Oxy Fuel

[makoman1860]

Me again,
finished browsing this thread and seen you have posted a pic of the small torch I inquired about. Just curious, what would my torch be worth?

Well,
Honestly not much. The marquettes are all o-ring sealed (internally under the handle) and so require overhaul (like I did) before use. Also tips are not available. Also typically the asbestos fibre stem seals need to be upgraded. So how much is it worth?? I would think about $10-15 as is, and maybe $75 overhauled with a full tip set.
-Aaron

[Skippii]

Okay....do you guys seriously use coathangers for welding?

I've seen a few references to them when searching the forum.
Seems like the ones made in the "good old days" work better than the new ones.

Do they really work for welding?

What about brazing? I could see that working a lot better than actual welding.

[Skippii]

What exactly is the difference between soldering and brazing? I've found some references saying that the only difference is that brazing occurs above 840*F, and soldering does not. Fair enough, but does that mean there is absolutely no structural difference or way in which the filler bonds to the parent metals?

Also, if you use a brazing rod with a really hot flame and metal the parent metals so they mix with the filler, that must by definition be welding. So do you not need welding rod to weld---in which case, why is there a difference. And by that I mean, what is it about true welding rods that makes them better suited than brazing rods? My guess would be the only difference is that the higher melting temperature of the welding rod simply means a higher tensile strength. My only hesitation with this is that I've heard a properly performed brazed lap joint can be every bit as strong as a weld--so what's the point? just for when lap joints aren't practical?

Next question:
Fulmer Oxy-Acetylne Welding Rods.
These are sold as welding rods in the O/A section of the hardware store. They are not sold as brazing or soldering rods.
Well, despite what they might be called, everyone says they are not welding rods, they can't be used for welding, and they are just a more expensive version of the "alumiweld" or "Duraweld" zinc welding rods sold online. Fair enough; I won't argue with that since they melt at around 700*F, while true aluminum would be arond 1100*F. That's not my question.
My question is, if you are melting the aluminum workpiece into a puddle that mixes with the "welding" filler rod, how is that not welding?
The bit I'm unsure about here is that I'm not positive how mixing is defined in welding. I mean, we all know that welding means the filler metal fuses together to form a single piece with the parent metal---but what if the two metals are different enough that they don't properly mix?
Some metals of different types seem to mix fine, from what I understand (using a Stainless rod to fuse stainless to mild), but I'd imagine some have more of a oil/water effect (though I have no proof of this--I just suspect it).
In that case, if you were to get a junction of metals that looks like a marble cake:

How would that be defined? Doesn't seem to fit the definition of welding as it's not reallya single peice of metal. It doesn't seem like it would be called brazing, either, though, as it's not using the filler like a glue. Additionally, if doing this with a Oxy/Ace or even a tig machine, it seems very likely you could achieve this result simply by heating the two metals, WITHOUT using any filler material. So what would a joint like this be called?

Bad.

Yes, I know that's how you all were going to answer.
But seriously, does this occur in oxy-fuel....um..."joining"?

Clearly, there are two forces at work here: a series of incredibly complex "dovetail" style joints (don't know the metal equivilent for the woodworking term), as well as the metals actually sticking together, which would be like a braze.

Last question...for now....
Is it still called brazing if you don't use a filler rod?
Hard to think of an application off the top of my head where anyone would do this, but let's say for some reason you needed to stick a rod of solid bronze to a sheet of mild steel. Is there really any point in using a filler rod if it's pretty much the same thing as the workpiece? If you just dipped the end of the bronze in flux, pressed it to the steel, and heated it with an oxy/ace torch until they stuck together, that would be considered brazing, would it not? Even though no brazing rod was used? (Well, no additional rod)

[makoman1860]

Ok here is the short version.

Welding-filler metal is "relatively" the same alloy as the base material, and the weld is interalloyed. Welding 1100 sheet aluminum with 1100 filler is a perfect example, however commonly the fillers are slightly different alloy, but not far enough to put them into another category.

