Soldering vs. Brazing

[Rockhammer]

I know this has been discussed before, but given that the concerns regarding purging with propane keep resurfacing, I keep wondering if would we be better off recommending that newbies solder instead of braze?

With solder you really don't need to purge due to the lower temperatures used. I know that the industry standard is to braze, but since our units (except for the handful of commercial builders in here) aren't shipped half way across the world and since they aren't cycled 20 times a day like an AC unit or a refrigerator do you guys think we could get by using solder?

I know that Harris makes a line of solders meant for HVAC work. Here is a quote from the Harris website:

"Silver-bearing solders are often used throughout the refrigeration/air conditioning industry instead of brazing alloys. Both Stay-Brite and Stay-Brite 8 produce an overall component with greater strength than a brazed component whose base metals are weakened by annealment from high brazing heat. Stay-Brite solders bond with all of the ferrous and nonferrous alloys. Joints soldered with Stay- Brite solders exhibit considerably higher than nescessay elongation for sound, dissimilar metal joints and vibration applications. Stay-Brite 8 is especially effective in filling loosely fitted couplings. "

Pardon me while I don my flame retardant suit.....

[Rockhammer]

I don't know Tom. I've done a bit of both now and I think it is a similar learning curve for both soldering and brazing. I guess I would say that tight-fitting joints are easier to solder and loose-fitting joints are easier to braze. Really none of it is all that hard to do.

But for the noob who is wanting to give phase building a try, not having to invest in a proper brazing rig with purging gear removes a couple of major cost barriers.

[jinu117]

I am not sure how many of custom build unit has been stay8 soldered. All the known failure related ones were regular plumbing solder in action really (totally unsuitable).
For most with proper brazing outfit though since cost of stay8 isn't any diff from stay 15 brazing rod... it makes almost moot point to find out...

[expansionvalve]

I like soft solder(usually), easy, quick, and if good practices are carried out the joints can be very reliable, just avoid plumbing soft solder!

As some of you know I work in the transport refrigeration industry and nearly all units I come across are silver brazed, but there is one manufacturer that uses soft on all pipes, copper to copper, copper to brass, brass to brass, on suction and discharge lines with 134a and 404a, I have seen soft solder blow out on both gasses for a number of reasons, the biggest reason is a crap solder at the factory but it's pretty uncommon these days, I think the field engineers have moaned at the factory enough they have changed their ways.
Some of the 404a units I see on a hot summers day run at around the 300/350 psi mark and soft solder has prooved to be very reliable, with lots of road vibration I find it stands up very well really. The one thing I will say about it is that you dont need megga heat and quenching is a no no really especially when brass is involved.
Get your joint nice and clean, flux and tin the joint, gently warm add solder and let it cool in a natural fashion.

Saying that, it does take a bit of practice to get soft solder joint done well, silver is allot easier I think.

When I eventually get round to glueing a single stage cpu cooler together I will use soft exclusivly just to prove a point, I bet 50notes it won't fracture and leak :D

[Rockhammer]

Agreed that basic plumbing solder is not suitable. And yes, the cost of the consumables are similar, but compare the cost of a basic propane torch to that of brazing/purging rig. Keep in mind that I'm talking about what advice we give to the hobby builder not the commecial builder.

Edit to fix a typo. Also, this post crossed with Expansionvalve's.

[[XC] MarioMaster]

i've done soldering with silver solder and i've found brazing to be easier, silver solder is thin when liquid and is a lot harder to get a good seal without dripping solder inside the pipe

[Xeon th MG Pony]

I like soft solder(usually), easy, quick, and if good practices are carried out the joints can be very reliable, just avoid plumbing soft solder!

As some of you know I work in the transport refrigeration industry and nearly all units I come across are silver brazed, but there is one manufacturer that uses soft on all pipes, copper to copper, copper to brass, brass to brass, on suction and discharge lines with 134a and 404a, I have seen soft solder blow out on both gasses for a number of reasons, the biggest reason is a crap solder at the factory but it's pretty uncommon these days, I think the field engineers have moaned at the factory enough they have changed their ways.
Some of the 404a units I see on a hot summers day run at around the 300/350 psi mark and soft solder has prooved to be very reliable, with lots of road vibration I find it stands up very well really. The one thing I will say about it is that you dont need megga heat and quenching is a no no really especially when brass is involved.
Get your joint nice and clean, flux and tin the joint, gently warm add solder and let it cool in a natural fashion.

