My latest plasma CNC cut.

[Gadget]

This was cut out of .080 aluminum for a friend. I made one previously out of thin sheet metal but this one is better.

Dan

[HerbD]

Gadget,

Neat job on the Jeep plate We don't use front license plates here in Arizona, so there would be a lot of possibilities. My Rover is black and I could see a plate like that on the front bumper (Rover of course, not Jeep).

Now you make me want to get those stepper motors out of the box and finish my CNC conversion on the mill, or maybe even fab a plasma table . . . so much fun to do, so little time . . .

HerbD

[Gadget]

Herb,
I couldn't agree with you more on the line so much fun to do, so little time . . .
I can't wait to retire so I have more time to play.
Dan

[HerbD]

Gadget,

The plate looks great and you've probably read my ongoing battle with slag when I try to clean cut stainless. How clean is the cut you get from your setup on aluminum? Did it take much finishing or is it pretty much what you see is what you got? I haven't tried plasma cutting on aluminum yet.

Thanks,

HerbD

[Gadget]

Aluminum is sloppy but soft enough to clean the back with a belt sander. The actual cut surface looks good enough but the back has hairy slag that doesn't chip off easily.
Stainless is the worst for slag and it is extremely hard to clean up. I use an angle grinder on stainless but it warps the metal pretty badly. I wonder if a water table would make a difference.
I am about to put the router table back on my unit to make some foam cores for aluminum patterns. Mostly parts for the table such as a better torch mount and router mount.
Dan

[HerbD]

Ah, I see. So there is no free ride - LOL. I have some aluminum sheet and after seeing your Jeep plate I was tempted to give it a try.

In an earlier thread I mentioned that I had been researching how to get a clean cut on stainless and found that the welders in the food equipment industry use a back gas apparatus when cutting to minimize discoloration, slag and distortion when welding and cutting, but I figured it was too complex to try to emulate at home.

This afternoon, while researching types of welding rod online, I came across just such a back gas fixture made by an individual. I emailed him asking permission to link to his pictures and credit him with the idea, hopefully he will OK it. The fixture looks like something that could be made with minimal tooling. If he OK's I'll share what he has done.

HerbD

[Gadget]

Sounds interesting Herb. I hope he approves the sharing of his post and info.
Dan

[jbman45]

Youse guys have been talking about clean cuts on stainless and a post on trying back gas to keep down the slag, but not sure back gas would do any good unless you're talking about shielding with argon or nitrogen. Just occured to me that I think original plasma cutters used nitrogen rather than air for cutting. Have any of you tried either nitrogen or argon for the plasma cutting gas?? Iknow it sounds expensive but wonder if it would be worth a test. With our rigs it would be easy to give it a shot, I would but don't have any stainless handy.

[Gadget]

I've only used compressed air for cutting. The volume of gas needed for the cutting operation makes using anything but compressed air too expensive for hobby use. I'm not making any commercial cuts with my unit and probably won't so it just isn't practical for me.
I still wonder if a water table would cut down on the slag, that's something I might try. I could use a tub of water as a testing unit. It would probably cut down on warpage when cutting too.
Dan

[woofer456]

Just occured to me that I think original plasma cutters used nitrogen rather than air for cutting. Have any of you tried either nitrogen or argon for the plasma cutting gas??

Hi
I got an e-mail form Simon a while back about using nitrogen as an alternate gas for the plasma,
Here is what he sent:
Bob,
We cannot be responsible for the nitrogen as our manufacturer advises against it. Please do not use anything other than compressed air.
Simon