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General question on welding


Dan110
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Hi all,

I'm finally going to have a bit more time to dedicate to tinkering from this September, so i'm thinking it's time I made myself more useful by learning to weld.

I don't suppose anyone can point me in the direction of any resources that might be useful in either learning the skill, or choosing a machine for home use - i'm currently thinking MIG (based on no specialist knowledge :wacko: ). Nothing really came up on the search function....

Or maybe someone knows a good instructor/evening class in the Kent or Devon areas?

My plans are pretty much limited to LR/car related repairs and maybe some light fabrication of fire pit....bike stand.....etc

Cheers!

Dan

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Mig welding forum is a great site.

When I first looked in to migs I was told a 150 amp gas machine would be all I should need so that is what I went for, but if I knew then what I know now and funds allowed I would have went for a 200 amp gas machine.

It just gives that bit of extra burn if working on heavier gauge metal. I'm on the lookout for a 200 amp stick job for slightly heavier metal.

I hope that helps a little.

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I have Mig and Tig. Tig is great and is like gas welding of old, but for lashing stuff together Mig is king.

Get Tig if you want to do aluminium or small steel parts.

My Rtech 161 Tig also does stick-welding.

The 180 cebora Mig I have now is good, but if you want to eat 6mm plate then the bigger machines are better for sure as said.

Any college courses in your area?

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Esab caddy c200i if you can afford the ~800 notes and a good auto dimming mask with leather coat and gloves.

It is absolutely brilliant.

Select material, gas and thickness and weld. It will compensate for your hand speed. Very good weld quality.

It will do 6mm mild steel in a single pass, 3mm aluminium, ss and copper steel (modern car body panels).

I don't weld every day, but every time I pick it up to use it I get a decient weld, no fiddling with wire speeds etc, and trying to remember what you used last time.

I don't expect I'll be buying another welder in the future unless it gives up the ghost and I don't use it in a business environment so it should outlast me just fine.

Rob

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Thanks for the input guys.

Having wasted (invested) a couple of hours on the MIG forum, and without the £800 budget for the ESAB, i'm half wondering about just spending £60 on a Clarke 110a arc machine and just having a play. I've no immediate plans to anything particularly thin, and I like the simplicity of not having to worry about wire/gas/wind etc.

Maybe then upgrade to a better-than-entry level MIG when (if) I get proficient.

More procrastination from the work I SHOULD be doing required, I think.....!

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Just a thought but if you go over 150 amps you will need a higher amperage supply than 13.

MMA inverter welders wil do TIG for stainless and mild steel and cast iron but with the right sticks will arc weld those and aluminium too.

If you want to TIG weld aluminium it's a different process and requires DC current and consequentially a much more expensive machine so you might consider just how much aluminium you think you might work with for that one..

inverters are also a lot lighter than MIG machines my therna larc 175se weighs 7.5kg compared to about 35kg for the MIG

Youtube has some really useful videos on welding techniques.

edited cause I spelt aluminium wrong lol

Edited by Tal
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We have a SIFWeld AC/DC MIG/TIG/MMA at work for on-site work and it's a great little machine , and coming with a 5 year warranty and euro torch as standard it's a good alternative to the ESAB inverter MIG which this replaced as the ESAB blew the main board at 20months old ....

In the transformer MIG/MAG welding plant choices the 200a would need a 16a plug .A good auto-darkening full helmet will make it a lot easier to practice too

cheers

Steveb

edit to delete model - will check which one it is at work

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Just a thought but if you go over 150 amps you will need a higher amperage supply than 13.

MMA inverter welders wil do TIG for stainless and mild steel and cast iron but with the right sticks will arc weld those and aluminium too.

If you want to TIG weld aluminium it's a different process and requires DC current and consequentially a much more expensive machine so you might consider just how much aluminium you think you might work with for that one..

inverters are also a lot lighter than MIG machines my therna larc 175se weighs 7.5kg compared to about 35kg for the MIG

Youtube has some really useful videos on welding techniques.

edited cause I spelt aluminium wrong lol

Aluminium TIG requires AC, not DC.

The rest of your post is spot on though.

Some of the welding guys who do videos on YouTube are REALLY good.

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AC for Aluminium TIG , DC for steel & stainless TIG.

cwazyrabbit on here did say something recently about knowing someone who could DC TIG al , but normally it's AC

If you fancy starting on stick then look out on eblag for an old style unit with the winding handle to set the current , cheap and smooth to use , 'kin heavy but that's a good thing as it means copper wire and a lot of it

cheers

Steveb

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Thanks for the input guys.

Having wasted (invested) a couple of hours on the MIG forum, and without the £800 budget for the ESAB, i'm half wondering about just spending £60 on a Clarke 110a arc machine and just having a play. I've no immediate plans to anything particularly thin, and I like the simplicity of not having to worry about wire/gas/wind etc.

Maybe then upgrade to a better-than-entry level MIG when (if) I get proficient.

More procrastination from the work I SHOULD be doing required, I think.....!