Saying that, it does take a bit of practice to get soft solder joint done well, silver is allot easier I think.

When I eventually get round to glueing a single stage cpu cooler together I will use soft exclusivly just to prove a point, I bet 50notes it won't fracture and leak :D


I all ready built a system using soft solder running R-290 then again I have years of electrical soldering under the belt but again it realy is not that hard to make a "pro" joint, just use good procedure, degrease, sand, clean with iso, flux and heat and solder. The majour thing is it must be lead free and silver berring as R-134a and POE oils will react with the lead.

[Xeon th MG Pony]

i've done soldering with silver solder and i've found brazing to be easier, silver solder is thin when liquid and is a lot harder to get a good seal without dripping solder inside the pipe

A trick you can use is ever so slightly expand the inside pipes mouth to tighten the seal with a standerd punch, works like a charm!

[wdrzal]

Rockhammer your first post is mostly correct, but those are only claims made by the company that produces staybrite8 To this day no formal refrigeration foundation such as RSES has accepted it . That statement could be wrong by I don't think so since I never seen a bulletin on it from RSES.

Also most refrigeration & air conditioning for sure does not have the wide swings in thermal temperature that we see here. Here the limits of single stage refrigeration are pushed to -60c++ and cascades much lower.

The thermal cycling is my main concern + the added fact you can't soft solder steel or stainless steel that most guys use for flex lines.

I,m sure everyone who never brazed before ,after they acquired the proper equipment will tell you how easy it is and would not consider soft solder.

Learning new abilities is what forums are all about, and personally to me doing the best job possible using the best materials is what makes you successful.
And believe me ,people notice.

[Rockhammer]

Thanks for the thoughtful post Wdrzal. Yeah, no doubt that Harris is trying to sell solder, lol. But then they sell brazing rods too, and they have a good reputation to protect, so the truth is probably not far from what they are saying I would guess.

I think we need to be realistic and recognize that for every noob like me that takes the time to register and post in this forum there are probably 10 that are just reading and building. If some of these guys are going to make a choice between brazing and purging with propane (like I did) or using solder with no purge, I think they are probably better off using solder.

[wdrzal]

I do agree with you last statement to a point,but once you develop a habit you will not tend not too change. So as one goes on to build cascades and work with gases of much higher pressure,they will see no need to buy brazing equipment or learn to braze.

The first thing I see most people due when they come here is run out and buy a expensive thermometer usually 100.00 or more, instead of spending 20.00 on a used 1000+ page book I recommend that covers all theories and safe procedures to build a refrigeration system and another 20.00 or so on a used regulator and get a small tank for nitrogen to make strong safe joint thats used by the industry worldwide with a superior track record.

Some of you this just is a passing hobby ,but many are selling rigs they make and who knows where they will go from there.But usually once someone is mechanically inclined to due this type of work,even if their professional life leads them in another direction, they do their own HVAC work as they have to tools and the knowledge.

.

[runmc]

I know this has been discussed before, but given that the concerns regarding purging with propane keep resurfacing, I keep wondering if would we be better off recommending that newbies solder instead of braze?

I don't think it would be a good recommendation to suggest to anyone to use a method other than the optimal. True there can be alternatives.

I have learned that MOST of the time you are better off buying the proper equipment to do a job right off the bat. If you go about doing a project the cheaper route, more times than not, you end up having to buy tools twice. Buy good, top of the line tools. Your job will turn out better and you won't have to buy twice. You can always sell the tools when you are finished with them. People always will buy good, used tools.(Sometimes you may have to postpone a project to save the money.)

If you don't have time to do it right the first time, how are you going to have time to do it again?

