HVAC brazing torch

ChrisJ

Hi all,

I need some input on options.
I have an acetylene turbo torch with a B tank I bought in 2013 with 5 tips. The tips I have are 3,5,8,11,14.

The issue I always seem to have is not enough heat when brazing fittings next to a wet rag, like the suction line valves on a condensing unit. Like, not even close to enough heat. It gets the job done, but it's a fight and I'm sure I come close to cooking something I don't want to. Trying to braze a 7/8" OD line an inch from a soaking wet rag is tough. I was using the A11 tip, because the 14 just seemed like I'd have too much flame all over.

I'm thinking I need a smaller flame with more heat..... A lot more heat...


What are my options?
is Oxy-propane an option? Should I go right for Oxy-acetylene?

EdTheHeaterMan

I got good at directing the heat away from the valves on that 7/8" suction line with just acetylene and a turbo torch. I can't remember which tip I used but it was probably the A-8 that came with the regulator kit the HVAC supply house sold.

I did have one mechanic that worked for me that preferred Oxy-Acetylene for this task. Have you tried to use Heat Sink Compound in leu of a wet rag?

ChrisJ

EdTheHeaterMan said:

I got good at directing the heat away from the valves on that 7/8" suction line with just acetylene and a turbo torch. I can't remember which tip I used but it was probably the A-8 that came with the regulator kit the HVAC supply house sold.

I did have one mechanic that worked for me that preferred Oxy-Acetylene for this task. Have you tried to use Heat Sink Compound in leu of a wet rag?

I have no problem aiming the heat away from the valves, the problem is how long it takes to get the joint hot enough to braze. In that time the copper/brass conducts enough heat that it gets concerning.

I haven't tried any of the gels etc at least not yet.

hot_rod

A lot more precise control with a oxy acetylene torch. I use it for T Drill joints also do you don’t soften as much tube
Easier on the ears also😗

ChrisJ

hot_rod said:

A lot more precise control with a oxy acetylene torch. I use it for T Drill joints also do you don’t soften as much tube
Easier on the ears also😗

Oxy acetylene doesn't soften tube as much?

ratio

You get the parts you need hot enough fast enough that you're done & cooling things off before the heat travels very far. I only use the small oxyacetylene kits (R & MC tanks) unless it's something I need say a 32 tip on.

mattmia2

You could always use a flare for just the connections to the service valves.

hot_rod

ChrisJ said:

hot_rod said:

A lot more precise control with a oxy acetylene torch. I use it for T Drill joints also do you don’t soften as much tube
Easier on the ears also😗

Oxy acetylene doesn't soften tube as much?

It's a hot, pin point flame compared to the wide flame of the turbo. Watch them build solar or refrigeration coils, it is always a welding type torch and tip.

At the JW Harris booth, AHR, they had a tip in a semi circle with two or three small flames for sil soldering accurately. Electronic control for the flame!

I put a demo on my IG reel recently showing a oxy / acetylene joint

ChrisJ

mattmia2 said:

You could always use a flare for just the connections to the service valves.

How would I do that if they come with copper socket connections?

ChrisJ

ratio said:

You get the parts you need hot enough fast enough that you're done & cooling things off before the heat travels very far. I only use the small oxyacetylene kits (R & MC tanks) unless it's something I need say a 32 tip on.

What size turbo tip would you have been using on a 7/8" connection to the condensing unit with the valve wrapped?

The A-11 worked, but I would've liked a lot more heat there. It could very well be me just being a noob but I want to be sure I'm not using the wrong tools.

heathead

CAP’N HOOK® TIPS Uniweld. I tried the other options but decided to use these and have had great success with little frustration. Not something I do every day, but way less stressful. I have used the turbo torch took way to long, then the oxyacetylene. Make sure you have a proper flame mix. IE Not to oxidizing. Last time couldn't find my oxyacetylene hoses and handles, and decided to buy the cap'n. hooks. They only fit a small torch handle, so just bought the kit. Then bought the flash back valves, just to play it safe note sure if needed. Hot Rod what is a t drill joint? Is that a hole in a pipe that you then put other pipe into like a make a copper manifold manifold?

JUGHNE

ChrisJ, have you considered soft silver solder on suction lines?

I have used StayBrite on 7/8 and 1 1/8" OD suction lines for 30+ years.
A minimum of flux on male fitting is all that is needed.
Heat needed is like that of plumbing solders.

From reading on another HVAC site, it is used more than I realized.

I can see a "boxer" or "briefs" discussion coming.

EdTheHeaterMan

JUGHNE said:

I can see a "boxer" or "briefs" discussion coming.

I prefer Boxers

ChrisJ

JUGHNE said:

ChrisJ, have you considered soft silver solder on suction lines?

I have used StayBrite on 7/8 and 1 1/8" OD suction lines for 30+ years.
A minimum of flux on male fitting is all that is needed.
Heat needed is like that of plumbing solders.

From reading on another HVAC site, it is used more than I realized.

I can see a "boxer" or "briefs" discussion coming.

I haven't, mainly because it seems like no manufacturers allow it.
That could just be from the fear of guys being sloppy with flux I guess.

hot_rod

A #2 tip in this torch. This was my dads torch, probably 60 years old or more! I can do a 1" copper tube into a 2" header with this setup.

I also use Blockade, a fraction of the price of silver blends, a bit lower working temperature. Flows nicely, you can do "bicycle frame" quality beads with this tip and rod

ratio

I'd be using the oxy kit for that, with whatever tip came with it, IIRC #2. Not much experience with turbo torch or B tank really, except the occasional times I need to do 2-5/8 or a big honkin' king valve. Really, I've found the oxy to be so forgiving, as long as it lights I can solder with it. I have used a rosebud in the past, and the Cap'n Hook, when I just can't get it done with the #2.

Oh, and 15% is my daily solder, but I do use fluxed 54% on difficult things (even steel!). Once I wet the surface, I can generally fill the joint with 15%. Which now that i think about it might just mean that I need to use flux, but the 54% rods are in my truck already…

hot_rod

This is a REMS tee puller, a bit simpler than the T-Drill, and less $$
Supposed to leave the depth nob showing, when you solder, so they say.

pecmsg

I find most techs get scared when the rag begins to burn. Don’t. A11 is fine for 7/8”. A small drip of water while brazing helps b

mattmia2

ChrisJ said:

mattmia2 said:

You could always use a flare for just the connections to the service valves.

How would I do that if they come with copper socket connections?

Cut off the swedged piece, put a flare nut on the tube and flare the tube.

ChrisJ

mattmia2 said:

You could always use a flare for just the connections to the service valves.

How would I do that if they come with copper socket connections?

Cut off the swedged piece, put a flare nut on the tube and flare the tube.

I guess that's possible but not without evacuating a brand new unit.  There's only an inch or two stub sticking out of the valve.

ChrisJ

pecmsg said:

I find most techs get scared when the rag begins to burn. Don’t. A11 is fine for 7/8”. A small drip of water while brazing helps b

That's literally what scares me 
The rag steaming and then burning if you take too long.

mattmia2

ChrisJ said:

mattmia2 said:

ChrisJ said:

mattmia2 said:

You could always use a flare for just the connections to the service valves.

How would I do that if they come with copper socket connections?

Cut off the swedged piece, put a flare nut on the tube and flare the tube.

I guess that's possible but not without evacuating a brand new unit.  There's only an inch or two stub sticking out of the valve.

I think that the stub is too short is both of your problems. Can you order the condenser with flare connections or plain tube ends?

EBEBRATT-Ed

Oxy acetylene is the best. Because you can work faster. Turbo torches are fine but the heat up time is a killer.

The question is are you better off with a cooler flame that takes longer (turbo) or a hotter flame (oxy) that works faster?

It's always a judgement call and there is no magic answer.

I piped a Trane unit a few years back that had ball valves on it that one look told you it would take a lot of heat and there was no way to manipulate the torch around the valve. (Right next to a sheet metal panel

This was going to cause me to have to cook the valve and burn the paint off the sheet metal and maybe destroy the valve or not get the braze to flow.

