Author Topic: Welding training troubles  (Read 2530 times)

Welding training troubles
« on: October 21, 2018, 01:08:10 pm »
MsC is trying to learn to arc weld in a hurry.

She's done a bit of mig welding, using fancy kit in her (ex) uni, and is fairly proficient at that.

She needs to weld 3mm strap together for a project.

I have a basic arc welder, so this weekend she came home to have a go with it.

She is struggling to get on with it - finding it so different to the mig, very hard to get an arc. I'm not a welder, only know very basics, not a good teacher and we have run out of time for practise. Wierdly she was doing fine with some rods, used them up, tried some others and just can't get an arc. I thought they were all 6013 rods.

I'm wondering if it is sensible at this point for her to be getting a basic no-gas mig. They seem to be cheap, but not having used them don't know if they would be any easier than my arc welder.

Anyone in London have one of these and can comment or even let her have a go?
<i>Marmite slave</i>

Re: Welding training troubles
« Reply #1 on: October 21, 2018, 01:12:13 pm »
For some reason  I think Ham may have welding kit of some description - (but, I could be wrong, and it might not be the kit you are looking for)  ???

Re: Welding training troubles
« Reply #2 on: October 21, 2018, 01:27:49 pm »
Your rods haven't got damp have they? If so trying to dry them off in the oven may help (the purists may not approve but it has been known to work!)

Re: Welding training troubles
« Reply #3 on: October 21, 2018, 01:30:19 pm »
New rods, so that isn't the prob.
<i>Marmite slave</i>

Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Welding training troubles
« Reply #4 on: October 21, 2018, 04:54:56 pm »
Firstly, welding with posh kit is nicer and easier than welding with cheap kit.

As long as there is a circuit the arc welder will weld, up the current till it does. 


Re: Welding training troubles
« Reply #5 on: October 21, 2018, 07:15:20 pm »
I do have mig kit, and I'm East London if that would help? I've not used "gasless" mig but mine can do that too (I Think). I just don't have any of the wire. It's this one (I just love the fact that it looks like it's LGBT)

Re: Welding training troubles
« Reply #6 on: October 22, 2018, 12:35:40 am »
6013 rods are great for clean metal work but 6011 are better if the work is not perfectly clean. If you have to, you can weld rusty or painted metal directly using 6011 rods.

Obviously the current needs to be set for the welding rod diameter and you should expect (current for current) slightly less penetration with 6013 rods than 6011 rods, if that is what you were using before.

A little trick that helps control is to cut rods in half and to use the shorter rods; this is a fair bit easier than long rods, especially if they are skinny ones.

I'm guessing that you have a basic AC set; this should be fine with 6013 rods (and 6011).

Re gasless MIG; in tests I have done, 1lb of wire only contains ~1/2lb of steel to start with (the rest is flux) and much of the steel disappears in spatter etc anyway. You might get 1/3lb weld metal deposit from 1lb of wire. The wire is fiercely expensive (about x5 vs standard MIG wire), feeds less well, the contact tip is more likely to overheat (no cooling gas flow),  there is more fume emitted, more spatter,  more UV and the fume is more likely to be poisonous than when using MIG or MAG welding.  The welds are less good too, despite a higher heat input into the work.   This makes it a process that is about the most expensive per unit of deposited weld metal.  The advantage is that it is all position and you can weld outdoors even on unclean material.  The niche that it best occupies is one of welding fairly thin section material in outdoor repair applications. For pretty much anything else there is a better welding process variant that works easier/better/cheaper/less hazardously.

So gasless MIG might well work fine for your present need but I wouldn't recommend it for every use by any means. Buying a machine that has reversible polarity and will do conventional gas MIG as well would be a much better idea.

Anyway I'd probably try some 6011 rods with the stick welder first BTW.

cheers

Re: Welding training troubles
« Reply #7 on: October 22, 2018, 08:44:29 am »
great feedback, thanks brucey. The gasless mig sounds to be an expensive limited use machine (might work out for her sort of artwork stuff though; always going to be small welds on new steel).

She was working on new, clean metal. so the 6013 rods should have been fine. I think it was mainly not having used an arc welder and lack of practice. Cutting rods in half was something she wondered about herself.

