MIG upgrade, TIG or Oxy acetylene

[Barry]

Here's a word or two I wrote to Chris (Jury on here), when he was having welder issues, which were centred around the wire burning back inside the tip, but the principles are the same whatever the problem ...


"Anyway, as for the welder. The two main differences between the full pro-welders and the DIY ones are the wire feed mechanism, and the quality of the rectification to produce a nice DC. The DIY one's give a very iffy version of DC, which I gather if viewed on a 'scope look pretty messy. I've seen an old Sealey DIY MIG running on a couple of 12v batteries, and it ran rather nicely: true DC of course.

Anyway, the trick is of course to make the most of what you've got.

1) With the wire feed rollers loose, check by hand that the wire feeds very smoothly: sometimes the inner liner can be twisted or kinked within the outer. Also check the feed with the torch at various angles, just to make sure it's not kinking internally in some positions.

2) Change the tip regularly.

3) Make sure there's not too much tension at the reel end: on my Kemppi I modified it slightly to reduce the pre-tension. You want it just tight enough so that the reel doesn't run on (creating a slack bit of wire between the feed rollers and the reel itself), but not much more.

4) Roller tension: with everthing ready to go, hold the torch fairly gently around an inch or so from an object (ideally wooden, and certainly not earthed to the welder: you don't want an arc). Pull the trigger: you should have a small amount of pushback, but if it tries to shove your hand back, or it can buckle the wire, you've got too much tension. If you just get slipping straight away, you need a little more.

5) If all of the above, set up your wire-speed. With your power setting selected, start off with an obviously low wire speed: you'll almost have the wire tick, tick, ticking as it slowly feeds in, burns back, feeds in etc. Now in stages increase the wire feed bit by bit: you'll go through a smooth window where you're in the zone, and then back out the other side where you're clearly getting too much wire through: lots of noise and spatter, and the gun almost being pushed away. As you're getting burn-back, you want to have the feed slightly towards the upper end of the 'correct' feed window. This will give you a bit more grinding, but helps prevent the wire burning back.

I think that DIY machines can have times when they run really very well, but the difference is that the full pro ones need much more to be 'off' before they misbehave: i.e. the pro machines are much more forgiving. Like I say though, that doesn't mean you can't get good results with yours, you just need to take extra care over:

Wire condition (buy small reels, and keep spare ones indoors / in the warm and dry), rather than buy a 5KG or bigger: as soon as there's any roughness on the wire, it's had it.

Tip condition: change regularly, and before any really critical welds.

Don't run with the torch cable kinked around objects: work hard to get as smooth a route as possible.

Use big bottled gas (I think we've spoken about this before).

Roller tension.

I know what a right Royal PITA wire burnback is, but if you go through the above, it should help. The final thing is just to keep some tips in your pocket, with a small pair of pliers. That way you can just remove the fouled tip, swap it and carry on. When you're next at the bench you can sort out the blocked ones. Hopefully you'll avoid this if all goes well anyway .

All for now, and hope there's something in the above that may be of use!

Barry"

[911hillclimber]

Well....
I did not follow much of this excellent advice when I bought my shinney new MIG 4 years ago.

I had a lot of issues with wire feed and the stupidly critical wire feed adjuster. Seems one degree of movement coked the whole balance up. It is also next to the on/off switch so readily knocked using the switch..
VERY frustrating indeed. Nearly went into the canal.
I tried all the fancy gases and ended up with Machine Mart's CO2 for mild steel.
The welder was 'designed for professional bodywork welds' and is good for some shots at that but quite unstable.

The biggest break-through for me was a hands free helmet battery powered.

This allowed two handed control of the torch and precise positioning, best £45 I spent on welding.

It is all about right now.
If I get the power switching right the wire feed has to be a bit too fast, and after EVERY run/spot I have to clip 8mm or so off as the excess hanging out is rubbish.

Overall dissapointed with the equipment and I found it hard to find the sweet spot.

If I'm in a good mood and ready for the task and the welder is about right i can produce a surprisingly good fully penetrated run.

Practice makes perfect.

The small bottles are weak and leaks from the regulator really weak and I'm on my second reg now.
Tip life is extraordinarily good, I cannot recall the last time I changed a tip! (0.8mm wire)

Barry;
Thank you for giving all those tips, I will certainly try a few. My wire feed wheels are as tight as possible. Clean wire is v important indeed, but so is that helmet!

[Nige]

All this talk reminds me of the summer I left school, went straight into a welding job to save up for when I started college working for my Dad's friend who built skips. The workshop had six bays, each with two BIG Boomed MIGs. We'd get all the plate lined up ready and then each team (3 men per bay) would race to see who could build a skip the fastest. My job was to go inside each skip and seam weld the internals believe it or not I was a lot thinner back then so fitted through the smaller gaps that the older blokes couldn't. Those machines certainly had a sweat spot, something my DIY jobby doesn't.

[sladey]

Ah Nige - jumpers for goalposts isn't it?

Thanks for all that Barry - brilliant advice as always - I think I'm going to go the portamig route and sell my existing one. Sounds like I've got a problem with the wire - it's gone off, and whilst I know I can fanny around and correct that (and I will do) I like working with good tools - there's a lot of good feedback on the portamig on the welding forum I'm on - and Gary swears by his.

Glad I started this thread now - some great tips on there Barry

Cheers

Mark

[Gary71]

I think I'm going to go the portamig route ...Gary swears by his.

Good choice, it just means I can't blame the tools anymore! Still plenty of operator error

[jury]

Here's a word or two I wrote to Chris

...I listened to Barry, and it worked a treat

[Nige]

Ah Nige - jumpers for goalposts isn't it?

I'm not that old, probably more like track suit tops for goal posts.

[sladey]

Birthday present ordered....

[Barry]

Just Googled Portamig: they look very good indeed.

If I decide to replace the Kemppi (although it's only three or four years old, it's done a ton of work) I'd be tempted with one of these myself.

One thing I did find is that if you've started off with a DIY welder, it really makes you appreciate a 'proper one'. I just couldn't believe the results I was getting when I replaced my first MIG (a Sealey badged DIY one) with the Boramig. Good process to go through though, as the DIY ones force you to learn how to set up a welder.

I notice these Portamigs have auto wire feed. I know that Norman Butters (who used to make probably some of the best quality MIG welders ever built) thought it was madness to allow customers to change the wire feed rate. His view was that there was basically one wire speed for each power setting, other than some small degree of trimming. Therefore a 'real*' Butters welders just had a trim control. I guess the Portamig guys have the same view. As do Kemppi on the Minarc range in fact.

*Not the badge engineered ones available these days.

[Gary71]

Cool. Which one did you go for?

[sladey]

Portamig 185 - I can't see me needing the extra power of the larger ones so the 185b seems to tick all the boxes. Need to get mine sold now. My birthday isn't until 5th March but I believe the lead-in times can be a bit 'variable' so thought I'd get the order in now.

Very excited about it

[Gary71]

Probably a good choice going for the smaller one, my does trip the electric in the house if I run it too hard

It makes the lights dim even on low power so I get the feeling that our house is running on a long extension lead from a house down the road somewhere!

It really annoys the wife when I'm stitch welding...

[endo911rs]

Barry,

Regarding the spot welder...how important is it to have a built in timer? Also, do you have different tips for reaching different areas and if so, how many and what sizes?

Thanks for all the great info you contribute to this site, it has helped me A LOT!!!

Chris

[911hillclimber]

Not intending to answer for Barry, just my take having been there on several restorations:
I used to hire my spot welder as cost was so high to buy new.
It came with a timer and the hire shop said that this was the only one to hire because so many got damaged manually 'timed'
I got great consistency from the timed unit. The hire kit came with stacks of arms and electrodes and I needed them all.

The hardest bit was holding the flippin' thing as it was SO heavy.
Worst part was you could easily think you had a good spot weld but in fact you had a very very weak one, just looked good, but that is true of many welds (and welders)

[endo911rs]

Do you have any pics of the unit that you used?