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mizzouhvac
06-19-2011, 08:56 AM
Like many of you Im sure, I am always looking for new tips and techniques on how to do my job better. So I have a question for you all. In my opinion the number one enemy of a txv,(not including possible debris getting by a filter/drier) is my torch. I have always been curious why they make us braze a part in that is sensitive to heat and has short stubs to braze too. I prefer flare but as you know this is not always practical.

So my question: How do you go about brazing in a txv and protecting it from damage?

Myself I use a liberal amount of a thermal absorbing paste and wrap it with a wet rag.

maxster
06-19-2011, 09:02 AM
take it apart down to the raw body and torch away...:.02: power hat and all

jpsmith1cm
06-19-2011, 09:05 AM
Tear your rag into strips about 1" wide.

Wrap the body tightly with them.

Braze fast.

Meerkat82
06-19-2011, 09:41 AM
I also like to use heat paste and wet rag. I also like to flux the joint it seems to help the silfoss run a little faster, making for a quicker weld.

Home&Marine
06-19-2011, 09:49 AM
TXV's? I use what Certified Hacks use... StayBrite 8. :)

After killing 2 TXV's on a 15 Ton Trane, I won't use 15% on a TXV unless I can cut it out and braze the tubes to the TXV, then swage the tubes back together. I've also used 1" Rags and the Squirt on heat stuff.

timebuilder
06-19-2011, 10:26 AM
I pack it with a tub full of Hot Dam.

hvac wiz 79
06-19-2011, 11:52 AM
Tear your rag into strips about 1" wide.

Wrap the body tightly with them.

Braze fast.

that's pretty much the best method ive found so far

frio
06-19-2011, 12:21 PM
i wrap it wth a wet rag and i have a spray bottle with water handy to keep rag cool and wet.

Paul Bee
06-19-2011, 12:51 PM
Safety silv 1200 is 56% silver and is liquidus at 1200 degrees. Your Harris 15% is liquidus at 1480 degrees. That is almost 300 degrees hotter. Stay brite 8 is liquidus at 535 degrees. When I was an RCA Factory Service technician, we could only use Easy Flo 45% it is liquidus at 1100 degrees. You have to use flux with the "high silver" products. The copper tubing does not get discolored or a lot of oxides at these temperatures. Check out the Cap'n Hook torch tips from Uniweld, Smith versa torch has one too. Or a twin tip torch works well with a little practice. I did a walk in freezer txv with that small twin tip from Smith and wet rags. It turned out fine. The guys at one company I used to work for liked the orange or blue coated brazing rod, both are "high silver" products.

joemach
06-19-2011, 01:11 PM
Just replace the "guts".

Not much can go wrong with the valve body (no moving parts). Just replace the power head and internal parts. Throw new body away.

This requires no heat or torch.

Faster and safer.

*Note: This may not always work but will on 98% of TXV replacements.

frio
06-19-2011, 01:29 PM
can you use stay bright# 8 on a fitting that you just sweated off a part that previously had silphos or does it have to be completly clean?

hvacpope
06-19-2011, 08:35 PM
I use JB's Cool Gel,spray it all over the txv, number 3 tip, 15% rod and braze away, United sell it, way better than the paste, wet rag or paper towel would do the trick too.
Most of the TXV's I've replaced were made either by Danfoss or Alco and most failed cause the bulb charge leaked,I always replace them with Sporlan, have very good luck with that brand.

Home&Marine
06-19-2011, 08:54 PM
can you use stay bright# 8 on a fitting that you just sweated off a part that previously had silphos or does it have to be completly clean?

:hijacked:

John Markel is the SB8 expert but from my experience it needs to be Completely Clean.


I also keep CoolGel on the truck but Gosh Dang it's expensive!

msw951
06-19-2011, 11:19 PM
Thermo trap spray and a #0 tip. I find the 0's head is much more contained and I have had problems overheating the txv with larger tips. In fact, I use the #0 on everything up to 1".

ewwilt
06-20-2011, 10:33 AM
I relpaced a txv Friday (brass stubs to copper lines). I used the safety silv 56 with the orange flux coating, used a wet rag also sprayed with cool jel and wrapped the txv well with it. That ss 56 went on like butter, almost as easy as soft solder. almost :whistle:

hceptj
06-20-2011, 01:52 PM
spray it with coolgel, wrap it in a rag and use staybrite 8...:)

HvacCraftsman
06-20-2011, 05:14 PM
Another tip which i havent seen mention is Oxy/Acetylene torch to allow for precise
control of your flame. Definatly remove the power assembly, Scarf the body as much as possible. STAYBRITE 8 Can be used on refrigeration systems. It's joints have been tested
to be stronger than 5-7 mils of copper which is stronger than a piece of hard copper. STAYBRITE does require a very clean joint for it to take well. If your new to using it, don't try your experiments on TEV's. Me personally not a fan of it for this reason.

