What welding projects are you working on? Are you proud of something you built?
How about posting some pics so other welders can get some ideas?
av8or1

Recently I purchased a PrimeWeld CUT60 for the purpose of simplifying cutting tasks in general fabrication projects. However, the bulk of my hobby time is spent on automotive related endeavors. It seemed to me that a plasma could come in handy during those too. I mean, I already use a cutoff wheel on a 4.5" angle from time-to-time. Mostly it's a grinding disc or flap disc, but there are times when you need to cut. To that end, the role I saw the plasma fulfilling primarily involved frame work, removing rusted panels and the like. Stuff that you wouldn't necessarily care about the heat input too much because you wouldn't be re-using it. "Just to cut stuff off" was the phrase that came to mind. After using the CUT60 a few times I could see how it would perform well in those scenarios.

That said, I have an on-going project to (essentially) build a car for the wife-eee. The next step in that overall process is to cut a body panel. However the distinction is that in this particular case, the panel would definitely be re-used. For that reason I need something more than a tool that can merely hack something out of the vehicle. So I looked at the cutting devices that I have on-hand when I considered how to go about doing this. I didn't like any of them if to speak openly, at least not in this context. That is due to the vibration that they generate. In other application contexts that isn't much of a concern, and so they do well there. Hmmmmmm... I took a break and gave it a think. And that's when it happened: "What about the plasma?" Oh boy. I hadn't really ever contemplated using the plasma in that context. However at the end of the day a vehicle's body is just sheet metal, 18ga usually, depending. Thus if the conditions were right, why not use the plasma?

Well I had a couple of reasons against using the plasma on a body panel that came to mind. The first of which was that it would almost certainly damage the paint. However I'm already planning a respray, therefore that just-so-happens to not be a concern for me. The second concern I had was the heat input and potential distortion thereafter. I did a Google search regarding this whole notion and saw generally positive indicators that plasma cutting body panels is a thing. I mean, with the plasma there would be no vibration, certainly. And that would be to-the-good. With those two concerns addressed, using the plasma in this context began to seem more plausible to me.

And having said all of that, I thought I would post on the forum to see if anyone has feedback. I attempted to apply an experiment of my own tonight in order to assist in making a decision. More on that in a bit...
Last edited by av8or1 on Fri Sep 18, 2020 11:31 am, edited 1 time in total.
av8or1

I happened to be out yesterday making salvage yard runs for some parts to be used in the build for the wife-eee. At the last stop, I decided that I would bring home a body panel that I had no need for beyond a test specimen. I wanted something relatively flat, but that would have a modest curve or two. And so I brought home this hood from a 2001 F-150:
sunroof 96.jpg
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The only downside to it of course was that any hood will have an inner support structure and that might skew the results. However, if the test cuts were made in locations where the bracing didn't really do much, then I felt that it would still be an apples-to-apples comparison/test.

And so I plopped it on the newly-built table, brought it into the workshop and configured the CUT60 to go to work.
Last edited by av8or1 on Fri Sep 18, 2020 11:32 am, edited 2 times in total.
av8or1

Not being all that experienced with a plasma, I gave this scenario a bit of a think to include a consultation with the manual. I was interested in the recommended settings for the material type and thickness above all else. Travel speed still has this quasi-intangible aspect to it that I don't have a handle on just yet. I do know what to look for (the angle of the spray underneath) but in the few runs I've made to-date, I've relied mostly on the feel of the torch as I have moved along the work piece. Correct me if I am off-base here, but I'll tell ya, I can feel when the plasma makes a clean cut and when it doesn't. To my hand anyway, there is a sensation that is clear and overt. So. After such consideration it seemed to me that 18ga wouldn't need much more than the minimum that this particular plasma can produce, which is 20A. However, given my relative inexperience I didn't know that for certain. It was more of a 6th sense I had based on my welding experience. And intuition coupled with common sense I 'spose. I mean 18ga is quite thin and F still equals mA, so ...

I had watch-the-lil-un duty for part of the night, so I only had time to get-in 4 test cuts. I documented each right on the hood itself so that there wouldn't be any confusion. Here is the at-large picture of the results:
sunroof 97.jpg
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av8or1

More pictures will follow, but in the end the notion that 20A at normal travel speed (or at least what seems "normal" to me) would most definitely be enough to complete the task. Running my CUT60 in 110V mode, at 55 psi, 20A, normal travel speed the resulting cut was clean with no distortion. Admittedly I think that the underside of the cut might need some cleaning afterwards (seemed that there might be a touch of slag ... possibly) but that wouldn't be a problem. Achieving a clean cut with no distortion such that the panel could be re-used is the goal. It also seemed to me that the total time that you have the trigger depressed would be the ultimate factor in heat input and thus potential warpage. With that in mind, I suppose that if you were to make the big-picture cut in smaller segments with sufficient cooling time in-between that you could further reduce the likelihood for warpage. Hmmmmm...stuff to consider.

