earth clamps......

[Ragnarok]

so, been having a play with my new Lorch, great machine, but I got an SWP earth clamp and cable with it, and matt1978 also sent me one (thanks matt), the cables are fine so I'm not really bothered but the clamps are absolutely awful, the most appalling shoddy bits of welding kit I've ever used, way way worse than the ones that come free with SIPs better welders, I haven't been getting a very good connection from the clamps, many arc strikes even to the cleanest bits of metal, I just gave the jaws of the clamp matt sent down a quick going over with a flap disc because the bolt was sticking out of the jaw a bit making a really small contact patch, and I was very shocked to find that they are copper platted steel!! the clamp is the usual pressed steel type with "copper/brass" jaws, after sanding that one I did the same to the SWP one just to see it that was the same, and it is.. so then I thought I'd have a look at a very similar but much older one that I've had on my old arc since I was a kid, I think it cost £4 from a local supplier back then, and it has real brass jaws, it's shocking in my opinion, the steel jaws just don't conduct very well, and when welding on middleish amps, the wire is getting a bit of a ball/globular transfer an quite a bit of spatter, I'm putting this down to the clamps for now, and I think I will have a bit of a go at the same power with my tigs earth clamp later or tomorrow see what the difference is, and I'm going to order a genuine navada clamp next time I put in an order with rapid welding.

also been having slight trouble with the Lorch ML2500 torch, trouble being to do with the liner and tip holder, not sure quite what it is but when the torch has been coiled up, then uncoiled again, the gas flow goes a bit sputtery, and removing the tip holder and refitting it solves the problem.

not having the smoothest start up with this Lorch am I! haha ah well it's all good

don't be fooled by the copper plating, on the jaws of these cheap earth clamps anyway! they're not copper!!

 

[Ragnarok]

just did a side by side test, the steel jaw clamp VS the ESAB copper jaw clamp, with the copper jawed one the arc is more stable, and makes a nicer buzz, with the steel one less stable, less nice buzz more spatter, clamps positioned the same, welder set the same, but results are noticeably different with the copper contact, gunna have to get that order for a good quality 300-400amp clamp in soon!

 

[Bsmith]

The earth clamps that come with the welders are complete rubbish. I binned and made my own from 2 flat pieces of scrap stainless steel bar. Welded drilled lugs in middle for pivot, s/s bolt welded on for attatching cable, pins welded between ends to hold a valve compression spring off an old cylinder head and a couple of dabs of s/s weld at the other ends for good contact. Works fine

 

[Ragnarok]

haha yeah i'd thought of making one too, unfortunately i can't find and scrap copper around, i need to start hunting some out really, and i don't have a lot of stainless either nothing much other than 1.5mm wall 25mm box and 50mm tube, so i think i'll get the Nevada one looks like a nice tough clamp, the disappointing thing is that both my sip topmig and turbo weld 6 came with nice solid cast brass earth clamps, seems hard to get anything decent with out ordering online too, did look for something abit more substantial, i know one place i could get a brass screw type one but it's a way a way and i would cost more to drive there than the clamp would cost it self haha the ESAB one that came with my tig is great too, bit small to be running on the mig though haha nevada looks good.

can't believe the copper coated jaws and bolts though.... it's clear dissipation seeing as they always used to be solid copper or brass....

 

[Paul G]

It's down to the bottom line, a fiver or twenty quid?
Most pay the fiver.


I modded my "return lead" with a bit of 6mm copper, brass stud, brass nuts and a chromed brass lug.

My bench has a brass lug bolted straight on.

Paul G

 

[pedrobedro]

I wonder how many people are welding away with their Lorch thinking they have copper contacts and they are really only plated, wondering why they are having arc problems and a blob of metal on their wire ? None I should imagine, I bet they are just welding away with no problem. I've used old vice grips and all kinds of different arrangements over the years and if it's a good earth to sound metal it doesn't make a difference what the clamp is made of. It sounds like the silver cored speaker wire that brings out the highlights in your tweeters and gold contacts in your connectors that everybody needs to make their computer faster. Send me the Lorch and let me evaluate it under clinical conditions (out in the shed) and I'll send you back a full and detailed report. I might be able to arrange the loan of a SIP 130 while it's away

 

[Ragnarok]