Trane was doing the start up after we piped it. So, I put it to their service tech. He said, "I agree, I am ok with StayBrite. (It was R-410A) so that what I did.

We brazed the whole job except the two connections at the unit.

I have heard that code requires brazing because they don't want the joints coming apart in case of a fire (phosgene gas)

But JW Harris states on their web site that Stay Brite is a stronger joint because it doesn't anneal the pipe.

Since the connections to the unit were on the roof I wasn't concerned about phosgene.

pecmsg

ChrisJ said:

pecmsg said:

I find most techs get scared when the rag begins to burn. Don’t. A11 is fine for 7/8”. A small drip of water while brazing helps b

That's literally what scares me 
The rag steaming and then burning if you take too long.

Don’t worry. 

Practice.

Tinman

I used an A-14 tip for 7/8” and 1 1/8”. No
problems, no cooked service valves. 99% of the time I used wet rags. Now there’s tons of products available. 

ChrisJ

Well.

What I'm gathering from this discussion is oxy may help but isn't the main issue, it's me. I need to do more brazing and even experiment a little with some stuff on the bench to see how hot I can get something that's wrapped with a rag before I'm risking damage. When that rag starts sizzling and I know the clock is running out I get real nervous.

The other thing I think I've learned is the turbo torch chart that shows what tip to use seems to be aimed at a joint in the middle of no where rather than a joint an inch from a massive heat sink.

If I get an oxy-Acetylene setup I could do other things with it like welding and cutting.
On the other hand.......then I need to deal with an oxygen tank. An oxygen tank + B tank is getting a bit....heavy, awkward etc. Trying to haul a 60cuft N2 tank and a B tank around is already enough fun, I'm not sure I want more.

I'm surprised no one here is running oxy-propane? I know we have a setup at the shop for it because the guys wanted to get away from dealing with Acetylene but I have no clue what the downsides to it are. One benefit for me would be I only have a car and laying the tank down is highly frowned upon and having to let it sit upright for whatever length of time can be a pain. With LPG as long as it's anchored I wouldn't be near as concerned.

JUGHNE

I use Thermo Block spray. It gives you a little more torching time before you cook things.
It goes on like thick snot and clings to parts.
If you overspray and get it on the joint you have to wipe it off.

Some spray it on and also do the wet rag wrap for redundancy.

If you get an oxy-act set up IDK if the hose will fit on a B tank.

And could someone elaborate on why to not lay an acetylene bottle down??

I have been told of some mesh screen inside?

The relief plug is on the bottom, if it let go then the bottle lying down could become a torpedo.
Standing up it would be a "safer" rocket going thru the roof?

ChrisJ

JUGHNE said:

I use Thermo Block spray. It gives you a little more torching time before you cook things.
It goes on like thick snot and clings to parts.
If you overspray and get it on the joint you have to wipe it off.

Some spray it on and also do the wet rag wrap for redundancy.

If you get an oxy-act set up IDK if the hose will fit on a B tank.

And could someone elaborate on why to not lay an acetylene bottle down??

I have been told of some mesh screen inside?

The relief plug is on the bottom, if it let go then the bottle lying down could become a torpedo.
Standing up it would be a "safer" rocket going thru the roof?

There's a porous material inside soaked with acetone, not mesh. The acetylene dissolves into the acetone allowing it to be stored safely. When you lay the bottle down the acetone ends up near the valve of the tank and if you use it you'll end up with acetone leaving the tank in the gas which can damage O rings etc as well as obviously removing important acetone from the bottle.

Standing it up for a length of time allows the acetone to settle back down where it belongs away from the valve.

That's my understanding but I'm not a doctor nor do I play one on tv.

ratio

Trying to solder with oxyacetone is an exercise in futility. & It smells funny!

hot_rod

These are handy if you just do occasional jobs. O2 goes quickly with cutting torch, but great for portable brazing.

EBEBRATT-Ed

@JUGHNE

You can buy a simple brass adapter at a welding supply to put a larger Acetylene regulator on a "B" tank.

I use a "B" tank with an "R" (I think) oxygen tank which I think is 20 cubic foot oxygen tank.

