help needed please

[skippy]

hi every one great site just found it very usefull i have a bit of a problem i bought a cosmo 130 duel purpose mig a couple of years ago (wish i had not!!)
have never used it till the other day it is a load of rubbish! i can arc weld ok so thought it would be easy to mig the problems i have are as follows


1.the gun has stopped flowing gas and the gas valve in the gun is stuck and wont move

2 .the wire feed control is rubbish it wont slow down much from the slowist speed to the highest slow is about 5-6m per minute and fast about 10m pm

3.it seems to vary the weld a lot i am new to mig so not exspecting great resualts to start but i can get it to weld ok for a few inches then try again and it is useless the weld just sits on top of the sheet im only welding 1.2mm steel

4 is it just me?? or shall i throw it in the bin?? i have been put off mig with this unit and am concidering getting a good oxford arc welder what do people think i am welding from 1mm-4mm steel

sorry rant over! many thanks for peoples advise jon

 

[Luke]

Don't be put off by a rubbish welder

There's no point welding with no gas - it won't work properly at all.

A half decent clarke or similar for 1-4mm won't be that expensive, imho in your situation it'd be better to spend out on a new working welder than spend good money on bad.

 

[malcolm]

SIPs aren't so bad, though yours does sound very faulty. Was it sitting somewhere a little damp?

Try removing the gas valve from the torch and giving it a little tap with a hammer. If it's broken at the moment it can't get any worse.

Wire speed might be down to dirty connections if it's been sitting. I'd open the thing up and remove and reconnect all the connections to see if that helped.

If the wire has any surface rust then wind off the rusty stuff until you get to good clean wire - it'll cause all sorts of variability.

For 1mm MIG is great. You'd need a root gap and V edges for the 130 to have a chance at 4mm (otherwise weld will sit on top).

 

[skippy]

thanks for the replys i have it set up to run on gas from the beginig i did try to give a litle tap but i think it has had it i think i will just start again with a new welder would mig be best or tig for what i need 1-4mm i have a litle arc welder for the heavy jobs
thanks for the help jon

 

[malcolm]

I should still go for MIG unless you really need the extra control that TIG offers (and can put up with the extra control that TIG needs from you - TIG needs more skill than I have for out of position welding).

As Luke said the Clarkes are probably the best of the cheaper MIG welders. If you have a lot of 4mm go up to 150 amp output (the Clarke 160TE).