Spark Gap Contacts

[Ron66]

I've had my Power pro 256 about a year now. When I first got it I tried to weld some aluminum but had a lot of trouble controlling the arc. Over time it just got worse and worse until this month when I couldn't even get the arc to start unless I scratch started it. I decided to open up the unit last night and look at the spark gap electrodes. One of them was twisted like a pretzel. I used a needle nose pliers and straightened them out and set the gap to 0.03" with a feeler gauge. I haven't had a chance to try it out again but here is my question. Do other people find that their spark gaps get misaligned over time? Or once you set them they stay set? My machine has been on a cart in my garage and hasn't moved more than four feet since I've bought it. I looked at Miller's spark gap and they look like something the military would have spec'd out. So I have started to design my own spark gap. I am going to mount it remote from the high frequency board on a piece of polycarbonate. Two aluminum blocks will each hold a piece of 4mm tungsten rod. The gap will be set just like the Miller set up by sliding the rods in the clamps and locking them down. I will round off all corners of the clamp to reduce ionization losses and use good quality high voltage wire to connect the unit to the board. Any thoughts? I think it will make this machine almost bulletproof.

[Brian Ski]

I have very little idea about what you are talking about. I have seen a couple threads with the spark gap mentioned. I see you have a combo machine. Now the questions. Is the spark gap on all plasma cutters??? Just combos??? On TIG machines also???
I am guessing it is inside the cover. Is it a maintenance item where it needs to be adjusted???
Do you have any pictures???

Thanks for any info... Brian

[Ron66]

This should help explain.

[Ron66]

Here is a similar setup in their cut50

vs
Miller's

[Ron66]

Mine would look more like this

[Rivets]

Ron,

The 250 EXT has a much improved set of points. There's a picture of them somewhere on this site.

I tried to buy a set from Everlast so that I could upgrade my own PP256, but to no avail. I even pestered Duncan to bring me back or ship me a set from China during his last factory visit, but he did'nt do it.

I would certainly be interested to know how your build turns out.

Cheers,
rivets

[Brian Ski]

This should help explain.

Thanks, will have to dig into the video later. Dial up is ridiculous!!! I am in a dead zone!!!

All I can get out here is dial up... I am making a collection of videos when high speed is available.

Thanks for the other pics guys...

[NRM]

I can't remember what member did modified his unit but he put his homemade points on the outside for easy adjustment and is happy with the outcome. I will try and find the post for reference.

[Ron66]

I would love to what others have done. If you move the points to the front you could access the points by just taking off the front cover.

[Jake98]

I think it was 'Lamename' that made those points, but I don't think it was on this forum?

[Ray]

If the points are properly adjusted and in alignment they will hold there adjustment and will not wear appreciably. In with Tig welding they should be active briefly when starting the Tig arc. Plasma cutting in the case of a multiprocess unit is a little different as they are firing while the pilot arc is running. But I have never seen them bend from heat.

The contact faces are made from a very hard metal probably tungsten or hafnium, mounted to steel blades by a copper brazing, this acts as a heatsink and attachment. If the contacts are out of alignment arcing will deposit copper and copper oxide in the arc area and eventually cause the gap to effectively change.

I’m not necessarily defending the design, as I too would like to see something easier to adjust. But the face of the contact is convex, and when properly adjusted will center the arc in the contact face and create a wide almost corona like arc that sounds like gas flowing rather than a sparking sound. In short I think it works pretty good.

The Tig welders seem to work the best set around .028” -.035”. mutliprocess machines will require a little wider gap to insure the plasma pilot works reliably, usually .035” - .045”.

My experience having set many once it set right it will stay that way, barring metallic dust or being out of alignment.

[Ray]

I can't remember what member did modified his unit but he put his homemade points on the outside for easy adjustment and is happy with the outcome. I will try and find the post for reference.

Truth be known it was working well before making the homemade points, once he set it to .028 it worked well, he just chose to mountthem external. I think they would have been fine otherwise.

[Rivets]

Thanks for the info Ray.

Still, I would like to improve the ease of the points adjustment on my unit.
Do you happen to have a set of 250EXT points kicking around that I could purchase, and if so how much ?

Thanks.

Andy

[joop]

will they wear out with time?

I ask because I use my plasma the most and I just tried to went some aluminum tonight and it will not start an arc the hf seems to be working but maybe not enough?

[Rodsmachineshop]

what would work and last a long time would be a double platinum non-resister spark plug

[Rambozo]

what would work and last a long time would be a double platinum non-resister spark plug

Tungsten is the preferred material and about twice as tough as platinum. Considering there are plenty of 30-40+ year old welders with their original tungsten points still in service and working well, I don't think lifespan is a real issue. Just look at any older transformer machine that uses continuous HF with thousands of hours on it. Tungsten points will outlive their owner.
Platinum is used for spark plugs partially because it is a catalyst for gasoline combustion.

[srp]

It's true that other welders have more heavy-duty points. Some people say the points erode over time, but I have never had to adjust any of my Miller or Everlast machines. The light weight points work just fine for me, in fact I don't think they would ever be a problem as long as they are not over adjusted and become week.

The Miller Syncrowave has 3 settings for high frequency start (soft/med/hot) and it will not adjust to have that positive/snap start like the Everlast does, so they do work good.

I know the points are light weight and I would rather have some heavy-duty ones like the Syncrowave, but if it's going to add another hundred bucks to the list price, I would rather get the light ones and just let Everlast deal with it under warranty if it will not hold it's gap.

[performance]

I believe we have made changes to the points and redesigned them in most of the latest models so they are carbon contacts with screw adjustments.

The new 210 EXT does not use points, similar to the new dynasty series. The HF start amps and duration are adjustable for AC and DC operation.

[Brian Ski]

will they wear out with time?

I ask because I use my plasma the most and I just tried to went some aluminum tonight and it will not start an arc the hf seems to be working but maybe not enough?

I don't think that as much as wear out as maybe get dirty.

Also The points are used for the HF starter arc. It sounds like they are working. It looks like there is another problem. Why is it problems like this creep up on the weekend??? When HQ is closed.

[Rambozo]

Why is it problems like this creep up on the weekend??? When HQ is closed.

I believe that has to do with some guy named Murphy.