While it's not true to say that little of what you learn to become a good MMA ("stick arc") welder will be of much use when it comes to learning MIG, the two techniques are very diffferent. MIG is a voltage controlled process, stick (and TIG) is current controlled so the hardware is different too.

Buying a cheap machine to have a play with is a good way to learn more about what you want to spend real money on. Plenty of cheap second hand stuff on e-bay.

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AC not DC .....LOL I'll blame the memory fairies for that one I think

The ones on youtube you can learn some stuff from are really good so don't expect results like that straight away.

I'm self taught (AC not DC :huh: ) and have put several welding jobs through MOT's successfully so your welds dont have to look awesome to work but if you can make them nice.... all the better

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The best advice that could be given to a beginner is:

1. avoid the gasless MIGs, they are not the best things to learn on and do not give very good results

2. Spend the money getting a good branded auto darkening welding screen. It's not worth Buying a sub standard one from China/eBay for the sake of saving £15 over a half decent branded one. They are there to protect your eyes

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I agree with Dangerous Doug, an auto darkening helmet is a necessity.

Cost wise I would go for an Inverter arc welder. Much easier to use than an old sit up and beg arc stick welder. Portable, and if you get the stick white hot by dragging it across a test piece or the earth clamp, it is easy peasy to strike up on the intended weld. Keep your welding rods next to your central heating boiler so they are completely dry.

Keep practising on test pieces. Its fun and you can always grind the welds off and try again.

Best of luck

Barry

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Honestly, if you want to work on automotive stuff, a MIG is the machine to have. Stick welding takes mode practice to get a decent result and can be incredibly frustrating on thin stuff as it blows holes very easily. MIG is king 0.5~3mm, and as already stated, forget the gasless option. A gas bottle from www.hobbyweld.co.uk is inexpensive and won't cost you annually - only for the fills. Wire is also cheap.

Start on thicker stuff - 2mm will be perfect and will allow you to get the hang of it without worrying too much about blowing holes. As you get more used to setting up the machine, moving and holding the torch and what makes a good weld, move to thinner stuff. TIG is lovely on really thin bits, but much trickier when under a Landy! Decent auto darkening helmet, as already mentioned, is a must. Don't forget that the welder will give you evil sunburn too!

If it sounds like frying bacon, you're not the right track. If it smells like it, you're on fire ;)

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Lo-fi's pretty much nailed it with the above post I think. :D

So I'll add to it:

The best advice that could be given to a beginner is:

1. avoid the gasless MIGs, they are not the best things to learn on and do not give very good results

I'll go a step further - avoid, avoid avoid the blue Clarke and the like hobbyist machines. They produce terrible results, and you will struggle to get repeat-ability.

Do yourself a favour, save some money, buy an inverter MIG.

It doesn't have to be the ESAB, the GYS machines can be had for about £400 and they're great, even on the thin stuff.

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Another point to note is that mig welds can look and seem perfect while doing them, but in truth they may be like a bead of toothpaste squeezed into the joint - and have a similar amount of strength. So when you do your test welds,stick em in the vice and try to beat them apart, you will soon see what I mean if the fillet has only stuck to one side of the two pieces you are joining.

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Thanks for the input again all. This forum never lets me down! (and the lack of shouting and abuse is credit to the members and the mods)

As with many things there's obviously no right or wrong but there seems to be a certain consensus on MIG being a good all-rounder and good place to learn. I've found a cheap 2nd hand Cebora pocket turbo 130 which seems to have a good reputation so maybe i'll start there. In terms of buying 2nd hand, would that machine and MIG's generally be largely reliable? (no absolutes, I know) repairable if it did fail?

Nick - you mention the difference between a voltage-controlled process and a current-controlled one - I don't suppose anyone could expand on that a bit could they? I've read up on the general differences between arc and MIG, but specifically what characteristics are changed by those two things? Hope that makes sense.

Cheers!

Dan

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That sounds like an excellent start point, was about to suggest a second hand one.

They are all generally repairable, especially the bigger makes (like cebora). 130A should do you 4-5mm (perhaps in 2 passes though).

Use argon/CO2 mix, makes a big difference too :)

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The best way to avoid leaking seams is to always try and work on the heavier section and stick the other section to it. For instance you can weld 4mm to 1mm by working the 4mm side but if you try 1mm to 4mm, working on the 1mm side you will have problems.

I believe working with the earth on the component away from the one you're working on ( ie, so the arc carries the molten metal across the weld gap) also helps with that. certainly seems to work for me anyway

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I would recommend getting a mig with gas, much better than without so long as it's not too windy. Hobbyweld do contract free gas although BOC universal is the best I've ever used.

If you want to be able to repair it you have to go for one of the bigger brands really, it can be hard to get parts for the unknowns. Some have PCBs which can often be the weak points. Mine is a fairly dumb sip migmate 170p, it's just switches and transformers. The only crummy bit is the wire feed, it's a driven roller that presses the wire against an undriven roller, if you clamp them too hard they bend away from each other and let the wire slip. The esab at work has more rollers and is much more substantial, but that was three times the cost so you get what you pay for.

