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rosenjm
Joined: 21 Dec 2010 Posts: 249 Location: Ballston Spa, NY
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Link Posted: Thu Jan 27, 2011 11:47 pm Post subject: Coiling stainless tubing |
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Well, I just destroyed 50' of stainless tubing trying to recoil it for the HERMS coil. On my first attempt, I used a tube bender like Kal suggested, but it really dented the tubing and kinda mashed it up even though I was just doing tiny, tiny bends every 2 inches or so. I was extremely difficult to maintain a constant "coil" with the tube bender as the handles kept getting in the way as it coiled up.
I then moved to Kal's foot and wire tie method which seemed to be working much better, but I could never get the diameter of the coil small enough to fit in the kettle. The straw that broke the coil, so to speak is when I got to the end where I had started with the tube bender, the tubing instantly and completely kinked at one of the weak points where the tube bender mashed the tubing. I cut the kinked end off and lost about 6 feet of tube. Figuring I had already done the damage, I thought I'd refine my technique on what was left so I don't repeat this on a brand new coil.
Bottom line is nothing I tried seemed to work. Bending it by hand seems to be the "easiest" method, but it really wants to kink up when I get the diameter small enough. I have a new 50' coil on the way. I hope I can find a shope with a tube bender who will do it for me, I really don't want to destroy another 50'!
MODERATOR EDIT: For those who do not want to attempt coiling their own, pre-coiled ones are now available:
See: http://www.theelectricbrewery.com/custom-herms-coil
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crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
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Link Posted: Fri Jan 28, 2011 12:06 am Post subject: |
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I've heard some people put rice or sand in the tube when bending small angles by hand. But I'm really surprised the tube bender really mashed up the coil.
I unintentionally bought an extra 25' of 1/2 OD coil (1/4 ID - 1/4 OD was what I wanteded, seems nobody can make up their minds which diameter is being measured...) I also just ordered a tubing bender (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=380303524809&ssPageName=STRK:MEWNX:IT). I'm surprised to hear it kinks the tube, since that's the main point of getting it. I guess I should play with the 25' first to hone my skillz.
I've recoiled 3/8 OD copper tubing by hand before - it was fine wrapping it around a corny keg, but kinked when I tried to make a right angle. It was just for a gooseneck siphon, so no real concern - the restricted flow helped my chiller!
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rosenjm
Joined: 21 Dec 2010 Posts: 249 Location: Ballston Spa, NY
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Link Posted: Fri Jan 28, 2011 12:32 am Post subject: |
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That is the exact same tube bender I have. The pictures aren't the best, but you can see how the bender mashed the tubing and eventually led to its failure. I'll have to try the sand/rice trick next time...
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Another failure, on the second attempt. |
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Failure while trying to bend by hand at one of the deformations from the bender. |
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Deformations from teh tubing bender |
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crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
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Link Posted: Fri Jan 28, 2011 12:44 am Post subject: |
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Wow. Thanks for the pictures. Sometimes they speak a thousand words, but I'm sorry to say that your one word - "destroyed" sums it up here. That's not good. Now I want to cancel my order for that bender! I thought a tubing bender would make it all better!
Did you try taking it reeeaaaallllyy slowly?
EDIT: I wasn't thinking of using the bender to recoil the tube (since that's not such a tight angle), but just for bending the ends. If you look at Kal's tube, it's got some pretty tight bends near the ends to get it back to the outlet. Kal, how on earth did you manage that with your bare hands?!
To recoil, try to find something with the diameter a little less than your kettle, like a corny keg, or an smaller kettle. I've got an old 5 gallon canning kettle that I think is a good fit, so I'll bend the tube around that. The kettle "pushes back" while bending, distributing the force along a length of the tube and continually moves the force along the tube as it's bent - in contrast to when holding it and bending, where the force only moves when you choose to change your grip, or if you don't grip, the force will usually be parallel to the direction you are bending, so the point that is 90 degrees from where you are bending will get nearly all of the force (and will most likely fail, unless you take it painstakingly slowly.)
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11122 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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Link Posted: Fri Jan 28, 2011 2:02 am Post subject: |
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crush wrote: | EDIT: I wasn't thinking of using the bender to recoil the tube (since that's not such a tight angle), but just for bending the ends. If you look at Kal's tube, it's got some pretty tight bends near the ends to get it back to the outlet. Kal, how on earth did you manage that with your bare hands?! |
Very carefully - very slowly!
To rosenjm: Did you use tie-wraps to keep the coil in? When I did mine by hand I wasn't trying to get it to stay in the proper shape by itself. I was only bending it enough (slowly) by hand and foot and then using tie-wraps every few feet or so to hold it together. The tie-wraps were doing a lot of the work. Had it cut the tie wraps the whole thing would have sprung open to 2-3 times the size.
