Where To Drill For Couplings?

Been away; too busy.

Want to drill kegs for couplings so they will be ready to just weld when I deliver them to the welder dude. Aiming to put in two per; do many people cut them in half and use as shorter couplings?

Guessing the down bend of tubing inside of keggle reaching into the lowest portion of bottom of keg determines how well it will drain, but to be able to easily weld the coupling into the keg wall, what do I use as a measurement for allowing ample room around the coupling for access by welder to the lower portion of the weld?

Guessing also that minimum diameter of hole to coupling OD will make welding easiest...?

Need a 'do this, don't do that...'

First, I'm rethinking using couplings at all. As orfy argues, it would just mean you need a close nipple to connect your ball valve. I MIGHT go with 2" nipples instead. I'm not positive though because I already own the couplings.

You don't want to cut them in half. You need to be able to thread in to both sides.

If you're putting in a port for a thermometer and site glass, consider welding a Tee directly in. You'll need one anyway so why go coupling, nipple, tee when just welding the Tee in works?

Thanks for the different slant Bobby.

I can see the nipple deal working outside for the valve, but on the inside, aren't you still having to use something to adapt to the tube? I'm not seeing male NPT going direct to tubing...

I saw...somewhere in 'net land, somebody had cut them and used them as shorter; I have access to NPT taps, just wondering if it is worth the extra hassle to try and save any space...

I can see the advantage to welding in a SS tee, odd leg up I presume, for the thermo, but guessing that any external lip on the internal leg of the tee should be removed, and smallest hole possible drilled....not sure if they have this, just remembering how black pipe ones look...

Interesting how you think that you are going in a direction that you have seen countless times, (just using couplings) and finding that the standard way is lacking....sure is nice bouncing things off others before embarkation...

Here is some information on converting a keg:

https://www.homebrewtalk.com/wiki/index.php/Keggle

Cheers

"This means the bulkhead/ball valve must be installed a couple inches above the bottom."

Okay, a generic, nominal 'two inches'...this is what everyone does?

Here's the hieght I fitted mine and it works fine.
The picture also demonstrates the advantage of using a nipple instead of the more commonly used coupler.

Thanks, Orphy, for the 2027 words.

Inside, do the compression fitting's threads match the npt thread pitch of the nipple without die work on the nipple's threads? Guessing that is a 1/2" brass barrel farrel(sp?) inside the compression nut...

I was going to say that you'd have to use a fitting to adapt either a coupling or nipple to your dip tube. I would have never thought Orfy's setup would work, it's brilliantly simple.

On the tee, I was thinking of going with 1/4" FPT since I know I can get dial thermos with 1/4 MPT from Stpats. As soon as I verify that I can get 1/4 MPT to 3/8" tube compression fittings that is (for the sightglass). Yes, odd leg up for the sight glass, end leg for the thermo.

I've always drilled out the hole so the fitting fits really snug. It makes it easier for the welder.

The compression fitting fits directly onto the nipple and seals hand tight with out the need for tape or a spanner. I don't know the sizes etc. but I think it's a tap fitting out of my spares bucket

I take a picture when I'm at home. (next week)

Here's another part saver. A compression elbow fits straight into the ball valve.

Another thing to consider.
Using a T in order to have sight glass and inlet/outlet on the one hole means that you can have problems with siphoning/pumping. That is, as you drain/pump, air gets sucked in through the sight tube giving you bubbles in the line. As you drain/pump, the sight glass becomes inaccurate because of the suction, just when you might want to know how much liquid to move, meaning stopping and starting.
Many prefer to drill two holes, and mount the sight glass separately, avoiding all this.

Cheers,
Yorg.

I'm not advocating coupling a sight glass with the drain. The best solution is to have a dedicated 1/2" bulkhead drain and then a separate kettle penetration for the sight glass/thermometer. That's where the Tee goes.

Bobby's thinking like me; I wasn't even considering combining valve and sight glass, hence the two couplings or whatever type fittings per keggle.

So now I'm searching for how 1/2"NPT male threads at 14 threads per inch can fit a compression nut for copper pipe-isn't 1/2 pipe a 5/8 OD? A 5/8 UNC fitting has 11 threads per inch (TPI)...

