Can I get away without a backing on this one?

[Shiloh]

On the flat, on the soon-to-be back.

[carpentertimw]

what size board is that?

[lesken2011]

If I took a chance on it, I would probably use rawhide.

[ionicmuffin]

so you guys are telling me that the grain is terrible? i use boards like that all the time! i just finished one up that had grain run offs and its going strong at 50 lbs at 26 inches! its a bit long but no matter.

[tgtmatt]

I'm no expert but I just recently made a 50# red oak and it held up without a backing and the grain looked similar.

[Shiloh]

what size board is that?

A home depot 1"x2"x6'

[rossfactor]

A board bow can survive with grain run offs.  Lower weight bows survive them better.  The angle of the run-off generally determines how much a problem they are.  The steeper the angle the more likely they are to break.  Also, the different types of wood are more likely to survive growth ring violations (which is what a runoff really is).  Red oak is not a wood that tends to survive with significant grain run offs.

If the board you showed us if flat sawn or plain (not rift sawn) I think you should look at the edge grain.   The run offs on the edge grain are what represent growth ring violations.  However when the back grain moves from one side of the board to the other this generally means you will have grain runoffs on the edge.

The board you showed will have pretty decent run-offs.  It could survive without backing, depending on how "high stress" the design is, but those runoffs are a big liability.  Backing a board bow with runoffs (in my experience), with a low stretch fabric such as linen or silk, can greatly improve its safety.

Id say, keep the bow long (68") and a bit wider than usual, and keep the weight under 50lbs.  But given the option I'd back it with linen.

Gabe

[Shiloh]

Thanks, I'll err on the side of safety and back it.

[Shiloh]

OOPS! One other question; does anyone have experience with recurving/heat-bending board bows? I've got a cousin who's begging me to make her a recurve, doesn't have to be a static recurve or anything to fancy, but she's really into those.

ETA: Whell, turns out it's not going to be my bow after all! Someone just commissioned me to make them a #35 target bow with a linen back. Methinks this board is a good candidate. 

[steve b.]

Forgive, and correct me (anyone), if this comment is out of line:

I'm a little concerned that there are people giving advice here that shouldn't be, that there are people who are giving advice here that should be and are not being taken seriously.  Also, if you have ever seen a bow explode or seen some of the injuries that result from it you might be a little more concerned with the integrity of the bows you are making, especially bows you are making for others. 

[Carson (CMB)]

as to you two and not quite understanding him, i believe what he means is that by getting the backing to a very fine point with absolutely no rough edges then there shouldn't be any splinters unless the bow wasn't going to be one anyway. As to the shellac i have no clue what hes talking about lol 

So lets cut some slac and admit that sandig it fine is helpful, on a grain violation bow....and about shellac.   Have you guys ever tried dry shellac flakes or is all this based on spray can shellac and pre-mixed shellac?  if you mix fresh shellac flakes in alcohol...thick cut, it is like glue. Used as a pore-filling finish on an extremely porous oak board bow, it seems would provide additional backing protection. Heat it up a bit and it plasticizes.

[DarkSoul]

Does shellac have tensile strength? Because that is what is required on the back of a bow. Compression or shear strength will be useless on the back of a bow. While shellac might act as a glue, it does not offer tensile strength. According to your theory, a layer of wall paper glue would even function as a bow backing, right? Shellac could be a good finish for a bow, but it does not serve as a functional backing.

[bubby]

A board bow can survive with grain run offs.  Lower weight bows survive them better.  The angle of the run-off generally determines how much a problem they are.  The steeper the angle the more likely they are to break.  Also, the different types of wood are more likely to survive growth ring violations (which is what a runoff really is).  Red oak is not a wood that tends to survive with significant grain run offs.

If the board you showed us if flat sawn or plain (not rift sawn) I think you should look at the edge grain.   The run offs on the edge grain are what represent growth ring violations.  However when the back grain moves from one side of the board to the other this generally means you will have grain runoffs on the edge.

The board you showed will have pretty decent run-offs.  It could survive without backing, depending on how "high stress" the design is, but those runoffs are a big liability.  Backing a board bow with runoffs (in my experience), with a low stretch fabric such as linen or silk, can greatly improve its safety.
x2, this was well explained, Bub
Id say, keep the bow long (68") and a bit wider than usual, and keep the weight under 50lbs.  But given the option I'd back it with linen.

Gabe

[bubby]

Shiloh, you can steam or use dry heat but I've had more luck steaming in recurves than dry heat, but if you haven't got a lot of experiancejust flip the tips a little, or you can do a glued on reflexed tip, Bub

[Squirrelslayer]

Why dont you want a backing?