'Bending' is probably the incorrect term too. I was more 'repositioning' the tubing into a different sized radius and then holding it in place with the tie wraps.
Quote: | To recoil, try to find something with the diameter a little less than your kettle, like a corny keg, or an smaller kettle. I've got an old 5 gallon canning kettle that I think is a good fit, so I'll bend the tube around that. |
I tried that first. My coil was simply too stiff. There was no easy way to wrap it around and hold it in place. The foot and hand method worked best for me but it was slow. Probably took me an hour or so of going slowly to do the whole thing.
Kal
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My basement/bar/brewery build 2.0
Last edited by kal on Fri Jan 28, 2011 7:47 pm; edited 1 time in total
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crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
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Link Posted: Fri Jan 28, 2011 2:12 am Post subject: |
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Once the coil is all tied up, do you have to leave it like that for some time so that it sets in place? What stops it springing back to the original size when the ties are snipped?
oh, I think I get it. the fact that it's held in place by the compression fittings in the kettle...
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11122 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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goatbrewer
Joined: 04 Jan 2011 Posts: 14 Location: Walla Walla
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Link Posted: Fri Jan 28, 2011 3:48 am Post subject: |
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That looks exactly like my coil rosenjm. I have the same tube bender too. Fortunately I only kinked it on the ends so I think I'm going to cut that part off and try again by hand. I'm with you crush, I don't know how Kal did those tight bends by hand and that is why I primarily bought the tubing kinker. You must have some real mits Kal...
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sjch
Joined: 16 Dec 2010 Posts: 46 Location: Norway
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Link Posted: Fri Jan 28, 2011 8:51 am Post subject: |
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I have no experience with this myself and its probably hard to accomplish at home, but I have seen this trick once on some 'How its made' episode on the construction of trombones. Lots of bended tube in there
What they did is fill up the tube with (very) soapy water and freeze the whole thing with one end closed (and the other open). It seems to make beautiful bends. It has something to do with the soapy ice not cracking but being very smooth.
Of course that method was shown to work with rather thin brass and copper tubing. How this would work on stainless steel I dont know.
But maybe its an idea. Those living cold could give it a try
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sjch
Joined: 16 Dec 2010 Posts: 46 Location: Norway
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Link Posted: Fri Jan 28, 2011 9:23 am Post subject: |
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Another option would be to buy a coil that already has a diameter small enough, such as these:
http://kegman.net/ss_coils.htm
Meant for cooling draft beer, but could they also be used for a herms setup like the one on this website?
More expensive, but already fitting and saving the painful hours of trying to recoil?
They have the inlet and outlet on the same level, but that should be no problem when you are using a pump anyway.
Meant for heat exchange so ideal if you ask me. Of course the different OD of the tubing would need different parts to connect it to ballvalves etc...
just an idea.
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rosenjm
Joined: 21 Dec 2010 Posts: 249 Location: Ballston Spa, NY
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Link Posted: Fri Jan 28, 2011 11:42 am Post subject: |
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kal wrote: |
To rosenjm: Did you use tie-wraps to keep the coil in? When I did mine by hand I wasn't trying to get it to stay in the proper shape by itself. I was only bending it enough (slowly) by hand and foot and then using tie-wraps every few feet or so to hold it together. The tie-wraps were doing a lot of the work. Had it cut the tie wraps the whole thing would have sprung open to 2-3 times the size.
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I did use wire ties, but maybe not as many or as often as I should have. I think next time I'm going to make this a 2 person job and go crazy with the wire ties. I spent a good 2 hours coiling it by hand, but the diameter was too big. When I cut all the wire ties and tried to recoil it tighter is when I ran into problems.
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iowabrewer
Joined: 16 Dec 2010 Posts: 53 Location: stranded in Iowa
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Link Posted: Fri Jan 28, 2011 3:06 pm Post subject: |
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@sjch I was thinking of going with the pre-coiled beverage coils too. I called my keg parts supplier to see if they could make me a custom coil out of 1/2" OD, no can do. I found they bring their coils in pre-coiled and do very little fabrication in-house.
50' of 5/16" w/compression fittings is listed for ~$80 US, for $175 US you can get 120'. How would the smaller diameter tubing affect the heat exchange rates, better or worse or no affect?
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MillWerks
Joined: 16 Dec 2010 Posts: 35 Location: Seattle
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sjch
Joined: 16 Dec 2010 Posts: 46 Location: Norway
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Link Posted: Fri Jan 28, 2011 3:45 pm Post subject: |
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Since those coils are designed to cool down beer from the keg on its way to a glass, I presume it is also possible to use them in a herms.
Small diameter means lower contact area/surface, but also less volume to thermally equilibrate. How this looks in absolute numbers, I leave to someone else to calculate. What I do know is that the volume is proportional to the square of the radius of the tubing, whereas the contact area is proportional to the radius.