I wonder how many people are welding away with their Lorch thinking they have copper contacts and they are really only plated, wondering why they are having arc problems and a blob of metal on their wire ? None I should imagine, I bet they are just welding away with no problem. I've used old vice grips and all kinds of different arrangements over the years and if it's a good earth to sound metal it doesn't make a difference what the clamp is made of. It sounds like the silver cored speaker wire that brings out the highlights in your tweeters and gold contacts in your connectors that everybody needs to make their computer faster. Send me the Lorch and let me evaluate it under clinical conditions (out in the shed) and I'll send you back a full and detailed report. I might be able to arrange the loan of a SIP 130 while it's away

hahaha tell you what if you didn't notice the difference between the bad steel contacts that make arc strikes and there for a bad/intermittent earth, then there would be no point in you using a Lorch, may as well stick with the sip 130 the simple fact that there is a noticeable difference between using the ESAB copper contact clamp and the cheapo ones with the steel jaws shows that there is a problem, the wire gets a blob on the end because of the intermittent earth, when the arc stalls for a split second then comes back on the wire burns back, and it doesn't get back to the nice perfect arc length immediately, also causes more spatter, this response is very ignorant, it seems as though you don't think a good earth is important, also I have no doubt the vice grips would work better than these cheapo earth clamps, the have a stronger grip, not only do these things have steel jaws, but quite weak springs, the metal had been fully cleaned, and there was a difference between the copper contact jawed earth and the cheapo steel one, I don't know what your reply is supposed to be getting at, why do you think all the good earth clamps have copper or brass jaws? why do you think the cheapo clamps plate the jaws and fittings to make them look like copper?

I don't have a bad word to say about Lorch, after all matt sent me an earth lead free and I'm very grateful, the one I bought when I bought the machine was an SWP, the clamps are basically free with the lead and dinse plug anyway, I'm purely talking about the bad quality of cheap earth clamps here and the fact that they effect performance and arc stability, if you don't care about the welders performance there is no point buying an expensive welder.

 

[Ragnarok]

It's down to the bottom line, a fiver or twenty quid?
Most pay the fiver.


I modded my "return lead" with a bit of 6mm copper, brass stud, brass nuts and a chromed brass lug.

My bench has a brass lug bolted straight on.

Paul G

that looks good paul, I might take the jaws out of one of my old clamps of the same design for now, they're a bit worse for.... weld rust, but the brass jaws should work nicely till I get a decent clamp

 

[pedrobedro]

hahaha tell you what if you didn't notice the difference between the bad steel contacts that make arc strikes and there for a bad/intermittent earth, then there would be no point in you using a Lorch, may as well stick with the sip 130

I was going to arrange for you to borrow a Sip, I'll keep using my Kemppi thanks. You are welding with steel wire and you are clamping to steel what difference does it make where the steel comes into the equation whether it's at the end of the copper earth cable or a couple of inches further along at the end of the clamp, that's all I would like to understand. As long as the contact is good and the spring is strong enough to maintain it I don't see a problem with a steel clamp.

 

[Ragnarok]

I think this will clear up the whole conversation, and make it clear why the clamp wasn't getting a good earth

first image shows the contact jaw from the end, see the edge of the bolt sticking up, that is pretty much the entire contact area when that jaw clamped the work, I was going to sand that off due to the fact that it was getting arc strikes, on both it and the work, when I sanded it, as you can see it the photo I realised it was steel and not copper, as well as having only had a small contact area, while I'm sure this would work uk once sanded so that it has the full contact patch it should, and a much better earth, I be leave that a copper contact is MUCH better than a steel one, I have now fitted the brass jaws from an old clamp to the body of the new one and it just works better, I can't believe that you think the earth has no part to play in the smoothness of the arc, I also can't believe that you wouldn't do anything about it if you were getting arc strikes on your work and clamp due to a bad connection/contact, I take your attitude as the typical "I'll argue about anything in a nonconstructive manner" attitude that turns up on the internet so often..

photos.

first shows the end view of the jaw bolt sanded one side as it was on the other, second is all the copper plated parts, third is the brass parts, last is the clamp with the brass parts (works much better good consistant earth)

 

[keith19]

In theory, the conductivity of copper is much higher, see table below.
In practice, a lot depends on how tightly the metal is clamped, assuming clean surfaces all round.
A strong metal clamp will conduct better than a weak copper clamp, for obvious reasons.
With equal strength clamps, copper will conduct across the interference fit gap better than steel.

But maybe a surprise, brass is not nearly so good a conductor as copper, and is nearer to steel in the conductivity order.

Generally, so long as the clamp is good and tight, it should not matter too much, as long as there is enough contact area. But if there is not, copper will have the edge.

Real (Dwarvish) welders use Silver, of course.

 

[pedrobedro]

I think this will clear up the whole conversation, and make it clear why the clamp wasn't getting a good earth

I take your attitude as the typical "I'll argue about anything in a nonconstructive manner" attitude that turns up on the internet so often..

