Working with cast iron castings.

J
Ron, what do you think of aluminum oxide for rust, and do you have any concern with this media? Will it work in a gravity feed gun? I want to thank you for your help. I am lost here, and that means I spend a lot of money on wrong things. Like to get the right materal and equipment at least the second time around, I usually get in right on sixth or seventh time. Chester


Aluminum oxide will be OK, other than it's more expensive than sand.
 
What he said. :+1: The aluminum oxide is fairly aggressive so "in theory" you would need less of it than you would some other material that is not as aggressive like sand.

I'd go with the aluminum oxide.

-Ron
 
What he said. :+1: The aluminum oxide is fairly aggressive so "in theory" you would need less of it than you would some other material that is not as aggressive like sand.

I'd go with the aluminum oxide.

-Ron
If I do this outside and clean up and wash everything down, could there be a residue that could harm my dog? Chester
 
Not unless your dog has a taste for sandpaper (aluminum oxide). ;) Basically, you'll end up with your blasting media (be it aluminum oxide or a silica based "sand"), iron oxide, iron, paint, crud, and anything else that might be on the piece you're blasting. Nothing that could really be much of a hazard. Soda blasting, on the other hand, leaves all that soda on everything. Probably not good for anything's health in high quantities.

Oh, another little "warning" - If you're not using a cabinet this crap goes everywhere! Do not do it anywhere near your (or especially your wife's) car/truck. Covering your vehicle in abrasive material is not a good idea. Make sure the wind is blowing it away from anything you have an attachment to, preferably towards that neighbor's place (whom you don't like too much). :biggrin:

-Ron
 
Unlike steel, aluminum, brass, or bronze which create nice curls of swarf, machining cast iron is like machining a block of sand - grains of dark coal-like cast iron fall off of the work like sand falling off of a sand core. The only way to machine cast iron is with a bit of elbow grease and lots of perserverance. Keep the vac handy so that it doesn't get all over your machines. Some people lay a cloth on the ways of their lathe as the cast iron filings are like putting a bucket of sand on the machined surfaces.
 
Take the cast iron shavings (dust) mix it in with your fertilizer and spread it over your yard. Your grass will thank you for it!
 
Not unless your dog has a taste for sandpaper (aluminum oxide). ;) Basically, you'll end up with your blasting media (be it aluminum oxide or a silica based "sand"), iron oxide, iron, paint, crud, and anything else that might be on the piece you're blasting. Nothing that could really be much of a hazard. Soda blasting, on the other hand, leaves all that soda on everything. Probably not good for anything's health in high quantities.

Oh, another little "warning" - If you're not using a cabinet this crap goes everywhere! Do not do it anywhere near your (or especially your wife's) car/truck. Covering your vehicle in abrasive material is not a good idea. Make sure the wind is blowing it away from anything you have an attachment to, preferably towards that neighbor's place (whom you don't like too much). :biggrin:

-Ron
Ron, I have a small green house, 5' height 3' witlh and 2' depth. I think I could make this into a cabinet, it is covered in heavy clear plastic over plastic rods. I may have to replace plastic rods with 1/2 in. copper pipe. Bought this at a hardware store for maybe 30 dollars, was going to used it to grow my own tomatoe plants from seeds. Thanks, Chester
 
CI that's not been de-glazed is tough to work on and eats carbide like popcorn. Most folks will "pickle" the CI in muriatic (hydrochloric) acid which pretty-much dissolves the glaze. I've never done this but it's a known common practice. I don't know the concentration that's used but I do believe that George Wilson and/or others know the answer. It's commonly available at many places and pretty cheap.

Of course, CI is loaded with carbon and pickled or not, it's going to make a mess. I'm not fond of machining it but have done it many times. It's really sexy looking stuff once it's been surface ground though... Have a look.

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Ray

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One of my first jobs as a engineer/designer, after I left the machine shop and school, was to design (copy) a cast iron bridge plug that we use in the oilfield for plugging oil wells with. The entire plug is made of class 40 gray iron. I thought I knew every thing about cast iron, that was an under statement. Thirty years later, I'm still learning! Anyways, one of the things I was involved with was machining of cast iron by turning and drill/milling. The newer generation of machinists have no clue how to machine cast iron as their grandpa's and great grandpa's did 60 plus years ago.

We talk about how abrasive cast iron is and how it tears up cutting tools. The biggest reason for this is not applying the proper speeds and feeds. Cast iron cuts best when you hog it with high feeds and slower surface feet than that of mild steel. It likes broad nose tools, taking shallow depths of cuts, with coarse feed for finishing. It likes sharper pointed tools with good nose radius taking deep cuts with coarse feeds. Fine feeds is what kills the edge on cutting tools cutting cast iron. When you use this approach the "skin" that everyone talks about is not an issue.

In our world of today, it's unheard of to use the old method of tooling that was used in the old days. Today, we use super coated carbides and PDC tipped tooling to cut cast iron. If done correctly, you can still hog it, in fact, you want to hog it with high feed rate with as deep of cut as you can take. Finish cut need to be done with coarse feed too with large nose radius tools. But the HSM usually doesn't have the luxury of doing all of this. A lot of excellent advice has been given and I wont repeat any of it. But hog it every chance you can within reason and you'll be surprised how much more your cutting tools will last.

One last suggestion, I prefer to cut it dry, but if you insist on cutting it wet, use flood coolant.
 
One of my first jobs as a engineer/designer, after I left the machine shop and school, was to design (copy) a cast iron bridge plug that we use in the oilfield for plugging oil wells with. The entire plug is made of class 40 gray iron. I thought I knew every thing about cast iron, that was an under statement. Thirty years later, I'm still learning! Anyways, one of the things I was involved with was machining of cast iron by turning and drill/milling. The newer generation of machinists have no clue how to machine cast iron as their grandpa's and great grandpa's did 60 plus years ago.

We talk about how abrasive cast iron is and how it tears up cutting tools. The biggest reason for this is not applying the proper speeds and feeds. Cast iron cuts best when you hog it with high feeds and slower surface feet than that of mild steel. It likes broad nose tools, taking shallow depths of cuts, with coarse feed for finishing. It likes sharper pointed tools with good nose radius taking deep cuts with coarse feeds. Fine feeds is what kills the edge on cutting tools cutting cast iron. When you use this approach the "skin" that everyone talks about is not an issue.

In our world of today, it's unheard of to use the old method of tooling that was used in the old days. Today, we use super coated carbides and PDC tipped tooling to cut cast iron. If done correctly, you can still hog it, in fact, you want to hog it with high feed rate with as deep of cut as you can take. Finish cut need to be done with coarse feed too with large nose radius tools. But the HSM usually doesn't have the luxury of doing all of this. A lot of excellent advice has been given and I wont repeat any of it. But hog it every chance you can within reason and you'll be surprised how much more your cutting tools will last.

One last suggestion, I prefer to cut it dry, but if you insist on cutting it wet, use flood coolant.
 
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