Welding

[frogfot]

It seems like welding skill would be a great tool for amateur chemist since many chem experiments require metallic vessels.

Recently, I've fooled around with a car battery, couple of starter cables and a welding carbon rod (8 mm). Made a little steel cup (7,5X10 cm) from 0,7 mm steel plate, heres a pic of it, sorry about poor graphics:
http://www.geocities.com/frogfot/stuff/cuptest.jpg (copy&paste...)

Now, connections is a bit ugly and I don't wanna think about its strength, but that's not bad for a first time :) It was very easy to make side joint, but fusing bottom was a bit harder. Bottom still have some small holes, that I'll fix when battery have charged (2nd time, now I know why noone uses car batteryes for this). My battery is most likely raped to death after 5-10 times of such rechargings, but I really wanna finnish this cup to any price...

Enough of that damn cup, moral of my story is a thoat to by a real hobby welding transformer for 80$:
40-140A
43-48V
Those transformers uses very cheap welding electrodes. Anybody have experience with similar? ..I'm in need of an addvice. For example, this transformer got a safety of 16 A, would it be wise to connect this beast instead of kitchen oven? Since it's the only thing that eats comparable ammount of current (<20 A).

Anyway, do we have members that weld? Would be cool to see some projects they've accomplished and how long it took to adapt the skill.

[mr.pyro]

Hey Welding is cool..

I learned how to 2 years ago during the summer at a tech school. I learned arc and mig. That cup weld looks pretty crappy(no offense) to what I was doing. I built my self a grinding rail for skateboarding, that is now rusty from not using. And a little utility trailer,

Edit: Ill try and help instead of critisize, try moving the rod back and forth quickly while pulling it towards yourself over what you want to weld. Also instead of going back and forth you can do figure 8's.

[Skean Dhu]

I plan on taking a welding class before the end of next year and I recently aquired a welding text book from a family freind who has a degree in metalurgy. so as of right now all I lack is a welder
its very interesting too, the garage at the edge of my property has a giant power outlet( the ones for electric stoves, and dryers, i think they're 220v?) its almost as if it were meant to be.

i've also been looking for free instructions on building a propane fueld(sp?) foundary, and a good book on crucible making. then i can cast my own Al, Steel, copper, and what ever i need or want . very useful for making platter charges, or shaped chage cones.

if you want I could scan in a few pages on select welding topics, give me a general topic you want to know about and I could get it within a week or so.

[A-BOMB]

I weld with a oxy-mapp torch so its abit harder, I think it would easier for you to braze your joints its easy just go to a DIY store they should have brazing rods there that will allow you to braze together just about anything with a propane or mapp torch.

[frogfot]

Gas welding is out of the question for a rookie like me, since it's very expencive. I've seen those brazing rods, quite expencive, but they would be ok for many projects, I also like idea that it's portable so one can do it outside.
Arc seems to be cheapest way, however since I will do this at home, dunno what to do about smoke.. maby I'll wait with this stuff sofar.
Thanx Skean Dhu, but I'll start with sites on internet, not if you like scanning ofcaurse :) Gotta learn basics first, so I can ask for specific things.
Hay mr.pyro, it's a piece of art.. well afterall, it's a piece of something ;) I realised that one have to be quick, which I wasn't at first. Most annoying thing is how fast battery dies, also, one have to wait from time to time for it to cool.

[xyz]

Welding is actually very easy to learn, I'm 15 years old but can use with an Oxy/Acetylene torch, an arc welder, and a mig welder and produce good quality welds with any of them.

Arc welding is probably the best way to go for beginners (the equipment and electodes are cheap). The main thing to remember is to cover up exposed skin and wear a proper facemask to avoid eye damage from the massive emissions of ultraviolet light.

If you look at the arc with no eye protection for any longer than about 1/5th of a second, you will get "welding flash" where your eye gets burnt by the light, nothing happens at first (like sunburn), but your eyes will hurt like @#$% about 8 hours later. This has never happened to me BTW, so I am speaking from other's experiences that I have heard about.

[Axt]

I think you did alright for a car battery and a set of jumper leads!

Welders arent expensive these days, I think I use a gasless mig the most now, they are messier then gas and only good for mild steel but thats 90% of welding jobs, are cheaper then migs and one consumable is always better then two.

Anyway, if your after an on topic project heres (http://ww1.altlist.com/~52497/rogue.altlist.com/images/droptest.jpg) a drop test rig that will gauge impact sensitivity of explosives, there is only 3 welds in it and very simple.