Take my attitude how you like, I just have an enquiring mind and probably do argue sometimes but it is only to get my point across. Nowhere did I say that a good earth is not conducive to a good arc and I don't think I was not being constructive in my "argument" keith19 has explained my thoughts for me. When you say the only point of contact was the rough piece of the bolt I just thought that the other side of the clamp must be doing something, sorry if that sounds argumentative but it's how I think.

 

[Ragnarok]

interesting, as i said in my last post, i think the main issue came from the fact it had a small contact patch due to the edge of the bolt, but after sanding the bolt off and realising it and the jaw were steel, i thought it best to swap the jaws for the brass ones, i'm sure the steel is conductive enough, but i don't think it make such good contact with the metal, copper is clearly ideal, brass is fine, steel would work, but could also get surface rust if it has no coating, and would probably need more clamping force, there are drop forged steel screw action clamps that work fine after all.

my original point was that the jaws of these cheap clamps are steel even though they look like copper, and that copper would be better, i only discovered that the jaws were steel after i had some earthing problems, realised that the clamp had arc strikes on the bolt and jaw and sanded that bolt to get a better contact patch, i wasn't as pedrobedro makes out welding along fine but for no reason thinking something was wrong, then just deciding it was steel jaws that were the problem, there was a problem, i found the problem, and solved it.

I think other factors come in to play as well as conductivity when you put a bit of copper or brass against a bit of steel i think it makes better contact with it than a bit of steel would, same as how the wire in the mig is copper coated to pick up the current better, could even be why the copper coated the jaws, how ever, because the bolt needed sanding off flush to stop it contacting with only the edge of the bolt rather than the whole jaw, as soon as i sanded it it went through to bare steel, so pretty pointless, i'm sure that clamp would work with the bigger contact patch, but i have no reason to use the crappy cheapo jaws now that i have fitted the brass ones, they work fine.

though i've also just ordered a proper nevada 400amp earth clamp

this whole thing has gone too far, i thought that it'd be obvious that copper and brass would work better than steel, based on the chart there copper is the clear winner, but brass is still almost twice as good as steel and wont rust plus being soft will probably offer an advantage and i just thought i'd let people know that the cheapo earth clamps have steel rather than copper or brass jaws these days, they didn't a 8-9 years ago.. overall quality has gone down.

but the whole thing about whats best would really come down to what transfers the current from the jaws to the steel, the actual conductivity of the metal isn't that important, as the current will have to go through the steel anyway, i think copper and brass transfer the current better, with the lower clamping force that these clamps offer, end of story really.

as you say a strong steel clamp would work fine and a strong copper one would work fine, how about a pretty weak steel one vs the same copper or brass, plus as i said and have shown, the real issue was the very small contact patch that jaw offered, and sanding it uncovered the steel thing, so i just swapped it for brass and it works fine so all's well with me.

 

[Ragnarok]

Take my attitude how you like, I just have an enquiring mind and probably do argue sometimes but it is only to get my point across. Nowhere did I say that a good earth is not conducive to a good arc and I don't think I was not being constructive in my "argument" keith19 has explained my thoughts for me. When you say the only point of contact was the rough piece of the bolt I just thought that the other side of the clamp must be doing something, sorry if that sounds argumentative but it's how I think.

clamp was bad quality the webbing was hardly connecting the other side, found out when I went to change the jaws to the brass ones, the clamp had also arced to the body, don't see why you need to use a hostile argumentative attitude.

I'm not an idiot, I've got a lot of experience welding having started at 12 from scratch (no friends or family that welded) that clamp got a bad earth, I've sorted that, I'm sure steel would work for an earth clamp, but I'm also sure copper would be better, and that the copper coating is basically there to make it look like you're getting copper jaws, which essentially was the point of my post, if you want to sand the jaws a bit to clean them up/get a good large contact patch and they're copper you still have a copper contact, if they're copper coated you have a steel contact, with a fairly weak gripping crock clamp I don't think it'd be great, and as I had some brass jaws why not use them, they work well after all, I've also used all kinds of things as earth clamps, like little G clamps vise grip clamp type things, good tight grip and they work.

I often clean up a bit of box section and stick connect the clamp to the end one jaw in the tube one out, usually i'd put the side with the cable connecting on the out side of the tube, with the other on the inside, could also play a part in the other side of the clamp getting a bad connection, but trust me, that clamp was giving a bad/inconsistent earth.

 

[Bsmith]

I was very shocked to find that they are copper platted steel!!

don't be fooled by the copper plating, on the jaws of these cheap earth clamps anyway! they're not copper!!

