SIPMATE 100 Welder..broken

[Mickymoody]

I got given the task of assessing, my Father's machine, and the case had excessive rusting, but the control to vary the voltage, was siezed, and slightly cracked.

So a lot of WD40 later, this bar that slides across the transformer, was moving again.

I've never seen a transformer to use a bar like that to adjust voltage in the transformer. And the hardened grease on the bar seemed like solid, preventing it's movement.

The WD40 has freed the bar off, to adjust the voltage, but it needs the case stripping, and repainting. Any advice?

 

[bernardgreen]

So a lot of WD40 later, this bar that slides across the transformer, was moving again.

Do you mean the contact that moves across the coil where the insulation of the coil wire has been removed ? ( A photo would help ) If so then the use of WD 40 may have affected the remaining insulation of the coil. One side of the wire has to be bare to allow the moving contact to collect current but the insulation between the wires must be intact otherwise a shorted turn can be formed and this becomes a hot spot. Dry all traces of WD 40 before using the item.

 

[SimonH2]

I've never seen a transformer to use a bar like that to adjust voltage in the transformer.

Some welding sets use a movable section in the core to alter the magnetic circuit - and hence the available current. Dad has one that does just that though I don't actually know the details of what's inside it.
There are no variations in electrical contacts, just the movable iron in the magnetic circuit.

 

[RF Lighting]

My arc welder works in the same way. It is a piece of presumably iron that moves in and out of the core of the transformer to vary the available output current.

 

[Mickymoody]

Yeah, I was worried that the use of WD40 might cause a flashover of the transformer, later models have a fan in the case too, so obviously they must overheat. The bar, as others have stated is plastic, presumably with iron inside, and is available as a part on later sets, that look similar.

I can't find the origional website at the moment, to show a picture.

But the welder has been used to repair that pesky metal plate out of my washing machine OK, without the case fitted (ohh heath and safety!), and tips on getting rid of the rust, and best paint to use to repaint? (not used by me btw, I can't weld for toffee! - solder yes, weld no.)

 

[SimonH2]

... but it needs the case stripping, and repainting. Any advice?

Personally, I'd be :

Stripping it down (attempting to save any labels, and definitely removing any riveted on data plates). If there's any data labels you can't save - photograph them and note the details so you can put the data back afterwards*.

Fully degrease it all before proceeding any further - otherwise you can be stripping off the paint and spreading the grease to the freshly exposed metal.

Grit blast it all (not the transformer obviously) down to bare metal. Obviously that's dependent on having access to the facilities - if you don't then wire brush and abrasive paper, driven by a lot of elbow grease and/or power tools, but it doesn't do as good a job.

Repaint with a good red-oxide primer followed by a couple of coats of a decent machinery paint. A local agricultural place sells "tractor paint" made by VAP which seems OK - the back axle of my Land Rover (and some other bits) is "Grey Fergy" grey, aka Stoneleigh Grey.

Finally re-lable it. Rivet on any plates, and re-attach any stick on labels you managed to salvage. Otherwise, you'll have to use Dymo or whatever to make new labels.

There is nothing worse than getting some bit of equipment and finding that some **** has removed the data plates - motors are a good case, I've seen several with the plates missing

 

[Mickymoody]

Cheers for the info Simon, (I'm only doing the outer case, which has been removed), the labels just state Sipmate 100, or whatever, and are totally rusted, it looks like battery acid corrosion, but was stored in an understairs cupboard, that seems to have suffered damp? Why it would deteriorate so badly is strange.

So my thoughts are use a rotary wire brush to strip the rough, wire brush anything else, then use wet and dry paper to make a good surface, then degreaser, I think I just used my last for paintbrush cleaing oops! prime etcher, I have that, spray on undercoat, can do, I'm trying to follow your tips, with the actual materials I have...then maybe a laquer, or sealer, spray on, then finished off, with red caliper paint, which is paint on, then spray over with the laquer again?

Maybe the labels will have to be stencilled, but I'm rubbish at arty stuff like that, maybe that would provide a half decent finish? Would you agree, it's an industrial item, designed to do a job, and get a few knocks...I'm rubbish at DIY, and what I do, tends to go wrong.

I have a full set of paints for localised car repairs, but its black. And the welder is red. I have the red caliper paint, which is good against heat, so surely the method, might work? I think it might be OK. Do you agree or is there a flaw? Which I'm sure there is!

 

[SimonH2]

Once rust gets started, it can progress quite quickly in the right conditions - like damp. I think you're going a bit OTT with the paint. I'd just use one or two good coats of red oxide primer, and a couple of coats of whatever is to hand (not sure about caliper paint though, a bit pricey IIRC).

Degrease everything as best you can before you start - otherwise all your wire brushes and abrasive will have grease one them, and then it spreads to everything else they touch. Then a final degrease before you attempt to paint it.

Oh yes, for labels, I agree it's industrial equipment - function is what matters, form is a distant second. Dymo labels, laminated labels*, or even hand written as long as it's clear what the functions are AND what the machine ratings are.

* You can pick up laminated label makers now for a pittance - though they make the money up on the label cassettes. Here's a selection from Brother, there are other makes and it's worth shopping around.