Nice alternative to brazing

[FoxTrottZero]

Hey all... I just found these fittings in the Grainger Industrial Catalog... http://www.grainger.com/images/products/2P159.JPG

You've already seen them on shrader access valves quite possibly.
Anyway- there you go! just flare the ends of your tubing with a flare tool, fit these babies and tighten! (don't forget to put a female coller http://www.grainger.com/images/products/2P147.JPG on the tubing before you flare it! lol!)
1400 psi rated at -65F - Look ma! no brazing!

And you can break the tubing down if needed to make adjustments... still trying to figure out if I can make these work with capillary tubing but it doesn't look good... they only come as small is 1/4"... darn!

still... should save loads of time and money for those of us building single stage units...

comments?

[Pandrone]

You would need to use like 10of those. I don't know but if they are so good why doesnt ppl use them? I believe they are prone to leak or something.

Btw, i have seen capillary-tube with flares at the ends here in Sweden, they should have in US too. :)

[FoxTrottZero]

oh nice! I need cap sized ones...

Yeah... ten or so... but it's only like 18$ and you can take the system apart if you need to.

No leak problems! the 1/4" size is rated at 1400 psi!!! I suppose if you were concerned, you could squirt some sealant in there before you tightened it but I doubt you would need it.

[cold_ice]

I asked severak HVAC techs here, and most of them prefer brazing over using the flare connections. They may prone to leak after some time, nothing goes over brazing :)

[Beenthere]

Brazing is always preferred but if you don't have that option available, a PROPERLY flared line and fittings can be used. The operative word here is PROPERLY since we are working with substantial and dangerous pressures/gases !!!

[FoxTrottZero]

Oh man! there MUST be a simple way to ensure a good leak free connection with these little things!

I knew it was too good to be true... has anyone out there used these things? Anyone with good or bad experiences?

[FoxTrottZero]

Brazing is always preferred but if you don't have that option available, a PROPERLY flared line and fittings can be used. The operative word here is PROPERLY since we are working with substantial and dangerous pressures/gases !!!

cold ice was saying that it will leak over a period of time... if that's the case, and the longevity of these things is questionable, then I would never use them.

having said that, I can't believe that people don't use these things... interchangability would be really great if you could make the stupid things reliable enough.

any comments on using some sort of additional sealant precaution? like silicon or something like that?

[Pandrone]

These fittings are used everyday in the residential refrigeration/heating. In heatpumps and ac/s. I have not seen any new heatpump/ac that's brazed, you always use flares on them. A bad flare will leak, a good one will work ok. But as said above, brazing is prefered.

Why not braze your system instead of using these fittings?

[FoxTrottZero]

Why not braze your system instead of using these fittings?

Cuz it will make everything removable and adjustable... plus it would cost less and be way faster. everything would be interchangeable... if the compressor died, you could unbolt it, unscrew the fittings, then fit a new one in less than 15 minutes... youcould even use the same fittings.

[hatemi]

Cuz it will make everything removable and adjustable... plus it would cost less and be way faster. everything would be interchangeable... if the compressor died, you could unbolt it, unscrew the fittings, then fit a new one in less than 15 minutes... youcould even use the same fittings.

It isnt that much harder to braze the tubes to the compressor either. The only place I would recomend using flares(other that valves etc. where you must use them) is when connecting a stainles steel hose to copper evap/tubes. It is a real pain to learn how to brase stainles steel but when you've got the idea of it then tehre is no real reson to use flares.

[cold_ice]

cold ice was saying that it will leak over a period of time... if that's the case, and the longevity of these things is questionable, then I would never use them.

The might leak, one guy I asked made bad experiences with them. As said a good flare will be leak free for 95 percent, but brazing is better.

[pythagoras]

A phase change kit with only flare connections is possible. Imagine the benefits, you could buy a whole kit, which would only require a wrench to assemble. You could then take the kit to an HVAC engineer for a vac and charge.

If you had a vac pump and refrigerant you could do this yourself. Throw in a couple of shutoff valves and you could pump down the system adjust the cap tube and open the valves to tune, all with out a vac and recharge.

I would say a good flare joint is as good if not better than a good braze joint. Every time you braze a copper pipe you roughly half its psi rating! That dosnt happen with a flare joint. Also you introduce acid into the system and oxcidants (if you dont use a shield gas, and how many of these homemade systems have a shield gas when being brazed?)

I would like to see some of these claims that brazing is better than a flare joint backed up by facts.

From what I have reasearched I cant say a flare joint is better than a brazed joint, all I can say is the above facts which seem to point to the fact that it maybe.

To the people who say a brazed joint is better, could you tell me how you came to that conclusion?

Regards

John.

[gkiing]

A brazed joint is stronger, less prone to leakage, and brazing has a lower margin of error/less leaks. Use eneough brazing rod and even a noob can make a good braze. Flares, if not flared properly leak. You're looking for facts, well try to find a single refrigerator/freezer/industrial a/c that is ALL flare connections. Sure a few (a very few few) will have a flare here and there, but I would say 95% of all fittings on fridges, freezers, and other low temperature refrigeration units are brazed.

