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Cooling Looking for an elbow barb with a curve instead of 90º bend

Discussion in 'Hardware' started by severedhead, 7 Sep 2007.

  1. severedhead

    severedhead What's a Dremel?

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    OK... I'm looking for an elbow barb for the top of my Eheim 1250 but instead of having the usual, restrictive 90º corner to it I want one with a curve to help my already restrictive looking loop.

    Anyone know if such a thing is available with the relevant fitting (can't remember the thread size off the top of my head) at the pump end and a 1/2" barb at the other?
     
  2. naokaji

    naokaji whatever

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    i've seen some with 45 instead of a 90 bend...

    but, never seen one with a curve.. you might try different types of tubing though, as some suck (kink easily) and some rock (almost impossible to kink).
     
  3. severedhead

    severedhead What's a Dremel?

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    Having re-arranged my case a bit, Its going to be a sharp bend so will need a fitting of some sort instead of bending the tubing. My Tygon doesn't seem to like the angle very much.

    I might borrow a pipe-bender and fabricate my own, but would prefer to buy one so it doesn't randomly spring a leak.
     
  4. Krikkit

    Krikkit All glory to the hypnotoad! Super Moderator

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    I don't think I've seen one with a gradual bend, you're probably stuck with a sharper right-angle or tubing tbh. :(
     
  5. johnnyboy700

    johnnyboy700 Minimodder

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    I work in a Laser Physics lab and regulary fit water cooling alongside high voltage components (30KV+) and I've never seen a curved fitting, they are either straight or right angle. You do get Y shaped fittings but they're really meant for splitting one line into two. It is possible to get low profile right angle fittings, they might do the job instead of a curve.

    If you really need to have a curve then I reckon you have two choices, you can either try to bend a straight fitting to match the curve that you need or you can put a straight fitting on and very carefully bend some tubing to suit - however you do need to be careful with either option.
    If you go for the bending of the fitting it will depend on what its made from (I will assume you are using plastic fittings) as some materials that they use are made from what is known as a Thermosetting plastic which means in will burn before it melts so you can't bend it. Some plastics you can bend in very hot water, once you get the shape you want dip it immediately in cold water to set the shape but other types will need to be heated to a higher temperature than boiling water - try a high powered hairdrier but be careful not to burn the plastic or your fingers. If you are going to heat the plastic you should also watch that you don't kink the material when you bend it and most important of all is that some plastics will give off toxic or carcinogenic (cancer causing) gasses when heated to high temperatures. I think it goes without saying that you should not inhale the fumes and make sure you are in a well ventilated room or outdoors if possible.
    If you go for the tubing option you can buy extra flexible tubing which is made from a more plyable material but you have to be wary of the tubing kinking at the apex of the curve which will cause at least a flow restriction if not a complete blockage.

    I have had some situations where it simply isn't possible to buy a fitting that does the job required, at that point I'm forced to custom make what I need. If you are reeeeally stuck for what you need and simply cannot get what you want - I'll go out on a limb here and offer to make one for you and I'll do it for the cost of the postage only. We can discuss this later if you wish.
     
  6. severedhead

    severedhead What's a Dremel?

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    Thanks for the info johnnyboy700, it surprises me that there are no curved fittings out there.

    How much is flow-rate likely to be affected by having a 90º angle on the output of my pump? I may just go for the 90º fitting if its not too bad to save you messing about. But if the impact on flow rate is high, I may call upon your services - for which I am very grateful of the offer :thumb:
     
  7. johnnyboy700

    johnnyboy700 Minimodder

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    Provided you don't have a fitting that with a small internal diameter you should be fine, the bigger the diameter the less restrictive the flow. If you have a 1/2" barb as you mention above, I would say that you won't have a problem at all.
    One question I do have is that if you have 1/2" on one end, what size is the other end? If its the same size or even a bit smaller then its not a problem, a small diameter feeding into a large diameter will actually increase your flow slightly but a large diameter feeding to a small diameter will restrict the flow (basic fluid dynamics and kind of obvious when you think about it).
    I've made some cooling blocks in the past with a lot of right angle turns but because the channels were wide enough it didn't have any significant effect on the flow. It might surprise you at just how tight the turns are inside your cooling blocks that you have. I was looking at a website recently that had a photo of a water block with the lid off and they were a lot tighter than any I had made, I'll paste in the link if I can remember which one it was.
     
  8. severedhead

    severedhead What's a Dremel?

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    The pump uses a 3/8" BSPT thread on its outlet, the barb itself is 1/8" OD. I'll check when I get back from work, but I think they are about the same size internally.
     
  9. harvy

    harvy Minimodder

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    how about using 2 45 degrees?
     
  10. severedhead

    severedhead What's a Dremel?

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    Now why didn't I think of that? Might pop down to B&Q and see what they have in there tomorrow.
     
  11. KayinBlack

    KayinBlack Currently Rebuilding

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    How about using a 90 degree copper bend? They work just fine off the shelf, push the tubing over the expanded part and band clamp them...

    Also, DD does Delrin 90 degree blocks that take g1/4" fittings and smooth out the flow, as well...
     
  12. Bbq.of.DooM

    Bbq.of.DooM Custom User Title

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    How about a 90 degree copper pipe fitting? It's shown to have 1/9 the restriction of a plastic elbow.

    Or so.
     
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