Brazing-Base mateial not melted, and filler melts above 840
Soldering-Base material not meltes and filler melts below 840

There are a LOT of gray areas, and at times its possible to do both welding and brazing with the same base and filler materials, however it may not always be a good thing to do from an engineering POV. Here are some examples.

AL3003 base , AL1100 filler = Welding
AL3003 base , AL4047 filler = Brazing or Welding depending on technique
Bronze base , Bronze filler = Welding
Cast iron base , Bronze filler = Brazing
Bronze base , lead/tin filler = Soldering\
Pot Metal base , pot metal filler = welding
AL3003 base , pot metal filler = Soldering or Brazing depending on alloy of filler
Copper base, bronze filler = Brazing
copper base , copper filler = Welding

[Skippii]

Ok here is the short version.

Thanks. That does explain a bit.

Any chance of getting the long version?

Also, what is the broader term for describing all of these processes? Oxy-fuel jointing? Oxy-fuel bonding?

[makoman1860]

Thanks. That does explain a bit.

Any chance of getting the long version?

Also, what is the broader term for describing all of these processes? Oxy-fuel jointing? Oxy-fuel bonding?

You want the long version?? Go buy some text books

Jut think of welding as making a casting out of the base metal, and added "filer" metal of similiar chemistry.

Anything else is either brazing or soldering

This holds true no matter what the heat source is.

[lugweld]

Skiipi,
Your question has been brushed against before. But as Mako said... It has mostly to do with defining temperature. In brazing, you actually get more entrapment of the metal in the joint through capillary action. It is quite easy to get the hang of through alittle practice.

A broader term is Oxy/fuel process. But brazing can be done with carbon arc as well. Sooo....

[Skippii]

You want the long version?? Go buy some text books

Jut think of welding as making a casting out of the base metal, and added "filer" metal of similiar chemistry.

Anything else is either brazing or soldering

This holds true no matter what the heat source is.

I've been reading a lot.
That simple explaination make sense, though.

So...coathangers? Better for brazing, welding, or neither?

[john.mooretech]

makoman and other collectors, i've got a lot of catalogs at school from when torches were real torches if yall need info, part numbers, etc.

skippii - coathangers are what i call the hotdog of welding rods, you never know what's in there. but folks like them cause they flow so well. but they're great for practice and light stuff that doesn't need too much strength as a general rule of thumb, otherwise you need some real rods.
john

[denrep]

I thought that the torch aficionados might enjoy a look at this super-freak:
Attachment 30902
Airco handle with a Harris head!

[Skippii]

skippii - coathangers are what i call the hotdog of welding rods, you never know what's in there. but folks like them cause they flow so well. but they're great for practice and light stuff that doesn't need too much strength as a general rule of thumb, otherwise you need some real rods.
john

Excellent, thanks.
My work was just throwing out a bunch of them, so I'll have some practice stuff.
As far as stuff that does need strength....well, I'd rather just not weld that myself.
...yet.

[Skippii]

Okay, got another random question.

Technically a brazing/soldering question, but I think this is the right place to ask it...?

When I was about 15, I bought an Irish Banjo off ebay.
The bridge was broken--it was made with some funny hooks, so that the tension of the strings kept the two parts together--except that the hooks were broken, and it didn't work.

Knowing nothing about metalwork, but being a pretty good electrical circuit builder, it occured to me that my electrical solder could be a solution to permanently bonding the two bits of steel together.

I suppose the correct way to do this would be to heat up the pieces with a torch, and apply a rod to the joint, and let capillary action pull it into the joint as it melted. But I didn't know that. I wound up the solder into a coil, and put it in-between the two metal plates (basically, a lap joint). Then I squashed it together with a C-clamp, put it on the ground, and blowtorched it until the solder melted.

So, here's the interesting part. As a teenager, I was under no illusions and never expected my wimpy solder job to hold up to all the strain of the tension on those strings.
And yet, over a decade later, it's still holding up, sitting in my bedroom. (I'm assuming the solder is just holding what's left of the hooks in place, and they're taking all the strain).

Anyway--my question is (there is one!) what is the difference in joint formation and strength, etc, between heating up the base metal and then applying the solder/braze, and actually stuffing the crack full of bits of filler, clamping it in position, and heating the whole thing up?

