Welding Basics

[spamonkey8]

I've been teaching myself to use my new torch, and I've got brazing and cutting, mainly because I've known how to solder for so long. I have a really simple question I hope someone can help with.

 

When I try to weld steel, it either just gets red hot and does nothing or it sparks and acts like I'm trying to cut it. Is there some trick I'm missing to get it to flow together and produce a nice clean bead at the joint like I see all the time, or are those made with an arc welder?

 

Thanks!

[coquina]

I don't know much about welding. Are you using welding rod? I think the two metals you are welding together have to be the same. Hopefully, someone here knows more. I'm not at home right now - if you don't find answers I have books at the shop and can probably look some info up for you.

[YT2095]

as you`re aware, Brazing and welding are 2 totaly different beasts, I`ve done brazing (but not certificated) but I`m certificated in Rod welding, the bead/flow that you`re after is really only acheived with electrical welding. for brasing you`ll need to keep the "solder" brazing wire in intimate contact all the time with the metal junction, the use of a flux isn`t uncommon either, usualy a paste (it`s around the rods in rod welding, that brittle grey stuff, and inside the core on lead/tin solder).

 

it Sounds very much like your over heating the plates and your brazing solder has too high a melting point, when the metals hot enough it should melt very easily, what materials are you using?

[J.C.MacSwell]

I've been teaching myself to use my new torch' date=' and I've got brazing and cutting, mainly because I've known how to solder for so long. I have a really simple question I hope someone can help with.

 

When I try to weld steel, it either just gets red hot and does nothing or it sparks and acts like I'm trying to cut it. Is there some trick I'm missing to get it to flow together and produce a nice clean bead at the joint like I see all the time, or are those made with an arc welder?

 

Thanks![/quote']

 

I'm not an expert but I know it's a lot harder than arcwelding or brazing and is a lot less common due to arc welding. If you use too much oxygen it will burn instead of melt (I think).

[H2SO4]

Well, i know if you start cutting iron with the gas/oxygen mix then turn the gas of and let a flow of oxygen out only, you can cut through steel like that. Ive never used one of these "oxy" torches, and have only used a MAPP/air torch "which is actualy pretty impressive in terms of heat output" but i think maybe try different nozzles for the torch. Are you using a welding nozzle? Is there a possition marked on the regulators to weld?

 

 

 

Just curios, what fuel are you using. When i eventualy buy a oxy torch i want to get a oxy/MAPP torch becuase MAPP supposedly handles like propane (in terms of safety) but burns like acetylene.

[spamonkey8]

I'm teaching myself with scrap pieces of steel, for example the cheap little steel covers for PCI slots. I suspect that these may be plated/alloyed with something, though, as I have never known them to rust. At the time, I wasn't using any welding rods and was just trying to weld them without it, but I need to give that a try. I found that the one time when both pieces started to melt, I couldn't get the two beads of molten steel to merge and stick together. The other time I might have just needed to crank the fuel and match the flame with O2. I've had great results (even with stainless steel) brazing common metals with fluxed bronze. I guess this comes down to bead envy, I just can't get the perfect weld bead an arc welder can supply...sigh...

 

Any air/fuel torch won't provide the heat necessary to melt steel, and even if it could, it would be way too hard to work with given that the secondary flame would warp the metal (not a very concentrated heat) and it would be too hard to keep the metal hot.

 

The Torch (My research for a torch to learn on and use on a few small projects, you can skip this unless you're in the market. Just wanted to pass on a little knowledge to those interested )

 

I'm using a relatively cheap ($50 incl two tanks) entry-level Bernzomatic Oxy-MAPP (stabilized liquified methyl-acetylene and propadiene) or Oxy/Propane torch that uses disposable cylindars. It eats O2 like a mofo (rated 8-24 min. run time depending on application, lasts 1/40 as long as fuel tank), and the O2 costs about $8/tank, but it's very portable and good to learn on. You can compare that with small oxy/acetylene torches like a common Tote Torch (at least $300). The regulator knobs are on the tank fixtures, which is a slight inconvenience, I suppose, but as far as safety and portability it can't be beat. Just read the instructions and keep the flame at least 3/4 in. to avoid flashback. It doesn't come with gloves, welding goggles or a face mask, but those should factor into your purchase. MAPP burns a couple hundred degrees F hotter than propane in air, but in oxygen, it burns 700 degrees hotter, just shy of acetylene, though with a hotter secondary flame, which, I'm told, can warp metal. Also, when the oxygen is limited or it's not well mixed with air, MAPP produces a lot of soot that will float around and get stuff messy. Fortunately, this only happens when the oxygen tank runs dry or when you have just started it and haven't hit the O2. Count on $70 plus O2, and keep that air/gas torch around for jobs that don't require oxy/fuel. Bottom line, the torch is cheap, safer, very portable, and effective for moderate use. I fought with the price of the O2, but if you consider the $240 price difference with an oxy/acetylene kit, you can buy 30 tanks of oxygen to even it out. All in all, I'm pretty happy with it.

 

Edit: http://www.bernzomatic.com/bernzomatic/consumer/jhtml/productDetail.jhtml?attributeId=BMBZOPA000006&productId=BM019614

[YT2095]

the are indeed plated and oxy-acetylene is a bit overkill don`t ya think! LOL

 

your better of with gas/air brazing for that, or even solder with a 100W gun type iron

[spamonkey8]

Hehe, oh to have a job as easy as joining two little pieces of metal like that

 

That's not what I was getting ready to do, I just grabbed something steel and tried to get the basics down before I borked up my whole project. I haven't tried brazing with fuel/air, I was told that even mapp is "sorta able" to braze light stuff, but I'll give it a try. For now, I've come to the conclusion that some brazing will be just fine, but the parts I'm joining are attached closely to some plastic that would melt if I took the time to use air/fuel.