Lazy SIP..

[KJM]

Dear all,
I've modified my Father's old SIP with the "no psu mod" and the thing welds like a real welder now. No problems. Great welds.

But (and there is always a but, of course... - it behaves very strangely when I drag it out of the shed to do some welding. It doesn't want to feed. Grabbing the wire and giving it a tug gets it going, but it behaves in a cranky way for a bit and then settles down to perfect operation...

The thing has a steel liner and right now is running fluxcore wire (new and non-corroded). It did this last weekend too (maybe it wants a beer - it is the weekend, afterall!). Doesn't seem to be heat related - I let it cool right down for a couple of hours and it started perfectly. After a week, however....

Any thoughts?

Cheers
/Kevin

 

[Mr J Morton]

what size tip are you using?
Is the nut holding the reel on too tight?
Are you using the right side of the wire feed wheel, not the knurled one but the smooth one for 0.08?
have you tried kicking it?

have you got the brace mod fitted? if not that could be the main culprit.

jonnym

 

[Sean]

power setting buttons on the front can be temperamental have a go at flipping all the switches a few times.

if its had rusty wire run through a plastic liner in the past the debris collects in the wire liner in the swan neck this melts and when it cools glues the wire.

have you replaced the swan neck liner at the same time as the main liner?

Sean

 

[KJM]

Hey - that might be it!

what size tip are you using?
Is the nut holding the reel on too tight?
Are you using the right side of the wire feed wheel, not the knurled one but the smooth one for 0.08?

Tip is a 0.8 tip, that's fine. The 0.8 drive roller is the one being used

have you tried kicking it?

Naturally. And swearing at it too - just for good measure, of course!

have you got the brace mod fitted? if not that could be the main culprit.
jonnym

Ahhhh. How did I miss that!?!?!? My father bought this welder 15 years or so ago, and it looks like he's had the thing on max tension for all of those 15 years. The mechanism is built out of some kind of plastic - and I don't think it is glass reinforced nylon or anything similar - just cheapish plastic. You made me look closely at it - the "towers" that hold the rollers are kind-of bent outwards a tad

I might modify the stiffening brace mod a bit - cut open a jubilee clamp and use that, so I can cinch in the two rollers into something close to what they should be.

Many thanks (in advance ) I think that'll be the problem.

Have to say though - when it is going right, it is just like using a big industrial MIG, only a fair bit smaller..

Cheers
/Kevin

 

[KJM]

power setting buttons on the front can be temperamental have a go at flipping all the switches a few times.

I've already had to dismember those switches to make it work at all when I got it here. Reminded me of the electrical system on 1960's Italian motorcycles

if its had rusty wire run through a plastic liner in the past the debris collects in the wire liner in the swan neck this melts and when it cools glues the wire.

have you replaced the swan neck liner at the same time as the main liner?

Sean

Nah - it has metal liners throughout, replaced just before my aged father decided he was too old to weld anymore... They've done not that much wire. I'm pretty sure JonnyM's on the money on this. The electrics are fine now. The problem is definitely some kind of mechanical issue. I'll do the brace mod, check it out and then if it still drives me nuts I'll go replace the liners again.

Thanks for the suggestions, I'll have to monitor that liner. The fluxcore wire (which actually does a terrific job, BTW) is not "smooth" like the plain, so it might be grinding itself off in the liner and caking the tube with crud which perhaps rusts over the week. A theory, anyway. Hopefully the brace will fix it all!

Cheers,
/Kevin

 

[KJM]

Just a quick update. I did my quick hack with a jubilee clamp cut open and bridging the feed roller and bearing "towers". This isn't the right fix, but it did help. So I'll need to make a proper piece of metal. The jubilee pulls at an angle, because the two towers are of different heights.

/Kevin

 

[Mr J Morton]

I might be wrong, as I don't use flux core much, but isn't it 0.9 wire, so you should use an over sized 1mm tip or a drilled out 0.8. I'm sure I've read conflicting views on this forum but I'm pretty sure I couldn't get the flux cored through the 0.8 tip, even with brute force applied.
Good luck with the brace.

Jonnym

 

[pedrobedro]

Don't get too much wire tension it can cause as many problems as too little. You want to be able to stop the wire feeding and the feed wheel still spin without coiling the wire up inside the welder (birdnesting) It also grinds the wire coating and causes metal dust in the liner.