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jkoper
10-10-2005, 03:17 PM
Hey all,
Has anyone here ever tried to make their own petrobond type casting sand? I thought about using fine sand blast sand mixed with oil. I haven't been able to locate a source for clay for green sand in my area, and mixing the sand and keeping it properly tempered sounds like more work than its worth for the little bit of casting I plan on doing. Any thought?

Jim

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Jim Koper
J&R Machining

david_r
10-10-2005, 03:25 PM
kitty litter = bentonite clay

Alistair Hosie
10-10-2005, 03:27 PM
I think this method you are suggesting is used quite frequently look up Gingeries spelled (gingery)site for more information and good luck.Alistair

Radmachine
10-10-2005, 03:44 PM
For a gadget to grind up kitty litter to a fine powder, go to:
http://www.gizmology.net/mixer.htm
I made one, but modified the barrel with some internal vanes to aid the tumbling. I couldn't get any crushed granite for tumbling media, so used some nuts, bolts, and small metal parts for the media. Turns kitty litter into a fine powder, perfect to use in my casting sand. Noisy, though.
After you shake out your casting, just let the molding sand dry out and then run it through the tumbler. It turns your rough sand into fine casting sand. Only temper what you need for each casting and save yourself some work.
For a different way to cast, try lost foam casting. I do it almost exclusively, now. Check out:
http://www.buildyouridea.com/cnc/hblb/hblb.html
Good info here.

lynnl
10-10-2005, 04:07 PM
If you have a farmers' Co-Op around close you can probably get a bag of bentonite clay from them for 2 or 3$ ...already in a fine powder.

Somewhere in the last year or so I read the type of oil that you need to add to the sand for casting. I'm thinking it was dielectric oil, or maybe a it was a mix of that plus other ingredients. But can't remember for sure. (Guess that's not much help. http://bbs.homeshopmachinist.net//biggrin.gif)

neonman
10-10-2005, 05:36 PM
jkoper, I have made petrobond sand, however,
I havent gotten my frrnace working yet to try it out.

I purchased the petrobond from "Budget Casting Supply". Since then, they have discontinued selling it, and only have the ready made sand.
BTW, their prices have recently gotten a little on the high side.

I used 30wt non detergent motor oil (per the instructions on the petrobond.

You WILL need a muller, so if you don't have one, find a freind who does.

I used #120 white sand, and it makes a really nice casting medium. Hope to get my furnace working soon. I'll be casting bronze.

neonman

jkoper
10-10-2005, 05:40 PM
Thanks for the replies guys. I never even thought about the kitty litter. I had tried the co-op here in town before and the guy there didn't have a clue what I was talking about, but I called the one in a nearby town and they had clay for $8 a bag. I may play around with the oil mix and see what happens.Thanks again for the help.

Jim

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Jim Koper
J&R Machining

Waffenschmied
10-10-2005, 06:12 PM
Ever-You, "Sodium-Silicate-Wetting" With Carbon-Dioxide Sand; "Setting"?

No-Oil-Smoke!!!

[This message has been edited by Waffenschmied (edited 10-10-2005).]

CCWKen
10-10-2005, 06:35 PM
Ich weiƟ nicht, was Sie sagen.

Waffenschmied
10-10-2005, 06:50 PM
Kein Stress!!!

Casting-Silica-Sand, With; "Sodium-Silicate-Solution" Mixed.

Once-Over; "Master-Pattern" Poured/Tamped, Then; Carbon-Dioxide Gas-Apply.

Sand; "Sets", Casting-Mould! Kinderleicht!

Forrest Addy
10-10-2005, 09:19 PM
One book I can heartily recommend is C W Ammen's "The Complete Handbook of Sand Casting". In it he goes into scrounging up local materials including where to find clay and sand in natural settings like river banks and beaches, alternative sources for materials, etc.

Allmetal
10-10-2005, 11:01 PM
I have been operating a small backyard foundry for the last 15 years and have been making my own petrobond molding sand from the very start. You mix a 100# of #100 or #120 bank sand with 5# of Petrobond II and then add 5# of foundry oil and mull , this is the petrobond that doesn't require an alcohol catalyst to be added in the last stages of mulling. But as was mentioned you will need a muller or it won't mix up right and will need to be remulled after each use. You can go to an oil supplier and just ask for a 40 wt. base oil or if the have it by the brand name Amoco 150 they should be able to sell it to you in 5 gallon pails. This oil has no additives of any kind added to it yet and is cheaper then non detergent motor oil and will work better. I was getting this oil at a foundry supply house and was paying twice that I now can get from a local oil supplier under a generic name so try them first. I still have to get my Petrobond II from a foundry supplier but a 50# bag, which is about $60 a bag, will make up a 1000# of molding sand. I get my bank sand from a local sand pit that grades and dries it for $20 a ton so it isn't that expensive or that hard to make up a batch of petrobond molding sand yourself. Bob

Norman Atkinson
10-11-2005, 03:14 AM
Horse Manure- or camel dung.

