Stainless CFC Compression Issues

[tsb22]

About to wrap up my stainless steel CFC & decided to go with bore through compression fittings in order to seal off the Tee.

Unfortunately I did not anticipate the extremely tight tolerance of the compression fitting. The compression fitting stops at the first 1/4" of the tubing & will not slide down the tubing to connect to the tee, I am assuming because the tubing is slightly bent.

Anyone have any suggestions for getting the compression fitting the rest of the way down the tubing to seal off the Tee so my cooling water flows out the proper way with no leaks?

Current non-forum suggestions have included:
1) Find someone with a grinder and cut off the first few inches from the tubing, perhaps the middle parts are straighter.
2) Try to grind off the slightest about of thickness from the tubing in order for the compression fitting to slide more freely.
3) Have a machine shop bore out the compression fittings just a little more for the compression fitting to slide more freely.
4) Buy some 1/2" Stainless plugs, have the middle of the plug drilled out & slid over the tubing, then braze or weld the plugs directly to the tubing.
5) Rig up some-sort of bit to a air-hammer gun to hammer the fitting down onto the tubing, not sure how well this would work.

Any input is appreciated guys, as soon as I'm done I wanted to do a quick write up, after-all, it might be one of the first 1/2" Stainless CFCs on HBT.

 

[OneHoppyGuy]

I do, you need a bored out fitting. BrewersHardware has them.

 

[tsb22]

What, you mean like this?

I have 2 of the bored through on the right, they are the ones i cant get to slide onto the tube.

 

[Bobby_M]

You did mention "bore through" fitting so I assume that's what you have. If the bore is really that tight, you should be able to use a 7/16" drill bit to ease it out a bit. That would certainly be at least as easy as drilling a completely new hole in a 1/2" NPT plug and silver soldering it.

 

[OneHoppyGuy]

Sorry, my bad...

 

[Bobby_M]

Is it the metal ferrules you're having trouble with or the fitting itself?

 

[tsb22]

Onehoppyguy, no worries, I wish it was that easy

Bobby M, Don't even have the ferrules in there but have managed to slide the fittings dow all the way through the fitting. It is definitely that the tube is bent, I just don't really know the best way to fix it.

Funny, most people have problems bending their tubing, I need to straighten mine.

 

[BrewinBigD]

Onehoppyguy, no worries, I wish it was that easy

Bobby M, Don't even have the ferrules in there but have managed to slide the fittings dow all the way through the fitting. It is definitely that the tube is bent, I just don't really know the best way to fix it.

Funny, most people have problems bending their tubing, I need to straighten mine.

Nix the ferrules,,get 2 or 3 o rings that will tightly slip over the tube and just into the taper of the fitting and slide the nut down and tighten. should hold up to the abuse!

 

[krazydave]

Knowing me, I'd just force em in whatever way it took. When tubing is bent, it tends to obtain an oval circumference rather than perfectly round, which is why your ferrules are sticking. The Ferrules should go around the slight oval and straighten back out enough to create a seal once you tighten the fitting down on them though, it'll just take a good deal of force to get in there. Other than that, I don't know that I would try any of your other suggestions other than maybe the first.

 

[jakesz28]

If you use an adjustable wrench and turn it around the tubing, you can make the tubing round again. This is done in the refrigeration field all the time on copper. Have the wrench loose and start turning it around the tubing and tighten the wrench until it starts to form the tube.

 

[BrewinBigD]

If you use an adjustable wrench and turn it around the tubing, you can make the tubing round again. This is done in the refrigeration field all the time on copper. Have the wrench loose and start turning it around the tubing and tighten the wrench until it starts to form the tube.

+1 on this ive done it a few times works great for soft copper and brass tube

 

[tsb22]

krazydave, I didnt even have the ferrules in there, just trying to get the hollow compression fitting onto the tube, the ferrules themselves actually slide on pretty easily.

I did my best to not take a wrench or pliers to the tubing when straightening, so is NOT the diameter that is bent. The bend is going down the length of the tubing. The fact the compression fitting itself is about 1" long straight length, if you have any bends going down the tube the compression fitting will only slide down til it hits the bend. ie) the bent tubing is kinda scraping one side of the compression fitting as it slides through.

Once I realized it wasnt sliding down because the little bends going down the tube, i took a decent sized plumbers wrench and with the tubing pointing straight up in the air, i locked onto the compression nut and used a twisting/pushing motion to slowly force the fitting down the tubing. This probably would have been much easier with a vice, but I dont happen to have one installed in the apt.

Here is the result:

Its not pretty, but I just need the ends to seal. And yes BrewinBigD I will be using silicone rings to seal it up. As much as this chiller is probably going to get tossed around the next few years I think silicone might hold up a little better than metal ferrules.

Thanks for the help guys! Should be posting a build thread here soon!

 

[OneHoppyGuy]

No vice in your apartment?!! I hope you're getting a discount.

 

[spearko520]

If you use an adjustable wrench and turn it around the tubing, you can make the tubing round again. This is done in the refrigeration field all the time on copper. Have the wrench loose and start turning it around the tubing and tighten the wrench until it starts to form the tube.

+1 - was just going to say that's how i do it!

 

[BrewinBigD]

Ill look forward to the build thread. I made a 3/8 cf chiller but its so small in dia it clogs easily and cools dow wayy too fast. Looking to build a 1/2 or 5/8 chiller to use with my pump for recirc chilling in thhe future.

 

[tsb22]

Yup, clogging was def. an issue I considered.

Thread can be found here:
https://www.homebrewtalk.com/f51/1-2-stainless-steel-cfc-315298-new/