First 'plasma' project

[gerrymoore]

I've had my plasma cutter for months but haden't used it until now.

Not getting any (paid) work over here so decided to 'make' something that hopefully I can sell. Had a pice of very rusty 1,5mm steel so used that to save wasting it.

Only thing I found was the plasma slag was a swine to grind off and there was a lot...considering it's a quality (RTech welding Plasma 40HF) machine I'm wondering if I had the air too high (or too low) at 50psi and used 23 amps...I'll post in the plasma forum anyway.

First pic is the steel, then the bits cut out, then Terry Dactil.

I've only just finished it so it needs painting......black I think??

 

[Sam]

Looks great dont you think it will be fine rusty!?

 

[JayRS4]

Looks good. I think your travelling too slow, thats why your getting the slag underneath, thats what i found anyway. If the amps can be set lower, i would, for that thickness 10 amps should be more than enough. For removing slag, i use a cold chisel and knock it off, saves grinding.

Oh, and I woudn`t paint it, either leave it rusty (have a look at some of chunko`s work to see how much charcter it can give) or maybe wax or laquer it, leaving the rust.

 

[peterd51]

Hi,

beautifully done!

As 'engineers' we tend to think that rust is a bad thing, we clean it all up and paint it or preserve it somehow.

The trick with this type of stuff seems to be to start thinking like an 'artist' where rust is 'texture'. It's hard, I know, as I'm pretty useless at arty type things.

As for the plasma, I tend to use 20A = 20 psi, 30A = 30 psi, etc, and that seems to work OK.

Also you may get 'excess' slag if you're moving too slowly as it widens the slot that you're cutting and that extra material seems to stick to one side rather than being blown away.

Regards
Peter

 

[chunkolini]

Looks good, definitely dont paint it. Try letting it rust, then lightly rubbing it down with fine sand paper and varnish it. A much better finish, and one that can be topped up when needed rather the fannying about with paint. It is also a finish that changes in response to the light, from orange in the evening to almost black in bright sunlight with slight metallic sparkles in some lights.

re cleaning the slag off, just go aroud the edge with a small ball pein hammer, giving it a small crack onto the edge and you can with practice go around the whole piece in no time. It also leaves a more organic texture then grinding and wont have any nasty sharp burrs.

Chunko'.

 

[gerrymoore]

Thanks for all the kind comments guys....I will leave it rusty and do what Chunko suggests with the varnish. The plasma cutter only starts at 20 amps and recommends 50psi in the manual. I've a bit of spare steel so I'll have a play with different pressures.

As for moving too slow, I cut out templates for the 'bird' from ply and it was quite difficult following it round with the cutter so I was moving very slowly......next time I'm planning to make a much larger Velociraptor which should be easier to cut out!!

 

[chunkolini]

Try drawing it freehand with a permanent marker then runing over that with the plasma torch, drag you hand along the surface of the metal to keep the torch steady, with practice you can get a real tidy edge that needs almost no finishing. I always think that if I have to grind it I have messed it up.

Chunko'/.