That uses a "hammer" made from an endcap and fittings on a 15mm pipe sliding down a 50mm pipe. I use a 3kg weight with a drop of 1m in 5cm increments. Heres some figures -

PETN: 40-45cm
ETN: 30-35cm
AP: 0-5cm

So that length and weight is good for explosives in the sensitivity class of PETN, if you wanted to make it for testing primaries/peroxides you would use a lighter weight for more accurate measurements, or alternatively a heavier weight to compare less sensitive explosives.

heres (http://geocities.com/roguemovie3/) a movie, goodluck.

[Anthony]

I'f you're in Europe then you can run a 16A welder from a standard mains socket. For example, sockets in the UK are rated for 13A, but a 16A welder is fine as the load is only a very light duty cycle.

[DBSP]

The biginners first choise id the mig, fucking easy. Just press a button and point it in the right direction and you're set. As easy as that, allthough it's a bit expensive and hard to move around.

The arc welder is really great once you learn how to use it properly, I don't mean just lighting the arc but knowing how fast once should move the electrode in different situations etc. Not like with the mig where you can clearly see how things are going.

Oxy/ace welding as harder than it seemes but I first learned how to weld on one of those. The hardest part is getting the welding object which may vary in thickness and size to the right and same temperature, like when welding a plate onto a solid bar or similar, the plate gets really hot really quich and melts before the bar has even got red.

The same problem arouses when using the other welders but it's easier to controle them.

The cheapest and best in my oppinion is the arc welder, not to hard once you learn how to use it and the weld is the strongest one of the above mentioned. I infact leared how to use the arc welder just today. Hadn't touched one untill today. But I have done lots of welding with oxy/ace and mig before and I'm a really quick learner. But still.

[mr.pyro]

By the way, if you do happen to get eye burn go to bed that night with a thick slice of potato over your eye, it helps them tremendously.

[xyz]

Mig welding is easiest but cannot be used on thick metal or metals other than steel.

Arc welding is stronger and can be used on just about anything, but it is harder, and just like Mig, it can only be used on steel.

Oxy/Acetylene welding is the hardest to learn and much slower than Arc or Mig, but you can weld anything you like with it.

Overall, I recommend Arc welding for beginners (Mig gear is much more expensive than Arc).

[Axt]

You can definately weld Aluminium with mig, and I feel sure ive seen Al electrodes for the stick welder also. You can also definately use migs on thick steel, bevel the ends and you can weld any thickness, may take a few passes but same with the stick, they are also as strong as each other, which is stronger then the parent metal so irrelevant.

Size and portability is a big thing for most people especialy if you havnt a big shed to put it in, in that case its only out of a stick welder and a gasless mig (bad name!), stick is more versatile but harder and gives you the shits when the electrode runs out during a weld. Gasless mig is easier, but as far as I know they only have mild steel flux cored wire available. Another big advantage of these two if that you can use them outside in the wind where it will blow the shielding gasses away with the mig/tig/oxy.

At a guess, price for a cheap stick welder $80US and cheap gasless mig $200US.

Soooo... depends what you want to spend and what you want to weld!

(Note that when I say gasless mig im refereing to a mig running flux cored wire so not a mig at all, you just use it the same way)

[Flake2m]

How many types of welding are there?
I have heard of MiG welding, TiG welding, fusion welding and there are probaly others..
I know that MiG and TiG welding both involve the use of an inert gas like Argon.
What is the difference between the welding type?

[Axt]

ok, here we go...

Arc welding is anything that uses electricity, all welding here is fusion welding but most often given to oxy/acetylene welding.

Stick welding also called "manual metal arc welding" is where you use the flux covered rod, thats the cheap one people are refering to as an "arc welder" the weld gets covered by a hard layer of flux that must be chipped off.

MIG (metal inert gas) is where an electrified wire is fed off a spool into the weld as its blown over from an inert gas to protect from oxidation, gasless mig is the same but the gas is substituted for a flux core which is scrubbed off with a wire brush after the weld.

TIG (tungsten inert gas) uses a tungsten electrode that resists melting due to its high melting point, so you are only melting and joining the parent metal, though you can feed in wire like with an oxy if needed.

Oxy/Acetylene obviosly uses a hot flame to melt the melal and a filling rod to feed in metal to fill the weld, since you dont need electricity its portable.

Thats all that you would use at home, but there is a number of others mainly machine driven, such as spot welding which uses two electrodes on either side of the metal using the resistance through overlapping sheets to fuse them together. lasers/electron beams are also used, friction welding is another specialised weld where the metal is spun so fast it melts into another piece. I think the four metioned are the only ones you would actually have use for at home.

Oh, and dont forget thermite!

[Anthony]

Don't forget explosive welding! :)

[xyz]

Flake2m, Fusion welding is just another name for Oxy/Acetylene welding, because the metal is fused together. It has nothing to do with atomic fusion if that's what you were thinking :( .

