Looking for info on Sodium Silicate Mold/Core Washes for Cast Iron

PatJ,
I am absolutely on board with the hardener vs CO2. For the last couple days I have been trying to run down some propylene carbonate locally rather than order some from a thousand miles or more away. But looks like I will have to just be patient---not my strongest suit.

And thanks for all the good info above. I will get this nut cracked somehow. Your input is a big help.

Denis

 

PatJ,
I think the hardener that I (we) want is Diacetin otherwise known as glycerol diacetate. The commercial products listed as diacetin are really made up of a mixture of mostly diacetate, but also mono and tri acetates. Actually getting some in a reasonable time and at reasonable cost may be a challenge. I live on the wrong side of the continent and am purchasing in too small quantities for that it seems. I have located a source of propylene carbonate in Portland located about 250 miles from me. I may be able to get it here through a connection with someone who commutes to Portland. That would be a good start, but since it is not a true catalyst, as cold weather approaches its reactivity will slow form already marginal to too slow I fear. So, its utility may not be all that great for me since I mold in an unheated barn. Not likely to see very much in the way of freezing temps but plenty of time in the 40 and 50 range. It sounds like the esters concentration like diacetin will be adjustable to compensate for lower temperatures.

https://www.alfa.com/en/catalog/L12708/

One thing I read in a post not on AA or THF was that Portland Cement will mixed in small amounts with SS will cause rapid hardening of the SS. That sounded very attractive as an alternative. Only thing is....it does not work. I ran down to the local hardware store and bought a 94 pound bag of fresh portland cement and gave it a whirl. Even mixing it two volumes of PC with one of SS caused no setting whatsoever. Either I am doing something very wrong or the poster was full of it. Anyone need 93.75 pounds of portland cement? Free pickup. ;-)

Kelly,

You got a couple of the motivations and another one is to see how much effect if any making a mold with the lowest possible (short of lost wax) thermal mass will have on relatively thin-walled CI casting hardness. This is not something I could find having been done before. I want to try it out. The castings I make are finished using hand tools, so softness is a desirable feature.

Denis

 

That is the problem with foundry information that you find in general across the web; half the people know exactly what they are talking about, and half of them are full of something, and you have to be able to differentiate between the two somehow.

Someone mentioned that the folks here seem to be the more experienced crowd who generally have been casting for a pretty long time. I would agree; the folks here have a lot of depth, and that can be very helpful, especially when you are having problems.

 

Here is an interesting paper on using di and tri acetates for curing sodium silicates. Loks like the curing times were in the hours range and not necessarily minutes.

http://www.imerys-additivesformetal...No-Bake-Sodium-Silicate-Binder-Systems_EN.pdf

I am still working on finding a nearby reasonable source of diacetin or similar.

Denis