I'll throw in my $0.02...
1. ...grain appears to run.....at slight angles....
2. ...do I need to straighten the lines on the back?
3. should I put a backing on it?
4. If so what should I use?
5. How wide should the limbs be?
6. how much taper?
7. oh and should mention the board is 2"x6' and I would like to make it pull 50#@28".
8. Any and all help is greatly appreciated.
1. "slight angles" - without seeing the board I cannot really help. I've made some pretty decent red oak board bows out of 1x2 boards where the growth rings weren't 100% straight. As a general rule of thumb, I'd say if the limb has 3 or less rings running off the sides at a LOW angle (maybe about 5 degrees) you should be relatively safe.
2. I'm not exactly sure what you mean by straighten the lines, but if your board is wide enough you can follow the growth rings (lines). I've done this before with great success.
3. Only if you feel the need to. Personally, I hate backing bows, but if it means the difference between kindling and a bow, then by all means back it. Do you need to? Refer to answer #1
4. If you decide to back it I'd suggest linen, silk, or rawhide.
5. With board bows (or any bow) of questionable integrity, I always start off as wide as I can. You can always reduce the width later on without much effect on draw weight.
6. Once again, with bows from questionable wood, I like to keep the limbs full width to mid limb, then taper to 1/2" or 3/8" nocks.
7. Is the board truly 2" wide or is it a 1x2x6? A 1x2 board will only be 1.5" wide. If the board is truly 2" wide I'd glue on a handle riser and make a narrow, non bending flatbow. If it's 1.5" wide I'd make it a bendy handle D-bow with a
slightly narrowed handle (about 1.25" wide) and leave the handle area 3/4" thick so it only has the slightest give near full draw.
8. That's what we're here for!