How many turns does that nut turn onto the nipple, Orphy? Could it be a lucky deal that metrics make this work?

I think you would be just as well off to get a 1/2" tube x 1/2 NPT (female) swagelok fitting and drill it out to pass 1/2" O.D. tubing through the pipe thread portion of the fitting. The tube fitting side facing in. Cut a hole just big enough to pass a 1/2" close nipple and use lock nuts and washers on the outside to secure the nipple tight. The face of the swagelok fitting on the female side will be your sealing surface. Just use good gasket material.

Look at this picture where the outlet of the MLT is:

http://i7.tinypic.com/53ztusj.jpg

Henry, where are you at in the decision process? I'm still dragging my feet on the bulkhead/drain portion. I've already placed my order for the 1/4" Tees and 1/4" MPT dial thermos from Stpats so the thermosight side of it is ready to go.

I also scored an amazing deal on some 1/2" 3-piece 316 ball valves through an off-Ebay transaction. I just happened to notice this guy won a large lot of valves and asked if he'd throw a few over. $35 shipped for 3.

As risky as it sounds, I'm tempted to try to find a welder that is good enough to weld one end of the 3-piece valve directly to the keg. That would leave a 1/2" FPT flush with the inside for my compression fitting and also have the shortest possible protrusion on the outside. I am slightly concerned that it will warp the sealing surface upon welding and/or reduce my chance of changing out a bad valve.

Maybe the simplest solution is to forget welding altogether and use one of these from buyfittingsonline.com. It's $20 for 1/2"MPT to 1/2" tubing:


I suppose you just add silicone Orings and call it a day.

Thinking, thinking...and not brewing.

I am at the waiting for enough money to get-my-azz-going stage. While I wait, figuring just EXACTLY HOW to proceed seems the wisest use of my time. I have been see-sawing on the 2 keggles-1 cooler approach, and the 3 keggles with one insulated like a MOFO....SS is as permanent as it gets, and a cooler, while fast, cheap, and ready-insulated, may breakdown over time, ( I think LONG TERM), and I already HAVE three Sankes; two cut out and 1 pristine one that still needs it....definitely want to go the pump route!

I may take my friggin' time doing stuff, but when I'm done, the planning shows...

I WOULD NOT weld the valve to keggle directly, (looking back now and noticing you're thinking 3 pc., but still not comfortable with idea...), too much to risk for what you actually will gain. Whatever4 type of thru the side welded fitting is forever, and valves and things can be damaged, and may need to be replaced.

AFA 'to weld' or 'not to weld', I feel that a good welded fitting is forever and a weldless approach is a problem waiting to develop...whether it be breakdown of the seal, an overheat-underfull keggle, etc., I'm welding....but you have AGAIN caused me to re-examine my 'just going to use 1/2" couplings, like I have always seen' idea, by the 1/4" tee and 1/4"npt thermometer idea...hmmmmmm....

Bobby_M said:

I suppose you just add silicone Orings and call it a day.

Click to expand...

Goretex gasket material is far superior to o-rings for this application.

Heh, well, the 1/4" Tee idea was great until I lost my only source for cheap 1/4 MPT probe thermos (St Pats see other thread). I'm still going to weld in the Tee, but it's going to be 1/2", oh well. 1/2" seems to be quite adaptable to every application. Even Lowes carries compression fittings between 1/4" and 5/8" tube to 1/2 MPT so that's fine and almost all dial thermos have 1/2" thread as well.
I already have a bunch of 1/2" couplings so I'm going to have them welded in along with the 1/2" Tees. I'm tired of agonizing over this even though the cost of welding (and worse, rewelding) is what has me pondering.

Bobby,.. quit agonizing and weld that sucker in there! I pondered whether or not to get my keggle welded with SS nipples for the valves. To me it was really a no-brainer. Because I could always change the valve out anytime I wanted. Just do it man! Really if you don't like it then you can resale it and make a profit. I'm sure someone would like to buy a keggle like the one you're gonna make.