Anyway, more detailed/zoomed-in-view pictures follow.
Last edited by av8or1 on Fri Sep 18, 2020 11:36 am, edited 2 times in total.
av8or1

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av8or1

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av8or1

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av8or1

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av8or1

I 'spose that at this point a few caveats are worthy of mention:
1) I would build a jig to include a "fence" so that I would not need to free-form any of the cutting. I could just hold the torch up against the fence and let it do its thing. The fence would be on one side only, so I suppose there is a potential for the cutting to go awry by pulling away from the fence; however in this context that portion (the inner portion) will be discarded anyway, so that wouldn't be a concern.
2) Starting is something that I am still working my way through. Seems like I cut a slightly bigger hole there because I am uncertain regarding the point at which I should begin moving the torch. That can be seen in the above pictures. My plan is to use every last bit of this F-150 hood to gain more experience with that aspect of the operation.
3) As I expressed in #2 above, I plan to continue to test and practice prior to attempting the real McCoy. I'm not ready at this point and I am aware of that.
4) If restarts are normally kind of tricky, I suppose that I could always start towards the inside of the fence in this scenario because, again, that portion will not be re-used. So the idea would be to start inboard, move to the fence and then run along the perimeter for some pre-determined distance so as to minimize the potential for distortion.
5) The CUT60 employs a certain amount of compressed air post-flow in an attempt to keep the consumables and torch cooler after the cutting is completed. I would plan on moving the torch along the freshly-cut material in order to keep it cool as well. So the game plan would be to begin the cut inboard, move to the fence, run along the fence, release the trigger and then move the torch backwards along the path that was just cut until the post-flow air ceases. I currently have the post-flow time set at 20 seconds, but more can be added. The upper time limit on the CUT60 escapes my memory at present, but I suspect that it is around 60 seconds. I used this technique during the 4 test cuts tonight. It is a rudimentary affair, but one that seems like it would bear fruit.
6) I would likely need to attempt this from underneath the given panel. So that would mean donning my welding jacket and thick gloves. I've only worn my welding helmet on a lighter shade thus far when running the plasma (no sunglasses) and that would be the case during the cutting of the real-life panel as well. So I would be protected, but I wonder how much of an issue the falling minusha might cause with accuracy. I suppose that if the fence was locked down well enough and if the runs were relatively short in duration and length, it wouldn't matter too much.

Anyway, just thoughts.

Thanks!
Last edited by av8or1 on Fri Sep 18, 2020 11:43 am, edited 1 time in total.
DavidR8
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Definitely following this adventure!


Sent from my iPhone using Tapatalk
David
Millermatic 130
Primeweld 225
cj737
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If you rig up a magnetic jig to act as a fence for cutting, you’ll get great results. Keep the cut on the waste side and then the kerf will be within your patch area. A gentle cleaning of the cut before welding. Bobs your Uncle.
av8or1

cj737 wrote:If you rig up a magnetic jig to act as a fence for cutting, you’ll get great results. Keep the cut on the waste side and then the kerf will be within your patch area. A gentle cleaning of the cut before welding. Bobs your Uncle.
Thank you for the feedback CJ, I appreciate it. I plan on doing some additional experimenting with all of this later today. Good to know that folk who are in-the-know don't consider the idea as being too far out there...seemed rather logical to me, but I am still quite new at it, so ... :D
av8or1

Alright so I decided to get in a little practice tonight with the plasma in the context of cutting a body panel. First I established a fence similar to the one I'll need:
moon roof practice 1.jpg
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And then gave it a go:
moon roof practice 2.jpg
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I began by running at 110V, 55PSI and 30A, as that amperage value seemed to result in fewer mis-cuts with a faster travel speed.
av8or1

I observed several things tonight while attempting this, but perhaps the most surprising one was that the panel was cool-to-the-touch relatively soon after I had completed the cut:
moon roof practice 3.jpg
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Granted, I used a post-flow of about 25 seconds after each cut. However I decided to see what would happen if I went after it in larger passes rather than the smaller mini-cuts that I had planned. As it turned out, that didn't seem to affect it much. No real distortion to speak of. Perhaps it was the faster travel speed. I dunno, still experimenting.
av8or1

The cuts themselves came out relatively good:
moon roof practice 4.jpg
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Though I could use more practice (and plan on doing that). The hood was glued together in places and thus a few sections were more difficult to achieve a clean cut via the first pass:
moon roof practice 5.jpg
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However on the panel I'll be cutting when attempting this for-real, that won't be the case and thus isn't applicable.
av8or1