It's just silly to put something together entirely with flares. And also, flares can be unscrewed, loosened with rattling etc. Brazed joints cannot. I'm willing to bet that the reason FoxTrottZero wants to have everything as a flare fitting is because he doesnt know how to make brazed connections.

It's really easy, just learn! Read the brazing guide! You can use a small MAPP or even a propane torch, and silfoss brazing rods. It really doesnt take a lot of skill to make them leakproof, it just takes skill to make them look nice.

So far, ive built five smallish direct die systems and one waterchiller, and only one of the brazed joints I did leaked, and it was because I was brazing a steel/copper without a high eneough silver content brazing rod.

[pythagoras]

Hi Gkiing,

I'm not saying am correct, I simply dont know, but the lemming argument wont convince me ;)

well try to find a single refrigerator/freezer/industrial a/c that is ALL flare connections. Sure a few (a very few few) will have a flare here and there, but I would say 95% of all fittings on fridges, freezers, and other low temperature refrigeration units are brazed.

That could simply be a cost factor, its much cheper to braze the joints up than flare, also its easier to braze a joint up after construction than make a flare.

The working pressure for a brazed joint is about 500psi, burst pressure for a brazed joint is 5000psi, the copper pipe itself is about 9800psi burst pressure. A standard flare joint working pressure is about 1500psi, I havnt found the burst pressure yet. But I have found flare connections with working pressures of 10,000psi! Thats all for 1/4" pipe these pressures reduce for larger diameter pipes.

Really high pressure industrial refrigeration units and cryogenic systems use either a flare or a flange connector.

Anyone anymore thoughts?

Regards

John.

[gkiing]

Hi Gkiing,

I'm not saying am correct, I simply dont know, but the lemming argument wont convince me ;)



That could simply be a cost factor, its much cheper to braze the joints up than flare, also its easier to braze a joint up after construction than make a flare.

The working pressure for a brazed joint is about 500psi, burst pressure for a brazed joint is 5000psi, the copper pipe itself is about 9800psi burst pressure. A standard flare joint working pressure is about 1500psi, I havnt found the burst pressure yet. But I have found flare connections with working pressures of 10,000psi! Thats all for 1/4" pipe these pressures reduce for larger diameter pipes.

Really high pressure industrial refrigeration units and cryogenic systems use either a flare or a flange connector.

Anyone anymore thoughts?

Regards

John.

Brazing > Flares. Period. Ask chilly1 why he brazes his suction lines. If indeed those figures are true , it's still irrelvant, we aren't dealing with pressures > 400psi, even on a cascade or autocascade.

[pythagoras]

Well its definately not as conclusive as Brazing>flare. Heres one discussion I have found:

http://hvac-talk.com/vbb/showthread.php?threadid=48662&pagenumber=1

All HVAC engineers, and that conversation isnt conclusive either way. I love this forum, the way people inovate and try new things. However, what I dont like is the lemming arguments and urban myths that can arise, x or y does it this way (who is a GOD!) therefore thats the best way.

All I'm asking for is a discussion with facts to back up your opinion.

Regards

John.

[gkiing]

Well its definately not as conclusive as Brazing>flare. Heres one discussion I have found:

http://hvac-talk.com/vbb/showthread.php?threadid=48662&pagenumber=1

All HVAC engineers, and that conversation isnt conclusive either way. I love this forum, the way people inovate and try new things. However, what I dont like is the lemming arguments and urban myths that can arise, x or y does it this way (who is a GOD!) therefore thats the best way.

All I'm asking for is a discussion with facts to back up your opinion.

Regards

John.

Throwing insults including "lemming argument" does not support your topic. Don't go that route, I dont want to stoop to that level. If this turns into a flame thread I have no doubt that mods will close it. I'm not an HVAC engineer, but I know that brazing is always preferred (note the use of PREFERRED, not necessarily STRONGER) over flares, it's not some sort of phase-change myth, its a fact. I believe Chilly1 is the only HVAC engineer on the forum (with the years of training etc), he might be able to give some more in depth information about the subject. From my experience working with both flare connections and brazed connections, it may be "Better" just for the fact that it is easier, less likely to screw up on, and nearly any connection can be brazed. With brazing you can braze a 1/2" pipe to a 1/4", you can't flare a connection like that. It may just be for convenience.

[FoxTrottZero]

"I'm willing to bet that the reason FoxTrottZero wants to have everything as a flare fitting is because he doesnt know how to make brazed connections."

nope GK... Brazed for years...
I'm just interested in experimenting with interchangeability.
Starting to think that's not going to work though.

might try it to see if I can make it work just to reverse this "urban" legend ;)

[gkiing]

"I'm willing to bet that the reason FoxTrottZero wants to have everything as a flare fitting is because he doesnt know how to make brazed connections."

nope GK... Brazed for years...
I'm just interested in experimenting with interchangeability.
Starting to think that's not going to work though.

might try it to see if I can make it work just to reverse this "urban" legend ;)

There's no urban legend that you CANT flare everything, its just not practical.
If you know how to braze, just do it! There are no associated problems with it, as long as you put proper vibration dampening bends at the compressor suction/discharge.

