I've used EA-40 in a 1:1 ratio in the few bows I've made. Several of those are still operating wonderfully after 20 years. The 2A:1B ratio states it has better heat resistance (not a concern I don't think) and improved properties. Are the improvements applicable to bow performance and for those of you who have used 2:1, is the difference noticeable? Or is it a case of "better" must be better?
The thing about smooth on at least 1-1. Never more hardiner than resin. I always use little more resin. And my hotbox usually gets to 130. Have had only two bows in 20 + year delam. Pretty sure one was a dry fire.
I mix mine closer to 2:1 resin to hardener, and pretty much just eyeball it. With too much hardener it's got a yellow tone to it and the viscosity is thinner. When it's 2:1 or close to it, it mixes up white in color and lays down much nicer with a putty knife. I always spread both surfaces in an even thin coat before going in the form.
Another little trick I use is putting both parts in a paper cup, and pop it in a microwave for 10-15 seconds before mixing it. It mixes much better when it's warm and spreads easily with a putty knife.
I've had really good luck with smooth on over the years with very few issues. But I've never mixed mine 1:1 so I can't compare strength quality.
The wood will fail before the glue when mixed at either ratio as long as everything was prepped correctly. I started mixing 2:1 a few years ago because thats what guys on here were doing.
There wont be any performance difference though. Ive been playing around with core material and had some performance gains by using carbon behind the veneers and making tapered spectra-ply core lambs instead of bamboo.... nothing dramatic though. I think performance comes from design and usually that means sacrificing smoothness and forgiveness. The increase in weight per inch of draw is more dramatic in more extreme designs that I have made and I haven't found a way around it..... this has been my personal experience, there are alot more experienced guys on this thread that could verify or debunk, ultimately speed dosen't kill deer and my fastest builds aren't my favorite bows.