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New and improved DIY sidearm

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by kabbott, Oct 29, 2008.

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  1. kabbott

    kabbott Member

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    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.

    Attached Files:

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  2. Nofossil

    Nofossil Moderator Emeritus

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

    deerefanatic Minister of Fire

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    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...
  4. steam man

    steam man Minister of Fire

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    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
  5. deerefanatic

    deerefanatic Minister of Fire

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    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.....
  6. kabbott

    kabbott Member

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    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.
  7. DaveBP

    DaveBP Minister of Fire

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    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.
  8. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    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
  9. chiefburritt

    chiefburritt New Member

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

    steam man Minister of Fire

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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
  11. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    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
  12. JustWood

    JustWood Minister of Fire

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    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. :p
  13. chiefburritt

    chiefburritt New Member

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    Thanks for the answer now I understand.. I was beginning to wonder where you put the gunpowder and bullet..
  14. btuser

    btuser Minister of Fire

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

    Got any numbers? GPM at a rated temp?
  15. Gooserider

    Gooserider Mod Emeritus

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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
  16. kabbott

    kabbott Member

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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:
  17. kabbott

    kabbott Member

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    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.
  18. rowerwet

    rowerwet Minister of Fire

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    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.
  19. kabbott

    kabbott Member

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    Because I could... :p

    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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