What glass? 40 or 50?

[Appalachian Hillbilly]

Is there a rule of thumb for when to use which thickness glass on the  back and belly?

Getting an order ready for glass and supplies to start my limbs with.

[Crooked Stic]

Most of my bows are between 40-50 lbs. I use .040. Even up to high 50s

[Noah70]

Totally agree, .040 gets you a wide range.

[TradBowyer]

My rule of thumb was 040 up to 60lbs...then 050. Experimented some on using 040 for back and 050 for belly

[Jeff Freeman]

I use .040 on the back and .050 on the belly. I believe it gives more uumf this way and helps a straight longbow from taking to much set. That's only with Gordon Glass , other glass manufacturers not good. IMO. JF