So in theory there is a lot less wort to cool/heat over a smaller area in an equal length of tubing.
Therefore I don't think there will be a problem with using the smaller diameter tubing.
Kal must have chosen 1/2inch tubing out of convenience or for reasons of availability rather than it being the one and only optimum diameter that works best?
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Enggboy
Joined: 25 Jan 2011 Posts: 7 Location: Edmonton, AB
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Link Posted: Fri Jan 28, 2011 3:49 pm Post subject: |
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iowabrewer wrote: | @sjch I was thinking of going with the pre-coiled beverage coils too. I called my keg parts supplier to see if they could make me a custom coil out of 1/2" OD, no can do. I found they bring their coils in pre-coiled and do very little fabrication in-house.
50' of 5/16" w/compression fittings is listed for ~$80 US, for $175 US you can get 120'. How would the smaller diameter tubing affect the heat exchange rates, better or worse or no affect? |
There is a twofold effect on the smaller tubing diameter. Heat transfer depends on surface area per unit length and temperature difference, while the temperature change of the coil liquid is also related to its volume.
If you increase the surface area (SA) to volume (V) ratio, you will get a hotter liquid out given the same flow velocity and external temperature (in this case it is the HLT water temp). As a side note, the SA/V ratio for the 5/16" tube is about 12.7 and the 1/2" tube it is 8.0.
With the smaller diameter tubing though, you flow less liquid overall because the line is smaller, providing a higher pressure drop, which means that the pump cannot flow as much. So, you get a smaller quantity of warmer liquid at the output of the coil. Now I have no experience with this setup (my build plan is still in the 5 year range), but I don't see it as a problem as you could always just turn up the temp in the HLT to make the mash liquid warmer if you find that you cannot maintain the temperature using the 5/16" tubing.
Hopefully you can understand my quasi awake ramblings...
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sjch
Joined: 16 Dec 2010 Posts: 46 Location: Norway
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Link Posted: Fri Jan 28, 2011 3:55 pm Post subject: |
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another point to make is that the wort flow is probably slow enough for none of this to actually matter.
The slow flow ensures that the recirculating wort is taking up the temperature of the surrounding water in the HLT, which is the whole idea of the HERMS. Lower diameter tubing, as long as its a metal, will not fail to accomplish this.
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crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
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Link Posted: Fri Jan 28, 2011 4:11 pm Post subject: |
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iowabrewer wrote: | @sjch I was thinking of going with the pre-coiled beverage coils too. I called my keg parts supplier to see if they could make me a custom coil out of 1/2" OD, no can do. I found they bring their coils in pre-coiled and do very little fabrication in-house.
50' of 5/16" w/compression fittings is listed for ~$80 US, for $175 US you can get 120'. How would the smaller diameter tubing affect the heat exchange rates, better or worse or no affect? |
That's a good deal. I've already bought the 1/2" OD tube, but would have gone for this if I had known about it. My tube was $70 from ebay, and the compression fittings were $20 each at morebeer, so $80 all in is a good deal!
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kal Forum Administrator
Joined: 12 Dec 2010 Posts: 11122 Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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Link Posted: Fri Jan 28, 2011 7:38 pm Post subject: |
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sjch wrote: | Kal must have chosen 1/2inch tubing out of convenience or for reasons of availability rather than it being the one and only optimum diameter that works best? |
For adequate flow rate. There's less restriction.
The general consensus on brewing forums is to go with at least 1/2" ID throughout the system to avoid flow rate issues. The march pump may have issues pushing through 50' of pipe that is smaller in diameter and/or you may have pump priming problems.
Kal
_________________ Our new shop with over 150 new products: shop.TheElectricBrewery.com
We ship worldwide and support our products and customers for life.
Purchasing through our affiliate links helps support our site at no extra cost to you. We thank you!
My basement/bar/brewery build 2.0
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sjch
Joined: 16 Dec 2010 Posts: 46 Location: Norway
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Link Posted: Fri Jan 28, 2011 8:02 pm Post subject: |
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[quote="kal"] sjch wrote: |
The general consensus on brewing forums is to go with at least 1/2" ID throughout the system to avoid flow rate issues. The march pump may have issues pushing through 50' of pipe that is smaller in diameter and/or you may have pump priming problems.
Kal |
That is good information, thanks. Didnt know this.
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crush
Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway
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Link Posted: Fri Jan 28, 2011 8:46 pm Post subject: |
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Just cancelled my order for the tubing bender. The ebay seller was great about it, and did everything professionally and without a grumble. SS is harder and less ductile than mild steel so that may be why it kinked.
Psyching myself up for the wrestling match that will ensue in a few weeks: in the red corner, Crush, and in the blue corner...50' SS tubing. Fight!
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