I don't know what a seed sieve is but I have been collecting large quantities of seed for many years without one. Presumably the sieve allows the seed to fall through and leaves the chaff behind? Seed is heavier than the chaff and I find that by using a shallow container the seed sits on the bottom and I can either blow or pick the chaff off the top. The resultant seed is clean enough for acceptance by the societies that I donate to.

Thanks Bulbaholic.
Yes, up to now I have used the "winnowing" technique but it's not 100% effective. I just fancy trying the sieve for certain types of seed. I joined the Cottage Garden Society a few years ago and I contribute to their seed exchange. They don't like any chaff! And I like new techniques and gadgets!
Any ideas of where I can buy one?

Googling gave leads for seed sieve - most were in Australia and the States and cost $200 or more for EACH SIEVE, but I did find this one in the UK.
http://www.gardening-naturally.com/acatalog/Seed_Tray_Sieve.html
It costs £6.98 and has 2 interchangeable screens, but I think it might be for sifting compost for seed trays as the mesh sizes seem rather big.

I reckon Bulbaholic's method is the best, for price and effectiveness.

Same as Beattie I am afraid Steve, My searches took me to the USA and $190.00. Or huge agricultural machines.
But thinking back to my school days...We used lots of fine sieves in the science lab. Maybe you should look in that direction...Or ask your Society Members what they do....Then get back and tell us.

Thanks Beattie and Pimpernel. Still no luck so I have written to the RHS. The sieve I am looking for is featured on page 151 of their book Propagating Plants! If I find one I will post the supplier on the forum as suggested.

try making one SS! Or find someone who can if your not practical in that way. Theres lots of different gauges of meshes available...the rest should be easy. You could make a quadruple stacker!

Hi Pajo. I did think of that but not confident it would be good enough! If I can find one it will become a family heirloom!