Hello all. I have spent the last month rewiring my garage for my new plasma cutter and air compressor. Now its time to get back to building the '29. So can anybody give me some advice on plasma cutting. What is the best way to save my consumables and also advice on making clean and straight cuts would be appreciated. I used the thing last night to open up the firewall and it went pretty good, aside from the imperfection of the free hand method. My machine is a Miller 220v. Kurt
Now this kinda stuff impresses me. Wish I could help, but don't have and never used a plasma cutter. Hopefully will get one soon.
I've just started using one. This is what the guy who gave me a quick crash course told me: 1. Always drag, dont push. 2. Keep the torch perpendicular to the metal. 3. Start from the edge of the metal if you can. 4. Use both hand to guide the tip--one on the trigger, one on the top of the torch head 5. Don't set shit on fire. I've since learned: 1. Wear welding goggles with a tint for torch work (I tried a regualr welding lense and couldn't see well enough) 2. Move the nozzle quicker, and you'll get a cleaner cut (I'm cutting thin stuff, 12 ga and under and was going too fast) 3. Don't lean up against a surface you just cut--you'll burn the shit out of your arm. Not that I did that. Of course not. I've been using a soapstone to lay out my cut lines, and it's pretty easy to see while cutting. I still can't cut a straight line, though. It's a great tooll--I just need more practice.
If cutting spring mounts and shock perches off of axles get a "good enough" cut with the plasma then break out the grinder for the rest of it. I blew through a 9" and a D60 axle trying to get just a little closer with the cutter. Luckily I could just weld up the small holes I made in them.
Be sure to install a high end air dryer for your cutter, water in the line will brake your pocket in consumables.
The guy who sold me mine said try to put the ground in line with your cut so it cuts square, i.e. it tends to cut a bevel, at least on thick stuff.
I use 2 of them at work one hooked up to the machine I use and a handheld job. Try not to cut close to the metal, seem to wear out the electrodes and tips faster. When cutting thick metal(I cut I beams for tractor trailer frames)go slow it cuts better. I push the tip forward, I don't drag it because you can't see the mark. When your electrode wears out it will cut a bevel even if you have it straight up and down. As said use both hands to guide the tip and use a dryer in the air line. Oh yeah wear a welding jacket or something because your arms will get splattered on, I got scars to prove it. later shawn
This is all good advice. I make patterns from 1/4 masonite. Subtract half the torch head diameter and make your pattern accordingly. I cut the patterns out on a verticle bandsaw, a jigsaw would be just as good.
Keep the tip up off the metal approx. 3/16" or so, don't set it down on the metal and push/pull. Keeping a set stand off height will give you much cleaner cuts. Miller sells a little wheeled device that clamps to the torch that allows you to set a stand-off height. It works really well for long straight cuts. You can still use a a guide or "fence" with it too!
I do patterns also, Make them out of paper first, then I can test fit, and change till I get it right. Then the thin masonite is used for the pattern. Works great.
we have a miller at my shop and for straight cuts we use a piece of flat bar and clamp it 5/32 of an inch from the line where you wanna cut and it usually comes out perfect, also miller makes a fixture for cutting out circles
Make sure you change the tip often...once it's used some, it tends to not cut thru the metal straight down...will usually cut on an angle...and will make a wider cut...a new tip will solve both of these problems. R-
Exhaust tubing, pipe or whatever you have that is round can be cut on a bandsaw or chop saw to about 1/4" thick or whatever you need to hold your torch up off of the material. These can be left round or smashed into oval for a repeatable template.
Its easer to drag the torch across you metal but wears out tips and electrodes faster. Miller rates theirs at 10' per minute of travel. You can cut thicker stuff at slower speeds but you are not as steady. There is also an accessory that has wheels to guide the torch and keep it a set distance from the work.
and one other thing a plasma is not a hammer if u cut a piece and it doesnt fall dont use the head to hit it it will cost u a tip everytime. cant get one of my employees to understand that. and it will burn your eyes just like a welder.
O.K. this is helpful. Is there any advice about amp settings? Does this effect the cut quality? Will a high amp setting on thinner metal cause poor cuts and distortion. Kurt
A word of caution.--- Be very careful when using a plasma cutter. Even small ones will cut through flesh and bone like a hot knife through butter! and fast. I have been to safety siminars where they show how easily using meat from the butcher shop. When using a plasma cutter they like a very smooth rate of travel. I always use the lowest ampherage setting that produces a good cut. Don't really know why but they must have had a reason for putting the adjustment on the machine. I'm sure the consumables last longer at the lower settings. Ted
I have just spent the afternoon with my new toy! I am just tickled with how well this machine works. I have the roller attachment and also am using a fence. Using the two in combination produced very clean and straight cuts with very little slag to clean up. Cut-off wheels and saw-zalls have there places, but they just moved way down the food chain! My next practice session will include cutting radiuses and circles. I don't have the attachment for the circle cutter but I plan on getting one and hope it works as well as the roller. I feel a crazy look in my eyes as I run out of scrap metal and start asking..."Do you need anything cut?"
The Jalopy Journal