I might get some 6011 rods for my own use, since whenever I have to weld, it is on old rusty material.

Ham, that looks like a good bit of kit. I'll have to read a read of the site you linked.
<i>Marmite slave</i>

Re: Welding training troubles
« Reply #8 on: October 22, 2018, 10:40:08 am »

Ham, that looks like a good bit of kit. I'll have to read a read of the site you linked.

I'm happy to report that appears to be good value, I've had a few bits from them and no complaints. When I was looking I was after something better in the 240v line than the cheap'n'cheerful Clarke boxen, but didn't think I could justify the spend of the pro gear (like what Aunt Maud splashed out on). After much deliberation I ended up with the queer welder (as I like to think of it), it seems well thought of in the wending forums, one reason was the "spool on gun" aluminium option which might be useful in the future. If you're considering  don't forget that there's additional cost for the gas. (pm me if you want a 7.5% discount code). Only negative issue I've found with it so far is that the "digital display" for welding is only visible while welding, so effing useless, but as it's all down to "twiddle a bit this way/that way" it doesn't really matter.

Gattopardo

  • Lord of the sith
  • Overseaing the building of the death star
Re: Welding training troubles
« Reply #9 on: October 22, 2018, 10:56:54 am »

Ham, that looks like a good bit of kit. I'll have to read a read of the site you linked.

I'm happy to report that appears to be good value, I've had a few bits from them and no complaints. When I was looking I was after something better in the 240v line than the cheap'n'cheerful Clarke boxen, but didn't think I could justify the spend of the pro gear (like what Aunt Maud splashed out on). After much deliberation I ended up with the queer welder (as I like to think of it), it seems well thought of in the wending forums, one reason was the "spool on gun" aluminium option which might be useful in the future. If you're considering  don't forget that there's additional cost for the gas. (pm me if you want a 7.5% discount code). Only negative issue I've found with it so far is that the "digital display" for welding is only visible while welding, so effing useless, but as it's all down to "twiddle a bit this way/that way" it doesn't really matter.

Am quite jealous, nice welding equipment makes the job easier.

Re: Welding training troubles
« Reply #10 on: October 22, 2018, 03:35:05 pm »
Ham's machine looks like pretty good value to me. It has a eurotorch fitting and that makes for rapid changes of torch when required.

FWIW I will say that for the money, the Clarke machines are actually pretty good.   They use M5 threaded contact tips and the gas shroud nozzle is that bit smaller than most M6 threaded ones (most eurotorches) and that means better access into tight corners, and lower running costs; the minimum gas flowrate can be less with a smaller torch.

The Clarke machines have one very cunning feature that you wouldn't realise is there. It may arise from cost cutting, it may be deliberate; I am not sure. But anyway the two controls are wire feed speed and transformer voltage tapping.  Almost all traditional welding power sources have a feature which is called 'droop'; this means that when you draw current the voltage drops slightly. The more current is drawn, the bigger the droop. 

Wire feed speed in MIG welders directly affects the current drawn; faster wire feed, more current.  In many machines the wire feeder has a separate power supply, so that the feed is as stable as possible. In the Clarke welders they usually have a tiny 12V power supply that just drives the mains relay (that engages the main power supply when you are welding, so that you have a so-called 'dead torch' the rest of the time).  However the wire feed motor itself is driven from the main power supply (which delivers the wending current), but the voltage is scaled to a certain fraction of that by the speed control. This means that as more current is drawn, or the voltage tapping is changed the drooping/lower  voltage slows the wire feed rate down automatically. This means that there is less fiddling around with wire feed speeds required even when you change voltage tappings.  Essentially the heat input per unit length of wire delivered remains more constant than it would be otherwise. It also influences the stability of both the arc and the welding process, probably both in a beneficial way.

So I have owned and used a lot of welding kit, covering a wide range of qualities and costs; however I have always been surprised at how nicely some of the small hobby MIG machines weld; they (like any machine really) just need to be kept in good shape and used in the right way.  I would go as far as to say that if you want to weld thin gauge material, some cheap low power sets are actually better than many quite expensive welding machines;  there is no delay before the wire feed starts up, and the simple trigger gives fully independent control of the gas flow too; almost ideal for doing tricky delicate work in short bursts.

cheers

Aunt Maud

  • Le Flâneur.
Re: Welding training troubles
« Reply #11 on: October 23, 2018, 10:46:23 am »
In defence of my extravagance, M'Lud......I just wanted to learn to mig weld in an hour, which is why I went and bought the expensive stuff. Plus it was cheaper to do it myself, even after I bought the decent gear.

It should last a long time, so I'm happy with that.

Re: Welding training troubles
« Reply #12 on: October 26, 2018, 11:30:37 am »
If you stick (excuse the pun) with the arc welder, you need to be sure you have the current right. If it's a basic one, I'm not sure how much adjustment you have. Lower current won't penetrate as far (nor will it burn through thin metal so quick) but is harder to strike the arc. At higher current the arc is easier but burns down the stick faster and eats it's way through thin metal rather quick.

Some packets of welding rod have basic ranges for the current suitable for the stick diameter printed on the box, check you are within the range given by the manufacturer and have a play with current settings on some scrap metal if you can.

I've been doing night school which is predominantly arc welding on lovely expensive kit in a nice clean environment but if she can get the hang of arc welding, I've since found MIG welding in the real world to be even easier than it was before.
Duct tape is magic and should be worshipped

Re: Welding training troubles
« Reply #13 on: October 26, 2018, 12:17:40 pm »
'traditional' cheap stick welders output AC and have the simplest controls possible; for example



this is typical.  The big knob in the middle adjusts the current output by a simple transformer; the adjustment is actually performed by sliding an extra piece of soft iron in and out of the transformer core, which affects the total flux linkage between secondary and primary windings, and therefore the output of the transformer.

IME such welding sets work quite well (for hobby uses) if you use them in the upper part of their current range. However IME if you take a 150A set of this type and try to use 'sparklers' (1.6mm rods, which require 20-50A) on thin section material then you can have the most miserable time you can possibly imagine; bird poo, unstable arcs, blow-through, rods sticking, rods wobbling around, you name it.   In fact I would go as far as to say it is often 'impossible' to stick weld using this combination, if you are an inexperienced welder.

  However is not 'impossible in absolute terms; I have seen skilled welders make really good welds in situations that I have found 'impossible'. The welds look fine, the welding process looked stable etc whilst they were welding but afterwards they will often say 'that was a bit tricky' or 'I wouldn't want to do that all day' or something like that.  So I have seen skilled chaps use the thinnest electrodes and they welded car bodywork thickness steels using some crummy hobby welder and they made it look quite straightforward. I have done quite a lot of welding (various ways) and I find the same thing nearly impossible.

Modern stick welding sets are increasingly becoming switch-mode type and these sets output DC. Crucially they behave much better at low currents and are usually easier to weld with at any current.  They were quite expensive, but you can now buy a nice switch-mode type welding set for cheap; eg there is one that is sold by Aldi and it costs just £60.
https://www.aldi.co.uk/workzone-inverter-welder/p/085506226214500

OK it only goes to 80A but this is enough for 2.5mm electrodes.  [I have a 'proper' set and it is a similar size but does 200A off a 13A plug; however it did cost a lot more...]


 You can often use the same PSU for scratch-start TIG too.  I suppose that if a cheap MIG welder blows up you would be able to rebuild it using such a PSU.

  Soon the only reason for buying a 'traditional' (AC transformer) stick welding power supply is that for some reason you want to use AC, and/or you expect to leave the thing for extended periods in a damp shed and want it to work when you come back to it.   I leave my inverter welding PSUs indoors where the damp won't wreck them.

cheers

Re: Welding training troubles
« Reply #14 on: October 26, 2018, 05:58:28 pm »
'traditional' cheap stick welders output AC and have the simplest controls possible; for example


That's my welder.

IME such welding sets work quite well (for hobby uses) if you use them in the upper part of their current range. However IME if you take a 150A set of this type and try to use 'sparklers' (1.6mm rods, which require 20-50A) on thin section material then you can have the most miserable time you can possibly imagine; bird poo, unstable arcs, blow-through, rods sticking, rods wobbling around, you name it.   In fact I would go as far as to say it is often 'impossible' to stick weld using this combination, if you are an inexperienced welder.

You've described what MrsC was trying to do.

Hmm. I'm wondering if she needs to get a mig for this job, even a cheap second hand welder.
<i>Marmite slave</i>

Re: Welding training troubles
« Reply #15 on: October 26, 2018, 06:46:47 pm »
cheap secondhand MIG welders are brilliant for learning.....

...how to fix secondhand welding machines.....

All of which stands you in good stead for the future (without doubt) but can be very frustrating if you are just starting out.

A working MIG will be a piece of cake to use but if it isn't quite right and you don't know why....

cheers

Re: Welding training troubles
« Reply #16 on: October 26, 2018, 09:50:21 pm »
Hmm. I'm wondering if she needs to get a mig for this job, even a cheap second hand welder.

Have only skim read the thread, so this might not be appropriate, but...
might the Black Horse Workshop be a solution? (Either to identifying the original problem or providing use of a MIG welder.)

http://www.blackhorseworkshop.co.uk/about/

Re: Welding training troubles
« Reply #17 on: October 27, 2018, 12:20:03 am »
+1 ... the lady that taught me welding there was fantastic. I have her contact info if that's useful.

Re: Welding training troubles
« Reply #18 on: October 30, 2018, 07:40:35 am »
Hmm. I'm wondering if she needs to get a mig for this job, even a cheap second hand welder.

Have only skim read the thread, so this might not be appropriate, but...
might the Black Horse Workshop be a solution? (Either to identifying the original problem or providing use of a MIG welder.)

http://www.blackhorseworkshop.co.uk/about/

That would be perfect, Nikki. If it were in Sheffield. . .

I know I was originally asking about London, however there has been a hitch. My daughter needs to make this 'thing' in Sheffield and was originally going to build it at the university. The uni has now said that they will not permit welding on their grounds.

So we are looking for a similar place to blackhorseworkshop, but in Sheffield. I had a search last night, but drew a blank.
<i>Marmite slave</i>

Re: Welding training troubles
« Reply #19 on: October 30, 2018, 07:54:12 am »
We are making a New World (Paul Nash, 1918)

Re: Welding training troubles
« Reply #20 on: October 30, 2018, 08:34:12 am »
You could try Sheffield Hackspace:
http://www.sheffieldhardwarehackers.org.uk/wordpress/

(Their online info is annoyingly thin, but I spotted a few forum posts about welding and metalwork)

Re: Welding training troubles
« Reply #21 on: October 30, 2018, 04:08:56 pm »
She isn't at uni anymore - that is probably the problem.

I've messaged the hackspace people. They might know of venues.
<i>Marmite slave</i>

Re: Welding training troubles
« Reply #22 on: October 30, 2018, 04:47:46 pm »
Brucey is right about the transformer welders at low current. The arc is unstable, and you get blow through at the worst times. I had one for years and the only thing I could do with it (with thin stuff) was set stuff on fire!
The little inverter welders are much better at low current, so are definitely a better bet. If you want to do TIG, then it's
 worth getting one that has lift start at worst (ideally HF start), otherwise you will blow through your precious argon repeatedly failing to create an arc or sticking the electrode to the work surface (DAHIKT). I ended up buying a large secondhand Murex MIG from a guy who services welders for industry - it meant it was set up properly, came with a regulator for a decent sized gas bottle and had capacity for a big drum of wire. If you are practising, then this website is invaluable - post pictures of your setup and welds and people will help you out and get you on the right path: https://www.mig-welding.co.uk/forum/ (they do TIG and ARC as well as MIG).

No useful information about Sheffield, but if anyone in Oxford wants to play with a MIG welder for some reason (friends of mine built a tallbike in my garage - I've almost finished an Atomic Zombie trike), then send me a PM...

Good luck.

Re: Welding training troubles
« Reply #23 on: October 30, 2018, 07:19:34 pm »
I built my first 3 recumbents using a stick welder like the Clarke one pictured upthread...  ::-)
If it ain't broke, fix it 'til it is...

Re: Welding training troubles
« Reply #24 on: October 30, 2018, 07:47:05 pm »
Good job none of them were intended to ride a straight line  :demon: ;D