# How to re-hydrate PetroBond?



## Inflight (Mar 20, 2013)

I have about 75 lbs of PetroBond (oil sand) for casting aluminum that hasn't been used in about a year.  I store the sand in open 5 gal buckets in my shop.  Today when I tried to ram up a mold, the sand was obviously too dry and falling apart so I added a little water, then mulled the sand by hand.  My next pour was a bit of a disaster since i failed to properly vent and I even neglected to secure the cope & drag together.  So the result was a steaming blowout at the parting line and some burned lawn. :whistle:

Ok, I went on to make a couple more pours that were more successful but this leads me to my question.  How do you home foundry-men re-hydrate your oil based casting sand without the use of a power muller?  Is water acceptable?


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## xalky (Mar 21, 2013)

Check this out, It might have the info your looking for.

http://www.alloyavenue.com/vb/archive/index.php/t-2785.html?


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## Pacer (Mar 21, 2013)

I have had my petrobond for some 8-10 yrs and can sometimes go for months (yrs?) without using - I do keep it in a "dedicated" sand box with a tarp over to help in maintaining it, and, it maintains well. I keep a common squirt bottle with a mix of Ethanol and 2 stroke oil in it along with the other supplies in the cabinet. I just guess at the mix, but probably something like 6-8 ethanol to 1 oil. I have one of those 'claw' gardening tools that I have in one hand mixing/clawing and the squirt bottle in the other and "mull" the mix until it 'feels' right. (dont you love all these precision directions)) I also sometimes use the squirt bottle to "skeench" (another technical word) the edges of the pattern before lifting, seems to help with the edges breaking. This is no doubt a hold over from using green sand.


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## oldgoaly (Mar 23, 2013)

Second the use of two stroke oil, over the years I have had to add a small amount of oil ever couple of years. I've  used the mixer works better than the muller for adding oil, but the muller is much better at reviving the sand after pouring.  tt


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