Casting sand

[Tobho Mott]

Capilano college used to have a casting program but closed it down in about 2013. They sold off their muller and a local fellow here bought it. When he picked it up the fellow on the loading dock said "That has to go too". He said it was petrobond and there were 20 or 30 20kg sacks of it. I got 2 of them but I am still trying to figure out what it is. The bags are deteriorated but it says "Hy-Bond" on the front and "A Hy-Bond product" from a company called Fairy and Co. in Surrey on the back in smaller print. Of course they have long gone out of business. I talked to a fellow at Greenbarn pottery in Surrey who said he worked for Dave Fairy when he was a student 30 years ago. He knew nothing about casting but said they had a whole line of products that went under the generic brand of Hy-Bond. He said they had several products where they bought the raw material in large quantities and repackaged in smaller bags. It is a pale yellow and if there is sand in it it is extremely fine (to the point where I think it is a straight clay product). I have a bit of bentonite from a pottery shop and it does not act at all like this stuff. Bentonite with water forms a thick slippery paste. This stuff does not mix with water at all and just settles out. I tried Varsol and 10 weight non detergent oil but neither mixed or dissolved the clay. If anybody knows anything about this stuff I would love to hear about it. I tried to track down a fellow that knew quite a bit about the Capilano course but he did not respond to my email.

Brian

I really meant to come.back to this thread sooner! Sorry. I hope late is better than never...

Do you think you might have the organoclay binder that can be used to make oil bonded sand? If so that is something I've been hunting for, for a few years. Nobody wants to sell me less than a pallet of the stuff.

Denis Foster (makes cast iron straight edges, I know him better as melterskelter from the home foundry forums) did some interesting comparisons between western bentonite, southern bentonite, and bentone organoclay mixed with oil, water, and both. Perhaps his results will help you figure out what you have:

Identifying bentone vs bentonite based on physical charecteristics.

Background: In another thread (http://forums.thehomefoundry.org/index.php?threads/mixing-up-k-bond-sand-similar-to-petrobond.1759/) on mixing K-Bond...

forums.thehomefoundry.org

Good luck!

Jeff

 

[bhowden]

When I first got the clay I was very hopeful that it would be suitable for oil bonded sand as the loading dock guy referred to it as petrobond but I am pretty sure it is not. I have run the tests you linked and it does not act at all like either form of bentonite. My best guess at the moment is that it is some sort of refractory clay for repairing a furnace.

Brian

 

[TonyK]

Sand casting. Interesting stuff. My first question is how desperate are you and how much money do you have to spend. Take a look at Princess Auto https://www.princessauto.com/en/petro-bond-casting-sand/product/PA0009028150 Expensive but, so is everything these days. Ten pounds $100 that is a bit nuts. I have purchased it from a place in Milton Ontario years ago ( 11 years ). 50 LBS with tax and delivery $200.

First Petro bond sand can be used for aluminum and brass but cannot be used for steel. Sand for steel uses Bentonite and a bit of water due to the high heat of the metal to be poured. Petro Bond sand uses a clay called Bentone and it is a redish brown colour. It can be reused but you have 2 choices when the metal is poured the oil burns off and the sand becomes black and dry. Once the part has been removed you can discard the black sand or it needs to be reconditioned. Meaning you need to add more clay and oil to that sand to allow you to reuse it. It also must be sifted. I purchased 20 pounds of Bentone from a fellow in New Jersey and the Synthetic oil ( see attached picture )from Walmart in the USA and still have half a gallon.

As for smoke, don't open the mold until it cools, depending on how big the part is, well, it may be the next day. Here is a video I did years ago

If the link will not open then go to my channel, go to YouTube and search for fiatx192040 and search title for Home Metal Casting the Heat. I am casting an aluminum hammer form that weighs about 15 pounds. The video is only 3 minutes. It is only the pour not opening the mold.

Here is a more detailed video of the sand casting process done in my shop.

Flask's can be made of wood providing that you have at least 1" of sand between the part and the side of the wooden flask. If not, then it will burn. Also large parts the aluminum tends to lift the parting lines of the flasks, so they should always be wired together to prevent this from happening. If you forget then the flask separates and the molten aluminum dribbles down the side of the flask and catches fire.

Also it should be noted that to activate petro bond sand after it has sat for a while it needs to be dribbled with white gas or naphtha camp fuel. This causes the oil in the sand to become sticky. When the sand is mixed, mulled or beaten, when you run a gardening shovel backwards through it, it should appear to look like cookie dough. Grasp a handful and compress it in your hand now break it in half. If it breaks cleanly without crumbling you are good to go.

TonyK.

Grimsby Ontario Canada

 

[Tobho Mott]

Nice setup. I have some casting videos up on YouTube also.

FYI Tim Smelko retired since you bought your sand, so the Smelko Foundry Products in Milton you knew is now called Foundry Supply Source, and they've also moved to a new address. Still in Milton though. I have an email from almost exactly 2 years ago with a quote in it - at the time they were selling petrobond for $155 per 25kg bag, before tax or shipping. But I understand it's gone up by at least $30 per bag since then. Last time I was there, hobbyists with cash in hand who'd called ahead to set up a visit didn't pay tax. I'm making a run there next Friday to get ingredients for cast iron rated greensand and some ferrosilicon inoculant. Their petrobond is pricey but it's a good deal, especially compared to the tiny tubs from princess auto. Petrobondforsale on eBay would be a little cheaper if it weren't for the border crossing involved (not to open that can of worms). If they would sell the binder for petrobond separately I'd be very happy, but they only import it pre-mulled.

The real P1 catalyst is propylene carbonate. I have most of a 5 gallon bucket of the stuff, but I usually just use a couple spritzes of methyl hydrate in the muller to reactivate mine instead. It's easier to get locally and if I spray in a little too much then excess will evaporate out before long and I can save my P.C., which doesn't evaporate out, for making new K-bond sand (homemade petrobond if. I can ever get my hands on the binder) or for mixing up core sand, since it's also a catalyst for sodium silicate binder. Using camp fuel for the catalyst is a new one on me, but if it works it works. Apparently there are a bunch of things that will work. High percentage isopropyl alcohol is another popular choice.

Jeff