Welding a tank connector to aluminium

  1. James7519 New Member

    Messages:
    29
    Location:
    England
    Hi guys just joined up looking for some help.

    I’m completely new to welding I’m trying to build a aluminium tube radiator from scratch as a little hobby.

    Im going to use 50mm x 50mm square aluminium tube and I’d cap the ends with a piece of square aluminium and weld the edges to seal it shut.

    the tank connector would be inside the cap I weld on. I figure I can’t use a rubber grommet as the heat generated from welding the cap on would destroy the rubber grommet?

    Do you guys have any advice on how I can achieve this?

    my current plan would be to weld the tank connector directly to the aluminium cap but it is made of brass and I’ve read that there are issues with welding brass to aluminium?

    thanks for any input you guys have
     
  2. hotponyshoes Member

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    2,874
    Location:
    Somerset. Uk
    Can you not buy or make the connector in aluminium rather than brass and weld it on?
    The other option is use a thicker piece of aluminium for the end and tap a threaded hole to screw a connector into.
    Or, weld on one end, let it cool down, fit the plastic fitting with a long extension bar & socket then weld the other end on.

    You might want to think about using round tube rather than square if possible as it will cool better.
     
    Retired likes this.
  3. James7519 New Member

    Messages:
    29
    Location:
    England
    Update I’ve found out I can get an aluminium bung npt thread.
    prefer using square just for the designer flat panel look.

    I’ve recently just found out I can get an aluminium npt weld on bung.

    would these be easy to weld on?
    Thanks for your reply
     
  4. James7519 New Member

    Messages:
    29
    Location:
    England
    Also if I’m on the right track can anyone recommend the cheapest option for a mig welder + spool gun that I could do this with? I don’t need any expert level kit. Just want to achieve a solid water tight join

    thanks
     
  5. slim_boy_fat

    slim_boy_fat Forum Supporter

    Welcome aboard, James :waving: If you'll pardon my frankness, that seems a very ambitious project to start out with, but I'm sure some of our professional/accomplished welders will be along to give specific advice as to suitable kit [don't forget to budget for PPE (personal protection equipment...mask, gloves etc) and technique.

    Once all the bases have been covered, the mantra is usually 'practise, practise, practise', generally on scrap material of the type you're going to be using. Check out the forum tutorials [green buttons at the top of the page] for good starting info/advice. :thumbup:

    All the best.
     
    Last edited: Feb 14, 2020
    Yamhon and Retired like this.
  6. James7519 New Member

    Messages:
    29
    Location:
    England
    thanks for your response.

    I’m trying to build a custom cooling system that could potentially reduce cooling costs for my computer servers.

    only reason I’m thinking of welding is for this . I was hoping it wouldn’t be too difficult?

    what makes welding like this difficult? Is it just that it may look a mess? As luckily for this project the radiator will actually be out of sight so how it looks doesn’t matter too much
     
  7. You would be better TIG welding this
     
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  8. James7519 New Member

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    29
    Location:
    England
    Could you please explain why Baring in mind I’m a complete newbie I’ve only began researching the differences between tig and mig so far
     
    Retired likes this.
  9. Munkul

    Munkul Jack of many trades, Master of none

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    You'll struggle to get a watertight joint using a MIG spoolgun... that's if you don't blow the whole lot away. MIG on aluminium only really works properly at higher amperage.

    Assuming you're going for 2 or 3mm thick wall tube. This will weld best around 100amps TIG, depending on joint type.

    an AC TIG set is not cheap to start with, and you'll be a while learning the skills necessary to acheive it.

    Your heat transfer rate will be terrible if you're using 50x50 box for the actual cooling passages!

    Much better (and potentially cheaper!) buying a premade radiator
     
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  10. James7519 New Member

    Messages:
    29
    Location:
    England
    my plan is to mount the bars directly onto the heat source so the water is heated directly by conduction. The larger pipe is for larger water capacity To increase thermal capacity.

    if anyone on here has any other ideas on how I can water seal the ends so I can connect a water pipe to the ends I’m all ears
     
  11. James7519 New Member

    Messages:
    29
    Location:
    England
    A premade radiator in this sense is not ideal as the paint coating they use reduces thermal transfer via conduction
     
  12. Munkul

    Munkul Jack of many trades, Master of none

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    Oh I see, so you're actually wanting to make water blocks for components? Usually they have "torturous passages" to improve heat transfer.

    Paint coatings in well made radiators are negligible. You'll notice most aluminium radiators have a black coating - and it's a good thing, not a bad thing.
     
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  13. James7519 New Member

    Messages:
    29
    Location:
    England
    yeah black anodising would be fine but I’ve struggled to find flat panneled radiators that would be sufficient shape for me to mount the components too. So I figured it may be easier in the long run to make myself so it’s custom size and shape to fit my system
     
  14. Munkul

    Munkul Jack of many trades, Master of none

    Messages:
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    Location:
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    Sorry i meant to say, of course you're right about the thermal transfer from component to water block. Needs to be uncoated.

    Not really sure what you're trying to acheive here, could you sketch it up or take some pics?
     
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  15. James7519 New Member

    Messages:
    29
    Location:
    England
    got any ideas on how I may be able to achieve this?

    didn’t see your edit my drawing is terrible basically I just want to have a piece of box metal sealed so water can flow in one end via a piece of pipe and out the other side via a piece of pipe

    can’t take pics as I don’t have any of the aluminium box yet. Trying to come up with a feasible method of achieving what I want first before I commit to buying
     
  16. Munkul

    Munkul Jack of many trades, Master of none

    Messages:
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    Location:
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    How many bits do you need? if its just one, then a length of box, some 3mm flat for the ends, and a couple of threaded bungs is all you need... cut the ends to size, drill for the end bungs, and then take it to the nearest fabrication shop, ask them to TIG weld it up. Probably charge £20.

    heck, a member on here would probably do it for you for nix :)
     
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  17. James7519 New Member

    Messages:
    29
    Location:
    England
    If it works the way I want it would be 160 caps to weld together to get a big enough surface area for all my components
     
  18. James7519 New Member

    Messages:
    29
    Location:
    England
    Currently the electricity used for servers makes profit margins for cryptocurrency mining so slim. Cooling with AC costs a bomb. I think it’s stupid to pay for AC when that heat could be used.

    I want to custom build all my servers and directly mount all the components directly on the aluminium tube. I plan to then pump the water around my house radiator system and all the waste heat is then basically used and my heating bill goes down so much that my profit margins go up
     
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  19. Munkul

    Munkul Jack of many trades, Master of none

    Messages:
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    Location:
    Cumbria
    draw it up. Either as a 3rd angle projection, or for simplicity, as an isometric drawing. Then we can see what you mean.

    Laws of thermodynamics mean you're limited. If you're currently using refrigeration, then your water heatsinks aren't going to be effective. Air cooling effectively dumps the heat into the room already...
     
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  20. James7519 New Member

    Messages:
    29
    Location:
    England
    The aim would be to no longer use refrigeration and rely entirely on cooling via water. A small water chiller will be used to compensate for air cooling if the room air warms up too much but conduction is a lot more efficient than convection so the water should heat up a lot more efficiently than the air is my hope.
     
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