Variable quality with same settings.. why?

[men8ifr]

I've done a welding course a 6-7 years ago and have owned a SIP migmate non turbo (quite old one) for a couple of years.

The problem is highly variable weld quality on the same settings, sometimes it welds fine and on the same piece or work, same settings etc it just goes pop - pop -pop. you can almost weld like this but because the arc is going on then off it's hard to see where you're going plus the weld won't be great!

It may be temperature related i'm not sure it's hard to tell - but if so then the welder's overheated in a short space of time and on medium not max settings...

I've checked the wire feed, changed cables, adjusted the tension - it seems to be feeding fine.

One more thing to mention I have a longish 10A extension I use which powers the garage (though usually only a light and a radio run off it as well) maybe this is the problem? I seem to remember though I (think) I had similar problems welding a trailer outside when plugged into a house 13A supply (don't forget this is all 240v uk stuff) though maybe that time it was a bad earth as the trailer was a bit rusty...

One more thing - the earth is of the cheap type but I filed all the inner faces to try and get a better contact and didn't seem to make a difference...

 

[shenion]

A good extension will help, any drop in the line voltage will effect results.

Could just be characteristic of the SIP's. They have a poor feed control and sloppy feeder. Look though the mods in the SIP section.

A good earth may help some, but more on ease of use.

 

[men8ifr]

I don't think its the wire feed, i may be able to plug it in via a power meter and see how much power it takes plus if the voltage drops...

 

[SirDick Diodenob esquire]

I bought an old non turbo migmate which I am planning to use as an engine starter provided it can give out around 15 to 16 V on no load . The main transformer and choke are both aluminium wound and the internal connections are very poor and would all benefit from cleaning up . The wire feed motor on mine is surprisingly big compared for example to the miniscule motor fitted to a Nu tool mig welder of the same rating . Its hard to believe this is the original motor but then I cant see any evidence of it being retrofitted so wouldnt expect your problem to be with wire feed if yours is the same as mine , perhaps more recent fan cooled versions dont have this big motor fitted . The mains lead as already said is important and you would be losing proportionately the same number of volts on the output side because of it .

 

[mike os]

problem is sip are a load of crap

 

[shenion]

I don't think its the wire feed, i may be able to plug it in via a power meter and see how much power it takes plus if the voltage drops...

SIP are famous for inconsistent wire feed. Look at the half dozen threads on modifying SIP's to try to get a stable wire feed.

You don't see the same threads on other MIGs, just SIPs and their clones.

 

[BChild]

SIP are famous for inconsistent wire feed. Look at the half dozen threads on modifying SIP's to try to get a stable wire feed.

You don't see the same threads on other MIGs, just SIPs and their clones.

Unfortunately ^ is very close to the truth (slight caveat in that really old ones (SIP's) seem to be much better and don't suffer half the same problems

 

[Chris Stevens]

I've done a welding course a 6-7 years ago and have owned a SIP migmate non turbo (quite old one) for a couple of years.

The problem is highly variable weld quality on the same settings, sometimes it welds fine and on the same piece or work, same settings etc it just goes pop - pop -pop. you can almost weld like this but because the arc is going on then off it's hard to see where you're going plus the weld won't be great!

It may be temperature related i'm not sure it's hard to tell - but if so then the welder's overheated in a short space of time and on medium not max settings...

I've checked the wire feed, changed cables, adjusted the tension - it seems to be feeding fine.

One more thing to mention I have a longish 10A extension I use which powers the garage (though usually only a light and a radio run off it as well) maybe this is the problem? I seem to remember though I (think) I had similar problems welding a trailer outside when plugged into a house 13A supply (don't forget this is all 240v uk stuff) though maybe that time it was a bad earth as the trailer was a bit rusty...

One more thing - the earth is of the cheap type but I filed all the inner faces to try and get a better contact and didn't seem to make a difference...

In common with most beginners your main problem is a crap Chinese MIG set. Sometimes for little more money than a new Chinese set, you can find pro quality used MIGs on Ebay, which will eliminate about 75% of the problems you are going to have if you are using sub standard welding sets to try to learn with.

 

[BChild]

In common with most beginners your main problem is a crap Chinese MIG set. Sometimes for little more money than a new Chinese set, you can find pro quality used MIGs on Ebay, which will eliminate about 75% of the problems you are going to have if you are using sub standard welding sets to try to learn with.

You are a little ray of sunshine today aren't you

 

[SirDick Diodenob esquire]

Here is a photo of the motor in my Migmate which I have placed next to the motor in my Nu tool mig for comparison , the motor and gearbox is made by OSLV Italy . I also have a Thermal Arc GM180 and the Migmate motor looks better than the one fitted in that as well , never mind the Nu Tool which is in the bottom of the market . Have read the excellent threads on the SIP modfications but looks as though its mainly reffering to the newer model fitted with the smaller motor . When I first looked at this I thought that someone had retrofitted a much heavier duty motor/gearbox but there are no extra holes drilled and it seems to fit in nicely so I think it is original . The controller in my Migmate however is very poor but it does seem to work consistantly but I have to admit I have not actually tried welding with it .

 

[BChild]

Here is a photo of the motor in my Migmate which I have placed next to the motor in my Nu tool mig for comparison , the motor and gearbox is made by OSLV Italy . I also have a Thermal Arc GM180 and the Migmate motor looks better than the one fitted in that as well , never mind the Nu Tool which is in the bottom of the market . Have read the excellent threads on the SIP modfications but looks as though its mainly reffering to the newer model fitted with the smaller motor . When I first looked at this I thought that someone had retrofitted a much heavier duty motor/gearbox but there are no extra holes drilled and it seems to fit in nicely so I think it is original . The controller in my Migmate however is very poor but it does seem to work consistantly but I have to admit I have not actually tried welding with it .

Blimey that's a solid looking motor - How old is the migmate

 

[malcolm]

To clarify, the older SIPs (my guess mid-1980s) were made in Italy to a reasonable spec. They are quite different to the more common 1990s onward SIPs

men8ifr - you mention replacing cables - does it have a new wire liner, swan neck liner and tip?

Couple of quick tests you could do - first see what force it takes to pull the wire through the torch (http://www.mig-welding.co.uk/sip-wirefeed.htm) next with everything connected up motor some wire through the rollers and lightly grip the wire reel. If it takes hardly any grip to make the wire slip then there might be a problem with the rollers.

The suggestion of cleaning up all connections is good - my Syncrowave is only a little older and it needed that.

 

[SirDick Diodenob esquire]

Blimey that's a solid looking motor - How old is the migmate

Not sure how old it is but the bloke I bought it off told me his wife is 92 and he was selling off his engineering tools as he was getting too old to do this type of work and looking around his workshop he didnt have anything newer than about the late 60s or early 70s so I am thinking its about that vintage but maybe could be 1980s ?

 

[weldingscotty803]

looks like a wiper motor.

 

[hyper]

id say its the liner too. if you run wire through with rust on it, it wrecks the liner. iv got a very old sip welder(says made in italy on the label) aswell and its never given me any trouble. infact its as good as the 3phase welders i use in work for everything except real heavy stuff.

 

[SirDick Diodenob esquire]

looks like a wiper motor.

At first sight thats what I thought but its a 24V motor and dosnt have the reversing contacts you get in old wiper motor gearboxes , the motor is powerful and its difficult to stall or slow it when gripping the wire drive collar whereas the Nu tool motor stalls easily and has very poor torque . Ebay always seems to have a few of these older non turbo migmates being sold for spares , mine cost £9.50 so maybe worth someone with the newer model buying one even if its just for the motor.