Presto-Lite is for soft soldering. Staple of the Plumbing world.
In the HVACR Industry,it's mostly Oxy/Acc rig.
We Braze,Plumbers,Solder which Does require Fluxing,which 'I' prefer AMCO C Flux which pre tin's the joint compared to most.
Brazing need's 'around,1200 degrees to flow and nothing straight ACC will give this unless Air assisted like a Turbo set up but no where the capacity of Oxy/Acc set up.
MAPP is a hotter flame but only for Larger Projects or even 'some' copper to copper joining,but still,not on par with Oxy/Acc.
Some use MAPP/Oxy with good results but still,why not use the 'Standard,Oxy/Acc rig which you can turn down to even Soft Solder if you like or Cut thru Steel with a simple adjust of the Handle.
Tip flame(blue)size is the Key. You 'elongate the blue from the 'tight Pencil,to a longer,say3/8-1/2" and,once you get the piece heated,back IT off and just apply the Necessary Heat to 'Make it Flow' and live happy.
It's a 'Dance of Fire',Not a 'Burn to Death'.

 

Sometimes air/acetylene .... sometimes oyx/propane with a rosebud. Don't have a turbo for the air/acetylene. Don't think the oxy/propane is quite as hot as the acetylene ... but it puts down more more heat faster. Its a bigger rig with regulators ... not the hardware store bottles.

 

Better question is .. what should I be using? It seems the presto-o-lite torches are popular ... with a turbo tip. Oxy/acetylene gets really hot .... and I'd be afraid of burning a hole in something. The oxy/propane rig I have is no where near as "hot" as oxy/acetylene, but it does put down a lot of heat fast and the rosebud distributes the heat. I tend to overthink stuff I guess. Should I just get the turbo tip for the B tank?

 

Mr. Jones,
What,Exactly are You using to 'Braze' with?
ACC,MAPP,OXY/ACC,TURBO,???

 

if its SS to copper you will need a real silver rod with flux built on it already..

 

You will learn to love 45 55 is better yet you also would not believe how little flux you need to make a good joint.

 

Lil too much Heat there.
SS need less heat than Brazing and a Clean Joint.
There are MANY Discussions on Proper Torch 'Etiquette here and the Old,Welding,Pencil Tip Flame is Wrong.
You want HEAT,Not,BURN.
Glad you got 'er done loopy

 

Now you know!

 

Thanks for all of the input. I picked an ounce of Safety Silv 45 this morning, cleaned everything, mixed flux with some water and had another go at it. The solder flowed right in and is holding pressure. Not my prettiest work, but it's holding and that's most important.

 

Looks good to me Sorry for hijacking your thread Loopy. Please accept my apology.

 

I'm still struggling with this brazing thing anyway .. remember, student. I have a LOT of experience with torches, brazing, etc ... I'm struggling with HVAC brazing. My instructor says no flux .. and he dabbles the brazing rod on. I am used to .. situations involving flux ... and seeing capillary action suck the metal around the join. He says ... (no flux) you stay too long on the join you suck it into the join. That man did not fall off the turnip truck yesterday ...which should probably mean I need to shut the hell up and listen. Only .. it looks like such a crappy join when we are done .. globs of brazing stuff everywhere. I'm used to .. clean joins, just enough brazing rod to run around the join .. and it looks nice. I go out side an look at my heat pump .. it looks like crap. Am .. I being way too anal about this?

 

The 23'rd, "I shall not Want".

 

Guess its whatever floats your boat...... I have plenty of wire.... and flux and so thats what I use.

 

Problem corny is,
They will not sell you a 'piece' of 'wire'.you buy the Roll or walk.
Back when Silver was so high,you would go broke buying a roll and the Supply house's were selling the sticks separately.
I came from Old Skool with such but Today,the Stick is the Ship Man. No more dried paste,dirty 'wire and,
Brings a Big Smile to my face every time I use them.
You do as you feel necessary. And yes, I have used that 'flux,as 'flux is just about 'flux regardless. I've used Borax Powder back in the Day.:grin2:

In Your defense,I'll admit that the Bronze,coated,are less than functional and prefer the Paste & Dip for Them.
However,if You Try those coated,Silver Solder 1's,it will make a grump,Smile. Did me anyway.

