Are aggregate/soil washers worth the $$?

[dirtmonger]

We've been running a small soil lab for 6 years. Recently pondered the installation of a small aggregate washer. Before now, our soil wash has been done manually in a deep frame No. 200 sieve with rapid result. A demonstration of one washing-unit had such slow results I'm left to wonder if the $1000 price tag is worth it! Has anyone else found good reason to use this type of unit? Does anyone find soil washing happiness with the particular model they're currently using? Our test samples vary greatly, from dense clays to coarse sands/gravels, with sample sizes 200 to 500g.

Any info would be great. Thanks!

 

[dirtsqueezer]

Well, I remember having a tiff with a local firm that had one of those. They were getting a high silt/clay content and ours were in spec. The deciding factor was that they had an auto washer, and the reason was that it is thought that there is some breakdown of the aggregate if the wash is left in too long, or also if you have delicate aggregate- I imagine pumice or, say, high mica content. We didn't worry about our results because of that, and I've always thought that hand wash is a better way to go. It's probably fine for most aggregates, but 200 washes don't take that much time anyway. I'd just stick with what you got.