Plasma cutter usage tips and tricks?

[divorced]

Ok, I got the straight line cut figured out, but now I'm wondering if anyone can suggest any methods to using a plasma cutter to cut out semi-precision shapes?

Is there any type of material that would be good to use as a pattern for cutting multiples of the same part?

How could I make these patterns?

What could I use when making some 14 bolt spring perches and shock mount tabs to get the right diameter for the axle housing?

Does any of this make any sense?

 

[rdn2blazer]

i assume you dont have access to any machining equipment, so your next probably best material to use as a pattern might be wood. you would be useing the torch head diameter as the guide surface against the wood, it probably would bo far enough away and not in the line of fire to get burned or catch on fire. you could use hard wood and find some fire retardent spray and spray the wood with it to keep the fire hazard to a minimum. i would rather use aluminum but again you would need to machine it. with wood you can cut that at home with wood working power tools like a jig saw or scroll saw or other wood working tool thar are FAR less expensive the machining equipment. remember, you havt to off set your pattern by the ammount of the torch head diameter to the center line of your torch. hope this helps.

 

[big jimmy 91]

Make card board patterns first for one of a kind pieces and just cut them free hand
For mass produced items you can make a jig or pattern to use as a guide , just make them out of a suitable thickness material and shrink them enough to allow for the the size of the cutting head and tip
(leave off the amount it is from the cutting arc to the edge of the tourch head)

I hope this makes sence to you

P.S. I allways use heavy enough plate to build jigs and patterns at work but this is usually not available to people working at home. You may have to try using 3/4" plywood/particle board for patterns in the garage.
Then again you could just mark and cut freehand leaving a little material extra that you can clean up to precision with a grinder

 

[HarryH3]

I've seen flexible magnetic strips that seem like they would work nicely for that, but I can't remember where I saw 'em now.

 

[camiswelding]

I have 1/8 inch steel patterns for most shapes... circles and triangles...
I also use a circle/line cutting attachment when my hands arent steady... more and more as I age.... they make one for gas torches that i adapted to my plasma... works great

Straight lines are easy... any straight edge with magnetic clamps works great... Ive got the line measurement down to pencil width... speed with no kerf makes things pretty clean and accurate... within welding and fab tolerances... any closer and it would have to be waterjet or laser...


practice practice practice

clean ultra dry shop air with clean tips and a drag cap makes nice clean cuts

cam

 

[MNorby]

I use angle or other material and clamp to what I am cutting to make straight line cuts. On my plas I put my material about 1/2" from the line to but cut then check with holding the torch head against the material to check how it lines up on the line and adjust as necesarry.

 

[divorced]

I've seen flexible magnetic strips that seem like they would work nicely for that, but I can't remember where I saw 'em now.

Something like this would work good, I will check into it. I may go to our local welding supply where I bought the plasma cutter and see if they have anything.

I have 1/8 inch steel patterns for most shapes... circles and triangles...I also use a circle/line cutting attachment when my hands arent steady...more and more as I age....

I was thinking about calling Kert and see what it would take to cut some jigs/guides to certain sizes accounting for torch head width with his equipment. Just some circle rings, and possibly some 30*/60* and 45*/90* triangles like I used in drafting class in high school. I do need a lot of practice, and my hands aren't very steady - I think I get too excited when I use it




I also thought about plexiglass, but it may melt. Or some masonite(?) board. Both should be fairly easy to shape with a disk/belt sander.


Thanks everyone for the suggestions

 

[camiswelding]

forget anything that will melt or burn...so plastic masonite and plywood are out... they wont last and youll end up with goo on your torch

the magnetic strips are ok for pipe fitups... other than that I threw mine in my box years ago and never use them...once again the plasma burns right thru them
try a drag cup... it stands the tip of the torch off your work the right distance and you can just lay the torch on the metal and cut.... I have one way that I can cut the best... pulling instead of pushing... everyone develops their own sweet spot way of using the plasma... experiment until you find yours
I cheated on forms.... I used a buds ironworker to do most shapes... I have everything up to 8 inches.... I havent needed anything bigger yet...most good steel supply places have precut forms... I think 100 bucks would give you all the shapes and sizes you could ever need... and thats if you fab regularly... if its one off stuff... cut them yourself
cam

 

[MNorby]

be inginuitive (sp). I have ogne as far as using a soda can as a jig to make a nice circle.... maybe another idea