 

lol mrkelly ... my idea of flux is to scrap a bit off a borax cone and mix with distilled water. Then .. I'm decidedly old school

 

I like the wire and flux.... dont care too much for those flux coated rods.... Even brazing around the house on "stuff"... Ive taken those white covered bronze rods and beat the flux off them and used paste flux.

 

BTW: I have gotten Stay-Brite to work by tinning out the steel socket before making up the joint.

 

We can actually buy Individual sticks of the Blue or Orange Harris SS as IT is Expensive so Ask first.
You likely fried that service valve anyway after so many repeated 'attempts',so,good call on this too.

 

I'm going to pick up some 30% tomorrow as well as service valves. HO is having his collection delivered this weekend so it MUST be running tomorrow .

 

Steel-Copper=45% Silver Solder&Flux.
no 'Soft solder or 'Phoss of ANY kind will work.
Any other Co's around you could beg,borrow or buy from?

 

So, how do you braze copper to steel anyway? Keep the heat on the steel, keep the heat on the copper? Thermal conductivity coefficient for steel is a heck of a lot lower than copper. Seems like ..you gonna need a lot of heat going to get that done. Do most folks (remember, I'm a student) use air/acetylene .. with a big ass tip?? Nothing worse than finding out mid job ... that your torch ain't got the umph to do what you are trying to do. Been there, done that ... not pretty.

And .. on a side note. I got this stash of brazing rod I bought on ebay. Harris part 66000 ... sa

 

15% will not do.Do as pecmsg said. You will be there for a long time trying to do something that is wrong.

 

Well a few more tries and i still can't get anything to stick. I'm limited to stay-silv 15 rods, 94/6 solder and harris o phos/copper rods. I'm at the point where i want to take this valve out and replace it with a copper service valve. Even if i do get it to stick, at this point I'm not confident in the integrity of the joint. The systems I'm working on are for a wine cellar that will hold this clients multi million $ personal wine collection. The last thing i want is to have a call on memorial day because the pipe blew out of the valve.
Very frustrating.. I can braze or solder copper to copper with my eyes shut and one hand tied behind my back but i have zero experience with this.

 

Copper 'Brazing is essentially,Self Fluxing as long as the joint is fairly clean to begin with.
You find an old fitting/tube that's dark brown or 'nasty',you need to at least sand it off to rid the 'Ugly from it.
Or, you have a piece of pipe that somebody used Tape on to seal and some of the tape/residue is still on it,same thing.
Flux is generally used on Low temp Solder/Silver solder which you don't create enough heat for 'burn' off the Impurities like with Brazing.
If you Do use a 'flux,liquid or paste,use Caution as what you said about contaminating the System is a possibility.
The more you use,the better the chance of.

 

Interesting point techmanterry ... my HVAC instructor (I'm a student) says the same thing .. but I'm stubborn as hell and have experience brazing copper to copper for craft type stuff .. you don't flux it, it won't join there. And, those flux less joins are just so UGLY I've seen info that said to put just a tiny bit of flux on the outside of the join, seen other information that says flux will get in the line set and stop stuff up ... like the TXV. Opinions?

 

Keep your torch heat lower than Brazing Copper as wel,it's a little easier once Everything is clean and fluxed.
Years ago,the White Paste was all you got and most of IT 'sit's on the shelf anymore due to Harris bringing out the Coated Stick Silver Solder.
Blue or Orange. I keep a few sticks of both in an old SilFoss case.

 

Be SURE to BACKSEAT that King valve stem too and wrap IT well.

 

wrap the nut with a wet rag or better remove while brazing.

 

Thats Steel.

Clean it really good
flux the pole
35% silver or better if inexperienced brazing dissimilar metals. (I prefer 55%)