I'm afraid to even ask, because of how many possible carbon limb questions this might spawn.

I remember a thread a while back and someone posted a picture of a bow, I believe a one piece with a foam core, and IIRC it was not one of the full-time professional guys. Meaning, obviously someone sells this stuff. I can;t imagine bowyers are making it it seems like it wouold be some super high tech, highly controlled process.

Someone help a guy out.

Maybe you could call/email a bowyer that uses the stuff and buy some?

I know Bigfoot Bows (Kirkll) and Eaglwing Bows (Sixby) use the stuff.

syntactic foam comes in lots of variations.
Not sure what type is best or even works in a bow limb.

I found this place that at least sells strips instead of selling it in blocks...bet you'll have to buy a lot of it though...
   http://www.trelleborg.com/en/Offshore-Boston/Products--Solutions/Thermal-Insulation-Tape/

Here are a couple other places....
http://www.crg-industries.com/advantic.htm

http://www.synfoam.com/SynFoamPI.html

turns out CRG-industries supplies morrison archery ...

Dale Stahl carries it...

Surprisingly dense stuff isn't it?
The "stronger" stuff from crg is 40.5 lb/cu. ft.
That's about the same as walnut I believe.

...now the lighter stuff at 31.2 lb/cu. ft. is pretty light...but sounds a little weak to me....

Yeah I think you're right. Makes me think it's not worth the trouble over walnut or maple or something like that.

Not real sure but The Old Master Crafter may have it, they seem to supply quite a few bowyers.  I haven't used them in a few years but, they always had good quality lams and riser woods.

Well I suppose it might depend on your reasons for wanting to try it.

Might make a difference if you're making a really deep cored bow.

Maybe you want to use all manmade materials just for fun or in hopes weather/humidity won't effect the bow..?

Or maybe you just want to use foam just to do it.

I doubt it will turn a bow into a super bow...but it would be fun to try...

I know John at O.M.C. has some. PM me if you need more info. I should see him tomorrow night