View Full Version : Brazing qstn
simplyadvanced
02-18-2005, 03:57 AM
how many times can you heat copper to brazing temps and cool it down again before you should change it?
i'm just wondering cos my brazing material isnt sticking properly to the copper and it keeps leaking...
:confused:
berkut
02-18-2005, 04:42 AM
heat it up more
do not cool it with water etc. just let it cool off naturally
simplyadvanced
02-18-2005, 05:00 AM
i heated it up red hot...
natural cooling...
so there shouldnt b much a prob?
simplyadvanced
02-18-2005, 06:36 AM
i really overdid the bvrazing... used up almost the whole rod on 1 evap... but still leaking./....
now i;ve got a messy evap which still dun work... -.-
gclg2000
02-18-2005, 08:02 AM
lol can you show a pic?
i really overdid the bvrazing... used up almost the whole rod on 1 evap... but still leaking./....
now i;ve got a messy evap which still dun work... -.-
as gclg200 said we need pics and you need to be more percific.
first you talk about pipe next evaps they are both very different.
you need basic brazing skills first i think read sticky.
how did you heat the evap.
you need to put it on an oven and heat it flat out. then when it takes rods back torch off and do zig zags up and down to fill gap. i normally put a small lip on each surface with grinder and fill it with brazing.
they never leak on me.
should take about 2min of brazing once at temp, dont start until it gets to that temp.
gkiing
02-18-2005, 02:38 PM
If your adding a lot of filler rod to it and its still leaking you probably don't have it hot eneough for the brazing rod to flow properly. Make sure you are using a rod with phosphor in it so that it is self fluxing on copper, if not make sure to use white flux.
hatemi
02-18-2005, 03:20 PM
Or your using too much heat and the rod is flowing to the insides of the evap. I have blocked 1 evap with too much filler material....
gkiing
02-18-2005, 06:24 PM
Pictures would help a lot here
simplyadvanced
02-18-2005, 07:55 PM
http://img172.exs.cx/img172/4982/img16694tp.jpg (http://www.imageshack.us)
simplyadvanced
02-18-2005, 07:56 PM
at the edge,.... the small bubble... thats where its leaking
gkiing
02-18-2005, 10:28 PM
Try brazing around the seams again, try to get the brazing rod to be buttery and not completely liquid, this should fill any gaps that are there. I'm not sure where you mean on the block when you say bubble.
simplyadvanced
02-19-2005, 06:54 PM
sorry for the big pic
http://img173.exs.cx/img173/3243/img166995mc.jpg[/URL]
gkiing
02-19-2005, 09:27 PM
that's a really odd place for it to be leaking, its not even near the seam where you brazed the evap. Did you try covering the area around it with brazing rod yet?
simplyadvanced
02-19-2005, 09:51 PM
that's a really odd place for it to be leaking, its not even near the seam where you brazed the evap. Did you try covering the area around it with brazing rod yet?
any thicker it will overflow to the sides :stick:
hiaz... so close yet so far...
gclg2000
02-20-2005, 07:28 AM
YEah i don't see how its leaking from that spot. That's just a solid slice of copper by the edge no???
its leaking b/c you are trying to cool it down somehow. that warps the braze and will make leaks. re braze it and do not touch it at all untill it is room temperature.
runmc
02-20-2005, 10:14 AM
If you are using a good 15% silver rod, you don't need any flux. I don't know if you are using flux, but I have heard from a couple of the professional HVAC guys, that flux can cause pin hole leaks because of impurities in the flux.
Your brazing looks good other than that it may be getting tooo hot. When you get it tooo hot it will get blisters and leak. ;) Work your flame off and on the area you are brazing. Just get it hot enough to make the brazing alloy follow the heat from the torch. Don't get it so hot that the alloy runs every direction like water.
simplyadvanced
02-22-2005, 02:27 AM
ic, thanks.
simplyadvanced
02-22-2005, 04:25 AM
looks to me is over heated an too much flux, pin holes come from cooling down with water
use a StainlessSteel wirebrush to clean up copper
use a firebricks,ceramic tile on a hot plate, preheat material
use a smaller flame or tip then you had ...adjust flame
(Oxy-Acel)a5-o15lbs) set flame to a neutral flame then have 3 envelopes to the start of carbonize flame, thats the sweet spot you want. don't want oxidizing flame to hot an blisters material.
(map) a sharp point of flame crescent.
work with flame like its a laser beam, being right angle = 100% heat, 45degrees 60% @ point of weld
practice this an you be master welder :)
thanks for ya help :P
i never cooled it with water though... maybe overheated