mig gas/torch problems

[essexandy]

hi all i have got a rockworth 120amp mig welder, i know its only a cheapy but i was given it, the problem is i have got it all set up but the gas just keeps pumping, where it should only pump when i pull the trigger, it just keeps going, is this a common problem or is it a new lance? its causing major welding problems so need it fixing as well as losing loads of gas

 

[Robotstar5]

The gas valve is probably in the handle, normally a block with a button that is pressed when you pull the trigger, it may be stuck in?

 

[essexandy]

as you mention it i did open up the handle and i did see the block, and the button and i pressed it in, so its not stuck, its annoying, any other ideas?

 

[Robotstar5]

If pressing the button has no effect on gas flow, it must be an internal fault, try a couple of sharp taps on the body to free the valve. Not sure if they can be dismantled (carefully due to springs inside) might find a damaged/displaced 'O' ring?

 

[essexandy]

what afew taps to the welder unit? no it didnt stop it flowing, the moment you turn the tap on the bottle it comes out of the torch, even if you dont have the trigger in, so could it be a faulty lance?

 

[Robotstar5]

what afew taps to the welder unit?

Sorry a few taps on the block inside the handle, if it can't be dismantled/repaired, try a PM to Weldequip, he has a good selection of spares

 

[essexandy]

i will have a try, and cheer for the heads up on the pm, are they pretty much the same on all welders the block?

 

[Robotstar5]

They are similar, Steve will know which sort of block will fit your handle even if it doesn't have the same name on it!

edit: he will probably need a picture of it

 

[essexandy]

ok cheers i will get onto that

 

[penfold]

If there isn't a problem with the o-rings in the valve it must be a leak elsewhere, either at a joint or possibly a chafed bit of gas pipe. Can you hear where the gas is leaking from? Alternatively look for the leak with a spray bottle of soapy water.

 

[essexandy]

its not a leak, its all coming out of the gun like its ment to do, its just it wont stop even when the trigger is not pulled, i am thinking its that box that the air pipe goes into

 

[keith19]

Yes, as the guys are saying, it's probably the gas valve jammed inside the alloy block. The trigger is still going up and down but it's not hitting anything inside because the return spring is beggared, and the bit it should be hitting is jammed open. The pic is of a Clarke gun, but yours will be fairly similar, I should imagine.

 

[penfold]

If it is like the Clarke torch above just remove the valve spindle(the brass bit in the pic), clean any crud out of the spindle hole, clean the spindle itself and fit a new spring and o-rings if necessary. I've had to do it on my cebora, it uses the same system; I didn't need to replace any of the bits as it was just jammed with dirt and needed a good clean, once cleaned the spring had no problem shutting off the gas when the trigger was released.