I have noticed that the connection/contact bolts on starter motor solenoids are also copper coated mild steel, coating dos't last long on the exposed threaded ends either.

 

[pedrobedro]

I don't know where you are getting hostility from, I'm trying to understand your logic. The copper coating on mig wire is to stop it rusting before it is sold to you and clamping the earth inside or outside a tube is irrelevant as long as there is continuity, I'm bored with this now, enjoy your welding.

 

[hotrodder]

i think the main issue came from the fact it had a small contact patch due to the edge of the bolt

That'd be my guess

Got proper brass/copper bits in the return clamp that came with my Lincoln they used the other penny pinching trick by attaching the clamp to the worlds shortest return lead Unless you're welding some flavour of copper alloy the bit the return is clamped to will be something other than, err, copper...
I'm thinking (for the same reasons as gold plated HiFi connectors, copper plated starter motor and exhaust manifold nuts/studs) using copper/brass is more about corrosion and even more about reducing/preventing arc marks and/or the clamp welding itself to the work when people don't clean things

 

[Ragnarok]

That'd be my guess

Got proper brass/copper bits in the return clamp that came with my Lincoln they used the other penny pinching trick by attaching the clamp to the worlds shortest return lead Unless you're welding some flavour of copper alloy the bit the return is clamped to will be something other than, err, copper...
I'm thinking (for the same reasons as gold plated HiFi connectors, copper plated starter motor and exhaust manifold nuts/studs) using copper/brass is more about corrosion and even more about reducing/preventing arc marks and/or the clamp welding itself to the work when people don't clean things

for sure, like i say though, if i'd ordered a lorch clamp and it'd been bad quality i'd have been disappointed, but i didn't, matt just gave me one and i'm very grateful for it, lovely 4meter cable and dinse plug just a bad clamp, and the one i bought was an swp, so i'm not complaining about lorch at all!! just the cheapo clamps in general i've put brass contacts/jaws in it for now as it was getting arc strikes on things and marks on the clamp as you mention, but i've got a nice clamp on ordered, what i'd always planned to get at some point anyway

I think the reason they chose brass over copper for some things is that it's harder/stronger so threads are less likely to strip, like screws in plugs and plug pins and all kinds of other electric bits and pieces.

 

[Ragnarok]

The copper coating on mig wire is to stop it rusting before it is sold to you and clamping the earth inside or outside a tube is irrelevant as long as there is continuity, I'm bored with this now, enjoy your welding.

it's a very common misconception that the copper coating is to stop it rusting, i'll quote from some info on esabs aristorod, although you will see similar info in many places if you read about welding they make note of it on the aristorod in particular because they have changed the coating and don't want people thinking it's gunna rust more while in the machine or whatever, anyway bottom line is that i've seen many reputable sources saying that the copper is there to get better contact rather than for rust prevention, and also to help lubricate the dies while making the thin fairly hard wires, the coating my stop rust a tiny bit, but it's not the main reason for it being there as far as i have heard.

"The unique feature is the absence of the traditional copper coating and in its place is the patented Esab surface coating which is meant to enhance ease of wire feeding and reduce spatter (see more below). Copper coatings do lead to the majority of problems associated with Mig welding as it is this stuff that comes off as a copper dust and eventually blocks liners and guide tubes. It is there to ensure a good electrical pick up as the wire goes through the contact tip, nothing to do with rust prevention"

the clamp jaw being inside makes a difference as you can't easily clean the mill scale off the inside where as you can, and i do, off the out side, harder to get a good earth on the inside of a hot rolled steel tube than on the out side, mill scale isn't a great conductor.

 

[Ragnarok]

oh and as i've said already, it was coincidental that i found that it was steel, just when i sanded the jaw to smooth off the corner of the bolt that was clearly causing the trouble, i was just a little disappointed that it was steel, and would much rather copper jaws, which i think is justified, if it was working i wouldn't have cared, once i sanded it and reviled the steel, i decided to change the jaws to some brass ones, don't really see why i have to justify this, as if you ask me it makes perfect sense, also makes perfect sense to think that the jaws should be copper in the first place, they look like copper, all the good ones are copper or brass, why isn't every one using steel if it's just as good it's cheaper after all.

you can say it should be getting a good connection with the back jaw, it should be doing this or that all you like, if you'd used it you'd probably have done the same thing if you had the same bits around tbh they have 2 conductive jaws for a reason, i don't want to have to be thinking about cleaning the inside of tubes because the out side isn't getting a connection or swapping the clamp around so a different jaw is on the cleaned part, i don't want to have to think about the earth clamp while i'm working, clean the metal stick it on and it should work every time, if it doesn't it's not doing it's job right in my opinion.