solder vs epoxy

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lozz08
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Tue Sep 28, 2010 10:40 am

Hi people. I have never used solder and copper pipe would anyone know about how much pressure a solder bond could take? Does solder stick to brass?
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Ragnarok
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Tue Sep 28, 2010 11:08 am

lozz08 wrote:how much pressure a solder bond could take?
It depends on the exact solder, but if you've properly cleaned, fluxed and soldered everything, the pipe will probably fail before the joint.
Does solder stick to brass?
Yes - under the same caveats as it sticking to copper (i.e. properly cleaned and fluxed).
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Technician1002
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Tue Sep 28, 2010 11:19 am

Properly done a soldered joint is very strong. This picture comes to mind that I linked in another thread that shows the solder joint is just fine. The pipe failed near the joint. This looks like a brass fitting soldered to copper pipe.
Image
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Gaderelguitarist
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Tue Sep 28, 2010 5:27 pm

Use solder for your copper-copper and copper-brass connections. I would resort to epoxy in the case of dissimilar materials; i.e. metals to plactics.
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bighead33
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Tue Sep 28, 2010 6:33 pm

I'm pretty sure no matter what kind of solder you use it will be petty much inferior to epoxy, defiantly solder :wink: .
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Mr.Sandman
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Tue Sep 28, 2010 6:58 pm

bighead33 wrote:I'm pretty sure no matter what kind of solder you use it will be petty much inferior to epoxy, defiantly solder :wink: .
I believe the word you were looking for is "superior". Inferior is stating that you think the solder is weaker than the epoxy.
And iirc, soldering fuses with the copper on a molecular level which is a much stronger bond than epoxy which basically just hardens the two together.
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lozz08
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Tue Sep 28, 2010 7:13 pm

Ah, loveley, with this information i can fuss around so much less... I can't believe i overlooked using solder for so long... thanks guys.
whoa044
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Tue Sep 28, 2010 7:13 pm

Wouldn't the pipe be thicker wherever the joint is? As it is just two pipes overlapping each other.

I think the solder's main purpose in spud guns, is to prevent leaks, and to prevent the barrel from flying off when you attempt to fire it.
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ramses
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Tue Sep 28, 2010 9:03 pm

No, there is also as substantial axial force they must withstand. Assume a joint with a cross sectional area of 1 in^2. At 500PSI, that joint is being pulled apart with 500 lbs of force.

It is worth noting that if you overhead the drawn copper pipe while soldering, you soften it and reduce IT's strength. This is virtually impossible with epoxy.
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bighead33
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Tue Sep 28, 2010 9:21 pm

I'm pretty sure no matter what kind of solder you use it will be petty much SUPERIOR to epoxy, defiantly solder :wink: .
Mr.Sandman wrote:
bighead33 wrote:I'm pretty sure no matter what kind of solder you use it will be petty much inferior to epoxy, defiantly solder :wink: .
I believe the word you were looking for is "superior". Inferior is stating that you think the solder is weaker than the epoxy.
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whoa044
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Tue Sep 28, 2010 9:34 pm

Only a very quick jolt of 500 pounds.

The projectile would be far on it's way after that initial 500 psi burst.
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Tue Sep 28, 2010 10:59 pm

I would use solder over epoxy any day for copper.
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Tue Sep 28, 2010 11:03 pm

I have never soldered a single copper part so I have no experience there, but all the copper joints I have ever made were with JB weld. They have held up up to 400 psi, but solder is definitely better because it is actually bonding the materials much like solvent welding does to PVC
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Ragnarok
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Wed Sep 29, 2010 8:40 am

whoa044 wrote:Only a very quick jolt of 500 pounds. The projectile would be far on it's way after that initial 500 psi burst.
No - let's say this is a joint in a pneumatic (or hybrid) chamber. That loading will persist as long as the chamber is pressurised.
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Technician1002
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Wed Sep 29, 2010 10:14 am

If you have never soldered copper pipe, there are some very excellent online youtube turorials.
[youtube][/youtube]

If you move up to hard solder, often called silver brazing, you will want to prevent oxidization of the copper. Most refrigeration compressors are connected with this method. A protective gas is flowed in the pipe to remove oxygen. This is what flow regulator are used for. Flowing a shield gas of either Argon or Nitrogen needs a known flow rate, not a pressure.

[youtube][/youtube]
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