Text: 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 http://bbs.homeshopmachinist.net//Forum1/HTML/013817.html

See Also:

Source: