Welding

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tim-b
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Joined: 10 Oct 2009, 8:20am

Welding

Postby tim-b » 21 Jun 2017, 5:53am

Hi

There are several very sound engineering minds on here, and I need to buy a welder (not totally bikes and bits, but will be connected-excuse the pun)
I want to weld 5mm steel rods at 90deg (a cross or mesh arrangement) and I want to be able to infill parts with thinner sheet steel, and some occasional welding angle iron type jobs too

It's DIY so I don't want to spend £££££££££££££££££, but I want to learn to do the welding. What would you suggest? Arc, MIG, etc. Size, etc?

Regards
tim-b
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531colin
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Re: Welding

Postby 531colin » 21 Jun 2017, 6:32am

My welding would make [Inappropriate language removed]
Its an "interesting" thing to try to do on an amateur basis, you not only need to understand the theory, you need to develop the manual skills, and the "feel" for the job.....plastering might be a good comparison. Its too easy to "burn through" the thinner metal before you get the thicker metal hot enough to weld.
I bought a MIG welder when I was absolutely stuck and needed to do something in a real hurry, but its a poor way to learn, on your own. On the other hand, my brother is pretty good with a stick welder.
I would see if you can find a local Adult Education course on welding.....in the meantime, you can buy all sorts of mesh. (weldmesh, expanded metal..)

Brazing is a lot easier to control, a gas blowtorch gives enough heat to join 5mm rod, if you want to braze big lumps of metal then they take a lot of heating up and you need gas and air......and my brother brazes pretty well with his stick welder, but he is gifted.

Suffolker
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Welding

Postby Suffolker » 21 Jun 2017, 6:53am

I have a French made GYS inverter welder, which will do unshielded stick welding with several sizes of Rod, including 316 stainless and rutile. With the addition of a suitable torch and gas, it will also do TIG welding.

My own view, having also used a "bog-standard" Sealey arc welder, is that an inverter is far superior (easier arc striking, better arc control, cleaner welds).

Your main problem area, where TiG is handy, is with the thinner sheet. Depending on how thick it is, it's not easy to arc weld without blowing holes in it, although there are some techniques that can help. Your 5mm rod will also be a bit of a challenge, but practice will help.

When I bought my small and portable machine about 15 years ago, they were rather dear, but I see prices are now less for more. As usual, the more heavy duty a machine is, the more expensive.

I have also used a low-end MIG welder, both with and without gas, and personally wasn't too impressed with, among other things, the fickle wire feed and Torch problems. Perhaps I needed more practice, but I think with these machines, you really do get what you pay for.

As for learning, endless practice on scrap metal of different sizes and shapes helps. There are probably loads of YouTube videos available now, to show, among other things, how to prepare the workpieces, and forming the different types of weld. I myself learnt by trial and error in pre-internet days, and the best book on welding ( now long out of date ) I could find helped a bit.

One of the best investments you can make is the purchase of a good quality auto-darkening welding helmet. It helps to see where you're going when you start the weld, and a helmet gives you both hands free.

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ferrit worrier
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Re: Welding

Postby ferrit worrier » 21 Jun 2017, 7:52am

Suffolker wrote:As for learning, endless practice on scrap metal of different sizes and shapes helps. There are probably loads of YouTube videos available now, to show, among other things, how to prepare the workpieces, and forming the different types of weld. I myself learnt by trial and error in pre-internet days, and the best book on welding ( now long out of date ) I could find helped a bit.

One of the best investments you can make is the purchase of a good quality auto-darkening welding helmet. It helps to see where you're going when you start the weld, and a helmet gives you both hands free.


+1 for the above :D I was taught to gas weld and arc weld in my yoof and have subsequently learnt to Mig weld. I paid about £150 for a mig welder from B&Q several years ago when the drivers seat of the car collapsed and a second hand replacement was circa £600.

You may see people mig welding without gloves in videos, DONT you get just the same UV rays as stick welding, Auto shut down helmets are about £45 / £50 on ebay and are well worth it. the plastic (rear) and Glass (front) lens covers are cheap as well.

Good luck and get some practice in.

Malc
Percussive maintainance, if it don't fit, hit it with the hammer.