Flux in refrigeration systems is very bad. Safer and faster to set employees up with the self-fluxing 15% SilPhos brazing rod and a nitrogen purge than expect them to flux carefully enough to do the job without contaminating the system.

Why not SnAg solders (STAYBRITE8) ? Habit, mostly. When you've seen things done only one way for your entire life, it's difficult to open to a new idea.

I would not reccomend using any other form of Solder on a refrigeration system because
halocarbon-based refrigerants are incompatible with lead-based solders. They will eventually leak.

dave sulz
06-21-2011, 08:41 PM
I tie the wet rags on and always have a spray bottle too.

LT1
06-22-2011, 11:11 PM
Does anyone have any advise for joining brass to copper? Silver solder with flux definitely works well but it requires a lot of heat. I tried staybrite 8 with flux but was not satisfied ~ maybe I simply did not clean the brass sufficently before I fluxed?? I always wondered what the manufactures use on a VAX-4 access fitting.

seascott
06-23-2011, 08:01 PM
My favourite for sensitive jobs is oxy/acetylene with a small rosebud tip. Connections up to 7/8 can be made very quickly without the valve getting hot enough to make the wet rag steam. If I try using a straight acetylene or mapp gas the valve sucks up all the heat so it takes forever to get the fitting hot enough and by then my rag is all burnt. Oxyacetylene is the best for condenser repairs as well, saves a lot of fin trimming.

LT1
06-24-2011, 12:34 AM
seascott, could you tell me what pressure you set your acetylene and oxygen regs to.

seascott
06-24-2011, 04:39 PM
I will check but it doesn't much matter, I turned them up when I got my new cutting tip and they are set far too high for most of the tiny tips I use. I just crack the gas, fire up the torch and open my oxygen until I have a slightly reducing flame. My rosebud tip is tiny, the smallest I could find but it puts out plenty of heat to braze in a txv and the heat is very localized so it's easy to control. To accomplish the same with straight acetylene you need a #14 tip, lots of rags and still you wonder how the inside of the valve is holding up. For coil tubing you have to be a little quicker but it's the best way I've found to make delicate repairs.

marter
06-24-2011, 10:31 PM
what ive started doing and i think it worked well is to put in the valve and wrap a dry rag around the joint, spray the valve with the cool gel and also down from where the joint will be made, then braze.. seems to keep the heat where it needs to be and gets it there faster

msw951
06-24-2011, 10:57 PM
Does anyone have any advise for joining brass to copper? Silver solder with flux definitely works well but it requires a lot of heat. I tried staybrite 8 with flux but was not satisfied ~ maybe I simply did not clean the brass sufficently before I fluxed?? I always wondered what the manufactures use on a VAX-4 access fitting.
Brass to copper... I use blue or orange rod.

msw951
06-24-2011, 11:00 PM
As far as pressures go, I run my acetylene at 5 psi, oxy at 10. I think that was jw harris' recommendation if I remember right.

Hrdworkingacguy
06-25-2011, 11:33 AM
Keep the parts you don't want melted wrapped with a rag, make sure everything is clean, use the right torch tip, go hard, go quick and get it done, then cool it off...:eek2:

david chamberla
06-25-2011, 03:52 PM
ive used 8 LIKE IT WELL C00L GELL THAN 45% WOKKED REALY GOOD I LIKE WHEN ALL THAT IS WRONG IS THE POWER HEAD . THAT BETTER YET FASTER NIGHT 12 CALL OF THE DAY HOOYA .

Capz
08-07-2011, 06:17 PM
For the guys who use the Ace/Oxy torch, I'd suggest a slightly carbonizing flame ( take the flame to neutral, then back off some on the oxygen ). I always liked using a #5 tip on 1.125" copper and below. Rosebud tips are nice but too hard to keep the heat exactly where you want it. Neutral flames are too hot. Carbonizing flames, just right.

I silver brazed with 35%, 45% and finally cadmium free 56% daily when I was in the cryo tank install business. 35% was the best for control, 56% would run like mad. I preferred Mapp/Oxy over Ace/Oxy but not for quality of flame but for safety on the service truck and longevity of a single 30lb Mapp tank.