[johann]

I don't think it would be a good recommendation to suggest to anyone to use a method other than the optimal. True there can be alternatives.

I have learned that MOST of the time you are better off buying the proper equipment to do a job right off the bat. If you go about doing a project the cheaper route, more times than not, you end up having to buy tools twice. Buy good, top of the line tools. Your job will turn out better and you won't have to buy twice. You can always sell the tools when you are finished with them. People always will buy good, used tools.(Sometimes you may have to postpone a project to save the money.)

If you don't have time to do it right the first time, how are you going to have time to do it again?

i agree about quality tools.

I do not know however how anyone would want to solder instead of braze. Brazing is not rocket science is really easy.

If you have the rigth filler rods and a simple MAPP torch you can braze very well with ease.

I remember when i bougth my first torch, it cost £16 and a bottle of mapp cost £8. My very first joint i tried of copper 1/4" was fine and i could not believe how easy it actually was.

In London where space is very limited and expensive it is very impractical carting around tanks of oxy and acetylene/propane. I like the portability of my Rothenberger MAPP torch. It does everything fine. Heats quickly and is small and portable. Until I get a big workshop I will not consider another brazing setup.

Look at my sig and all the phase machines I have built. They are of top quality and it was ALL done with my MAPP torch with ease.

In all honesty soldering is alot more of a pain, you HAVE to flux everything, the solder melts at a low temp so you end up mostly overheating the joints anyway and to top it off, its not up to refrigeration standards. No one can recommend soldering phase units to anyone

[martinjon666]

(Sometimes you may have to postpone a project to save the money.)


Also a very good point, a lot of newbs want to build something and will go ahead with it when they dont have everything that they need. I have a few projects sitting on the side because i dont have all of the tools that i need to do exactly what i want.

Patience is a very good trait to have when messing with refrigeration.

Jon

[star882]

http://hvac-talk.com/vbb/showthread.php?threadid=121030
I do not recommend soft soldering for refrigerant plumbing. It's fine for very low pressure secondary loops and electrical wiring.

[Xeon th MG Pony]

Like I said, 95/5 and a proper prep, good as any braze, did you read the whole post? Fiew the guys there saying the same thing as me. I've never had problems with it and if you follow the proper soldering prep neither will you or any one, just learn to make a good solder joint first.

[wdrzal]

Like I said, 95/5 and a proper prep, good as any braze, did you read the whole post? Fiew the guys there saying the same thing as me. I've never had problems with it and if you follow the proper soldering prep neither will you or any one, just learn to make a good solder joint first.


Soft Solder is not as strong as brazing.....................PERIOD end of discussion.

[Xeon th MG Pony]

for you; Where are you ultra expert credentials to say that? No it is not the end by far. I figure I'll add on I've talked to techs older then refrigeration its self, the reason for switching to silphos was lazienes and speed as no joint prep was needed I don't know what version of reality your basing your opinion on but I'm afraid real life doesn't wholy agree with you, they can perform on par or at odds either case there is no 100% line between them!

A properly don solder joint the pipe will rupture LONG befor the solder joint, perhaps you are unable to make a good joint but plenty others can.

[Rockhammer]

All of this sounds like one guy's (or gal's) opinion to me. Aren't there any published facts on this stuff we can point to?

[johann]

I would say its the opinion of some experience refrigeration engineers not one guy.

[Xeon th MG Pony]

And thoughs opinions seem to be deeply devided, a Couple local goys both now retired are happy with either, they switched depending on their needs and the situation, like the one guy said in the other forum, Harris 8 worked great for ODS TXVs, I think I like the idea my self for Solenoids, be handy for doing tight solenoid joints.

If don well they hold well over 600PSI, a Logging camp I lived in had a 600PSI line and it was don all with 95/5, I personaly was scared of the dam thing just becuase of the pressur, but never a joint had failed on it, and it when't through more pressur shock cycles then any refer/window ratler unit ever will, and if it held I can gurentee any refer unit will too if the joints are don well. How do you think they did it befor they figured to use silphos?