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Gattonero
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Re: Welding

Postby Gattonero » 21 Jun 2017, 8:54am

tim-b wrote:Hi

There are several very sound engineering minds on here, and I need to buy a welder (not totally bikes and bits, but will be connected-excuse the pun)
I want to weld 5mm steel rods at 90deg (a cross or mesh arrangement) and I want to be able to infill parts with thinner sheet steel, and some occasional welding angle iron type jobs too

It's DIY so I don't want to spend £££££££££££££££££, but I want to learn to do the welding. What would you suggest? Arc, MIG, etc. Size, etc?

Regards
tim-b


You need al ot of practice and some scraps to get your hand steady.

Do not skimp on mitering, that is paramount. Also do not use cheap rods.
The wire with flux inside splatters a lot, using gas canisters is expensive but gives better results. Go this way when you're ready, so start with flux wire if you are going for a MIG one, they're easy to use, though I would advise to learn with an Inverter one.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

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meic
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Re: Welding

Postby meic » 21 Jun 2017, 9:12am

For a non-expert domestic welder the MIGs are cheap and easy to use.

You can buy a Clark or Sealey MIG welder and it comes with what you need to start straight away.
You will probably be better off with the lowest power welder as that is better for welding thinner sheet metal.

When I bought my last welder the bottom of the range was a Clarke MIG90, from Machine Mart, and that would be a good one to consider. Yes these welders might be limited but so are the intended users. :wink:
I was warned that stick welders (even cheaper) are not as good for welding thin sheet.

If you move on to doing lots of welding then you would have to invest in a bigger gas bottle and reel of wire as it is very expensive to use the small ones that come with the kit, it is more expensive to buy the big ones and not use them. Welders are big, heavy and go rusty if left in a damp garage on the other hand they can be very, very useful.

Preparation is crucial and a welder should go hand in hand with an angle grinder if not working on brand new steel.
Yma o Hyd

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NATURAL ANKLING
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Re: Welding

Postby NATURAL ANKLING » 21 Jun 2017, 10:34am

H,
Like someone else who did welding as part of training.

Braze Welding is by far the nicest to the eye, but needs time expensive gear and skill, two handed.
Arc is the most difficult for an amateur and almost impossible for sheet metal, cheapest by far, one handed but don't let that fool you.
Gas the most versatile, but needs skill for thin sheet, and probably the most expensive to set up, two handed.
Inverter, most professional, can weld most metals but skill needed, two handed.

Mig I would say is the most useful and cheapest up to say 5mm metal, quickest and easiest to adjust, sheet is still difficult but just use the thicker material as a heat sink is the trick, one handed and easiest by far for semi skilled.

Expense comes from the gas ! Not the consumption but the annual rent, only arc uses no gas, mig can be gasless with a fluxed wire but is expensive, developed for windy conditions on your car :)

I would go on a course if you plan to do any welding, otherwise you will pull your hair out trying, get a mate to give you some lessons is quickest cheapest option.

I would go for Clark mig and small too like meic suggest, as the sealy had a bad reputation, only other point is that a fanless mig will cut out often with extended use! you can add fan later if needed, if you are good at diy, I have two clark migs and they do 99% of what you want.

Edited-
Inverter is electric arc. Mostly used for TIG, and stainless.

All thin sheet (bicycle frames) will be best done with braze / braze welding.
NA Thinks Just End 2 End Return + Bivvy
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Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

Brucey
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Re: Welding

Postby Brucey » 21 Jun 2017, 10:53am

for the immediate requirement I'd suggest brazing would give the neatest result, and that it would be strong enough for most purposes. For general welding you are likely to need I'd suggest MIG with CO2 gas, although it won't make such a nice job of the crossed 5mm rods if you are averagely competent. If you keep all the welds on one side you may be able to make it look OK from one direction without a lot of grinding.

I second (or third) buying a low power clark machine. I have several welding machines (and have had access to plenty more besides in the past) and 95% of the time I feel I will do a better, quicker job using a 90A rated clark machine (with a fan added and a modified shunt) than I will with a machine that costs x10 as much. My favourite machine cost me £35 secondhand.

Unless you are definitely going to be welding outdoors on thin stuff without a wind shield, avoid gasless MIG; it is difficult to make a neat job, very messy, the fumes are terrible and the cost (per Oz of weld metal deposited) is horrendous.

BTW I only bother with an Argon CO2 mix when I'm MIG welding stainless steel. The rest of the time on steel I use a CO2. With the right regulator etc you can use the contents of a CO2 fire extinguisher for shielding gas; 2kg of gas for about £15 does lots of welding, no stupid rip-off bottle hire charge.

cheers
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pete75
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Re: Welding

Postby pete75 » 21 Jun 2017, 11:33am

Gas is probably the most versatile but current regulations make it difficult get cylinders if you're in a domestic property. I've managed for years with a relatively low powered - 160 amp max arc welding set. A stick welder would be fine for what you want and would be the most inexpensive. One thing to be careful of is keep the rods well away from damp or moisture. If you don't use them very often keep them in your boiler room or airing cupboard. Contrary to what some people say it's perfectly possible to weld sheet metal with a stick welder - you just use low amps and a thin rod. You can get reasonable results for brazing using a carbon arc torch with an arc welder as well.
Would never buy a mig myself as I don't know how to use one - have only ever used arc and gas.

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NATURAL ANKLING
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Re: Welding

Postby NATURAL ANKLING » 21 Jun 2017, 12:03pm

Hi,
If you have done good jobs with arc and gas then mig can be done blindfolded.
I have welded blind numerous times under the car when its impossible to get hand and torch, mask and my big head in the space :lol: Seriously!

Can you get co2 fire canisters legal and easy nowadays Brucey :?: , my last attempt the firm would not deal any more and they have clamped down so much.
My supplier is paid to decommission (cut up destroy with a band saw) any co2 tanks he can get his hands on...............by BOC......
Pub gas if you know a mate, I even thought about walking up to a driver at rear of pub...............

I have used co2 for twenty five years or more, argon mix does give a nicer smoother neater less splatter weld but for home use you get used to it and as said fine.

I am paying £20 a year for my tank even though I don't need a refill for several years as its use is spasmodic depending on appearing holes on the camper (one in ten years).
The gear drive for wire on my clark 100e is a bit worn but I guess that out of my £100 outlay I have earnt several thousand in paid and unpaid jobs of my own, I have a 150 amp mig too but you only go up about 2mm material thickness.
Angle iron needs about 200 amps for good fusion as mig takes time to heat the parent metal up.

Al good fun.
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

Suffolker
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Re: Welding

Postby Suffolker » 21 Jun 2017, 3:30pm

pete75 wrote:Gas is probably the most versatile but current regulations make it difficult get cylinders if you're in a domestic property. I've managed for years with a relatively low powered - 160 amp max arc welding set. A stick welder would be fine for what you want and would be the most inexpensive. One thing to be careful of is keep the rods well away from damp or moisture. If you don't use them very often keep them in your boiler room or airing cupboard. Contrary to what some people say it's perfectly possible to weld sheet metal with a stick welder - you just use low amps and a thin rod. You can get reasonable results for brazing using a carbon arc torch with an arc welder as well.
Would never buy a mig myself as I don't know how to use one - have only ever used arc and gas.

An airing cupboard is fine, provided that it doesn't ever contain damp or damp-ish materials (its purpose in houses where I've had one). I used to buy welding rods from an old boy who was trained up after the war, and had a mobile welding supplies business here. When I asked him about airing cupboard storage, I got a good laugh, as apparently any damp will pretty quickly transfer to the rods; especially if they're in cardboard boxes. I've usually stored the bulk in dry, airtight plastic boxes in my office drawer, and transferred a "ready-use" supply to thick plastic bags with a corner cut off to get them out, which I then close up with a clothes peg or crocodile clip.
I've also found that preheating the metal before welding can make a considerable difference under some circumstances.

pete75
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Re: Welding

Postby pete75 » 21 Jun 2017, 3:52pm

Suffolker wrote:
pete75 wrote:Gas is probably the most versatile but current regulations make it difficult get cylinders if you're in a domestic property. I've managed for years with a relatively low powered - 160 amp max arc welding set. A stick welder would be fine for what you want and would be the most inexpensive. One thing to be careful of is keep the rods well away from damp or moisture. If you don't use them very often keep them in your boiler room or airing cupboard. Contrary to what some people say it's perfectly possible to weld sheet metal with a stick welder - you just use low amps and a thin rod. You can get reasonable results for brazing using a carbon arc torch with an arc welder as well.
Would never buy a mig myself as I don't know how to use one - have only ever used arc and gas.