The reason I previously posted you may not be able to braze is because many people new to phase-change try to avoid brazing like it's some kind of huge danger, or are afraid to learn.

[pythagoras]

Its certainly not going t turn into a flame thread. If anything I have posted has insulted you, then I apologise for that, it isnt my intention. "The lemming argument" isnt an insult, or wasnt meant that way.

Regards

John.

[Epsilon]

The fact that it is cheaper is not true :).

A flaring block + tool cost 50dollar and the flares have to be bough too.
A simple torch is even cheaper (20dollar) and the costs are minimal because silfos costs 0.50 dollar / rod :).

[FoxTrottZero]

Good call epsie'

I already have a block to use... but to buy one new would not really be worth it (unless you have to have one for your TEV or something)

[LardArse]

Lets say you wanna join up a pipe thats very close to insulation... you'll easily burn of your insulation if you braze...
Or brazing onto a short end of a pipe connected right to a massive chunk of metal (heat exchangers, etc)..... would take forever to get the pipe hot enough...
Soee situations flare fittings are definitely prefered

[gkiing]

Lets say you wanna join up a pipe thats very close to insulation... you'll easily burn of your insulation if you braze...
Or brazing onto a short end of a pipe connected right to a massive chunk of metal (heat exchangers, etc)..... would take forever to get the pipe hot enough...
Soee situations flare fittings are definitely prefered

True. I once brazed too close to my rubber suction hose and had to buy a new one. You can get this gel stuff that you put on the pipe that keeps it cool though, it makes it so heat wont transfer down the length of the pipe.

I would say each have their strengths and weaknesses. Perhaps a combination is best :)

[froudeg]

From my experience with flare connections, they are fine and dont leak so long as you have the strength of a gorrila to tighten them up. I think thats where some ppl are goin wrong, ive found that a pressurised line will show some very small bubbles with leak detection spray, but if i tighten up further and further they will stop - and im talking VERY TIGHT

[HawainPanda]

flaring and brazing=ultimate :P
man those connections are pretty expensive though..18 for each, u def should stick with brazing

[Russell_hq]

You can get this gel stuff that you put on the pipe that keeps it cool though, it makes it so heat wont transfer down the length of the pipe.

Alternatively you can wrap a wet rag around your pipe :D

[gclg2000]

yep

[gkiing]

Alternatively you can wrap a wet rag around your pipe :D

Yeah ive done that, but sometimes a wet rage isint eneough. I could tell because the rag dried up and then started burning :D

[berkut]

my 2 cents...

flare joints were always unreriable for me, whatever i did (using a troque wrench, tightening to the max etc), the possibility of a leak is always preety big. I always pray when i leak test it.

i have bad luck with tightening flares as i tend to brake them cause im troquing them too much when i get pissed off and dont feel my strength (and they continue to leak). either the whole flare snapps off a lets say CPEV or the sleeves chip off.

you can not use a flare for w few times as the male surfaces wear off and after a few joints they dont hold anymore unless you use a file and some sand paper.

i agree flare joints are a very nice thing, for connecting evaporators (baker evaps for example, where the cap tube is inside the sucktion line), CPEV's, TXV's and other expansion valves. This makes them more reuseble and is safer for them as we wont overheat them during brazing (not all of us have oxy-mapp/acetylene torches).

still i prefer to flare a short piece of pipe to a PEV, leak test it and later braze it on to the system

about brazing- as long as its performed correctly with proper tools, good torch etc. i belive its the best way we can do most of the joints. i prefer brazing over flaring, once i finish my TIG welder and get a oxy-mapp torch i can bet ill love them even more.

[froudeg]

I forgot to mention that i use copper gaskets (trumpets) on all flare connections...without them it was hit and miss if i ever got a good seal.

I'd replace the trumpets everytime i undid and redone the connection.

[Russell_hq]

Yeah ive done that, but sometimes a wet rage isint eneough. I could tell because the rag dried up and then started burning :D

If the rag was drying up you can bet that this gel stuff will have cooked aswell. Sounds like your adding an awful lot of heat to cause the rag to dry out, the water in the rag can hold a good amount of heat. To combat this, have another rag handy soaked in a bucket of water or allternatively remove the rag, soak it in water and wrap it back around. This gel stuff just sounds like a money making gimmick. I'm sure it works but i'll bet it doesn't work that much better than a wet rag, how much does it cost anyway?

[buffarilla]

interesting reading

[Marci]

Always think about what COULD go wrong... with a flare there are more things that could potentially go wrong in comparison to a brazed joint. When it comes to fault finding there will always be that possibility that everything going wrong has been caused by one duff flare. We also operate in more extreme temps compared to household refrigeration etc... expansion & contraction caused by the temperature swings can have an effect on flare nuts...

Brazing is the easier way to get it right first time and get it to stay right. Personally, anywhere I've used a flare I've brazed it as well. I only ever use them to join flexible suction line to rigid copper or evap head. Every other joint is brazed.

So far the only issues we've had on units have been at the flare joints. I will admit that that's down to my own inexperience and lack of strength due to half a muscle missing in one arm, but I'm one of the firm beleivers in doing something once and it staying done... and imo, that's brazed.