerefanatic said:
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I see copper brazing done all the time on AC systems. I wanted to try brazing copper tube (I've brazed everything else). researching it  I found that "When brazing copper tube, however, the annealing of the tube and fitting that results from the higher heat can cause the rated pressure of the system to be less than that of a soldered joint". This is from  http://www.thefabricator.com/RepairFieldWelding/RepairFieldWelding_Article.cfm?ID=1569.

However, I have seen this in a number of places. The depth of insertion of fittings, thickness of tubing come into play.

Mike


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## BrownianHeatingTech (Oct 29, 2008)

Dry steam said:
			
		

> Sorry a steam guy here!!  What is the sidearm for?  Looks like nice work..



It's a concentric heat exchanger.  Run heating fluid (typically water, but steam could actually be used) through one side, and convection will draw water from the bottom of the storage tank into the bottom of the sidearm, heat it, and discharge it back into the storage tank at the top.

Joe


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## JustWood (Oct 29, 2008)

Nice !  I love it when you can take a few bucks worth of parts and DIY.  Then tell Sam Sidearm Co. to keep his sidearm.


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## chiefburritt (Oct 29, 2008)

BrownianHeatingTech said:
			
		

> Dry steam said:
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Thanks for the answer now I understand..  I was beginning to wonder where you put the gunpowder and bullet..


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## btuser (Oct 30, 2009)

Ya know, this is the kinda stuff that brings a tear to my eye.

Got any numbers?  GPM at a rated temp?


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## Gooserider (Oct 31, 2009)

BrownianHeatingTech said:
			
		

> Dry steam said:
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I'm sure it also gets the Homeland inSecurity and BATFE BBQ types all excited as well - I mean theres this website with all these people (many of them "backwoods" types) talking about making their own sidearms, and doing all sorts of other stuff with them, including firing them.... :coolsmirk: 

Gooserider


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## kabbott (Oct 31, 2009)

Gooserider said:
			
		

> BrownianHeatingTech said:
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Hmmmmmmmm never thought about that, guess i'm on a shortlist somewhere.
Headline...ATF questions kabbott about "coaxial sidearm", military interested too. :ahhh:


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## kabbott (Oct 31, 2009)

btuser said:
			
		

> Ya know, this is the kinda stuff that brings a tear to my eye.
> 
> Got any numbers? GPM at a rated temp?



Numbers? Only number i have is it keeps up with family of 4.
Actually I will soon have some sensors on the inlets/outlets so I may be able to make a guess. When I get some data I will post it.


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## rowerwet (Nov 5, 2009)

I think what you did is cool, but why go to all that work when regular fittings and solder are faster and easier? I made my own in a few hours that way.


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## kabbott (Nov 5, 2009)

rowerwet said:
			
		

> I think what you did is cool, but why go to all that work when regular fittings and solder are faster and easier? I made my own in a few hours that way.



Because I could...  

No the reason was manly because I had also been working on a hydraulic separator built the same way. It really was as much of an experiment as anything
and the pieces of 1/2 pipe slit in half would be MUCH SLOWER to solder on(don't have to clean and flux sil-fos) The Brazing Prolly only took 25-30 mins after 
all the pieces were cut. I can roll pretty good with my Heliarc. Took as long to slit the short pieces as everything else combined. I would wager that minus 
slitting the 1/2 I could do this way as fast/faster than fitting/cleaning/fluxing/soldering on fittings.

Dads a retired plumber and I raided the fitting and scrap pile = free...that might of had something to do with it to. :coolgrin:


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