SIP / Cosmo Wire Feed Solution

Hi all,

I've been registered on this forum for a while now, but have been lurking quietly in the background most of the time! Great site by the way - amazing how much I've managed to learn from here.

Unfortunately, I discovered this forum after I'd purchased a Cosmo welder - probably would have gone for a different machine if I'd have known about the bad reputation SIP / Cosmo have

Anyway, I have run about half a dozen small reels through it over the last few months without any problems. Then within a couple of days of putting in a large reel, I started to experience problems with the wire feed.

The motor was turning, but the rollers were slipping and not feeding the wire through.

On closer inspection, I could see that the plastic pivot that carriers the idler roller was flexing. This resulted in the rollers being out of true, and losing the grip on the wire.

I came up with a simple solution that stops this from happening. So far, I've run another large reel through without any problems at all - wire feed is much more stable and no signs of slipping.

A couple of photos below to show the simple solution. Hopefully this will be of use to anyone who's suffering these sort of problems with their SIP / Cosmo machine. Probably worth trying before changing to a steel liner?

Might get a better feed if the wire comes off the top of the reel rather than the bottom.
Just seen the sticker that says feed from bottom of reel but i would try it from the top as it will not be pulling at such a steep angle.

Nice Mod, think I'll give it a go.

Oddball, look at the pic it says 'attention feed the wire from the bottom of the reel' or very similar. Its a design fault by SIP, its designed solely for the 0.7KG reels, but put a 5kg roll on and its badly place for wire pick up. The whole wire feed unit needs moving up or down, so that it is in a compramise position so it will run ok with either. Good mod though, should improve wire feed and make it easier to get a nice weld

Agree with the comments about the position of the wire feed - not the best position when using a 5kg reel. I did try swapping it round to feed from the top, but that didn't make any difference as there was just no grip on the wire.

Welds have been much better since the mod as the feed is more stable now.

Very nice mod there - I had all sorts of trouble with my Clarke doing the same thing - doesn't grip the wire when the roller is at an angle. I used a slither of metal to prop the pivot at the right angle but much prefer your solution. I'll link it from the SIP wirefeed page.

god bless the internet

Hello everyone, Just found this forum while i was trying to find spares for my SIP welder. I will now be trying out darrencambs mod as i am having the same problem and it has got to the point were i cant get on with my project.

darrencambs you may just be a life saver cheers

I've done this mod today too. I Have recently added an additional feed transformer, which has made a world of difference. I just hope this adds the icing on the cake.

I'll find out later this week, then hopefully I can consign this as the mobile / lend out welder and treat myself to something nice for the garage.

bump said:

........ I Have recently added an additional feed transformer, which has made a world of difference. ......

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I'd be interested in doing this. Although the idea of setting the motor voltage somewhere near when selecting the power sounds good I reckon the welding current draw alters the motor speed, which affects the current, which alters the motor speed, which......

rtb, you are correct in your assumptions......

If you want all the details including relevant part no's and contacts then drop me a PM.

After getting Malcolm's approval I am going to make a post about the transformer supplier anyway. Really helpful guys and all.

Interesting, i just spent ages looking at the internals of one of the fat portamigs, one of the first thing you notice is the drop down transformer, that supplies the pcb and contactor etc. to me its unreal to take power from the coil (welding voltage), as you pull the trigger if welding voltage is 15volts, when not welding its likely to be higher so the wire feed will run faster, as the arc begins to much wire will be attempting to form a weld pool, as it welds the feeder will slow as the voltage drops off a little. end result will be a cold start every time. i would have thought if anything you want the wire to start slow and build up to full speed within about 0.25sec, this would help reduce cold start. but im not a welding engineer

I'd love to know more about the additional transformer (how to do it and what the benefit is). I've got a SIP that I bought just to mess around with the internals and understand more about the upgrades - could be a fun thing to try.

If you get a chance a new thread with loads of detail would be magic.

malcolm said:

I'd love to know more about the additional transformer (how to do it and what the benefit is). I've got a SIP that I bought just to mess around with the internals and understand more about the upgrades - could be a fun thing to try.

If you get a chance a new thread with loads of detail would be magic.

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If its something that makes for a smoother wire feed delivery, and is easy for the relatively competant to do, its a worthwhile exercise. Could help turn a poor welding machine into something that is at least average. I can see malcolm doing a custom page, soup up your SIP , with SIP owners all having meetings over the country showing off the modifications they have made, could be the new fashion for the would be boy racer, custom modified SIP welders

irondarren said:

If its something that makes for a smoother wire feed delivery, and is easy for the relatively competant to do, its a worthwhile exercise. Could help turn a poor welding machine into something that is at least average. I can see malcolm doing a custom page, soup up your SIP , with SIP owners all having meetings over the country showing off the modifications they have made, could be the new fashion for the would be boy racer, custom modified SIP welders

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We could have a competion against the "Clarke Gang" in our local Tesco carpark.

Consider it done Sirs!

irondarren said:

If its something that makes for a smoother wire feed delivery, and is easy for the relatively competant to do, its a worthwhile exercise. Could help turn a poor welding machine into something that is at least average. I can see malcolm doing a custom page, soup up your SIP , with SIP owners all having meetings over the country showing off the modifications they have made, could be the new fashion for the would be boy racer, custom modified SIP welders

Click to expand...

Maybe I'll add flames to my Clarke, down force wing in back, hood scoop, big low-profile wheels with spinners, neon glow underneath, and paint NOS logo on the bottle

nos and mig welder will i weld faster or run faster i don't know sounds fun pimp my MIG

Use an oxy plant and have real flames.

true nos needs fule to burn