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kpapa
29-08-2006, 01:16 PM
I would like to ask if someone has an instructional video for welding copper pipes. this is one of my first atemts, so i would like more help on the subject. i am going to use silder for welding medium

best regards
kpapa

justchillin'
14-09-2006, 08:26 PM
If you are doing just a repair then ok but to do a new instal, If i were you i would let someone else do it!!!!
You have to use refridge brazing rods not plumbing gear, and if the pipes is small like 3/8 then use a turbo torch....
Just get the copper very hot and let the braze run aroung joint ok
Hope this helps:confused:

MJF_07
23-09-2006, 04:44 PM
Hi Guys,

I am also very inexperinced in A/c & refrigeration but i can not reccomend highley enough suitable training on the brazing of the pipework.. If you need a good course then try the city and guilds British refrigeration flame brazing course 2078. You will need no further adviceif you pass, please do not even think of trying to use techniques similar to plumbing on A/c or refigeration installations.

Regards Matt.

Peter_1
23-09-2006, 05:10 PM
He's from Greece ;)

US Iceman
23-09-2006, 07:33 PM
Brazing is one of those arts that improves with practice and supervision. I prefer an oxygen/acetylene torch and an assortment of the proper sized tips to do this correctly.

For copper to copper joints these are fairly easy with a silver/phosphorus brazing alloy.

Joints with dissimilar metals (copper/steel, or copper/brass) are more demading to achieve a good joint.

Soldering and brazing is much more than just getting the joint to seal. You also have to ensure a full penetration of the melting alloy into the joint socket too.

Here is a link to something that should be considered as a method of certifying brazed joints.
http://www.copper.org/applications/plumbing/techref/brzng_prcdr/brzng_prcdr_spec_main.htm

Here is a link to purchase additional information and the video requested.
http://www.copper.org/resources/pub_list/soldering.html

And, here is a link to some free information that might be helpful.
http://www.copper.org/resources/pub_list/pdf/copper_tube_handbook.pdf

And, some more information on brazing alloys (remember to purchase cadmium free alloys to protect yourself!)
http://www.handyharmancanada.com/TheBrazingBook/contents.htm#Index
http://www.jwharris.com/jwprod/hisilverbrazealloys/

Happy reading guys.;)

Tycho
24-09-2006, 12:28 AM
I use a oxygen/acetylene torch on all soldering on any refrigeration plant, I wouldnt trust a turbo torch.

I use a medium size nozzle, couldnt tell you what it is tho, I just look at the flame to descide if it's appropriate.

for pipes bigger than 1-1/2" I will choose a bigger nozzle.


and always... always... ALWAYS have a small but steady flow of dry nitrogen (N2) flowing through the pipes you are soldering, to prevent oxidation inside the pipes.

If you dont use N2, you'll get small flakes of "soot" inside the copper pipes...


and when using an oxygen/acetylene torch, I always have a little more acetylene, so the flame looks like three flames <--- if that made any sense (large light blue, small little darker blue and bright white)

US Iceman
24-09-2006, 12:56 AM
and when using an oxygen/acetylene torch, I always have a little more acetylene, so the flame looks like three flames <--- if that made any sense (large light blue, small little darker blue and bright white)


Good point about the flame colors Tycho. Too much oxygen or too high of a pressure on the oxygen makes the tip sound like a cutting torch. You really don't want that!

A nice gentle flame that is steady.

Turbo torches are OK for small tubing, but when you get into working with larger pipe sizes you should be using oxygen/acetylene to do a good job.

Brazing looks easy for those only watching, but as anyone that has done large silver solder joints on steel to copper can attest to, it is more difficult than it looks, right?;)

winfred.dela
24-09-2006, 01:52 AM
US Iceman:
Brazing looks easy for those only watching, but as anyone that has done large silver solder joints on steel to copper can attest to, it is more difficult than it looks, right?;)



Tycho:
and when using an oxygen/acetylene torch, I always have a little more acetylene, so the flame looks like three flames <--- if that made any sense (large light blue, small little darker blue and bright white)

Thanks for the tip Tycho.

