Welding for Newbies - or, in this case, for me ... :)

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toakreon
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Welding for Newbies - or, in this case, for me ... :)

Post by toakreon » Tue Apr 17, 2007 9:39 am

OK ... my "Squirrel" valveless pulse-jet design is reaching the time when it needs to be tried "in the steel", so the time has come to build it!

This is somewhat hindered by the fact that (a) I have never welded in my life ... well, actually I have, but it was with oxy-acetylene and years ago ... and (b) I have no welding kit with which to do it.

Never mind. I guess I must must invest in something suitable, and some nice bits of scrap steel, and a "teach yourself to weld" book and have a go!

I've looked at "standard" arc welding - but that looks like being totally unsuitable for thin steel sheet.

I've looked at MIG welding - but bottles of gas and £350 welders seems a bit off-putting to a nervous individual like me.

I've also seen "gas-less MIG" which I understand to be rather like MIG but with a flux core built into the MIG wire - this, so what I've read suggests, is relatively easy to use and much more suitable for thin panels (such as car body panels), often used for repair of such. Something suitable for welding body panels on cars, thought I, might well serve to weld pulse-jet engines.

I've also, of course, heard of "TIG" but haven't a clue about what it really is.

So here's the question - would a relatively inexpensive, gas-less MIG welder be "appropriate" ... and if so is this something I can "teach myself" or do I really need to book up for welding classes?

John

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welding for newbies

Post by lojbeck » Tue Apr 17, 2007 11:12 pm

Hi John,

In my limited experience, for the money, I would invest in a gas (ox/acet.) setup. Flux-core and gas mig welders (at least mine) do not give a lot of control when welding very thin but-joints and burn-thru is easy. Arc welders require too high current flow. It may be possible to get good welds with a stitch welder attachment, but I haven't tried it. Tig is the way to go but the cost of the welder and tank may be outside your budget. I have found that with a little practice "almost tig" quality welds can be achieved on mild steel using small brazing tips and low pressures. I have not tried to gas weld ss but I know it can be done. Most torch kits come with everything needed except for the tanks. All of these suggestions are based on the need to weld thin gauge materials. Hope this has been of some help.

Jimmy

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Post by toakreon » Wed Apr 18, 2007 12:45 pm

Thanks lojbeck,

Yes, certainly another route to consider. I'll look into gas equipment - but having said that I have an "aversion" to toe idea a shed full of gas cylinders (I'd rather not even have a propane one there if I could avoid it, unfortunately that's just not going to be possible) so I would RATHER go "electric" if I could.

GRIN ... I'd even wondered whether you could do something with Thermite powder ... Back the joint with high temperature ceramic. Lay a thin "row" of thermite. Light the blue touch paper. Stand well back. WHOOSH!

But then sanity returned!

John

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Welding Opinion

Post by larry cottrill » Wed Apr 18, 2007 4:29 pm

toakreon wrote:I'll look into gas equipment - but having said that I have an "aversion" to the idea a shed full of gas cylinders (I'd rather not even have a propane one there if I could avoid it, unfortunately that's just not going to be possible) so I would RATHER go "electric" if I could.
John -

Don't know about your shed, but in mine I feel WAY safer with an oxyacetylene outfit than I ever would with the sparks from electric welding flying around everywhere, because of vented fuel cans (for lawn equipment and such).

As for stainless, I have welded it with my acetylene rig - but it is a tedious business, involving careful preparation of the work with high temp flux compound (some kind of fluoride powder). Also, it is difficult to keep the weld moving fast enough, because of the poor heat conduction of stainless (also tending to cause warpage, waviness, etc.). In other words, it can be done, but only with enough patience and practice to develop some expertise.

For mild steel in small / thin materials, however, I think oxyacetylene has no peer for nice quality welds with minimum hassle and little wasted time / effort. Once you understand the safety requirements of using and maintaining the gas equipment, your rig becomes one of the safest and most convenient hand tools you'll ever use. True, the cylinders are heavy and awkward to handle, but you usually just chain them up in one spot and leave them there until you need to replace them with full ones. My main safety problem over the years has been in mis-judging when a welded piece has cooled enough to be handled! High strength aircraft steel ("chrome-moly") is the most beautiful welding material you can imagine with oxyacetylene, and needs no special preparation - you weld it with mild steel filler rod.

L Cottrill

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Post by toakreon » Wed Apr 18, 2007 4:47 pm

*EDIT*

OK ... I've looked at oxy-acetylene "sets" and I see one advertised, new and at a price that seems reasonable consisting of:-

(and here I'm cut-n-pasting)

1 x 5mtr Set of Oxy-Acetylene Welding Hose
(With safety fittings fitted)

1 x Oxygen S-150 2 Gauge Regulator

1 x Acetylene S-22 2 Gauge Regulator

1 x Oxygen Flashback Arrestor

1 x Acetylene Flashback Arrestor

1 x No5 Series Welding Shank

1 x No5 Welding Mixer

3 x Welding Nozzles
(sizes 2,3 and 5 or as requested!)

