We’ve had a few questions as to how we closed our sandbags after filling them with scoria, so here are a few photos we hope will help.
We generally used two 2-1/2″ nails to close the bags, folding the ends like an envelope.
A note about the nails, at first we used Dipped Galvanized, which was a pain because the majority of nails in a 5 pound box didn’t have sharp pointed tips, some were like duck bills which made pushing them through the bags a nightmare. We ended up using “Bright Common” box nails, which seemed like a dream afterward. And stay away from “Big Box” stores when buying your nails. Mom & Pop hardware stores often sell them in bulk for a lot less.
Sometimes we used three 2-1/2″ nails if the folds didn’t seem like they were going to stay closed, or if we added a bit more scoria than the previous bags. Even though the 3/4″ scoria was mostly the same size, there were times when digging through the pile we came across larger and smaller pieces, so we had to compensate. The average amount of scoria per bag was about 7 gallons. (Your amount may differ).
We folded in the bottom of the bags before we filled them. (You don’t have to turn the bag inside out to do it). You place your right hand inside the bottom of the bag to catch the corner as your left thumb pushes it in. Try it a few times… you’ll get the hang of it.
Before we actually started building, we tested out a few bags by filling them with scoria, and then built a form that would make the bags uniform in size.
The form was made out of scrap 1″ x 6″ with the back and sides as one piece. The front panel was removable and held into place using two C-clamps. Once we filled the bag and closed it with nails, we removed the C-clamps and dropped the front panel down, which allowed the filled bag to lay flat… and this made it easier to pick up. The bags weighed an average of 40-50 lb each.
Since we didn’t have scaffolding, we filled the bags on the back bed of the truck as we got higher in the building process. We still had to heave the bags into place, which was tricky when you have a height of 17′, but it’s doable… and you’ll have a great set of biceps after you’re finished.
Here was the first bagging station we used for the first 40 cubic yards of scoria. We actually sifted the scoria before we filled the bags, because the scoria we had delivered had a lot of dust in it, and we were concerned that this would inhibit the insulation property. But we discovered that this took too much time if we were going to finish before the first snow. Insulation is only good if the building is closed… so after the second scoria delivery, we just filled the bags directly. We ended up filling a lot more bags faster by doing it this way.
Also notice our “Frankentamper” in the photo. We used a yogurt container for the cement mold which fit inside the form beautifully. This one tamper (along with a lot of Gorilla Tape) lasted through 2000 bags. (We plan on donating it to the Smithsonian.)
If we were going to do it again, we would have made three or four tampers beforehand since making another one would have broke our rhythm, and at the end of the day we could barely make dinner let alone a new tamper.
Note: We found out just in the nick of time before ordering that here in Montana scoria is a non-porous stone completely different from lava rock. So when you order your scoria, make sure it is what you think it is. Here in Montana, scoria and lava rock are two different beasts.