I've always said if there was a tig evening course locally I would do it, the local college has just starting offering one, £1300 for the full thing, I had to eat my words :closedeyes: Watch videos on youtube, get some scrap steel and have a go, once you've got it looking ok try and do some real stuff, then watch more youtube videos to see where you went wrong. Ie welding upside down or different thickness metals make it harder.

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Nick - you mention the difference between a voltage-controlled process and a current-controlled one - I don't suppose anyone could expand on that a bit could they? I've read up on the general differences between arc and MIG, but specifically what characteristics are changed by those two things? Hope that makes sense.

Cheers!

Dan

There's actually a lot of really quite complex physics going on in an arc weld, and if you really want to understand it then you'll need a decent text book: I recommend this. However, you don't really need to know a lot of it for most hobby welding - simple rules like making sure that the workpieces are as clean as you can make them and the pieces to be welded are straight with consistent thicknesses and gaps will get you a long way. The main thing which makes the difference is practice. Lots of it. Start with something simple and get that working reasonably well, and then change a parameter (thickness of material, filler, angle of torch, current, voltage, whatever) one bit at a time to see what difference it makes.

The point about current vs voltage machines at this level is that with TIG and MMA the main parameter which is controlled by the welding power supply is current, whereas with MIG the main control is on voltage and the current is varied mainly by changing the wire feed speed. This means that you can use a power supply which is designed for MMA for TIG and vice versa but you can't do MIG with it unless it also has some sophisticated voltage control. There are multi process machines (I have one of these, and it's an absolutely superb piece of kit) but they are expensive, and in practice the TIG capabilities are fairly limited in comparison to a dedicated TIG PSU such as this.

MIG is without question the most useful process for anyone doing motorvehicle repair/fabrication work, so buying a MMA/TIG machine isn't actually a very good investment, and unless you are prepared to pay upwards of £750 then any multi-process machine is going to be compromised in some way. A better investment for most people would be to spend as much as they can afford on a MIG only machine. Basic features like a removeable Euro-style torch and good solid wire feed mechanism will be more use than TIG or MMA capability.

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Cebora are a older established brand, Spanish I believe, I have a cebora tigstar 150 (not used much, want to replace with an r-tech, or gys)

Only thing to watch with cebora are the accessories and if you need any repair bits can be expensive as there seems to be one stealer (oh, dealer!) For the uk.

Transformer machines can be heavy, and the newer igbt machines lighter. Some say better reliability with transformer machines (less components, less to go wrong... but that applies to a series Landrovers too, but I don't see any new ones sold...).

Igbt offers power factor correction of near unity (simple explanation... I can run my 200a machine on a 13a plug top, as more of the current and voltage (power) is used and not lost by transformer efficiency)

Cebora machines can be considered a workhorse, as they seemed to be used a lot at one point as a business welder... that being said... some may have had a hard life...

Check the rollers for wear, tensioner etc.

All consumables are replaceable... this includes torch (a conversion to a euro torch, if it doesn't have one has probably been done on the mig welding forum... if you want a euro torch plus connector ... pm me, it's sat on the shelf for near 2 years as I was looking to do it on my old Clarke).

I buy my mig consumables from riverweld (China), they arrive in a week or so, I buy plasma tips there too.

Suggest replacing the liner with a metal one, they do wear, and a benzyl (may be miss spelt) one will serve you well.

Wire tension is something I never got right until I got the esab and read the manual... suggest a search for a c200i esab user manual as there is a good diagram in there and explanation (applies to all mig welders, and I'm sure there are millions of references to wire feed, but this is the easiest I found and works for me, think the tenancy is to over tension)

Gas flow rate, suggest getting a good flowmeter (vertical clear rising metal ball) as a waste of gas is a waste of money, my gas usage has improved tremendously... gas flow rate in the esab manual will apply to the cebora if it uses the same consumables (they normally do, thin they are mb15, or something to that effect) as they use a similar sheild... same size = same gas flow rate.... from memory I think mine is set at 8l/min... never change it.

Check the range on your flow meter... you want something that provides a top flow rate of just a little more than is recommended for your welder... that will give you a visible range of adjustment... my tig had a flow meter with too large a range, meaning it was hard to tell if it was say set on 8 or 10 l/min... which means it ate through gas....

L

Suggest getting some welding magnets that can be turned on and off, such as the magswitch (or similar, cheaper), if not, they end up a furry ball of grinding metal flakes and sharp shards (ask me, I know!)

Hope some of this may be of help.

Rob

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good tips rob , the torch of perfection is Binzel , not found anything that comes close for toughness and durability at high (350) amps or for DIY use . most small MIG sets will cope with a 3m torch which is long enough to reach across a vehicle , a dual drive wirefeed will do 5m torch length .

looking forward to seeing some practice pic's

cheers

Steveb

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