I took my hand truck and made a bracket out of threaded rod to strap the bottles to the hand truck.

If I have to get them on a roof top, I take the bottles off and rope them up unless there is a crane on site.

I put each bottle in a larger than normal pail and tie the rope to the pail handle and to the bottle

ratio

hot_rod said:

These are handy if you just do occasional jobs. O2 goes quickly with cutting torch, but great for portable brazing.

I highly recommend a metal carrier over the plastic ones. Also, if you get one of these kits with tanks included, keep in mind that you can't just swap tanks at the supply house unless they have a supplier's sticker on 'em, you'll have to find a place to refill them.

ChrisJ

ratio said:

These are handy if you just do occasional jobs. O2 goes quickly with cutting torch, but great for portable brazing.

I highly recommend a metal carrier over the plastic ones. Also, if you get one of these kits with tanks included, keep in mind that you can't just swap tanks at the supply house unless they have a supplier's sticker on 'em, you'll have to find a place to refill them.

What are standard tank sizes used by everyone?  Thats very important.

ratio

I use MC (C₂H₂) & R (O₂), just like in the kit @hot_rod showed above. The standard tip (#2 IIRC) they come with will do up to 1⅛ without too much trouble. The bottles can be swapped out at any HVAC supply house that I've run in to (provided, like I mentioned, they have the sticker on 'em). Note that it'll ring up as a purchase of a bottle & a refill, coupled with a return of a bottle. The State, in all its glory, has allowed us the privilege of paying sales tax on that total amount without worrying about getting a credit on the return.

ChrisJ

ratio said:

I use MC (C₂H₂) & R (O₂), just like in the kit @hot_rod showed above. The standard tip (#2 IIRC) they come with will do up to 1⅛ without too much trouble. The bottles can be swapped out at any HVAC supply house that I've run in to (provided, like I mentioned, they have the sticker on 'em). Note that it'll ring up as a purchase of a bottle & a refill, coupled with a return of a bottle. The State, in all its glory, has allowed us the privilege of paying sales tax on that total amount without worrying about getting a credit on the return.

Most supply houses should have B tanks as well, no?

What about O2 tanks?  How big is commonly carried?   I'm guessing there's a typical size to match a B tank.

ratio

Yeah, B tanks are generally available too.

The R tank is IIRC 20 CF of O₂, it's the green one in the screen shot above. If they've got MC tanks, they'll have an R tank.

EBEBRATT-Ed

I think the oxy tank I use is 40 cf. I thought it was an "R" but it's not.

Any welding supply will have tanks as well. The HVAC supply house gets them from the local welding supplier anyhow

hot_rod

This is the next step up for common size setups. 80, 122, and 244 cu' are available.
Very easy to find refills, even box stores and Tractor Supply type chains have these tanks. Not quite as portable.

It just depends on what you are trying to do, this size is mostly shop based.

The mini set sometimes has a smaller hose connector on torch and regs, but adapters are available, same with B tank to gauge.

Shop CL or FB marketplace for used systems, they typically have local stickers on the tanks.

SlamDunk

What I have done with hairy brazing work is:
-cut a cotton rag into 4" strips and into 2' sections
-soak them in water, wring them out, stick them in a freezer
-run to local hardware store for fiberglass insulation wrap about as wide as cotton strips (better yet,
kevlar strips.
-wrap frozen strips around component to protect
-wrap frozen strips with fiberglass insulation wrap the keep strips cold and go to town.

hot_rod

I bought a tub of this 10 years or more ago, I still have most of it. Just get it wet, after it crumbles from the heat. Like clay, and use it over and over.

Why risk the rag when this works so well?

EBEBRATT-Ed

It's always a compromise. The more you cool the valve or whatever it is your trying to protect the more heat and time it takes to do the joint.

On the oxy acyet torch hoses the small regulators and torches use "A" size fitting and the standard size torch hose fittings are "B" size.

So you can get hoses with "A" ends or "B" ends or you can buy hoses with "A" on one end and "B" on the other ends.

Welding supply houses can cut and shorten a damaged hose and crip new ends on or to change the size of the connectors