[Aaron-V2.0]

Dont forget resistance welding. That's where you use an item that looks like a jaws of life with chainsaw handles, the two electrodes touch together and just melt the material together.

I believe it's used on steel 1/8" and smaller, though it's not a commonly taught welding skill.

[IPN]

Aaron-V2.0:
I think what that you are describing is just spot welding, used mostly to weld thin metal plates together

My favorite has always been stick welding, with it you can make very tough welds and no need to hassle with inert gasses. A welder capable of +250A can nicely handle over 5mm welding sticks and they give a strong weld :) Although you can weld with a MIG welder without an inert gas but it tends to spit quite much and it doesnt make very clean and uniform weld…
With an inert gas it works well and is excellent for quick weld jobs. :)

[Aaron-V2.0]

Oop, your right IPN. Though the college course I learned it was reffered to it as resistance welding. Here's what is used.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=45689

[Flake2m]

I know, I have done some welding but it was mainly with an oxy set. I have also done some spot welding. I would like to try doing some MiG or Stick welding but I dont have access to the gear and there are dangers of "welding flashs" even if you do have all the safety gear.

[jeffchem2000]

Also one that hasn't been mentioned is the original "welding". I think it is done by heating both bits of metal to be joined and then when they are glowing red hit them together with a hammer until they have fused. I have seen this done with gold and I'm told it also works for Iron and other metals with high melting points.

Please correct me if any of it is wrong but as far as I know what I have said is correct.

[Tuatara]

You are describing forge welding. I believe the metal needs to be more like orange than red, and you need plenty of flux between the metal sufaces to carry off the oxides. There is also an immense shower of molten slag ejected when you hammer the join. (sounds like fun to me!)

[a_bab]

As I can see, nobody said something about the water welders. These are devices which are producing a stoichiometric mix of H2 and O2 from water by the means of the electrolysis. There are remarcable properties of the flame produced, like the ability of having a temperature up to 6,000 degrees C ! Now that's something usefull I would say.

Patents:
4,081,656 (http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=4,081,656.WKU.&OS=PN/4,081,656&RS=PN/4,081,656)
4,014,777 (http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=4,014,777.WKU.&OS=PN/4,014,777&RS=PN/4,014,777)

A description of the process here (http://www.lifenatural.com/browngas.htm)
A nice presentation of what this so-called "Brown gas" can do
here (http://www.spirig.com/products/microflaming/spirflame/overview/spirflame_overview.html)

The device seems to be rather simple to make; I guess I'll try it out.

[xyz]

Wouldn't there be a risk of a tremendous explosion unless the gases were collected seperately at each electrode?

In Oxy/Acetylene welding, the two gases are only mixed just before being burnt and only a few cc of the two gases is ever mixed at one time. The flame also draws some of it's oxygen from the atmosphere (this stops the flame "burning back" up the handpiece).

If you take an Oxy/Acetylene welder and adjust the flame till it is the type of flame normally used for welding, then quickly turn the oxygen up, you will get a loud bang and the torch will go out, this is because there was enough oxygen for the flame to burn back into the handpiece and cause a small explosion (fortuneately the handpiece is designed to withstand this and there is no danger involved) .

If you are using stoichometric ratios of hydrogen and oxygen, you will have to design your apparatus to collect them seperatel and then recombine them just before it burns them.

[a_bab]

If you'd read the references I linked, you'd understand that there is no risk. The "explosion" is in fact an implosion:
"Regarding the self-implosion characteristic of the gas, Dr. Ellyett noted, "If a spark plug is inserted in the gas and a spark passed, the gas immediately collapses to water with an 1860 to 1 reduction in volume. This creates a near vacuum""

If you deal wit a strong enough case, it'll be fine. Actually, the water welders do implode sometimes; all the effect being a dull sound.

[xyz]

Ok then, just making sure that you knew about that.

It is definitely not an implosion in oxy/acetylene welders though, I have seen blobs of molten steel from the work thrown 5 - 10 metres (that's why we wear goggles and aprons :) ) by the blast when the flame burns back inside the torch handle.

[Tuatara]

How could it possibly collapse like that when igntied? You're going from H2/O2 mix at room temp to steam at 2000C. You've only 2/3 the mols of steam, but the gas laws say your pressure will still jump by 60x. Even allowing for condensation of the water after the event, I'd still put money on it breaking things.

Personally, no matter what the fringe scientists say, I'd keep the two gasses separate as long as possible.

[Anthony]

I agree. It's interesting but a bit suspicious.