I now use a type of soft solder here that is silver berring (They doen't say exactly the amount) and it is seriously tuff and makes wonderfull joints, I use an alkaloid poweder flux for it. Now that I have tried brazing it works well to I rather like how fast and easy it is to do joints with the 15% I do not how ever like the looks of the anealment of the copper, can't be good for the metal.

How ever in the case of cascades, due to the higher temps and pressure I leave that to the ones with the most experiance, My experiance tapers off at the 600PSI range for copper works (I still hate having had to work on that line, never fancied the idea of air embolism).

[wdrzal]

Xeon th MG pony / just for your information Stay8 from Harris ,the soft solder for refrigeration that has 8% silver has only been on the market for about 5 years, So much for techs older than refrigeration it self ????

And yes rockhammer there is, RSES (refrigeration service engineers society)

Brazing is stronger and is used for many reasons over solder.

The main difference is brazing needs more heat than soft solder.

Not having to apply flux is NOT the reason as "old timers mentioned " you can ask them "old timers" that all most all soft solder sold prior to the 1980's had a % of lead with the tin ,from 95/5 to 50/50 commonly used for plumbing & copper heat pipe until the ban on lead solder about 15 or 20 years ago for potable water (drinking). It was just about 5 years previous to lead being banned, that all the "Lead Free" solders appeared and where readily available.They usually say "Lead free" "silver bearing" safe for plumbing, but give no percentage, it's lower than 1 % or 2% depending on brand and mixture some have even much less .

But with said ,lead reacts with the refrigerants causing corosion was one of the reason it was not used along with it does not have the tensile strength that brazing does. refrigeration requires much higher pressures and thermal cycling than plumbing.

[Speederlander]

Can anyone recommend some "get it right the first time" brazing tools (esp. a nice torch)? If I am going to spend the money, I would rather spend more upfront on better tools than do it twice and replace less than stellar stuff down the line. Thanks. :)

[wdrzal]

Nothing is hotter than a 2 gas torch,fuel and oxygen as a oxidizer.
But is also the most expensive.Acetylene/oxygen is the hottest,with next being mapp/oxygen then propane/oxygen.

Mapp is a combination of acetylene and mostly propane,but could also have butane. Acetylene is mixed in a percentage below where it is unstable.Pure acetylene MUST be stored and transported in special tanks that have a porous foam and acetone is used to stabilize acetylene.Even in this state your regulator output setting of 15 psi is red-line.Internal tank pressures are around 200 to 250psi for full tanks,this is only possible because of the foam holds the acetone and acetylene together stabilizing the acetylene.



then the single gas torches,same as above but use air instead of near pure oxygen,Air has 20.9% oxygen.

so it would be acetylene/air.............mapp /Air.........and the coolest ..propane/air.

[martinjon666]

Can anyone recommend some "get it right the first time" brazing tools (esp. a nice torch)? If I am going to spend the money, I would rather spend more upfront on better tools than do it twice and replace less than stellar stuff down the line. Thanks. :)



If this is your first time brazing, get a map gas torch ($30) and practice with that a bit, then buy an oxy/acet setup ($300+)

the micro torch setups are worthless as you cannot even braze an evap with a tank of oxygen (depending on the mass of the evap) and a bottle of oxygen is about $8

If you are in this for the long run buy an oxy/acet setup, if you have never brazed or welded anything before get a small cheap torch head and some mapp gas to get a feel for what you are doing and what colors the metal needs to be before it is a good idea to start.

The oxy/acet setup takes a bit more practice and skill but it is much better and faster, definitely worth the money.

[wdrzal]

I should give this warning: if buying a 2 gas torch,be sure to get some professional training before use. As there are many dangers if not used properly.Below is just one of the many.

Just the oil off you hand can cause a loud POP when mounting regulator,(its actually a mini explosion )on the high side of the oxygen tank regulator. so never use oil on threads or wipe wipe with a oily rag or it will be more than a PoP.

Thats just one of the dangers , So get profesional training.

[wdrzal]

If you want to learn more about torches, FIND and GO to a MAJOR supplier of bottled gas and professional welding equipment and talk to the people there.They all have a store where they display their equipment and exchange tanks. This does NOT mean Lowe's or home depot.

