I used all my sand for the first time in a year. The last 2 pails we mulled seemed heavy .....like cement heavy on the clay the other 4 pails where fine. ....does the clay settle when it sits in a large container over time. Thanks Todd
Curious as to what the answer to this question is too. I only have about 40# of green sand and that's a single small concrete mixer load for me. This had been out in the garage for 6 months and came back to life with mulling with a small rock and a few spritzes of water.
The sand/clay mixture would be exactly the same as when you put it in there. Moisture might be different, and if the moisture has dried out of it it could certainly harden up like a rock but the clay hasn’t moved. Busting it up and getting the moisture back into it in the muller should do the trick. Since you’re pouring iron you’re giving the sand that’s in regular circulation a pretty good beating, so the unused stuff will feel different for sure. That regularly used stuff will get the clay burnt out of it and the sand ground up from burning and mulling eventually, especially if your mixing the really burnt sand back into your heap. There’s nothing wrong with that but it will deplete your sand eventually. So yeah, the sand that’s been sitting idle might feel different, but it’s composition hasn’t changed. Dry materials like refractory in bags can settle the fines out through vibration during transport and handling, so it’s been recommended to me that the whole bag be premixed dry before wetting it, but that’s a different matter. Pete
The last sand most likely needs to sit 3-4 hours after the mulling. The sand will feel heavy or wet because the clay needs time to absorb the water. Let the sand sit awhile then mull it again, if the water is around 4% the sand should be very nice.
Usually it dries out and becomes lighter. Is it possible that it absorbed moisture somehow? If it is considerably heavier then that is most likely what has happened. It might just be the sand you use on the reg is fluffier and you have more volume in the old more condensed batch.
The green sand was settling and compressed from the weight of the sand above it. For the same reason road engineers pile up dirt for an embankment higher than needed and then remove the top layer after it's sat for several months to settle. Gravity and time handles the compaction.