Wrap with 1" dripping wet rags and keep a bucket of cold water close by. Pay attention and check the back side with a mirror.

kamersoutdoor
08-07-2011, 07:29 PM
Any tricks for those Bryant/carriers were the first stage txv sits farthest back and snug against the coil. Not to mention the 5 hp blower mtr in the way for reaching around.
Can't think of MN at this time.
Had a heck of a time with the back & side that rests against the coil.
Sure ain't too excited about seeing another any time soon.
Can those be rebuilt? (txv)
Sure would make for an easier day!

mrhvacmechanic
08-09-2011, 08:15 PM
Staybrite!

kamersoutdoor
08-09-2011, 09:00 PM
carrier/bryants?
You can't clean those stubs, off the distributor, good enough to use solder! Unless I'm missing a trick to cleaning them better. They can't be longer than two-three inches, so you can't cut them. I'll use Staybright on smaller resi's & reefers cause you can clean them up good & add stubs if needed, but the big boys (RTU's) & straybright don't sit well with me.

Am I wrong?

Air Dryer Tech
08-23-2011, 08:32 PM
take it apart down to the raw body and torch away...:.02: power hat and all

Off subject Maxter, Nice profile pic. I was an F14 Tomcat Plane Captain and Ordinance Man VF24 Fighting Renegades 1982-1985 USS Ranger and USS Kitty Hawk. Got Morgans and papers too !

CommtechinVA
08-24-2011, 05:18 PM
seascott, could you tell me what pressure you set your acetylene and oxygen regs to.

I attended a brazing class put on by a Harris rep and he recommended setting acetylene at 7# and oxygen at 16#. Seems to work fine for me at those pressures, but I'm not anal about them being exact. I set the flame up how I want it for a particular job, and just go to town. Hope this helps.:whistle:

Mac222
08-24-2011, 11:37 PM
Been running mine for years at 7#'s ace and 20#'s ox...works great

pafieldtech
10-02-2015, 07:24 PM
I found a heat paste that works like a dream! Im singing about this stuff from the roof tops! It's called "Viper wet rag" its made by Refrigeration technologies. I can't say enough about it. https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.btureps.com/product-lines/refrigeration-technologies/refrigeration-technologies-2/wetrag-refertech.pdf&ved=0CDQQFjAGahUKEwjwsI-S9qTIAhXFPj4KHRRmB48&usg=AFQjCNE_G0UAxtcIGj6OqMT_aVBatvVA9Q&sig2=QIczvHj6lAA-_-UtA_6tXQ

Replacing the guts is only an option in commercial systems anymore. Ever since the great txv fiasco of 2014(ish), I have yet to come across a txv from any residential mfr (@least not the big guys)that's got any mechanical fittings. Permenant powerhead, and you either have no way to adjust superheat or you need to pull the charge to adjust it... I work on commercial about 3 weeks a year only when residential is slow and I love getting a txv to replace because its 30 less pounds to carry/pull up and i dont need to worry about cooking the new one. I also can't help but think its a lot to do with fewer pennies per unit. I'd pay $10 more per unit to get some serviceable valves... Just saying.

skwoodwiva2
10-02-2015, 09:26 PM
For the guys who use the Ace/Oxy torch, I'd suggest a slightly carbonizing flame ( take the flame to neutral, then back off some on the oxygen ). I always liked using a #5 tip on 1.125" copper and below. Rosebud tips are nice but too hard to keep the heat exactly where you want it. Neutral flames are too hot. Carbonizing flames, just right.

I silver brazed with 35%, 45% and finally cadmium free 56% daily when I was in the cryo tank install business. 35% was the best for control, 56% would run like mad. I preferred Mapp/Oxy over Ace/Oxy but not for quality of flame but for safety on the service truck and longevity of a single 30lb Mapp tank.

Wrap with 1" dripping wet rags and keep a bucket of cold water close by. Pay attention and check the back side with a mirror.
How many agree that a slightly carbon flame is most always a good practice?

I am a SB8 fan.

skwoodwiva2
10-02-2015, 09:30 PM
Delete please

BBeerme
10-03-2015, 05:51 PM
If you're using Stay Brite 8, then yes, a cooler flame would be helpful. I've never used the stuff on refrigeration, but have on drain lines, and I just used mapp gas. I think. Boss man gave me a roll many years ago, but I was afraid to use a soft solder on refrigeration. So I just used the roll up on drain lines.

The only time I use a carburizing flame is with Safety Silv 45 or 56%. The lower heat of the flame helps to keep from over heating the flux.



How many agree that a slightly carbon flame is most always a good practice?

I am a SB8 fan.

corny
10-03-2015, 07:33 PM
I go into like a bear..... lots of soaking wet blue rag around the txv and distributor and covering anything else that might get hot then I braze it with as hot a flame as I can get and 15 percent... then I always have a rag ready to put on the joint when done.