I mean, if it works, why are there all these complicated procedures (leading with the torch, leading with the rod) for beveled butt joints, when it really would work just by laying the filler rod down in the groove and torching until it melts (or, in oxy/ace welding, until everything melts together?).

Seems obvious that the answer is "because it's not as strong that way"....fine, but if so, why does this method make a difference in brazing?

[john.mooretech]

denrep - airco 9500 series cutting torch, but never seen one that somebody cut off the head, then bent the tubes to mate up with another brands head, this case a harris head. that's wild! have you tried it? hows it cut? just goes to show, a little imagination and the sky's the limit! i like that a lot!

john

[denrep]

. . .what is the difference in joint formation and strength, etc, between heating up the base metal and then applying the solder/braze, and actually stuffing the crack full of bits of filler, clamping it in position, and heating the whole thing up?

I mean, if it works, why are there all these complicated procedures (leading with the torch, leading with the rod) for beveled butt joints, when it really would work just by laying the filler rod down in the groove and torching until it melts (or, in oxy/ace welding, until everything melts together?).

Seems obvious that the answer is "because it's not as strong that way"....fine, but if so, why does this method make a difference in brazing?

Good soldered/brazed joints require a strong surface bond. This strong bond can only be achieved by careful "tinning" of surfaces. Simply heating and flowing in filler will not properly "tin" a joint.

One reason for running a bead, and working the filler as "putty" is because there's a critical temperature where the filler will flow and still bond. Above the critical temperature "tinning" properties are lost, and also the filler will run-off, rather than wick, bond, and build-up. Heating an entire work piece to ideal bonding temperature, all at once, is often not possible, thus the progressive build-up of a bead.

Although there are a few joints that can be made with the "tin, stack and heat" method, most joints require more accurate parts positioning than this method allows.

Good Luck

denrep - airco 9500 series cutting torch, but never seen one that somebody cut off the head, then bent the tubes to mate up with another brands head, this case a harris head. that's wild! have you tried it? hows it cut? just goes to show, a little imagination and the sky's the limit! i like that a lot!

john

Crazy huh?
Yes, I've used it; works beautifully. It's still in service on a portable torch cart.
The workmanship looks excellent, especially the tube bending. I don't know who built it, or for what purpose, but I suspect it's not the only one.

If I recall correctly, I bought the hybrid in Chicago, at the Maxwell Street Market. I always sort of suspected that it had been built for a Chicagoland steel mill. Maybe the mill liked the rugged comfortable Airco handles, and the thinner Harris heads, with their very economic "thick seat" tips? And... there was only one way to get both.

I'll try to post some sample cut pictures.

Good Luck

[makoman1860]

Hybrid torches,
I have seen my share of them, both cutting and welding. I think it comes from a time period when people that were in the trades that used that equipment, were thought of as artists rather then grunt labor. An onder gentleman from the airport here had been welding fuel tanks ( aluminum) for over 50 years, his torch was completely home built. Not because he couldnt afford a "store bought" one, but because he tailored the torch to himself. The handle was a perfect fit for his hand, and all aluminum to be light. The valves were up in the front, and easy to adjust with one finger, with stainless needles and bronze seats for long life. It had a low pressure injector mixer, and a beautiful brass neck with interchangeable thread on tips. The tips had a pointed yet soft flame, perfect for aluminum.
He was not an expert, he was a true Master of the skill. Welding was his life, his joy, and his love. I believe he was even burried with it when he passed on a few years ago.

[Brainfarth]

That is a great collection, Makoman. I was reading though the new welding magazine and see they have an article on this thread. So I figured I would check it out. Lots of good information here. We mostly have Victor pro's in the shop and a few older Harris. I like the victor a bit better because you can spin the head assebly around so the control valves are in the best position and you can slap new ends on in no time. I've only had one blow-out on the torch when I hooked it up to the local steel mills oxy line which was running at over 120psi and I'm sure it had been a while since the torch was rebuilt.
I braze quite regularly, use the rose bud to heat and bend things, thermal transfer for some cast iron projects and cut on a daily basis. But I haven't welded anything since the high school days. After reading this thread, I'll have to break out the welding tips and see if I still have it.

