Plasma Cutters & Edge Prep.

[timgoz]

Hi All,

When welding 1/8" plate (M.S.) does a plasma cutter leave an edge ready to weld, or does one need to lightly hit it with a grinder? Guess I'm asking if it leaves a burr.

Thanks.

Tim

[alaskatrawler]

Having a good tip and electrode is the key to good clean cuts with a plasma cutter and also good consistant air supply.

Dan

[M&M Ovenden]

Even on a good cut with, good tip and good electrode the plasma cutter leaves an edge but it is more like an edge of slag than a burr. It breaks of nicely by scrapping/hitting it of with a piece of flat bar steel. I usually then run a quick sweep with the grinder. This is probably about a minute of cleaning or an 8ft cut.
With plasma cutting the key is indeed your air supply. Have it clean and dry (water separator and good filter) you'll have nice cuts and the electrodes and tips will last a lot longer.

Murielle

[timgoz]

That answers that. Thanks Dan & Murielle.

Tim

[Oldsalt]

Hello,
What a great site. Very informative.
I have been thinking of building a metal boat for some time now and have a few questions regarding plasma cutting low carbon steel.
If cutting with air plasma, just how big a deal is the nitride formation along the cut as it relates to welding.
Is this something that a quick pass with a mini grinder will eliminate, or does it go deeper than that.
Thanks

[Wynand N]

regardless of what type of cutting method is used, it is always a good practice to run a grinder over it. More so if you use Mig welding process

[SaltOntheBrain]

See if you can find a Coast Guard inspector who does haulout inspections on metal ferries, etc.

Not sure about steel, but you can't use a plasma cutter on aluminum hull repairs if they are to be Coast Guard certified. Microscopic stress cracks along the cut.

Lance.

[westlawn5554X]

get a heater... dry all rods or aleast have it under the sun for a while... use good welding water... yes knock witha black spring hammer and ehmmm... grindin is OK...

N.B. if the job is a zero mistake thing... test yur Oxygen for purity, TIG check yur Argon purity as shield gas... some mix gas goes well with some particular material... like 20% carbon dioxide with 80% Argon... I can mix it for ya if you need it... When welding anything dont get moody, think of the job by listerning to classic song and tapping you boots help... Chao

[westlawn5554X]

err... avoid strong wind or gust from fan or you'll have more blurr... watch your AMP...