I presume the American equivalent is Buffalo Chips!

The joke is that it is true!

Norman

uute
10-11-2005, 06:29 AM
I've always been told you still need a binder (clay) to get decent oil saand. I've made some H-bond (search for this and K-bond) sand, but the binding clay (NOT bentonite!) was outrageously expensive. I used an oil based drilling mud additive, like the recipie called for. Still need the alcahol, can mull by hand a little at a time, seems to work good.

Major cities often have a casting supply that mixes their own oil based sand (I know it was available in Denver from the place I got silica sand for my mix)

email me if you want more info,
uute

Norman Atkinson
10-11-2005, 07:31 AM
Whilst oil bearing sand is normal stuff, there is the logic that the oil is mineral- and pretty crude at that. This opens up a new ball game about what to mix in sand that is local. Certainly, there is the use of linseed oil, rosin and sugars in baking cores but there seems to be no reason why other oils cannot be used. Again, I have suggested that manures have been traditional for centuries.
If Tubal Cain could manage casting 14 foot hollow brass columns in the desert complete with adornments of fruit etc, there shouldn't be much of a problem, 6000 years later.

The hardest job- or so my wife says- is
smashing the gold fillings out of the teeth for re-casting!

Norman



[This message has been edited by NORMAN ATKINSON (edited 10-11-2005).]

Allmetal
10-11-2005, 09:14 AM
uute, the petrobond is the binder but what they make it with I can't say but I was told it was just bentonite and also hear it was iron oxide but in any case it mulls up to make great molding sand for both aluminum and brass casting. The K-bond that you mentioned was a mix developed by Kansas State University in which they used a food grade base oil. When I checked into what they were using I found it was still mineral based oil only refined so if it came in contact with food the food wouldn't have to be thrown out. It wasn't used for cooking but used in hydraulic lines and oven conveyors and the like which might at some point come in contact with food being processed. It was available but at about 3 times the price of what I was paying for plain base oil. My local oil supplier couldn't see were their K-bond mix would be any safer if you were breathing the smoke from it or the plain oil mix, I just don't breath it and wait for the mold to cool before shaking out the casting. As for using other oils that are not material based but something from the animal or vegetable groups then you are going to have the problems of the sand becoming renascent or oxidizing, setting up, in a short time so they wouldn't work to good. Some still use linseed oil to make cores in which you mix 40 parts sand to 1 part oil, mold your core and bake at 350* for about 1/2 hour or depending on the cross section of the core. I did use this when I started along with the sodium silicate but have gone to commercial no bake core binder which is a lot easier to use and produce less gas during the pour plus the core can set on the shelf for long periods of time without breaking down. Lastly, I agree about reading C.W. Ammen's books on foundry. I think I have all his books published on foundry,5, but there might be more and I refer back to them from time to time to get answers to a problem I have run into. Bob

[This message has been edited by Allmetal (edited 10-11-2005).]

[This message has been edited by Allmetal (edited 10-11-2005).]

uute
10-11-2005, 07:56 PM
Hi Allmetal,

All true! And Petrobond would be an execelent way to go. The best oil I ever seen was used motor oil, sand rammed well, molded well, smoked like crazy! Don't think I'd like to play in this any more. (what I use now probably isn't that much better for me!! : )

Anyway, the VG-69, or Claytone-5 clay is a substitute for Petrobond binder, then I use synthetic 2 cycle oil, which is suposed to smoke less (I think this was the object for developing K-bond). Seems to help - but as you say, Don't open the mold hot - The Flintstone Firemen will come put out your Barbeque!!

uute

PS for small amounts Petrobond would have been much cheaper!! As would the local brand of premixed oil sand.

I had to try mixing my own. Learned a little, enjoyed it alot, probably cost me a little more. Ever pay more for stock to make a part/project than the cost of part from China, bet yours looked & performed better! : )

[This message has been edited by uute (edited 10-11-2005).]

dalesvp
10-12-2005, 04:10 PM
I haven't yet tried to make my own casting sand but all your suggestions will be taken into consideration. You could try cold pressed castor oil as it does not smoke even when used as a cutting oil. It does cost more than cheap but smokey motor oils.....

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