In my Google surfing adventures I learned a little bit from a lot of different sources and then adapted it to fit what we are making. You should be able to do this pretty easily too. Here are some specs.
This is my feeder: http://shop.wbu.com/p/wbu-large-cylinder-feeder?pp=12
This is the seed block: http://shop.wbu.com/p/large-supreme-seed-cylinder/specialty-bird-feeders
The block is a 6" diameter x 7-3/4" tall cylinder with a 1" hole in the middle... probably so you can place it on a feeder with a dowel.
I read a few posts online and learned a bit about how other folks have tried to home-brew bird seed blocks:
A Birdseed Wreath: http://www.todayshomeowner.com/how-to-make-a-bird-seed-wreath/
Another wreath: http://www.thegardenroofcoop.com/2012/12/birdseed-wreaths.html
Some small blocks: http://www.themakeyourownzone.com/2013/11/recipes-diy-birdseed-cakes.html
Nothing about making BIG BLOCKS like I need.
The common thread in all these recipes is that you just need some gelatin, a mold, and a bunch of seed. It's not really rocket science.
But... what can I use for a mold to make a 6" x 8" round cylinder. BOOM.. then I saw it at Home Depot when I was working on some plumbing problems.
A 6" x 24" PVC Pipe!! http://www.homedepot.com/p/VPC-6-in-x-2-ft-PVC-SDR-35-Riser-Pipe-6006-2/202564459
I bought it, and then chopped it into three 8" long pieces. That took about 5 minutes on my table saw. It too longer to cleanup all the little white chips from the saw blade that got everywhere! UGH. While I had the saw out I decided to chop up the handle from an old rusty rake that I got for free at a yard sale to form the middle hole.
So here is the recipe to make a WBU-Style Birdseed Cylinder:
14 cups of birdseed. (my blend weighed about 4-1/2lbs)
3 cups water
8 1/4oz packets unflavored gelatin (2oz total)
1. Combine the water & gelatin in a pan. Heat to about 160°F to dissolve and active the gelatin.
2. Meanwhile put your seeds in a giant bowl and mix together as you wish.
3. When the gelatin is up to temperature pour it onto the seeds in the bowl and stir to coat every seed with the liquid gelatin.
4. Spray the inside of your PVC Cylinder with some PAM spray cooking oil so the block will slide out easier when it is set.
5. Place a cylinder on a cookie sheet (I used a toaster oven sized one to fit in the fridge) and pack about 3-4" of seed in the bottom of the cylinder. Tamp it down to pack tightly and jam the dowel in the middle. Re-tamp so the seeds will hold it up. Then fill cylinder with the rest of the seed-gelatin mixture. Tamp down every 2-3" so it will all fit. Place in the fridge for a day or two to set the gelatin.
6. After a day or two in the fridge you can remove it and un-mold the seeds from the cylinder. I made my dowel 12" long so it could function as a handle to assist in the un-molding.
7. Now you need to air-dry the block to remove the moisture and harden the gelatin. How long this takes depends on your environmental conditions. I live in Arizona... so I just set it in the garage and pointed a fan at it.
Tips: You want the thing to dry out as quickly as possible to prevent mold growth. A nice warm dry place with alot of moving air is great. A cool dry place is ok, but put a fan on it and turn it a couple times a day. The dowel hole helps air get to the insides too.
Don't use your oven to dry the block. The heat will just melt the gelatin and you will have a loose pile of crumbly seeds. Maybe a giant fruit dehydrator would work. My garage is a giant fruit dehydrator in the AZ Summers. Your mileage may vary.
You can make these ANY size you want, and use ANY kind of mold... think Tupperware or Bundt Pan. Using the recipe I provided the seed-gelatin mix should be nice and coated, but not sopping in excess liquid. Use about 1/3 cup of water for each 1/4 oz gelatin packet for every 1-3/4 cup of seeds. Fill your favorite mold with loose seeds. Measure how many seeds that took and then calculate how much water & gelatin you need.
Doesn't matter what kind you use. You can blend different ones together. The birds will eat whatever you put out there. I am providing a recipe chart so you can scale your batch to fit your mold volume. Don't get scared... it's 5th grade math. You can do it, or go ask your kid.