- Lately been trying to learn brazing but had a hard time learning how to make it look easy.

- Have been observing (20+yrs) a lot of technicians that makes it look so easy but can't do it myself (brazing that looks easy).

- The N2 inside the pipe has been an old practice, but the younger technicians don't want to do it. Especialy if oldies are not looking
:rolleyes:

frank
24-09-2006, 07:44 PM
Hi Guys,

I am also very inexperinced in A/c & refrigeration but i can not reccomend highley enough suitable training on the brazing of the pipework.. If you need a good course then try the city and guilds British refrigeration flame brazing course 2078. You will need no further adviceif you pass, please do not even think of trying to use techniques similar to plumbing on A/c or refigeration installations.

Regards Matt.

City & Guilds 2078 is for recovery of refrigerants, not brazing.

monkey spanners
24-09-2006, 09:58 PM
Hi Kpapa
I use a rothenburger/mapp gas torch for heating pipe up to swage.
A turbo snake/mapp gas torch for pipe upto 7/8 (has done 1 1/8 in an emergency)
A turbo torch/mapp gas with double barrel burners that will work upto 1 3/8, works well as the heat is spread over a large area.( have seen a tripple barrel one an american web site, more power lol :D )
A portapack style oxyaccetylene with a selection of nozles, ideal for compressor changes and installs with bigger pipework.
The most important thing to have close to hand is a fire extinguisher. A small tub for water and wet rags ( cotton, as man made fibres may melt onto any thing you're keeping cool ) A small hand water sprayer for damping down if you are brazing near flamable stuff.
Pactice makes perfect so keep at it. Aim to fill the whole depth of the joint with braze, not just making a nice fillet where you can see it.

Cheers Jon

MJF_07
25-09-2006, 08:54 PM
He's from Greece ;)

That isn't my problem:)

Only joking,

Regards Matty

MJF_07
25-09-2006, 09:03 PM
City & Guilds 2078 is for recovery of refrigerants, not brazing.

Well done frank, Sorry to lead others down the garden path, but all i can say is if you need to know how to do something right seek proffesional training. and it isn't that difficult to achieve at least 95% penetration if you adopt the correct methods. One tip that does work is the 4 quarters method and concentrate on a quarter at a time and sure enough with practise you will get the penetration.

Regards Matt.

US Iceman
25-09-2006, 09:18 PM
One tip that does work is the 4 quarters method and concentrate on a quarter at a time and sure enough with practise you will get the penetration.


I understand why you are saying this, but would offer some cautionary words to ensure that each quarter is overlapped to prevent a leak path from developing.

I would normally recommend heating the pipe first, then the socket until the entire joint is up to temperature. Then the alloy will flow into the joint evenly. After the joint is filled, then come back and lay a nice fillet on the joint to radius the edge.

bernard
25-09-2006, 09:45 PM
Hi

I enjoy brazing very much,I,ve also watched a lot of people braze and find they only try to seal the edge of the joint where I think penetration is very important,when I,m happy with this I reduce the heat on the pipe and take away the 90 degree edge of the joint,I probably use twice as much rods.

The last company I worked for never pressure tested new installations apart holding a vacume,we would check each others welds and reheated where needed.Using the above Method.

I,ve seen a lot of people use the method of letting the braze run round the joint,then move on.

I was told that if you have a blob of weld at the joint and then drag it back with your flame, that the length you drag it back on the outside it will do the same on the inside,hope that makes sense.

Also when making up a manifold/spider do you consider drilling the pipe and brazing the spider leg a satisfactory method or using a 3 way connector.

Regards Bernard

US Iceman
25-09-2006, 10:12 PM
...I probably use twice as much rods.


I can say it seems like this when trying to fill a joint completely. My favorite expression for this... "it seems like you are pounding sand into a rat hole". It just never seems to fill up.:D

You can look at a joint to see if it was hot enough. Too cool and the alloy looks like it was stuck on to the pipe. Warm enough and the alloy blends in smoothly to the adjacent pipe and fitting.



The last company I worked for never pressure tested new installations apart holding a vacume,...


Now that's confidence in your work. I like that.;)