1 x Protective Welding Goggles

1 x Protective Welding Gauntlets

1 x Set Nozzle Cleaners


Now this was described as "everything needed with the exception of bottles of gas" ... but as I wouldn't know a "size 3 welding nozzle" if one leapt out of the bushes and bit me, I'm not really in a position to know if this is "complete" or not!

So, before I spend my hard-earned cash, does this look like an "everything you need" to you? And as there is an "or as requested" by the size of the nozzles, are 2, 3 and 5 "sort of reasonable" for pulse-jet welding?

Sorry to an ignoramus asking questions!

John

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Post by multispool » Wed Apr 18, 2007 6:34 pm

Hi toakreon,

Just seen your messages.

Before buying it would be good sense to go down the local BOC to find the cylinder hire charges. Its not so much the gas refill charge as the cylinder rental which in this case would be for two cylinders and work out quite costly if only used occasionally.

A cheap gas (not gas-less) Mig welder will do all the jobs you want including s/s down to around 0.8mm without much practice and you can get throw-away argon bottles which last about 30 mins continuous welding for about £8-9 each. Thats quite a bit of welding time! Or a single large/ish argon bottle from BOC costs about £50 annually.

For 0.5mm sheet you really need gas or an up-market TIG with at least HF start and HF pulse plus a lot of practice.

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Post by toakreon » Wed Apr 18, 2007 6:58 pm

Ah ... another thing to consider ... It's not good being a complete welding newbie - the possibility of mistakes!

I shall see what the gas bottle would cost me.

John

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Welding Nozzles

Post by Al Belli » Wed Apr 18, 2007 6:58 pm

Hi toakreon,

The lower the number, the smaller the nozzle. I would suggest a #1 nozzle for thin material. ( or a #0 nozzle for very thin material )
I would recommend Solar flux type B, which is widely available.
Do NOT use a fluoride type flux, since the fumes generated during welding, are very irritating !

http://www.solarflux.com

Al Belli

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Inexpensive TIG Welder

Post by Al Belli » Wed Apr 18, 2007 7:25 pm

Hi,

Here's an inexpensive TIG welder that might be good for Your use. It will go down to about 5 Amps for very thin work.

You will need a bottle of pure argon, and some 0.040" ceriated tungsten electrodes and a 0.040" collet.

http://www.harborfreight.com/cpi/ctaf/d ... mber=91811

Al Belli

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Post by Mike Everman » Wed Apr 18, 2007 8:15 pm

wow, that's cheap! er, inexpensive!
Mike
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Post by toakreon » Wed Apr 18, 2007 8:48 pm

It is ... Kinda makes me wish Chicago was somewhere close to Surrey ... :(

John

Al Belli
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Welder source

Post by Al Belli » Wed Apr 18, 2007 10:09 pm

Hi toakreon,

The brand name is Chicago, but the item is made in the Orient, maybe China.

I'm sure that someone in Europe must sell the same item under a different brand name.

If I were You, I'd look on the Internet for someone near You.

Al Belli

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Post by toakreon » Wed Apr 18, 2007 10:23 pm

I'll have a look and see what's available around here ... :) ... And compare with gas ...

John

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Post by ed knesl » Thu Apr 19, 2007 1:48 am

Hey, Guys, be aware that Chicago Electric ( Made in China) TIG welder has no foot control, no finger control, no frequency control and no pulser
to control the heat input on thin sheet metal.
Then right equipment for building pulse jets would be TIG machines from
China going about $1,000, or ESAB ( Sweden) $2,000 and the top Lincoln and Miller machines costing around $3,000.
They all would be inverters in the lightweight packages. These are mostly AC/DC machines allowing aluminum welding. DC only machines cost about $ 400 less, they are OK for stainless steel.
They are also available in Europe.
MIG or Stick welders should be avoided by all means for this ki8nd of work.

I hope, this info helps.
...Nobody is right, nobody is wrong...

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Post by loco » Tue Apr 24, 2007 1:07 pm

12 months ago I was in the same position as you, and really was keen on building my own engine. I went to my local college and took up a night course. 22 weeks, 3 hours per week, £220. All the rigs you want to use (Oxy, MIG, TIG, manu-metal-arc, etc) tonnes of metal to weld, and you get a qualification at the end. An experienced instructor stops you from picking up bad habits, and sits with you to prfect your technique. Great fun, too, plus I met people who were in the trade who can help me out with equipment (guy at the college says I can use the industrial-sized pinch rollers whenever I like, for example)

I went for MIG as it looks like the best all-rounder, and you *can* do alu and stainless with it (though I understand it's not the best). The rigs are fairly reasonable, too.

Last week I bought a Sealey 150amp MIG rig with a £200 electric mask in a special offer for for £320. Hiring a bottle of argo-CO2 gas costs ~20p per day and a refill is in the order of £30. Whatever you do, don't go near the disposable canisters: total waste of time and money.

I'm pretty happy with the rig, though the motor isn't the most powerful for pushing the filler wire if the cable is twisted. Great for sheet steel, though.

I'm still a newbie, but can now stick metal together OK. Stainless is still out of budget, so I can't tell you how good it is at that.

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