1 side at a time with plenty of time to cool down in between...... rewet rags with cool water..... etc.....

I think when people try to pussyfoot around with a small flame that they end up heating the valve more than when you go in there full bore and get it over with quickly.

hurtinhvac
10-03-2015, 08:13 PM
I was switching out Carrier TXVs as a newbie with 6%, the simple torch head I inherited with the truck and never had a problem. It's only one 3/8 joint - gunk it with heat paste and tie a wet rag around in front of that and be quick about it...as you should with a single 3/8 joint anyway, right?

BBeerme
10-03-2015, 08:22 PM
That's my approach.

More heat faster is less heat than using a wimpy flame forever.



I go into like a bear..... lots of soaking wet blue rag around the txv and distributor and covering anything else that might get hot then I braze it with as hot a flame as I can get and 15 percent... then I always have a rag ready to put on the joint when done.

1 side at a time with plenty of time to cool down in between...... rewet rags with cool water..... etc.....

I think when people try to pussyfoot around with a small flame that they end up heating the valve more than when you go in there full bore and get it over with quickly.

obieone
10-03-2015, 09:16 PM
Obviously some exceptions have to be made to some of these recommendations:
1. Can't use soft solder(SB8) on R410A systems(per ASHRAE)
2. There are plenty of TXVs that don't allow getting it opened-factory sealed PH to the body.
What I do, is wrap in multiple layers of the coldest(ice water) rags possible, then bring in the flame from the copper tubing to the female fittings, to prevent direct heat transfer. Conduction via the tubing might not be as great.

pafieldtech
10-03-2015, 09:21 PM
I was switching out Carrier TXVs as a newbie with 6%, the simple torch head I inherited with the truck and never had a problem. It's only one 3/8 joint - gunk it with heat paste and tie a wet rag around in front of that and be quick about it...as you should with a single 3/8 joint anyway, right?
Well said. I think we can over complicate things in a hurry. Also if its in a tough location. I replaced a txv on a water furnace heat pump 2 weeks ago... The same txv is for heating and cooling. I'd been dreading it every day for the week we were waiting for the part. Well, It was an absolute nightmare! I had 3 blind joints with no way to get a line if sight at them... I had 3 mirrors trying to see something. By the end of it, I was waiting to have to order another one. I was on that job for 6.5 hours. After that one, I'm less concerned about a couple of easy access 3/8 joints because that water furnace txv(and drier for that matter) got flippin BAR-B-CUED! I must have stopped 6 or 7 times to cool it and pray[emoji20] . turned out just fine. At least for now. I guess we'll see if it keeps thru the winter. It was an eye opener to see it work in heat and cool after the heat I'd put that poor valve thru.

Sent from my XT1080 using Tapatalk

Poodle Head Mikey
10-03-2015, 09:24 PM
The most obvious answer is to wrap the TXV body and powerhead well with wet strips of heavy rag - like terry cloth - and then use Stay-Brite and a propane or Mapp gas torch to make the connections.

But if you are a guy who simply Must braze no matter how illogical it is - then still wrap well with wet cloth, use white brazing flux, and point the torch flame Away from the TXV while heating and making the joints quickly. If doing one joint makes excessive sizzling sounds come out of the rag wrappings - have more water handy to pour over the wet rag to cool it back down.

PHM
---------




Like many of you Im sure, I am always looking for new tips and techniques on how to do my job better. So I have a question for you all. In my opinion the number one enemy of a txv,(not including possible debris getting by a filter/drier) is my torch. I have always been curious why they make us braze a part in that is sensitive to heat and has short stubs to braze too. I prefer flare but as you know this is not always practical.

So my question: How do you go about brazing in a txv and protecting it from damage?

Myself I use a liberal amount of a thermal absorbing paste and wrap it with a wet rag.

Poodle Head Mikey
10-03-2015, 09:36 PM
Do not do this again.

From now on find three easily accessible points in the tubing - where you can easily re-pipe the line back in with couplings.

Then cut the entire 'assembly' out of the unit at those points.

Re-work the assembly out in the open on a bench or table - replacing the TXV and drier - and then re-install 'the assembly' and do the three couplings / joints in ease and comfort - out where you can get to them.

PHM
------




Well said. I think we can over complicate things in a hurry. Also if its in a tough location. I replaced a txv on a water furnace heat pump 2 weeks ago... The same txv is for heating and cooling. I'd been dreading it every day for the week we were waiting for the part. Well, It was an absolute nightmare! I had 3 blind joints with no way to get a line if sight at them... I had 3 mirrors trying to see something. By the end of it, I was waiting to have to order another one. I was on that job for 6.5 hours. After that one, I'm less concerned about a couple of easy access 3/8 joints because that water furnace txv(and drier for that matter) got flippin BAR-B-CUED! I must have stopped 6 or 7 times to cool it and pray[emoji20] . turned out just fine. At least for now. I guess we'll see if it keeps thru the winter. It was an eye opener to see it work in heat and cool after the heat I'd put that poor valve thru.

Sent from my XT1080 using Tapatalk

BBeerme
10-03-2015, 11:14 PM
Whoa.

Mr. Obvious strikes again.



I'm always perplexed how things more expensive than water have the claim to provide more cooling than water. A wet freakin' rag can suck up a lot of heat!



The most obvious answer is to wrap the TXV body and powerhead well with wet strips of heavy rag - like terry cloth - and then use Stay-Brite and a propane or Mapp gas torch to make the connections.

But if you are a guy who simply Must braze no matter how illogical it is - then still wrap well with wet cloth, use white brazing flux, and point the torch flame Away from the TXV while heating and making the joints quickly. If doing one joint makes excessive sizzling sounds come out of the rag wrappings - have more water handy to pour over the wet rag to cool it back down.

PHM
---------

pafieldtech
10-03-2015, 11:46 PM
I've always been cautious to try and keep too much water away from open joints. The last 3 txvs I've replaced I've used something called "viper wet rag". It's what heat paste wants to be. I've been able to hold the power head while heating it because I didn't want it blocking the door going back on. It's just awesome.

Sent from my XT1080 using Tapatalk

Fan Curve
10-03-2015, 11:57 PM
Safety silv 1200 is 56% silver and is liquidus at 1200 degrees. Your Harris 15% is liquidus at 1480 degrees. That is almost 300 degrees hotter. Stay brite 8 is liquidus at 535 degrees. When I was an RCA Factory Service technician, we could only use Easy Flo 45% it is liquidus at 1100 degrees. You have to use flux with the "high silver" products. The copper tubing does not get discolored or a lot of oxides at these temperatures. Check out the Cap'n Hook torch tips from Uniweld, Smith versa torch has one too. Or a twin tip torch works well with a little practice. I did a walk in freezer txv with that small twin tip from Smith and wet rags. It turned out fine. The guys at one company I used to work for liked the orange or blue coated brazing rod, both are "high silver" products.

X2 The hook works great! You go fast get it done. Never have had a problem. Make sure the head is cool or take it off. My Thought.

psycho-metric
10-05-2015, 07:24 PM
I also use wet rag strips and thermo trap (tooth paste). Cool gel works ok but you gotta be quick because if it gets too hot it just splatters.

mr_guy
10-08-2015, 09:40 PM
In and out fast with valve wet-ragged

ericonditioner
10-26-2015, 08:07 PM
use 92 8 soft solder with flux. actually has a stronger burst pressure than brazing. You do not have to add nearly the heat nor nitro in the system.

Sbogart40
10-28-2015, 09:17 PM
I worked in supermarket refrigeration for a while, was on some bug construction/Reno jobs, needless to say I brazed quite a few txv's, As one said before, get rags very wet, dripping, braze fast, wet down joints after. Never had one go on me.

nchvacservice
02-07-2017, 11:58 PM
I recently purchased the uniweld mtf-5 which has a 5 flame hook design. If you don't own one definitely look into adding it to your arsenal. Everyone I've had use it love it. Its cheap and I know this will save your tail in a situation. It fully emerses the pipe and depending on what direction your brazing the heat stays forward. Still recommend wrapping and cooling techniques also. I'm gonna do a youtube product review on it soon.

Also I just posted a article called Diapers!!! Interesting info.... under general section of forum. Look it up. It discusses wet diapers and how it can potentially be utilized for heat protection. I know its a little odd.

timebuilder
02-08-2017, 08:20 AM
One aspect of wrapping a TXV or solenoid valve with wet rags, is that you can overdo the cooling. I only pour water onto the wrappings AFTER making the joint in question, because if you try to add water as a part of the process, you can create such a good heat sink that you can have trouble getting the joint up to the melting point of the fill metal.

For the new guys:

Stay Brite works great....but it is not compatible with brazing rod metal. If you want to use Stay Brite, you have to cut back the tubing that has brazing residue on it, or replace it outright. I sometimes install fresh tubing stubs and braze them into place to get the lengths correct, and then my final step is to use the Stay Brite on the joints of the part. Use the correct flux (Stay Brite and brazing rod also use different flux) and apply it as a FILM, not globs.