Part 2 – 2004 – Mostly MIGMATE
In progress – Almost done.
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My MIG page has been one of my most popular pages despite being somewhat out of date. Until a few weeks ago I had done no MIG welding to speak of since 1999. My share in the WIA150 was bought to weld Aluminum for my chainsaw mill. Late 1999 I started full time work again, I also had a major theft of tools and I stopped doing my slab timber stuff.
The WIA is at Phil's place 90 minutes drive from here. I've never brought it home – just seems too much hassle – it is heavy and clumsy with bottle and all. I decided to buy a baby MIG that I could have on hand whenever I needed it. The main anticipated use was 1.5mm steel – that is furniture steel and steel framing for building. A small gas-less MIG (now AKA MOG) would probably do the job. I have a stick welder for heavier work and the WIA for gas work. I took a look at one sold be super-cheap auto (an Australian Auto chain which sells cheap imported tools). Aus $400 bought a 95Amp MOG which looked like crap. Bunnings (Ozzie hardware chain) had CIGweld MOG for the same money which looked a bit better but the CIGweld 135Amp MIG (around au$700) seemed better value. I waited and the price went up au$100 (and came down again after I bought something else). I UMM'd and RRR'd a bit and thought maybe I would go up in power and was looking for a 165Amp Cigweld.
In my travels on broadband I found a UK add for disposable gas bottles. These seemed like a good idea to me, BOC are charging $100 a year rental for gas bottles. This might be ok to a heavy user but for the rare bit of MIGging I do it would work out cheaper to use the little ones – particularly if I wanted a variety of gases. I was expecting to buy a conventional MIG with regs for big bottles etc and then try to get an adapter for the disposable ones. I remembered seeing little CO2 bottles at “Glenfords” (Ozzie tool store chain) but I wasn't sure what they were for at the time. Recently I've started working more with steel and had use for a MIG.
So I went to see what Glenfords had.... The pile of gas bottles was exactly what I'd hoped for CO2, CO2/argon and pure argon. I didn't notice any tri-mix (argon/O2/He) or argon/O2 but maybe I didn't dig enough. They were all Au$30 – a little dearer than I had hoped but still affordable.
over to the welders and checked out a MIGMATE 150. The welder was
there to look at but no box , no specs and no price. I looked
inside and then asked the guy at the counter. He was nice enough
and dug up a catalog which some very basic specs. It “seemed”
ok – I noted it only went up to .8mm wire but I could live
with that. What wasn't obvious (maybe it was there but I missed
it) was the pathetic duty cycle. The duty-cycle 20% at 95 Amps –
so what is it at 150Amps?? Not much.
The steel wire was .6mm but no .6mm tip was supplied.
I have found some websites which say MigMate is crap. I'd say it depends on what you want to do with it and what you want to spend. I was prepared to spend more money but I wanted something light. I can pick up this MIG up with one hand and I have hung it from the roof a few time to weld roofing joists – I wouldn't want to do that with a heavy unit.
I also welded some 6mm gal weld mesh. I had welded square gal
washer onto mesh (to use as security screens on the shed) using my
stick welder. This was a slow process. I had to clamp the job
because the stick does want to stick. The weld rarely worked first
go and I'd have to chip/scrape the slag and run a second bead to
stick it all together – it probably took 5 to 10 minutes per
washer. With MOG I could hold the washer in place with my glove,
tack it in a few seconds and run a very strong looking weld around
in one go – maybe a minute to do and a much better job. Wire
to wire worked well to. I did not do as well with MIG. I think it
is because of the thin wire – I have now go some .8mm wire
but I've not tried it yet (nope that wasn't it -see
Months later. After my 3'rd tip I did clean one. I used
bleach and a piece of wire to get the muck out of the tip. I seems
to be working again. Pete from the UK emailed me to say
anti-splatter spray would fix my problems. Maybe, maybe not. After
much navel gazing I'd decided that the white muck which came out
of the tip is not flux residue but unused flux. When I examined
the flux cored wire under a microscope I found the wire isn't tube
like say a hose is it is metal wrapped into a tube with a seam
along the side. I think that under some circumstances (molten?)
flux is force out of the side of the wire before it leave the tip.
I not certain of this and I don't know if anti-splatter would help
or not. Next time I will try my newly purchased ultra sonic
cleaner. I'll probably try acid as well. I'll update this after
I've tried it.
test – I think I smell lemon.
very touchy little bugger, it managed to slow the feed-rate down
and then I could stop the popping and run a weld. I'm not
impressed. There is nothing to the circuit and a fix may be
possible – changing the trim-pot to a multi-turn type would
be a step in the right direction. The results on the test welds
are below. The MAG results were not impressive enough to change
over from MOG to MAG. Now that it is set up I might use MAG a bit
just for practice.
I buy it again.
No I wouldn't. As a budget welder I can forgive it for being a little rough around the edges. I can not forgive it for having lousy speed control - this is vital. The speed controller is open-looped – that is it does not sense the feed rate so it can compensate for changes in friction etc. At very slow feeds it is not smooth and as mentioned earlier it has very touchy internal adjustment which drifts with time and bumps. This is probably typical for low cost MIGs – if I replace this MIG I will spend more on the new one.
It is possible some of the problems mention earlier were speed control problems which I didn't recognize as such. I sort of assumed a new MIG would give a consistent feed rate for a particular dial setting – this may not have been the case.
Ideally the speed controller should be closed loop or have a more predictable speed (such as stepper motor based drive). It must also have a force limit so it stops or shuts down in case of a jam. Ideally it would also be either set or read in standard units such as meters/minute. Then you can note settings for particular jobs for future reference and to share with others. If the Migmate had good speed control it would be a winner for the money.
Later – I've fixed the speed problem the migmate is working properly.
My ”tips for beginners” page has moved here.
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