I made several observations tonight. Kinda mini-learning-lessons if you will. This list will be rudimentary for those with more experience in the plasma thing, but for me they were worthy of mention:
1) Even though you have your torch held against the fence and it has a standoff on the nozzle, it is possible to twist the torch with your hand just a bit; this causes the cut line to fade inward or outward, depending. So the key element seemed to be to just let the torch rest on the work piece and pull it along with a light grip.
2) The CUT60 has a trigger guard. Be careful of that thing, it can get caught on your fence depending on how your fence was put together:
moon roof practice 6.jpg
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3) When restarting, it is difficult to replicate the exact torch position that you had in the previous cut. For that reason #1 seemed even more important.
4) The idea of starting inboard on the trash/waste section and then joining the cut line along the fence seemed like a good idea in theory. However in practice it didn't seem to work out all that well. I've decided to continue practicing to see if it is worthy of doing or overkill/unnecessary.
5) When running on 110V, I tripped the circuit breaker once. Not sure why. It happened in the middle of a cut; a cut that was no different from any of its predecessors, or at least it seemed. Therefore I decided to switch to 220V but remain at 30A. There appeared to be no difference in the cut from when running on 110V.
6) Corners seem to be something that are better left until the end, at least in this case. I found that it was better to run the straight lines to the corner area then join the straight lines via the corner separately. The reason is that the angle that you must maintain when dragging the torch requires a significant amount of hand movement over a relatively short distance. Or so it seemed. I definitely need more practice with making the run around the bends on this one...

Unfortunately my setup then encountered an issue tonight and so I had to cut things short, no pun intended. More on that in a bit...
av8or1

So the CUT60 began acting strangely tonight. I had made several runs, but none of them were all that long really and there were breaks in-between each cut. I was at 220V, 55psi and 30A. Hardly maxing the machine. However when I began a cut, I noticed a high-pitch and rather loud shrill or shrieking noise emanating from the torch. I began to move it but the arc extinguished after 3-4 seconds. Here is a quick video capture of the phenomenon:


It continued to do this no matter what I did in an attempt to find a remedy. I changed the ground connection (which I had flap-disc'd to bare metal), I increased the air pressure to 60psi per the troubleshooting guide in the manual, I did an air pressure test, I checked for water or other issues in the air supply, I tried cutting in a different location, I checked the connections to the machine, etc. The one thing that escaped my attention was the yellow light, which is an over-current light if I am not mistaken. I don't recall if that was illuminated now that I think about it. However at 30A on 220V, I don't see how I could have done that; but what do I know?

Anyway if anyone out there has experienced this shrieking/shrilling and a short-term arc let me know how you resolved it.

Thanks!
Poland308
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Might want to pull your tips apart and check them. Sounds like you might have gotten some blowback in there.
I have more questions than answers

Josh
av8or1

Poland308 wrote:Might want to pull your tips apart and check them. Sounds like you might have gotten some blowback in there.
Hi Josh,

Thank you for that feedback. I did unscrew the end cap; the tip fell out. That appeared to be normal. I looked at both the cap and the tip but didn't see anything that stuck out as being a problem. However being a novice I don't know that I would recognize an issue if I saw it. Anything non-obvious would likely appear normal. :lol:

I've sent an email to PrimeWeld. I'll see if they respond today.

Thanks again!
cj737
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Maybe I missed it, but did you encounter that shrieking when cutting another panel elsewhere? It's possible the air was blowing through a small hole in the backside (structure) of the panel and causing that sound. Maybe cut in an open area, single thickness to reproduce results?

I'd even consider lowering the pressure "just a bit" to see if that helps stop the whistling.
av8or1

cj737 wrote:Maybe I missed it, but did you encounter that shrieking when cutting another panel elsewhere? It's possible the air was blowing through a small hole in the backside (structure) of the panel and causing that sound. Maybe cut in an open area, single thickness to reproduce results?

I'd even consider lowering the pressure "just a bit" to see if that helps stop the whistling.
Thank you for the feedback CJ-

When I first encountered this shriek/whistle/shrill phenomenon, I was cutting the top of the hood from the F-150, just as I had been for about 15 - 20 minutes prior. During that time I had cut through both "halves" of the hood several times but never heard this shriek-thing. In the above video I am cutting only the underside of the hood, thus single layer. I adjusted the pressure both up and down without difference. 'Seemed like everything I tried made no difference. And of course, the real problem isn't the whistle/shriek, it is the fact that the arc extinguishes after only 3-4 seconds. I can't cut without a restart, which buys me another 3-4 seconds...

I haven't heard anything back from PrimeWeld just yet, but it's just after mid-day. If I don't hear anything later in the afternoon I'll just call the number listed and see what they have to say.

