Sifting, Sieving, Screening

“A good archaeologist can use anything, right?” – Roddy Regan

I received an email from “focus design” the other day, containing an advertisement for 21st Century Sifting Screens.  For the lucky readers who haven’t spent a few 100+ degree days mashing dried clay through 1/8th inch mesh, archaeologists generally push the dirt that they dig up through a screen, just to be sure that they haven’t missed any artifacts.  The amount of dirt that gets pushed through the screen and the size of the screen is determined by your research goals.  This work is done by a range of people, sometimes hired workmen (in the case of Catal), sometimes undergraduates, and sometimes, yourself.  I generally don’t mind screening (or sieving or sifting, depending on where you’re located geographically) if it is my own dirt–that is, dirt that I’ve excavated–but screening the dirt of other archaeologists is pretty tedious.  I’m sure that means something about my personality.

screen

Anyway, so the brochure shows features this fancy new screen made out of plastic.  It looks like a modified historic/California screen, which is a horrible contraption made out of wood.  I first encountered these things on the Cheney House dig, and have been just disgusted with the whole concept since.

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Basically, these things are built with one “leg” and a brace.  This makes them horribly unwieldy if you’re working by yourself, trying to heft 5 gallon buckets (that’s 19L for the metric folks) and pouring out the contents while balancing these damned things plus an artifact bag/bucket/whatever very often results in a lot of spilled dirt and cursing.  They’re not very well built either, and I’ve had to hammer them back together with the blunt end of a shovel more than once.  When you mention these points to any California or Historical archaeologist, they look at you like you have two heads.  That’s what they use and anything else is just weird.

Tripod screen, as seen in the foreground of this photo.

Tripod screen, as seen in the foreground of this photo.

Y’see, I was trained to use tripod screens.  These come in a lot of flavors, but I do recall hauling the heavy bastards out into the middle of the desert, along with a shovel and a bucket and all my paperwork and bags, setting up shop, digging, screening, then breaking down and moving to the next test pit.  They were made with three long metal poles, a big wood-walled screen, and a long length of chain that you used to hook each of the four corners of the screen.  Sure, sometimes the things collapsed, and as previously mentioned, they were heavy as sin, but once the thing was set up it was easy to dump buckets into it and you could walk away from a half-finished screen if something came up.  With the other screens, you were stuck unless you dumped the whole unfinished lot, which is, you see, completely unscientific.

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These are the screens that they use at Catal.  The umbrella is a nice touch, though I’m still undecided about the looped rope design holding the screen up vs. chains.  The looped rope restricts the movement of the screen–it’s harder to shake–and the screens are a lot smaller, so you can’t really dump a whole lot into them at once.  Still, anything is better than the stupid historic screens.

So, this 21st century design intrigues me.  I can’t help but look at the PVC and see it breaking after cooking for a few days in the Texas sun.  I also like the professional screener depicted in the brochure–clean clothes, garden gloves, and a silly floppy hat.  It’s like the undergraduates who come to the field with gardening trowels and safari clothes.  Cute, but a little useless.

sifter

I’m probably what qualifies as a tool nerd in archaeology.  Yes, as Roddy says, a good archaeologist can use anything, and believe me, I have.  Indeed, I’ll try just about anything…so if a 21st century screen comes my way, you know I’ll be fair and diligent in my review.  Hint hint.

9 responses to “Sifting, Sieving, Screening

  1. Aww, Laredo!! And a Siren site picture!!
    I saw one of those new fancy screens set up at the TAS meetings. It seems like an okay compromise on the 2-legged shaker screen vs. saw-horse stable screen. But it also seemed a bit flimsy. I couldn’t envision dumping a bunch of wet clay on it, or actually breaking up clods of dirt on it.
    Of course, all the screening I’ve done in the last few months is the little wooden handhelds we have. They have drawer pulls for handles and often have screws sticking out the sides. So that part reminds me of the tripods (the cuts). They’re heavy, but they hold up better than the plastic basin stack screens we used to use.
    Of course, in Belize we use screens made from metal dowels and have the workers cut forked stakes as the legs.

  2. Yeah, I forgot to mention saw-horse screens. We used those on the dig in Dallas.

    Did you see that they have a slot for holding your trowel?

    Those plastic basin screens were awful.

    Do you have any photos of the screens in Belize?

  3. I’ve used tripod screens before and really can’t stand them. I’m a big proponent of the rocker screens. I find them easier to use. Let gravity do the work, says I.

    Each to their own, though. I fully understand that we’re not necessarily doing the same sort of excavation. I typically don’t use 5 gallon buckets, for example.

  4. I’ve looked all over my pictures from Belize and I can’t find a good photo of the screens there. Weird.

  5. We have one of these at the Asian Art museum exhibit.

  6. Speaking as an undergrad student who did show up for her first week of field school in ‘safari clothes’ last year, I found myself chuckling along with you. I’ve only had experience with 2 kinds of dry screens: those on saw horses and wooden framed 1/4 inch screens over wheelbarrows, so I can’t say I like those historic screens you mentioned above. Looks unweildy.

  7. well…I realize this comment is about three years late, but…

    We used these fancy screens for the MSU Campus Archaeology excavations, and they are pretty great. First, they’re lightweight, and fold up nicely. Second, they can serve as a shaker screen, a la the wooden hinge screens, but then you can lock the screen in place and set it on four legs, making it more of a table screen. This lets you either dump dirt in without having to hold up the screen, or sort through your post-screening leftovers for artifacts. Then, unhinge again, and you can dump the excess dirt out.

    As for durability, they made it through three field schools worth of excavations, and small surveys without any breaking. You have to order replacement screens from the company, but the cost is minimal, and installing the screen is a breeze (and you don’t cut yourself on the mesh).

    But why not let a fun video do all the talking? http://vimeo.com/25564604

  8. Those 2-legged screens are much easier to use over a wheeled barrow. It can rest on top while you fill it with dirt. Using them without a wheelbarrow underneath would be very difficult and annoying indeed.

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