How could a reaction (H2+O2) which releases large amounts of energy CONTRACT on completion? Where would all this energy have dissapeared to?

Also, why is any other mixture of H2/O2 dangerous to store together or compress, but a stoichiometric quantity dramatically safer? I see no logical explanation for this.

How could you patent the resulting gas mixture given off by normal electrolysis of water? Such experiments have been done for centuries, and as far as I know, you cannot patent something "obvious".

The fact that the article is trying to sell these units automatically makes me sceptical. What really does it in is the page on the same site offering "free electricity" by your own personal generator that runs on permanent magnet technology (read perpetual motion bullshit).

I have wanted to create a H2/O2 generator/torch for some time and probably will do, although I'd seperate the gases.

Another thing I fail to understand from that article is why DC power must be used for the electrolysis cell when the gases are collecting together, why could AC be used, thus saving a rectification step?

[xyz]

Anthony, AC doesn't work well for electolysis, you need DC for it to work well (don't ask me why, it's one of those "it just does" things).

If AC worked properly for electrolysis, then all the worries about non corrodable anodes for chlorate production would have been solved long ago.

[ossassin]

What type of welding would be best for precise welding on firearms? What equipment would I need, and about how much would it cost? Sorry guys, I know nothing about welding. Thanks for the help!

[xyz]

I think that MiG and TiG are the most commonly used for firearms.

I only have experience with MiG though.

[Jacks Complete]

Cheap-ass spot welding seems to be common on a lot of the cheaper guns. It tends to be more precise than a MIG for beginners. It also lets you set it all up first, then zap, which a lot of MIG welders won't do. This lets you be far more precise in your weld.

For info, you can spot weld with a MIG, and 'seam' weld with a Spot welder, but neither is optimal.

Unless you can get the MIG nozzle into the gap you want to weld, it isn't going to help. Also, MIG costs more than spot, and you need a lot more practise. If you are skilled, however, the MIG will do everything better than a spot welder.

Don't forget that welds are good, but not as strong as good steel, as they are over-hard.

Most welds can be avoided by clever use of materials or bending/stamping/cutting operations.

[Mike76251]

Another thing that strikes me odd about that H20 welder is why on earth do you need 220v if it pulls such low current? (as they state in the comparsion section)

[keith]

Mig welding can be used on almost any type of metal that can be welded. Ive welded Aluminum & steel personaly and have seen ppl welding other alloys. You simply buy diferent wire for AL or for steel or what ever material your welding. And a good mig welder can handle 3/4" thick steel easily. It will melt all the way into it. Again thats only with a good one. mine cost about $1000

[Anthony]

Those things (assuming they're functional), would be pulling a hell of a lot of current. One of their models shows cables the size of garden hose for the low voltage DC supply. That's going to be hundreds of amps. The mains draw will be a lot less, but probably at least 20+ amps.

[Ammonal]

I can vouch (sp?) for stick or ARC welding as it is the only welder I have at my disposal, it is only a cheapish AU$500 140amp mains welder and the trick I have found with it is to have a variety of rod sizes. I keep 1.25mm rods for small seams and thin walled pipe and tubing, 2.5mm for general welding of 2mm + thickness steel, and some 3.25 and 4.1mm for welding heavy materials up to about 6mm thickness.

My neighbour has a AU$1200 MIG welder and he recently bought some stainless wire for it, he already welds aluminum, steel, bronze, and most other metals with it to a high degree of quality. Yes MIG welders can be easy to use but you cant always do with a MIG what you can with a stick welder. And as for TIG welding, it is just the duck's nuts when it comes to joing stuff together. Makes good weld done with a stick welder look like the shittiest stuff you've ever seen in your life.

BTW I saw a plasma cutter being used for the first time the other day, some forks were being cut for a forklift and and the material was solid sheet 2" thick with the outline of each fork scribed onto the surface, the guy with the plasma cutter moved through the steel like a hot knife through butter. If there was a way to remove a door or lock quickly it would be one of these! in half a minute the first fork was cut out and by a minute the job was done.

As far as welding for the home chemist type goes, here in Australia there are these inverter type arc welders which do not have the high power of their bigger counterparts but they are priced at about AU$400 - $600, which I would consider as being pretty affordable because they can run through a normal powerpoint (10amps around here) and come in a little case and are super portable. All you need to own is an extension lead and an inverter arc welder and you can go anywhere.

[xyz]

Anthony, are you talking about MiG welders?

If so, the reason that the cable is so thick is because it has to carry the gas as well as the electricity, it is basically a gas line that also has the wire inside it.

[Mike76251]

I think he is talking about those Brown Gas welders and not migs.

[Anthony]

Yeah, Mike76251 was asking about the H2O welders.