Thanks!
av8or1

Update-

After work today I went to the outbuilding to see what was what. The very first thing I wanted to attempt was a cut in order to verify that the problem has persisted. It didn't. The CUT60 is back online, cutting as well as it did when I first received it. Wha-? The weather here is poor, so I couldn't wheel the plasma table into the workshop to do any proper cutting. Therefore I ran the machine on 110V, 60psi, 30A. I just put the piece of the hood that I cut out yesterday down on the concrete floor (it has a natural bow to it, so it didn't lie flat, normal), connected the air supply, ground, torch, donned the helmet and gloves and let 'er rip. No issues. No whistling/shrieking/shrilling and no arc flameout.

So I dunno. That's both good news and bad news. Good that it is functioning, bad that I don't know the cause of the problem. However I didn't want to do anything to the machine or the torch, then have things work and as a result place the cause of yesterday's issue on whatever I cleaned up. The way I approached it will result in no red herrings.

No email response today from PrimeWeld. I did call them after I conducted the test. Kinda strange in that there is no voice greeting when their phone mail service answers the call. However I left a message, after 5pm their time, and they did return my call. So thumbs up for that. The guy I spoke with was a customer service rep and gave me the number of that George guy, who I have heard of in previous Internet plasma-related searches. So I'm waiting on him to call me; 'will see what comes of it.

The wet stuff is supposed to subside in an hour or so. At that point I plan on making it back to the workshop to see if I can replicate the problem. Was it caused simply by making several cuts over a 15 - 20 minute period? Seems doubtful. [shrugging shoulders] :?
av8or1

Alright so George called me tonight. Interesting character.

We went through the litany of causes that could result in the issue that I was experiencing yesterday. However several of the claims he made didn't really hold water IMHO and by the end of the conversation he pretty much agreed. His first "suggestion" was that the "ground, but it's not a ground" clamp wasn't attached to bright clean metal and that was my problem. "Uhhhh...George, it was. And I had been working for 15 - 20 minutes without an issue" was my reply. Through a series of other questions I told him that I was using the out-of-the-box consumables. He told me that those were 60A consumables and that if I was only using 30A that I should be using 30A consumables. He didn't suggest that this was the cause, but ... dunno. In the end the only thing that I heard from him that was indicative of something I was doing wrong was that the inlet pressure I had of 75psi wasn't enough. He said that it should be 90psi - 120psi. I can't imagine this causing the issue though. He did say that the arc extinguishing after 3-4 seconds means that it couldn't complete the circuit. I bought that, however why had it been working previously? And why did the problem persist even after I changed the work clamp to a new (and freshly ground via flap disc) location on the panel?

And why did it work today, ergo why did the problem not persist? That's a difficult question and not one that I expected him to be able to answer. So I dunno fellas. I am gonna just turn the other cheek for now and chalk it up to my inexperience. If it happens again, then I'll take it up with PrimeWeld at that point. So it was a big question mark that will remain that way for the time being.

I'll post updates on that particular development as/if they occur. Hopefully not though, I'd prefer for the CUT60 to just work without issue. I am not a "trouble customer" and don't want to have to deal with returning anything unless necessary. TBD.
av8or1

More observations/thoughts regarding this project. Perhaps as much for me as anything, but I thought I'd post anyway for the sake of completion:

1) I don't think that magnets will be sufficient to hold the fence in place in this context. I may need to tack it in a few places and am already planning on using clamps, provided I have or can source ones that are long enough WRT depth to reach the fence. And use magnets in addition to those two means of securing it (it = the fence).
2) You've likely figured this out, but the goal is to cut a hole for the purpose of installing a moon roof. So the panel in question is the roof of the car itself. The test fence I was using is the support ring that mates to the glass. It will need to be extended in both directions a bit, otherwise the plasma will cut inward of the line approximately 3/8" on each side. I don't recall the exact half-distance of the torch head at the moment, but if that is not taken into account the amount of material that would still need to be removed would warrant a new cut. To grind that much off would be problematic for a number of reasons.
3) The fence is a second support ring and not one that I will use in the actual installation. Ergo a spare or extra. Therefore I can enlargen it without concern.
4) The plan is to cut from underneath, or within the cabin of the vehicle. The interior has been removed entirely, to include the dash. I'll lay a welding blanket down over the stuff that remains up front and over the rear seat (prevent sparks from getting to the fuel tank. The cut area is far enough away from the rear of the vehicle that I feel ok with the plan. I might consider putting another barrier aft of the cut area but fore of the welding blanket too. In the end I'll likely just remove the fuel tank altogether, knowing me.
5) I'd prefer to cut from above, but I need to match the cut to the support ring and headliner. That's difficult to do from above.

Ok enough random thoughts for now...
kiwi2wheels
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" 5) I'd prefer to cut from above, but I need to match the cut to the support ring and headliner. That's difficult to do from above."
Is there no way you could use a .040" cut-off wheel on an air die grinder from the top and put a stop disc on the cut-off disc to regulate your cut depth in the critical areas ?

You'd still need to cover all glass, etc, but it would seem to require much less edge finishing to get the dimension you need.
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