Inconsistent wire feed speed on Clarke Pro 90

[woZa]

Hi all... Been reading the forums for a while now trying to get some tips for welding. Finally bitten the bullet and started welding my mk1 golf. Started on the easy stuff of welding up the bumper mounting brackets as I'm fitting some early bumpers that don't need the mount holes.

Anyway, i digress! I got a cheap (and I mean very cheap!) second hand Clarke Pro 90 which should be ideal for thin bodywork panels. Gave it a bit of a service (new liner, tips, shroud, earth clamp etc) and started welding.

It seems to be fine apart from the wire feed speeding up & slowing down which makes welding pretty tricky (especially for a complete novice!)

Any ideas what might be causing this? Motor, pcb, earths? I have had the multimeter on the motor and it only fluctuates by at most 0.05v when loaded which I wouldn't have thought would cause the problems I am experiencing.

Without a load on it (ie the wire clamp removed) it seems to have a constant speed (sound stays constant) and volts fluctuate again by less than 0.05v.

I have greased the wire holder spindle but that hasn't helped so I am at a loss now...

Any help greatly appreciated as my welding needs all the help it can get for now!

Thanks
Alex

 

[malcolm]

Is the wire new?

If it's a regular speeding up and slowing down is it in time with the rotation of the wire reel? That would obviously point to the wire reel mounting. Should be as loose as possible without allowing the wire to unwind itself.

Or it the reel has unwound itself in the past it could be a bit tangled and need winding out to the untangled stuff.

One thing you could try is tie a 1kg weight to the wire sticking out of the torch, unclamp the wire rollers, and lift the torch. The weight should pull wire through rather than lift up with the torch. That would point to liner not quite right, or that wire reel mounting.

Otherwise is it temperature sensitive? - could be the tip getting hot and gripping the wire possibly because it's not quite the right size (cheap ones can be a hassle).

Another thought - is there slipping at the rollers due to overtightening? http://www.mig-welding.co.uk/forum/showthread.php?p=42117 might help

 

[weldequip]

What gas you using Alex? CO2 can give that effect on low amps & thin sheet... doesn't seem to maintain the arc well & gives that 'stop-start' effect.
Also, you say you have replaced the torch lining etc, did you re-tension the wire feed? It's common for people to keep winding down the tension at the feed rollers (as the lining becomes blocked) & it ends up screwed all the way down; back it right off so there is just enough to pick up the wire & feed it smoothly.
weldequip

 

[Richiew]

Are you using the 5kg rolls of wire? I have a Clarke 151te but stick to the smaller spools of wire (0.7kg) as I find the wire speed a bit inconsistent with the bigger ones. Sometimes you can get a bit of a flywheel effect with the heavy rolls (In my experience). Maybe I'm just not setting it up right but using the smaller rolls solved my problem. It may help you too and only costs three quid to find out.

 

[woZa]

Is the wire new?

If it's a regular speeding up and slowing down is it in time with the rotation of the wire reel? That would obviously point to the wire reel mounting. Should be as loose as possible without allowing the wire to unwind itself.

Or it the reel has unwound itself in the past it could be a bit tangled and need winding out to the untangled stuff.

One thing you could try is tie a 1kg weight to the wire sticking out of the torch, unclamp the wire rollers, and lift the torch. The weight should pull wire through rather than lift up with the torch. That would point to liner not quite right, or that wire reel mounting.

Otherwise is it temperature sensitive? - could be the tip getting hot and gripping the wire possibly because it's not quite the right size (cheap ones can be a hassle).

Another thought - is there slipping at the rollers due to overtightening? http://www.mig-welding.co.uk/forum/showthread.php?p=42117 might help

It doesn't seem to be regular as such other than it regularly does it.

The reel does look like it may be a bit tangled so I should try unwinding it and rewinding neatly.

Not temperature sensitive. Does it right from the off. Seems to be more affected with low wire speeds. Fast speeds seem unaffected (but far too fast for my welding!)

 

[woZa]

What gas you using Alex? CO2 can give that effect on low amps & thin sheet... doesn't seem to maintain the arc well & gives that 'stop-start' effect.
Also, you say you have replaced the torch lining etc, did you re-tension the wire feed? It's common for people to keep winding down the tension at the feed rollers (as the lining becomes blocked) & it ends up screwed all the way down; back it right off so there is just enough to pick up the wire & feed it smoothly.
weldequip

Using Argon / CO2 mix (86% / 14%). I've wound the tensioner as lightly as possible so that it still grips the wire...

 

[woZa]

Are you using the 5kg rolls of wire? I have a Clarke 151te but stick to the smaller spools of wire (0.7kg) as I find the wire speed a bit inconsistent with the bigger ones. Sometimes you can get a bit of a flywheel effect with the heavy rolls (In my experience). Maybe I'm just not setting it up right but using the smaller rolls solved my problem. It may help you too and only costs three quid to find out.

Yes think it is the 5kg roll (it seems pretty big). Will give that a try if rewinding doesn't work.

 

[woZa]

Thanks for all the help so far. Will give the suggestions a go and report back...

 

[weldequip]

The reel does look like it may be a bit tangled so I should try unwinding it and rewinding neatly.

Could be your problem. It's not rusty is it? Rusty wire causes all kinds of annoying feed problems + blocks your torch linings & you are then back to square one.
weldequip

 

[woZa]

Could be your problem. It's not rusty is it? Rusty wire causes all kinds of annoying feed problems + blocks your torch linings & you are then back to square one.
weldequip

Not rusty. Unwound a load of wire and it was very tight and caught. Now the wire is free and it is better but now pulses fairly regularly. Have checked the wire spool mounting, greased it, loosened it as much as possible, loosened the feed tensioner as much as possible so I am thinking it may be due to it being a 5kg reel (it is pretty full hence heavy).

May go out and get a lighter smaller reel and see if that makes any difference.

Cheers
Alex

 

[greyshirtguy]

For what it's worth - I found that the 5kg "layer-wound" or "precision wound" reels feed so much noticibly smoother than the "rough wound" reels in my TransMIG 165, that I will never buy non-precision/layer wound again.

Normal (rough) wound:


Layer (Precision) wound:


This might seem a little more relevent too when I point out that the Transmigs use the same wirefeed as the clarkes (the whole welder seems to be a re-badged twin of the Clarke)

I don't think this will "solve" your problem - but it may well contribute to improving it.

 

[woZa]

Thanks for that. The reel I have is somewhere in between the two. I think it might be a precision wound one that has come unwound at some point. As I get further down it seems to get neater...