[lugweld]

Denrep,

If you bought it on Maxwell street, it was probably from some chop shop. Some guy probably got bored on a slow day in the stolen parts business and decided to try his skills out on his cutting torch... BTW, did Alfred best the guys at three card monty?

[denrep]

Denrep,

If you bought it on Maxwell street, it was probably from some chop shop. Some guy probably got bored on a slow day in the stolen parts business and decided to try his skills out on his cutting torch... BTW, did Alfred best the guys at three card monty?

Yup; Way back before Al Gore invented the internet.
Back when a guy could be proud of his giant carbon foot-print!

Back before WeldingWeb's Shop Trade Sell Forum, before Ebay, before Craigslist...
There were pawn shops, flea markets, and the big kahuna - Maxwell Street.
I bought a lot of stuff there.

It was mostly straight business, but like anywhere, I saw and heard a few hustles too.

Johnmooretech - I demoed the hybrid torch today, but I didn't have a card in my camera when I took the pics; now I'm having technical difficulties transferring the photos. But I'll get 'em.

Good Luck

[KAOSX]

I am welding on some 16 and 18 guage sheet metal making a tank and I am getting some under cutting,my tip size is 00. some times it will be ok then the next weld
will have under cutting. any ideas? Thanks

[makoman1860]

I am welding on some 16 and 18 guage sheet metal making a tank and I am getting some under cutting,my tip size is 00. some times it will be ok then the next weld
will have under cutting. any ideas? Thanks

Yes, its you causing the undercutting.
The tips size you gave doesnt mean anything without giving the brand. The numbers arent "standard" by any means. But in general for that thickness, start with an orfice size of .035". This would be a Harris #2 , Victor J #0 , Smith AW204 , Meco #2 , Oxweld #4 , or a Henrob #1. The weld profile is all up to YOU, undercutting is too hot, too little filler, moving too slow, or a combination.

[Billy]

Excuse my ignorance but what exactly is a "rosebud" (I am from Oz)
Can someone post a pic?

Cheers
Billy

[Skippii]

Excuse my ignorance but what exactly is a "rosebud" (I am from Oz)

Well, before the rose flower blooms, first it starts off as a little...oh...wait. This isn't botanyweb.com...

Can someone post a pic?

Cheers
Billy

It's used more for heating. Kinda like a blowtorch. Big, fat, and not precise at all.

[chinesebob]

This is awesome. I am a huge fan of OA welding. I am not very experienced but I find it relaxing compared to working my mig or arc.

For those that want to see what can happen when Acetylene goes wrong look up acetylene on You-Tube and watch some of those.

I have my tanks in the back of my "garage" (read very small 19th century carriage outbuilding" and a 50' hose on them. I'm a little paranoid about things going wrong when dealing with high explosive gases. That's why I don't enjoy the mig or arc. It's a lot of juice and I'm the kind of guy that would end up electrocuting himself. That being said I am very very careful with all of it.

Favorite past time right now is practicing on scrap metal from the junk yard, my own finds, or smoker related contraptions. I've got the harris 16, an OLD Purox, a henrob, and a Taiwanese knock off of the victor. It's actually made pretty well.

That's a distinction between China and Taiwan. Generally speaking Taiwanese manufactured materials are going to be closer to what you find from Eastern Europe. China is cheap labor but Taiwan is probably more expensive than some US made goods due to the cost of living, generally speaking of course.

I've got a ton of questions but I'll put them in a separate post.

[Billy]

Well, before the rose flower blooms, first it starts off as a little...oh...wait. This isn't botanyweb.com...






It's used more for heating. Kinda like a blowtorch. Big, fat, and not precise at all.

Yeah have the same here, just different name
Thanks
Billy

[David R]

If I ever get a new boss, I am going to ask for a separate forum for 0xy fuel.

This is good stuff, yet we have many oxy fuel threads below this one.

David