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Which type of solder???

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rotaryfrk

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Discussion starter · #1 ·
Got small Trane package unit that the outdoor expansion valve took a dump on. While attempting to solder new expansion valve into place using STAY-SILV 15 I could not get it to "suck up". I am soldering brass to copper. I've done this numerous times with no problems. I then purchased some SAFETY-SILV 56. I was told this is the right stuff for brass to copper. It seems to work great for copper to copper but still can't get it to suck up on the brass to copper. WTF???

Is there a better product out there that I should be using? This is Fricking killing me.
 
#2 ·
Flux???
 
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#5 ·
I had the same problem one time, expansion valve needed replaced and I spent hours trying to braze it in. Finally talked to somebody else and bought a roll of silver solder (can't remember the name of the solder, will check later). Then I spent about an hour learning the art of silver soldering.
Finally figured out that it has to be super clean, use plenty of flux, and that silver solder has a very small "sweet spot" where it will flow before getting too hot.

Good luck.
 
Discussion starter · #6 ·
I understand about the very small "sweet spot".

I soldered the copper to copper using the flux core rod with no problems, it's just that brass to copper that is kickin my ass.

I saw the roll of silver solder but the supply house did not have any flux to use along with it. So I opted to purchase the flux core rod instead.
 
#7 ·
You need the silver solder rods with the blue flux on them . If you cant weld it with that pack up your tools and go home.
 
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#9 ·
You need to use the white paste flux. Stay Silv flux I believe it is called. I use it with the 15% rods for copper to brass and never have a problem. if it dries out and gets hard in the container, add some water and get it pastey again.
 
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#11 ·
I've used the blue rods and the orange rods with good results. it's all about being clean and getting the heat right. it can be real difficult if one base metal is thicker than the other (say a valve body in brass to copper pipe).

good luck man

after getting a "root" in with the silver solder, I'll go over it with regular 15% silfoss for a nice heavy cap. this seems to help prevent cracking
 
#13 ·
I would only recommend using the oxy/acetylene torch for this type of brazing/soldering job due to the heat requirements. it is possible to get the joint hot enough with acetylene or mapp gas alone (depending on the size of the piping, etc...), but it just adds another element of difficulty to an already difficult job. I would stick with the oxy/acetylene torch and use a smaller tip for smaller jobs
 
#14 ·
I've always used 45% silver, I prefer the Harris Stay-Silver flux, have used the flux coated rods the work good to. Clean & flux the f**k out of it 1st, and watch your heat.
 
#15 ·
it aint the tools.


go back tomorrow, clean it up, slow it down , you'll be fine.
 
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#16 ·
for brass to copper I prefer to use the 46% silver, stuff comes in a wire form. Flux the male , easy on the heat and away u go:D
 
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#17 ·
jcarlding said:
I've used the blue rods and the orange rods with good results. it's all about being clean and getting the heat right. it can be real difficult if one base metal is thicker than the other (say a valve body in brass to copper pipe).

good luck man

after getting a "root" in with the silver solder, I'll go over it with regular 15% silfoss for a nice heavy cap. this seems to help prevent cracking
Click to expand...
I have been using this method for years with large Brass check valves on market and commercial refrigeration just coat everything with blue rod then 15% only had problem once. Old Fart told me to clean with muriatic acid, it worked great so now on all brass valves over 1 1/8 I clean with acid first to prevent over heating by taking too long.
 
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#18 ·
45% with Stay-Silv flux and watch the heat on the TXV! Soft solder is very good also with low heat and Bridgette brand soft solder with lots of flux and a super clean joint(includes oils from your hands).
 
#19 ·
graham
Regular Member Join Date: Mar 2004
Location: ottawa canada
Posts: 169

You need the silver solder rods with the blue flux on them . If you cant weld it with that pack up your tools and go home.

LOL.. That Graham is busting balls today!!!
 
#20 ·
...and I don't know who came up with this theory of only putting flux on the 'male' side of the joint as a general rule. the directions on the flux clearly direct one to flux ALL surfaces. unless you have a super-critical high purity system where some ENGINEER specifies 'flux male side of joint only', you would do good to follow proper procedures. I can see not wanting to get excessive foreign materials in the refrigerant circuit, so only put a thin film.

only clean and put flux where you want to the solder to go, I say

thank you
 
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