Brazing ball valves

[lmwilco1]

Hello Gents,

I am making a few changes to my air distribution systems and need to use a few ball valves. Can I braze ball valves to the copper tubing or would that high of a temp destroy the seals?

Thanks,
Louis

 

[Basskiller]

I always use a rag coated with some type of cool gel or paste product when changing out a txv. Something along the lines of this or whatever your hvac parts house has.

http://www.johnstonesupply.com/stor...l-gel-heat-dissipating-spray/prodR87-565.html

 

[sharkytm]

Um, Ball valves are designed to be soldered into copper. I did all my air lines with solder-on valves, and it No rags, just the proper amount of heat, good silver solder, and then cooling them down with a damp rag once I was done. Not a leak in sight. Just remember to open the valve when you solder, it keeps the air trapped in the ball from expanding and causing problems.

Threaded fitting aren't cheap, plus they add length, and another location for things to leak. Just use solder.

 

[lmwilco1]

Thanks guys, I looked up the joint strength of a 95% tin solder joint and it is rated at over 600psi so that should be plenty.

Louis

 

[rlitman]

Thanks guys, I looked up the joint strength of a 95% tin solder joint and it is rated at over 600psi so that should be plenty.

Louis

That would be the burst strength. I believe 200PSI is the working pressure. Still plenty fine for air lines, and actually depending on the size of the copper, brazing may reduce the working pressure, because it anneals the copper (which lowers the rating).

Just solder it and be happy. Yes, the heat of brazing will trash a ball valve.
Having the valve completely open when soldering is ideal. Closed MAY be ok, if the line is vented on both sides (so there's no pressure buildup from the heat), but make sure the valve is not half open. The heat may deform the seal, and keep it from sealing when it cools.

 

[Mr onetwo]

Actually, the rating is based on CWP or cold working pressure.Any decent quality ball valve,such as Nibco or Apollo, is rated for 600 lb. CWP or WOG.As system temp rises valve rating decreases.A valve rated at 600 LB. CWP is only rated at 150 LB. saturated steam service typically.These valves include the joint strength in their ratings.This is all per Nibco spec data.

 

[toyotadriver]

You need to solder it with a torch that raises the temp quickly....like oxy/acetylene. A regular propane torch heats up too slowly and as a result, the heat will destroy the valve.

Yes, I learned that the hard way!!

Have water close by so you can dip it in water to cool it once the joint is soldered.

 

[gmwelder86]

use IPS 3 piece ball valves. silver solder MIP's where you need them and than thread the valve into place. Best way to perserve the sealing ability of the valve and still have the strenght and more importantly the heat resistance of a silversoldered joint.

 

[rlitman]

Actually, the rating is based on CWP or cold working pressure.Any decent quality ball valve,such as Nibco or Apollo, is rated for 600 lb. CWP or WOG.As system temp rises valve rating decreases.A valve rated at 600 LB. CWP is only rated at 150 LB. saturated steam service typically.These valves include the joint strength in their ratings.This is all per Nibco spec data.

The valve may say 600WOG, but that's for the packing and the seal. The sweat joint itself is not necessarily so much.
Have a look here:
http://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf
On page 28, notice the really low pressure ratings for 50-50 solder?
That's what I was talking about. Now, for 95-5, it's not an issue, and that's what everyone is using today anyway.
And note that for saturated steam, that valve may be rated for 150PSI, but a solder melting below 1100F would only be rated 15PSI.

It is because of this, that when it's not inconvenient, I'll sweat on a male fitting, and screw my valves onto that.