[runmc]

NEVER USE OIL (WD-40) OF ANY KIND ON REGULATORS OR REGULATOR THREADS :stick:

Thanks wdrzal for your words of wisdom :clap:

[Brettbeck]

If you want to learn more about torches, FIND and GO to a MAJOR supplier of bottled gas and professional welding equipment and talk to the people there.They all have a store where they display their equipment and exchange tanks. This does NOT mean Lowe's or home depot.

I agree with this. The guy I know at our local BOC place is very friendly and helpful. He said if we ever weren't sure about something or needed help to just give him a ring :).


In regards to brazing setups...for our use I think oxy-propane is ample. Mine will melt solid steel with ease :D. And this was only with about 5psi fuel and 8psi oxygen... thanks jinu;) !

[Xeon th MG Pony]

Xeon th MG pony / just for your information Stay8 from Harris ,the soft solder for refrigeration that has 8% silver has only been on the market for about 5 years, So much for techs older than refrigeration it self ????

And yes rockhammer there is, RSES (refrigeration service engineers society)

Brazing is stronger and is used for many reasons over solder.

The main difference is brazing needs more heat than soft solder.

Not having to apply flux is NOT the reason as "old timers mentioned " you can ask them "old timers" that all most all soft solder sold prior to the 1980's had a % of lead with the tin ,from 95/5 to 50/50 commonly used for plumbing & copper heat pipe until the ban on lead solder about 15 or 20 years ago for potable water (drinking). It was just about 5 years previous to lead being banned, that all the "Lead Free" solders appeared and where readily available.They usually say "Lead free" "silver bearing" safe for plumbing, but give no percentage, it's lower than 1 % or 2% depending on brand and mixture some have even much less . But with said ,lead reacts with the refrigerants causing corosion was one of the reason it was not used along with it does not have the tensile strength that brazing does. refrigeration requires much higher pressures and thermal cycling than plumbing.

Older techs I am talking of 95/5 NOT Harris.

Here on the coast an old resterount was just (being apx a year ago or less) torren down, gues what the whole AC system was made with? For thoughs who guessed 95/5 your right (The origional, it was decommissioned in 97 as it was too small to handle the loads), it was made around the 70s-80s R-12 origionaly (Recharged with MP49) Minerol Oil As was the walk in freezer, but it was guted and replaced with a R-401a unit and evaps replaced, R-12 TXVs where used and adjusted for currect superheating.

Either way for eas I would use brazing or solder pending on the need, if your selling or realy worried about it fine, go with all brazing, 15% silver makes lovely joints, but this does not negate solder does and will work & being that now there is "true" lead free solders (assuming they wheren't in the 80ies as you claim in the US) then that issue is mitigated that IS my only point and issue.

Last I recall it was the newer R-134a that mostly reacted with lead with the POE. R-12 and R-134a on average have low head pressure and discharge temp aint quite through the roof either, for more high pressure refrigerants (Ie alot of the newer ones) Then yes perhaps brazing is the only way, I have only been around the R-22; R-290; R-12(as referance/comparision guid) R134a; R-152a; R-500 (I feel bad working on stuff with that due to its R-12 component, thinking I'll replace it with R-134a or R-290/R-134a Mix need to get a better scale though for that.

[Xeon th MG Pony]

Remember some thing that would smolder in air will expload in 100% O2 environment, never smoke or have any thing highely flamible around your O2 and tons of cleaning as best to keep dust down, reduces risks if it should ever get a high volume leak. and all ways have a damage controle system set up for the fun "what Ifs" and an escape rout ploted in the Oh sh*t moments

[runmc]

Remember some thing that would smolder in air will expload in 100% O2 environment, never smoke or have any thing highely flamible around your O2 and tons of cleaning as best to keep dust down, reduces risks if it should ever get a high volume leak. and all ways have a damage controle system set up for the fun "what Ifs" and an escape rout ploted in the Oh sh*t moments

Excellent suggestions MG Pony :clap: