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Novice mig help required
wombat - 19/4/14 at 01:13 PM

So I have a Butters AMT1800 Mig on long term loan and want to do a bit of minor bracket type stuff.
I have welded and brazed using oxy/acet but never any elect welding.

Watched lots of you tube tips and read up as much as can, feel capable of doing this , well did..........

New piece of metal in the bench, cleaned up nice and shiny, earth clamp is brand new, wire feeds well at all settings, gas coming through.

Machine on, 15 degree angle on torch, wire just through tip, press trigger and get arc, weld stops, feed motor running but no wire, move gun around and wire pops through, repeat, no welding ......Aaarghhhh

Don't want to be that bad workman blaming his tools but don't know what to try next...

Can you help?


NigeEss - 19/4/14 at 01:29 PM

What thickness steel are you welding ?
What power setting are you using ??
What wire feed speed ???

Sound like any, or all of the above need matching.


wombat - 19/4/14 at 01:35 PM

3mm mild steel
Setting 2 of 6 on power
Setting 6 of 10 on speed


NigeEss - 19/4/14 at 01:48 PM

Ok, so assuming a 180amp machine.

I'd up the power to 4 and tweak the wire speed from 4-6.

It'll take a few tries to get the setup right. Also try practicing on something a bit thinner as your melt
pool will form quicker giving you the best chance to get thing right. Practice, practice



Slimy38 - 19/4/14 at 02:04 PM

It sounds like you're getting the wire burning back before it can maintain the weld. I would actually turn everything DOWN until you can maintain a weld pool (ignore the fact that you won't have any penetration at this stage). Once everything is feeding and you can get a bead going, then start turning up the power to get the bead into the metal. As you turn the power up you'll come back to the wire melting back and not maintaining the pool, just turn the wire speed up at that point.

I agree with Nige though, start on 1mm as it's easier to deal with. As a guide, my NVQ level 1 was on 1mm steel, it wasn't until much later on in level 2 that we went on to thicker plate.

Edit: Just seen your other post, you are getting burn back. Turn the power down or the wire speed up.

[Edited on 19/4/14 by Slimy38]


wombat - 19/4/14 at 02:55 PM

Nige, Slimy,

Thanks for the input, tried the settings you suggest but same result, if I could get the feed going it would be a start!

Not got any thinner stuff at home so will have to wait on that one.

Is my wire too thin, using 0.6 ?


big_wasa - 19/4/14 at 03:06 PM

Also the linear could be grooved this makes the wire stick, same with an old tip.

Mine is in need of a new linear.


Peteff - 19/4/14 at 03:09 PM

Try a new tip, what size wire are you using ? Stick with the 3mm metal or you will just blow holes till you get used to it, turn the feed up full and power on full hold the tip about 10mm from the metal and push the gun away from you holding it steady resting on your spare hand. It will probably feel like the wire is pushing back at you so turn it down gradually till it stops pushing and sounding like a machine gun. Has the machine been stood and the wire gone rusty ?


wombat - 19/4/14 at 03:19 PM

Pete
Using 0.6 wire, part used reel which i have taken several metres off now, looks ok.

Could the gas setting affect it?

Blew the trip when i turned it up to full :-)


big_wasa - 19/4/14 at 03:33 PM

You would need that welder on a 16a supply at full power.


wombat - 19/4/14 at 04:25 PM

Ok a little progress, got some weld, well lumps of molten wire really.....
Managed to start a pool, backed the settings off a bit and was better but still machine gunning and burn back.

4 on the power setting and 9 on the wire speed.


teegray19 - 19/4/14 at 04:37 PM

The wire spool is feeding ok? I'd go half on everything as a starting point, do some spot welded to start with. Hold the torch still, start welding count to three and stop. See how that goes. What has are you using? You should be able to hear it hiss out the end of the torch to get you going


wombat - 19/4/14 at 05:10 PM

Wire feeds nice and smooth.
Watched a video teaching a newbie and he said exactly the same, count to three just to get started.
Been trying to do that all bloody day !

Yes can hear the gas coming through.

Thx


Mr C - 19/4/14 at 05:21 PM

I'm far from an expert just starting out myself, though 0.6mm wire sounds way too thin/small for your settings, 0.8 is the norm for most work.


Slimy38 - 19/4/14 at 06:52 PM

quote:
Originally posted by Mr C
I'm far from an expert just starting out myself, though 0.6mm wire sounds way too thin/small for your settings, 0.8 is the norm for most work.


I've used 0.6mm for welding my chassis and wishbones, it's certainly enough to blow a hole through 2mm thick metal (guess how I know!).


big_wasa - 19/4/14 at 07:05 PM

Most use 0.8 because the cheap wire feeds handle it better.


blakep82 - 19/4/14 at 07:19 PM

Is the polarity correct? I think this welder can have the polarity reversed for gasless wire.
Molten lumps of wire makes me suspect polarity


scott h - 20/4/14 at 10:36 AM

On my welder the wire feed roller has one groove for 0.6 wire and another for 0.8 wire. Check you are using the correct groove.


teegray19 - 20/4/14 at 02:39 PM

Plus one for polarity thinking about it...

Google the set up of the welder. It's not hard atall to get a spot weld. Sounds like your doing all the right stuff but equipment is stopping you.

P.s make sure your earth is really close and is as clean as your welding spot


wombat - 20/4/14 at 04:44 PM

Thx for that, google not being particularly helpful, can't find a manual or settings, prob because they went bust.....

Having just watched a you tube of a guy welding rusty iron shuttering bars using the same machine, I'm even more frustrated.

Once the Supersports have finished I will nip out and see if I can find a polarity switch......


wombat - 20/4/14 at 05:23 PM

Had a look and the torch is on positive and the clamp negative.
Marked on front of the machine this way.

Going to get new wire and tip, is the Screwfix stuff ok?
Saw some info regarding dodgy Chinese wire ??

Thx for all the suggestions so far.


blakep82 - 20/4/14 at 05:23 PM

Polarity most likely won't be a switch, but you actually unscrew a nut on the ends of the earth and torch cable and swap them over.
Cant find it now, but I didnt find a page last night suggesting this welder can be run on gasless wire, which needs polarity switched


wombat - 20/4/14 at 05:26 PM

Blake, so that's a take the case off job then yes?


mark chandler - 20/4/14 at 05:40 PM

Sounds like your welder is set up for flux cored wire with a positive torch.


Minicooper - 20/4/14 at 05:49 PM

quote:
Originally posted by mark chandler
Sounds like your welder is set up for flux cored wire with a positive torch.


A positive torch is normal, so it set up for gas and wire

David


wombat - 22/4/14 at 07:02 PM

Well today I bought a new reel of wire and some tips and tonight I welded MIG for the first time.

Practised on some scrap stuff and then boom welded on the bracket that had been delaying fitting the body.

Painted the bracket and have locked the garage door before I'm tempted to slip the body on.

Cheers for all the help guys.

Wom