An airing cupboard is fine, provided that it doesn't ever contain damp or damp-ish materials (its purpose in houses where I've had one). I used to buy welding rods from an old boy who was trained up after the war, and had a mobile welding supplies business here. When I asked him about airing cupboard storage, I got a good laugh, as apparently any damp will pretty quickly transfer to the rods; especially if they're in cardboard boxes. I've usually stored the bulk in dry, airtight plastic boxes in my office drawer, and transferred a "ready-use" supply to thick plastic bags with a corner cut off to get them out, which I then close up with a clothes peg or crocodile clip.
I've also found that preheating the metal before welding can make a considerable difference under some circumstances.


Dunno - I've only ever taken stuff out of the airing cupboard and it always seems pretty dry to me. I keep my rods in the boiler room. Presumably now most houses have central heating they'll have a boiler room so it's the obvious choice.

mig
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Re: Welding

Postby mig » 21 Jun 2017, 4:57pm

NATURAL ANKLING wrote:Mig I would say is the most useful .


cheers dude 8)

Brucey
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Re: Welding

Postby Brucey » 21 Jun 2017, 6:03pm

NATURAL ANKLING wrote: Can you get co2 fire canisters legal and easy nowadays Brucey :?: , my last attempt the firm would not deal any more and they have clamped down so much.
My supplier is paid to decommission (cut up destroy with a band saw) any co2 tanks he can get his hands on...............by BOC......
Pub gas if you know a mate, I even thought about walking up to a driver at rear of pub...............

.


Pubs don't use so much CO2 these days; many of them use a Nitrogen mix instead (no good for welding). A problem with pub gas CO2 is that the empty bottles would often get left open. If they get moisture in them and are then not dried properly before being refilled, the CO2 turns to carbonic acid and can corrupt a steel bottle from the inside. In the past quite a few pubs have been blown up by failing CO2 bottles.

You can buy a new 2kg CO2 fire extinguisher outright for ~£25 and a refurbed one is about £15 or so (exchange). I've bought them at car boot sales for just a few quid too. There are also 5kg extinguishers. You just unscrew the horn and attach a regulator. Companies that do refurbs will often let folk have any surplus (full) extinguishers in short date for pennies so that they can use the gas for welding; otherwise they may just have to vent it to air, I think. When a fire extinguisher is going out of date it needs to be emptied, cleaned, inspected, pressure tested, then repainted and refilled. The bottles are aluminium so presumably don't suffer carbonic acid in the same way.

My local car spares shop (as well as smaller disposable bottles) also sells big bottles of CO2; you buy the bottle (~£30, one-off) and then buy the gas (~£25 for an exchange fill). The bottles vary in size but ~7kg of gas is typical.

BTW the welding parameters will vary a bit with gas type; CO2 runs a bot hotter than Argon/CO2 mixes. With the right setup a CO2 MIG weld isn't much worse than argon CO2 mix; not a big deal and certainly not a deal breaker. Also, welding sets that operate over a wide current range often don't work that well at the extremes, so if you want to weld at low currents, a high current set that (in theory) will just do that low current is liable to be less good than a low current set.

BTW you can use MMA for welding car bodywork thickness steel but it is not at all easy; the electrodes look like sparklers and in average hands, are about as effective. I've only ever known a few blokes who can MMA weld thin steel with any real degree of competence.

cheers
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Abradable Chin
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Re: Welding

Postby Abradable Chin » 21 Jun 2017, 8:18pm

531colin wrote:my brother brazes pretty well with his stick welder

Could you expand on this process, please? I'd just assumed brazing was only done with a flame.
Does this mean you can do bike frames with a stick welder?

BTW, Lidl had an inverter arc welder for £60 a couple of weeks ago. It only went to 80A, so largest rod would be 2.5mm, but it had a three year warranty, so beats cheap stuff on eBay.