bentonite clay

Supplier information and Creative Rummaging
bobbydigital
Posts: 15
Joined: Thu Sep 20, 2012 7:33 pm

bentonite clay

Post by bobbydigital »

i have approx 100 lbs bentonite clay that i dont need due a recent purchase of petrobond that someone can have for free if theyre near st augustine florida or i can mail some to anyone for some postage or a trade of some sort of whatever
F.C.
Posts: 560
Joined: Sat Jun 04, 2011 10:28 am

Re: bentonite clay

Post by F.C. »

I'd hang onto it... experiment with creating a variety of green sand mixes to see if you can outdo your petrobond sand's ability to draw detail. I can reproduce a finger print smudge on a wax pattern with my green sand mix. 5% bentonite, 5% water, 5% corn flour (each by volume to the sand ratio). Sand mix: 80 grit (1/2), 120 grit (1/2). It packs well, has tremendous green strength, too. Plus, it'd be a good back up sand if you're doing something repetitive and need to produce a volume of product.
bobbydigital
Posts: 15
Joined: Thu Sep 20, 2012 7:33 pm

Re: bentonite clay

Post by bobbydigital »

ill think about it but i doubt it,im looking forward to getting rid of my greensand in favor of the petrobond ive been trying to get my sand right for a couple of months now,ive even built a small muller to help mix it more evenly and its not really helping any except its a lot less work and time for me to make up a bunch of crappy moulding sand sand,lol,right now im using 10 percent bentonite and 7 percent water by weight to sand that i get out of my backyard here near the beach in florida and its terrible,i wish i gould get some 120 grit sand but i cant find anything except home depot sand and it leaves a terrible finish probally about 60 to 80 grit do ya know anybody thats used the petrobondforsale website?
Rasper
Posts: 628
Joined: Sun Aug 07, 2011 4:05 pm
Location: Huatulco, Oaxaca, Mexico
Contact:

Re: bentonite clay

Post by Rasper »

Get sand blasting sand from a place that sells industrial stuff to shipyards, metal fabrication shops, bridge painting companies. Jacksonville will have a bunch of them if you can't find one there. I don't remember what mesh sizes of sand are available as it's been a few years since I bought any, but they have a variety. It's clean, sized, and packaged in paper sacks.

Richard
Silverforge
Posts: 40
Joined: Mon Sep 10, 2012 12:21 pm

Re: bentonite clay

Post by Silverforge »

I would like to see the inside of that muller! So how did you grind all the bentonite? Or did you get "Bentonite"?
dallen
Posts: 2321
Joined: Sat Jun 04, 2011 9:06 am
Location: Oklahoma

Re: bentonite clay

Post by dallen »

this is what you want to look for

Image
David and Charlie aka the shop monster

If life seems normal your not going fast enough" Mario Andrette
bobbydigital
Posts: 15
Joined: Thu Sep 20, 2012 7:33 pm

Re: bentonite clay

Post by bobbydigital »

,i have had really good luck grinding up kitty litter,anyone that says that dosent workj is just using the wrong kind,i got the bentonite by accident from a ceramics place i only wanted a little bit but the guy gave me 2 50 lb bags and im probally not going to use it now ive tried to mix greensand up before about 5 years ago and made a big mess after this attempt im ready to give up,lol,ive seen so many people getting awesome finishes with the greensand that i decided to try it again now that im getting back into casting after taking about ten years off lol ,ive just ordered 100 lbs petrobond from petrobondforsale and cant wait for it to arrive im totally frustrated with my attempts to mix this silly sand
volcom7114
Posts: 17
Joined: Tue Oct 22, 2013 7:50 pm

Re: bentonite clay

Post by volcom7114 »

Hello all im new to the foundry stuff but i understand it well and have done a lot of looking around. I like to buy as much as I can locally so i called around and found a well drilling company that had bentonite clay it says granular but its not it is in powder form and i paid 20 bucks for 50lb bag..

may i ask what mesh of sand would be best to use for green sand ?

thanks Dennis
Attachments
bentonite clay.JPG
User avatar
Jammer
Posts: 1488
Joined: Thu Jun 02, 2011 4:04 pm
Location: Ohio

Re: bentonite clay

Post by Jammer »

Welcome Dennis, good to have you on board. What part of the world are you from?

I think Frank answered your question in another post, 50/50 80 and 120 grit. I believe about 7 to 10% Bentonite is the correct amount. I went by weight, 100 pounds of sand and 8 pounds of Bentonite. Add water very sparingly, it doesn't take much.
quando omni flunkus moritati 8-)
F.C.
Posts: 560
Joined: Sat Jun 04, 2011 10:28 am

Re: bentonite clay

Post by F.C. »

ABSOLUTELY NOT!!! No more than 5% bentonite, no less than 3% on the low end. And as for water, use the same ratio... 5% being the MAXIMUM. Sand from the beach "IS NOT" the same as sandblasting sand. You need sharp shard crystaline silica sand. Beach sand has round grain structure to each crystal, it won't pack for shit. It's like try'n to pack a box full of bird shot with clay bentonite as a binder. Also, beach sand is a compilation of a shit load of other rock materials, most of which will not react well with molten metal. That crap won't work for casting,it has granular crustacian shell fragments in it and it's also saturated with salt. You may as well be pouring your metal in the dirt in your back yard. It's no wonder you've had such a headache try'n to make yourself a green sand mix and the product you've cast no doubt didn't fare well either. Either go to the library and check out "All you need to know about casting metal" (it's a thin pocket book with all you need to know to get started) or read through the threads on this forum to learn how to make a proper mix. I've been preaching how to make a sand mix since I became a member here and it astounds the hell out of me so few of you will even attempt it. Yall act like petrobond is the holy grail and y'all invest wads of moolah to get your hands on it.. HAHAHA.... If you can't get your head around how to make a decent green sand mix you're not going to understand how petrobond works either. You'll no doubt dump shit into that mix eventually think'n there's something wrong with it, too. :lol: :lol: Petrobond sand has to be maintained just like green sand... fair warning. And it ain't cheap. But hey, it's your money and time wasted. Have fun. :D
Post Reply