Ceramic plasma cutting table "slats"

[52 Ford]

I have a plasma cutter but no dedicated cutting table. Most of them I see have have steel slats to support the stock and I guess you just have to deal with them as consumables. I've been making cuts on some small-ish pieces - Mostly 4 to 12 inch long cuts in approx. 1/8" tool steel plate - and think I would benefit from a small plasma table. Maybe 3 foot wide and 2 feet deep.

I was thinking a out how I want to build it and decided that easily replaceable slats is a must. The obvious solution would be a bunch of slots (edit: to drop the slats in) - which is what I'll probably do, but my other idea is as follows; drill holes instead of slots and instead of steel slats, use steel round rod with ceramic tubes on them. I found a cheap source for 9.5" long ceramic tubes that I believe are meant to protect heating elements in a particular brand/model of electric grill. I guess they're considered a consumable because of the grease that'd get dripped on them. Since the tubes are only 9.5" long, I'd have pieces of steel plate coming up to support the steel round rod between each section of ceramic tube. They'd run front to back, and the supports for the round rods would be left to right and have the holes in them.

The only reason I can think to not use ceramic is it could crack from thermal shock. Or if I drop something on them they would shatter - obviously.

By the way - I still haven't made those insoles I was talkin' 'bout. Too many projects. Keep getting distracted.

 

[memphisjed]

There are a few ceremic "paints" out there for slats- but I do not know any shop using them. More than saving the slat it appeals to me so the slats do not have the rough edge when you are digging parts out of the table.
The best I have seen - and if I ever build my own - are wood slats with a water table. Last almost as long as steel and no rough slag edge. Bonus is you can run a drill on the same table.
If you go steel have them sprung in a curve shape while in the table. This stabilizes your plate. Does not need to be much curve.
You will drop steel on your table. You will drop hot parts on your table, once you realize that they are hot. 1/8 will not land hard, but 1/4" is starting to get some umph when you drop it on the table.

 

[mnl]

Similar to the first rule of glassblowing, “If you drop it, don’t try and catch it.”

 

[GregSY]

I thought the first rule of glass blowing was 'never suck, only blow'.

 

[Ries]

seems overthunk to me.
I have been using 1/4" x 4" flat bar, set vertically, since 1992.
works fine, needs changing every ten years or so, assuming you are running a LOT of plasma.
I hit em with a hammer to knock off the slag maybe once a year, flip em top to bottom once every 3 years or so.

My guess is using ordinary flat bar will be a lot less work, wont break, and will outlast your use, as you dont run it all day every day.

 

[DDoug]

I can see a couple of problems
1. Doesn't conduct electricity
2. Will not "yield" to the plasma stream, and deflect it back up.

 

[Ries]

Doug is right about the conducting electricity thing. If you have ceramic slats, you would need to put the ground clamp on the material being cut every single time. Big pain. You want the slats to be ground.

 

[Cole2534]

I don't think I've >not< dropped something on my plasma table.

Programmed via Mazatrol

 

[52 Ford]

Yep. Overthunk it. Steel slats it is.

Thanks!

 

[DDoug]

I too made one with 1/4" thick slats.

But my new one is 1/16" thick (hey I have allot of rusty sheets of it) and set on a curve.

Much better, as the plate can't move, your not aligned over a slat for any length, and thinner pierces easier when the torch passes by, making for a more continuous cut with no interruptions/blowback.

 

[Cole2534]

Yep. Overthunk it. Steel slats it is.

Thanks!

Honest to god, I don't know which is worse in the vast majority of things-

To Overthink or to Underthink

Programmed via Mazatrol

 

[Milland]

Honest to god, I don't know which is worse in the vast majority of things-

To Overthink or to Underthink

Programmed via Mazatrol

Hmmm. Let me think about that...

 

[metalmagpie]

My buddy has a Rubbermaid shop cart. The top forms a shallow box. He has two or three inches of sand in the box. When cutting, he puts in about an inch of water. He puts workpieces across the top, or puts a grate across the top and the part on standoffs above the grate. To ground a workpiece, clamp it down with a piece of sheet copper clamped so it hangs off the edge. Bend the copper strap so it hangs straight down and hook your ground clamp to that.

You can store the plastic cart out in the weather. It will never rust.

 

[52 Ford]

My buddy has a Rubbermaid shop cart. The top forms a shallow box. He has two or three inches of sand in the box. When cutting, he puts in about an inch of water. He puts workpieces across the top, or puts a grate across the top and the part on standoffs above the grate. To ground a workpiece, clamp it down with a piece of sheet copper clamped so it hangs off the edge. Bend the copper strap so it hangs straight down and hook your ground clamp to that.

You can store the plastic cart out in the weather. It will never rust.

That's an interesting idea. I may just have to do something like that.

Thanks!

 

[Bill D]

Marble or soapstone is the stone of choice for fireplaces and woodstoves.
Bill D

 

[52 Ford]

Marble or soapstone is the stone of choice for fireplaces and woodstoves.
Bill D

I imagine something inch to two inch river rock under the slats would do a good job difusing the air jet. Plus, if you had water in there, it'd reduce the splashing.

I don't currently have any marble, but I do have a stack of small granite countertop slabs.

 

[boslab]

I wonder if that honeycomb reinforcing would be any good, we used to have sheets of it in work, it’s made from flat strips bend like half hexagon
Mark

 

[52 Ford]

I wonder if that honeycomb reinforcing would be any good, we used to have sheets of it in work, it’s made from flat strips bend like half hexagon
Mark

What's it made of? I don't think I've ever seen it in any high temp materials.

 

[DDoug]

That's an interesting idea. I may just have to do something like that.

Thanks!

So how doo you hold pieces smaller than the tub ?

 

[Cole2534]

So how doo you hold pieces smaller than the tub ?

That's what the grate is for?

Programmed via Mazatrol