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Posted: Wed Nov 04, 2009 10:35 pm
by skyjive
I'm not worried about the steam melting it, I'm worried about the propane flame that I will be applying to heat the steam melting it. Since as I understand it I would use a propane torch to braze the joint in the first place, it seems logical (at least to me, I've never brazed before) that applying the same flame again to the same area, even though for a different purpose, would remelt it.

Posted: Wed Nov 04, 2009 10:49 pm
by hi
your supposed to braze using an oxyacetylene torch, but the kits at the hardware store are oxy/mapp gas, which works fine for small jobs like the one you want to do.


You're not going to melt it with a propane torch, especially if you don't put it right on the joint. Propane just doesn't produce enough heat.

Posted: Wed Nov 04, 2009 10:58 pm
by Technician1002
The problem with brazed joints is the dissimilar metals acting like a battery, the anode metal will be consumed. This is why in plumbing when joining copper and iron at a water heater an electrically insulating section is used to prevent the corrosion from electrolysis. I would highly discourage the use of brazing for a steam boiler application, or plan on scrapping it each year before it fails. The Wikipedia article below has more info on the subject.

http://en.wikipedia.org/wiki/Galvanic_corrosion

A dielectric water heater connection to stop electrical current between iron and copper looks like this.
Image

Posted: Thu Nov 05, 2009 3:23 pm
by psycix
Take extra care with steam... one of the most dangerous pneumatics ever.
One leak can give permanent burn marks, not to mention a sudden explosion/big leak.

Isn't there any way in which you can replace the copper pipe by a steel one and have it welded, or find other pipes which allow you to use standard fittings instead of a custom connection?
This connection really needs to be done in a fail-proof way, unless you are operating your device from a distance.