Spot welder

[B1N9S]

I am new to welding. Done a little bit on my car project with a MIG and am considering buying a spot welder to attach some large panels. Rear quarters and a roof skin.

I have my eye on one, but I have never even seen one in the flesh, let alone used one. Is there anything I should know ? They look pretty much point and squeeze. But like most things in life, it's probably not that easy ?

Cheers
Wayne

 

[Paul G]

Hi Wayne,
Yes it is that easy, but that's not the whole story.

If you've ever watched (on the telly) a car being built you might have noticed the huge number of robot arms involved.
Each one is fitted with a particular set of arms to do a particular weld, and each panel is added in a carefully designed order.
This is not the case with a restoration job. Most of the joins you simply won't get to with the short arms on a hobby unit.
That said, for the joints you can get to they are wonderful tools, and way quicker than plug welding.

HTH
Paul G

 

[500e]

As Paul says the arms are the costly parts + tips but a good tool if you can get to the welds.
If you do get one keep the tips cool, our Wallace used to dip the arms in a bucket of water to cool tips this was before H&S I hasten to add, industrial's are water cooled
Have a look here with prices
http://www.sealey.co.uk/PLPageBuilder.asp?gotonode=DoProductSearch&method=mProductSearch&productdescription=&productcode=&category=16&catgroup=325&catmicrogroup=1131&analysiscode=&requiredresults=16&fulltext=0

 

[B1N9S]

Thanks Guys. Most of the areas are very accessible to both sides. Around the roof gutter, should be straight forward, and then just up the B post for the quarter panel and across the base of the rear window area.

Thanks for the info on the tips, I'll bear it in mind.

 

[B1N9S]

I think I have found a spot welder now. It is a Sealey one, with a separate timer unit and the guy says it has plenty of extra terminals, so it sounds ok. I'll get some pics of exactly what I get, when it arrives.

 

[B1N9S]

Bleedin' spot welder turned up the other day, so I go out to the garage today for a bit of a play and the damn thing ain't working !!!! Gumtree, so probably no chance of getting my cash back !! Gutted.

It's an old Sealey SR12. Has anyone got any repair knowledge on these ?

When I first had a go, the timer unit came on (i.e. The neon came on !!) but no power getting to the welder and no relay noise or anything. So I opened up the timer box and found, what I imagine is the timer unit, unplugged and loose inside the box. I plugged it back in, just incase it had come out in transit from N Ireland. Now I can hear the timer relay operating, and cutting in/out, but I am still not actually able to weld anything ?

Any ideas ?

Cheers
Wayne

 

[B1N9S]

I'll post some up later pdg.

I am thinking it is something to do with the timer box, not supplying any, or enough juice to the welder, since that is just a big step down transformer, can't see that much could go wrong with it, unless the primary winding is knackered, but I can't get at it to do any testing.

I am thinking, I might bypass the timer unit and see if it works without it.

Not actually mine, but this is an SR 12 welder. Old, as you can tell.



After some digging, I have found this, which is an SR 10. I assume a previous identical model, but without the timer. So, I might see if I can bypass the timer.

 

[B1N9S]

OK. After having a brain fart, I decided to do a simple lamp test on the timing unit. So I rewired a lamp to the '3Ph plug' that goes into the timing unit and also wired a micro switch, to the plug to replicate the welder and hey presto. The lamp goes on and off with the timer.

So, I then rewired the welder with a 13A plug and nothing !!! So the fault is in fact in the welder itself.

Has anyone any experience of faults on this unit ?

 

[B1N9S]

The 13A plug was attached to the welder. I removed the red 16A plug which would have gone into the timing unit and replaced it with a 13A plug. Then plugged it into a wall socket. But I get 'nothing' from the welder. i.e. It doesn't do anything.

I will pick up a clamp meter today from work. It might just need a damn good clean ?

The guy I bought it from, insists it was working before he posted it and he seems genuine enough.

 

[B1N9S]

Ok pdg. I think I have sorted this.

I decided to open up the welder and take a look. No continuity in the primary winding, so I took a closer look and found two wires sticking out doing nothing. I buzzed them out to each individual primary circuit end wire !!! Then shorted them together and soldered to then have a complete primary circuit.

I don't know what they are/were for ? They would have been putting out 240v ? But at least the welder is now working !!!! I just tidied up the other connections, with a couple of butt joints. The small nick in the blue wire is where I nicked it to check for continuity.






My only question is:

When the welder is operating it crackles and buzzes and there are some sparks inside the unit (from the secondary) where the arms are joined. Is this normal ? It welds ok, so just assumed it was, but I have no experience of them.

 

[B1N9S]

Those two 'bits of wire' could have been for a thermal fuse, or they could be a broken primary winding - either way (or anything else) if you had an open circuit primary with them apart and a continuous primary with them joined I'd say joining them was the fix needed Is that charring/burning from your soldering or was it like that already?

There shouldn't be any sparking or crackling from inside the unit at all - if there is then something is awry, it'll hum, but a buzzing would be something I'd investigate further. Recommend stripping it down to clean and remake all the secondary side connections.

If there's any high resistance points you're going to be losing something, and a spark indicates an intermittent joint. You've only got a couple of volts to be playing with so getting them out to the prongs as efficiently as you can is most important.

Yeh, that charring was there already. You are most likely right about the thermal fuse. But I'm a bit concerned now about the sparking. I think, I'll strip down the other end and give it a good going over.

Cheers mate.

 

[500e]

There definitely should not be any sparks from secondary side wiring to arm connectors

 

[B1N9S]

I stripped down the front end and the secondary was a bit loose around the other winding, but that is to be expected I guess, as it is rigid bar and it would normally be secured to the arms. But, I then noticed that the two ends could touch if I moved them in a similar motion to operating the arms. So I guess they were shorting at this point creating the sparks.

So, a bit of cardboard to secure them and a thin piece of wood wedged between the windings (should have taken a picture ! Sorry mate) and it now operates perfectly, thank duck for that !!!! Just a nice steady hum when it's operated and a much better weld.

I cleaned all the connections and the arms and sharpened the tips. So, I can now get busy fitting panels to my '02 project.

Cheers pdg.
Wayne