Core Binders

Home enthusiasts discuss their Foundry & Casting work.

Moderator: Harold_V

User avatar
Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Core Binders

Post by Pipescs »

Furnace is not running lately due to traveling with work.

While I was home last week I made time to do a core box out of plaster to make the cores for my journal boxes.

While the core molds out plaster of paris came out usable the attempt at making a core with Sodium Silicate as the Binder was a flop all three times. This was a bummer as I had seen it work fine with a friends furnace. My problem turned out to be the fact that I could not get a consistant flow of CO2 through out the core sand.


Arriving back here in Maryland on Monday i drove over to the Lancaster Foundry Supply to buy Bronze ingots. In the discussion I ended up buying a two part core binder called ALpHaSET (Spelled that way with Caps) It is a two part binder with variable set times based on the Catalist used. This was originaly recommeded by Benjamin at the Cat Tail Foundry.


Trouble is the product has a fairly short shelf Life. for that reason I bought the smallest kit.

So my question becomes, what are other core binder systems or methods besides the sodium silicate that are out there?
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
User avatar
steamin10
Posts: 6712
Joined: Sun Jun 08, 2003 11:52 pm
Location: NW Indiana. Close to Lake Michigan S. tip

Re: Core Binders

Post by steamin10 »

Sure. You can use sugar, which is normally molasses and bake it dry like a cookie. The casting heat will burn it off enough that it will decayand shake out. Another answer is to use linseed oil, adding just enough to get it to stick together when squeezed by hand. These are baked to set them, but mom wont like the paint smell in her oven. Very traditional.

Your silicate cores can be set by putting them in a warm oven, where they will skin pretty quickly with the CO2 from the oven. They should need just a bit of CO2 from a paint ball cylinder or other source, I find it best to let them set in a tight box, like that for office paper, and flood the box with gas and let it sit, to cure. A plastic trash bag is a good trick too.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
tomc
Posts: 375
Joined: Sun Oct 16, 2005 7:04 pm
Location: Sw of the Windy City

Re: Core Binders

Post by tomc »

How thick are your cores? We got a tank and made a lance out of copper that would work with our regulator and just squirt the co2 into a plastic bag held around the wand and it hardens up like a rock in seconds. We made round & square cores for our journal boxes and pedistals in 3 3/4 scale whick should be bigger that yours. I think our next batch will be made with a plastic box with a lid and a small hole to put the lance in.

Tom C.
tom_at_srclry_com
A student of the Southend RGS!
User avatar
Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: Core Binders

Post by Pipescs »

Can Sodium Silicate go bad?

Fenders efforts produced hard cores almost instantly. Mine atbest were soft even when the CO2 applied
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
tomc
Posts: 375
Joined: Sun Oct 16, 2005 7:04 pm
Location: Sw of the Windy City

Re: Core Binders

Post by tomc »

Interesting question. I don't know. try google.

Tom C.
tom_at_srclry_com
A student of the Southend RGS!
RONALD
Posts: 754
Joined: Sun Oct 26, 2003 7:27 am

Re: Core Binders

Post by RONALD »

tomc
Posts: 375
Joined: Sun Oct 16, 2005 7:04 pm
Location: Sw of the Windy City

Re: Core Binders

Post by tomc »

So from that topic i gather it doesn't go old. What type/kind of sand are you using and what mix percentage?

Tom C.
tom_at_srclry_com
A student of the Southend RGS!
User avatar
Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: Core Binders

Post by Pipescs »

Not to scientific.

Play sand for 3.00 a bag and the mix by weight on the can from Budget Casting.
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
User avatar
steamin10
Posts: 6712
Joined: Sun Jun 08, 2003 11:52 pm
Location: NW Indiana. Close to Lake Michigan S. tip

Re: Core Binders

Post by steamin10 »

Um, when you say play sand, soemtimes it is pebbly, like what is called torpedo sand for mixing mortar. I found this grade too big and unsuitable for molding. I am only guessing here. White silica is used in swim pool filters, and is available at most big box home stores as filter sand, or blasting sand, and is quite cheap.

I use white silica, ( in my area we have bank sand, or beach sand similar to the sand on the Shores of Lake Michigan). White silica will be of fine grade and sharp, not wave tossed and rounded, which operates better for founding purposes. A grade #80 is plenty fine enough. Keep it cheap, because we normally throw out core material, by sifting through a 1/4 inch mesh vibrating screen, that allows all the synthetic sand through, and catches only the gravely pieces of the coremold materials for disposal. Anyting smaller will not present a huge problem as the material is mulled and reconditioned, it will grind up, and decompose into the base stock.

Yes, sodium silicate is a water based agent, and can react with co2 from the air and get skinned or crystalize, if not tightly sealed. I have been using a military engine sealer, bought surplus and have had no problems, but the can is years old, and rusting out from the outside. The seal is now questionable, because of forcing the sticky lid, like a paint thinner screw cap. Waxing the threads with auto wax helps some, but seems to promote rust. It will be transfered to a food grade lalstic container from the dollar store, for further storage, but anything plastic, will have a shorter life because of the compromises in the plastic itself when manufactured.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
User avatar
Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: Core Binders

Post by Pipescs »

Thanks for all the input. I am going home by way of Dallas and should be home by the first of Sept.
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
User avatar
Pipescs
Posts: 2194
Joined: Wed Feb 03, 2010 10:16 pm
Location: Lester Alabama

Re: Core Binders

Post by Pipescs »

Spent the weekend with Fender learnig about green sand composition, pattern making and casting with aluminum.

The effort on Fenders sand makes me believe that I have mixed the wrong sand with too much binder. I believe I have not left enough air space for the gas to permeate down thru the sand to set off the binder.

More experimenting when I get home
Charlie Pipes
Mid-South Live Steamers


Current Projects:

Scratch Built 3 3/4 scale 0-4-4 Forney
Little Engines American
20 Ton Shay (Castings and Plans Purchased for future)
User avatar
steamin10
Posts: 6712
Joined: Sun Jun 08, 2003 11:52 pm
Location: NW Indiana. Close to Lake Michigan S. tip

Re: Core Binders

Post by steamin10 »

A buddy with experience to provide vistas in what works, is the traditional student/professor, master/apprentice relations. You are very lucky to have such a partner to be shown his style of working.

Kudos to you both, for sharing resources and knowledge.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
We have enough youth, how about a fountain of Smart. My computer beat me at chess, but not kickboxing
It is not getting caught in the rain, its learning to dance in it. People saying good morning, should have to prove it.
Post Reply