ASL form build for Newbie

[Goldxxx]

I’d like to build my first longbow in the ASL style. I figured it would get me started down the road with laminated fibreglass backed bows. I have .040 glass and Smooth-On. I plan on grinding my own laminations out of maple.
 I’m not trying to reinvent the wheel. I just purchased the Graf book on ASL bows and I found it a very good read.
 My question is…am I forced to build a straight flat form for my first ASL? From what I’ve read so far it’s taboo to use any fibreglass less than .050. If I build my first bow in the 45-50lb @28 range will I end up with massive string follow if I’m only using .040 on back and belly on a flat form?
 If I build a form with 1 or 2 inch backset will .040 be alright? And to build a backset form how do I calculate the curve of the upper and lower limb? Is there a standard way of marking out the bend towards the tips of the limb. Do you start so many inches from the fade outs where the taper starts and then gradually curve it every so many inches per limb length until it’s at 1 or 2 inches of backset.

[Longcruise]

Lots of questions in one post! 

am I forced to build a straight flat form for my first ASL?

No, and all the alternatives you list below this quote are acceptable and doable.  However, I would not suggest using any certain shape of form to ameliorate the possible effects of glass being too thin.  I haven't read Graf's book, but if he is suggesting staying with thicker glass then I'll say we are in the same camp.  You can easily use the .040 on the back, but go with the thicker on the belly.

Try to keep your glass to wood ratio at about 20% or a bit more to the glass with a bit more glass on the belly.  Set in a glass bow takes place in the wood core.  Specifically the wood under the belly glass.  The glass itself will not take set.  Some set is almost inevitable in an ASL but you do want to minimize it if you want to maintain performance consistent with the initial specs of the bow.

And to build a backset form how do I calculate the curve of the upper and lower limb? Is there a standard way of marking out the bend towards the tips of the limb. Do you start so many inches from the fade outs where the taper starts and then gradually curve it every so many inches per limb length until it’s at 1 or 2 inches of backset. 

All of the above.    Forms have been built in every way you might imagine.  Some in an arc through the entire length of the bow.  some with an arc starting at the ends of the riser.  Some with an arc starting a bit beyond the end.  Some with a continuous even radius and some with an accelerating radius.  degrees of backset have ranged from very minor to extreme. 

Just my opinion here, but I'd suggest doing your first on a flat form.

What are you  planning in terms of the formula for taper on width and depth?

[Goldxxx]

Not really sure what I was planning on width, taper or depth. I was hoping that there might be some plans in the Graf book to work off of. Right now I’m probably going to wing it. I’ve sold all of my ASL bows so I have nothing to reference from. And up in my neck of the woods ASL bows are a rare as hen’s teeth. Any help would be helpful
 

[bucknut]

All the info you need is in the book.  Very informative.

[Goldxxx]

Yes it’s very informative. I sat down and read the whole book in a single sitting. I would recommend it to anyone starting out. I wish I had it before I ordered my glass. If I can make something in the 45@28 range with the .040 glass I will be happy. I will go over it again to see what I may have been missing.
 I was even able to find some of the DAP powdered glue to laminate the risers with. How does using non epoxy adhesive for the risers fair when the bow is put in the heat box to cure. Any issues with the non epoxy glues popping apart on heating.