Brazing steel with mapp?

[keatonx]

Hi. I just bought a bernzomatic propylene torch at princess auto for 50 bucks. I was nearly certain it would be able to braze, but it didn't. The bronze rods turned black and didn't melt too well, even though the metal I was brazing was tiny and glowing bright red. After a VERY long time, I got it to somewhat braze, but it was tiny and dirty. And the flux on the rod was bubbling and burning. Is it possible to braze steel with this torch? Princess auto says that "your purchase isn't final until your satisfied". Should I take this torch back, and get the oxy/mapp torch that I was debating about getting? It's only 35 bucks more, and it comes with everything you need, unlike this torch.

 

[Al.Fisherman]

bernzomatic propylene is used primarily with solder. I use propane and oxygen, to braise. Maybe the map gas might do. Buy the smallest braising rod you can find, I know NAPA has some small rods. With MAP gas you will need a braising tip. I have a large bottle of O2 and a 5 gal propane set up. Also have one of these.
http://www.torchbrazing.com/torch-brazing/buy-a-brazing-torch-for-sale.htm

 

[loquin]

There is one propane/mapp torch that'll work.

I've had a Wingaersheek spitfire torch since the early '80s. It has a long combustion tube; the air has a long time to swirl/mix with the gas, and you have to adjust it so that the bulk of the combustion occurs outside the tube, else it'll be glowing cherry red. It'll put out enough heat to braze smaller parts - pipe up to 1 inch or so, for instance.

Unfortunately, I don't think that Wingaersheek has sold the spitfire for years. I've seen a bernzomatic mapp torch with "swirl technology" that's used for silver-soldering. I don't know if you can use it for brazing also.

As late as 2000, Wingaersheek still sold their "Crossfire" line of plumbing torches to the trades, which also used the same swirl technology, and which will braze (depending on the model) fairly large pieces/pipe. You may still be able to find them used. The 1000 series (I believe) had a very small flame, though - 1/4 inch diameter. It was used for silver-soldering AC/refrigerant tubing. The other model series (2000, 3000, 4000 series) are progressively bigger.

 

[loquin]

BTW - this torch, this one and this one look as if they should be able to braze, as the air inlet is 5-6 inches from the end of the torch, implying the thorough mixing action of the spitfire style torch. (the second one states that it IS a swirling combustion chamber, and both the second and third one say they can be used for brazing...) I don't know their total heat output, so the object size may be limited...

 

[keatonx]

Here's the torch i have.

http://www.princessauto.com/worksho...components/8260960-swivel-head-torch-mapp-kit

the air inlet is in the black sparker box. It has angled fins in the tube for a swirly flame. Whenever i use the torch the steel tube glows bright red, and so does the metal i'm brazing, but the bronze rod refuses to melt.

here's the
oxy-mapp torch I think I should get.

http://www.princessauto.com/worksho...8305278-cutting-welding-and-brazing-torch-kit

 

[keatonx]

I also heard that these oxy/mapp torches use oxygen really fast

 

[bmc_az]

they do use ox very fast and its very expensive consider the "real" torch kit that HF has on sale for $110 you have to get tanks but its a lot cheaper in the long run and you can do much more with it.
bmc_az

 

[keatonx]

So i went to princess auto and spent the extra 28 bucks on the oxy mapp; Then noticed i forgot my 6 dollar welding goggles!

 

[loquin]

they do use ox very fast and its very expensive consider the "real" torch kit that HF has on sale for $110 you have to get tanks but its a lot cheaper in the long run and you can do much more with it.
bmc_az

However, keep in mind that it's possible that gas supplier won't refill tanks that they don't provide...

 

[keatonx]

Today I was trying to braze some steel from a weed eater clutch with the oxy-mapp torch. I adjusted the torch so the inner green flame (the only one i could see) was about a centimetre (2.5 centimetres=1 inch) long. Over what felt like my whole oxy tank (really only 8 mins, heard too many horror stories of oxy tanks lasting 5 mins), I couldn't get the metal to glow. However, I did get it to braze a bit. Any tips on getting this thing to heat metal cherry red? After all it's supposed to be able to cut through 1/2 steel bolts!

P.S. everyone says the oxy valve is very touchy and diffucult. It's actually super easy!