PDA

View Full Version : Who asked the "cutting cast iron question?



torker
03-18-2006, 10:43 PM
I can't remember who or what but I ran into a new deal the other day that may help someone.
Had to cut off a heavy piece of cast from an old machine.
Tried the air arc gouger and it cut the first pass fairly well but that was it.
It got the usual coat of carbon on it that you can't do anything with.
Did the usual chipping hammer trick and knocked the slag out for the next go.
Got very little depth with the gouger.
This piece of cast was bad...a lot of carbon.
It was also pretty big and I didn't have all day.
I tried Zip discs on the 7" grinder....zip it then gouge and so on. It worked but was still really slow.
Then a lightbulb came on....I tried feeding 1/8" welding rod into the cut as I was gouging. But it just got blown away.
Then I got fed up and tried another thing.
Cleaned out the slag with the chipping hammer then buttered the bottom of the groove with 1/8" 6010 @ 105 amps.
Then took the gouger back after it. Turned the heat down and the air up. A nice steady pokita pokita noise (that REALLY irritates the mechanic in the next bay http://bbs.homeshopmachinist.net//biggrin.gif)
It worked much better. The cast now had more iron in it so the gouger could bite.
I got almost twice as deep per cut.
Next time I'd like to try 5/32 6010 @ about 135 amps...it may be better.
It still took a long time but not as long as my other thought...a big geezuz axe and beat it to death http://bbs.homeshopmachinist.net//biggrin.gif
Russ

Fasttrack
03-18-2006, 11:47 PM
"a big geezuz axe and beat it to death " lol your my new hero!

Out of all the mechanic/machining/metalworking etc field i think i like arc welding/cutting the best. Thats really what first got me into this, that and blacksmithing. Out of curiosity, what does a plasma cutter do to cast iron? A lot worse than the air/arc setup?

torker
03-19-2006, 07:45 AM
Fasttrack...the smaller plasma cutters don't work well on cast. They don't like anything dirty.
The really big units may work but I'm doubtful. Once the carbon is there you have to remove it to finish the cut.
I've done lots of gouging with 600 amp machines turned up full and on cast they don't do a lot better than the 250 amp jobs. They just bring on the carbon a little quicker.
However...the 600 amp jobs and lots of air are great if you want to really annoy everyone else in the shop....especially the poor slob with a hangover http://bbs.homeshopmachinist.net//biggrin.gif
Russ

wierdscience
03-19-2006, 11:18 AM
Russ,I love arc gouging,seeing those little balls of steel form up and go running off the side is a sight to behold.

We got an old P&H 600amp static machine at work that I use for gouging.With it turned up all the way,everytime you strike it off you can see all the lathe chips on the floor between the leds start to "dance" http://bbs.homeshopmachinist.net//biggrin.gif

Ever use a blowpipe on LOX? http://bbs.homeshopmachinist.net//biggrin.gif

[This message has been edited by wierdscience (edited 03-19-2006).]

tattoomike68
03-19-2006, 12:34 PM
Ultra-thermic cutting rods will cut almost anything , rocks , iron, steel and concrete.

I have ran one, it was a realy cool. all it needs is a 12 volt battery for ignition and a bottle of oxygen with a regulator.

the unit is simple and cheap, the rods are spendy.

http://www.brocoinc.com/default.aspx?page=primecut

torker
03-19-2006, 01:00 PM
weird...yes 600 amp gouging is cool.
600 amps, 1/2" stick, 80 psi air, night time, thick clean steel....priceless!
If you mean an oxygen lance...nope I've never ran one but worked around a couple. They where cutting 12" (plus) thick steel. That also was impressive.
Mike...Those are cool!
They must be pricey...the company is embarrassed to list the prices, unless I missed it.
I like the part where you can fracture big boulders.
These would be good for the cement equipment repair I do. The cement coated stuff requires lots of jackhammer work before you can work with it.
I like the warning when you cut alu with these...full head coverage, etc. I'm thinking this is pretty wild. They say alu is "volatile"
Russ

tattoomike68
03-19-2006, 01:41 PM
the 24" thermic cutting rods I was using were $7 each and burn for around 30-40 seconds, thats where they made thier money.