How bad can grain be on a belly lamination?

[PEARL DRUMS]

First things first. Del's idea of butt jointed blocks wouldn't work, so don't let that tell you anything. Secondly, if you use straight grained slats you wont have any issues as said, with the materials. 

[Ballasted_Bowyer]

Another thing you can do with a flatbow made from boards and structurally backed is rip two layers of good quality belly wood from the same piece, lay them up with the center layer turned over to the belly. Think of the slices as being really tall pages. You open the book and rip out a page and lay it down in that position over the other. In this way the faults of the wood mirror each other and cancel out twist in the grain. This does not fix a weak point in the grain such as a pinhole knot or figuring. But it does help avoiding a propeller bow. It is important to have some idea how thick the belly will be after final tiller. Your core should be about 2/3 the total belly if you are using this method. That is not applicable if you are using three different woods in a tri-lam.

[Acheulean]

Secondly, if you use straight grained slats you wont have any issues as said, with the materials. 

You're telling me that nobody has ever had a properly constructed straight-grained bow break on them?

[Ballasted_Bowyer]

The sooner you break this bow, the sooner you can start a new one. To PD's defense, I don't see how that's a problem. 

[Bryce]

Secondly, if you use straight grained slats you wont have any issues as said, with the materials. 

You're telling me that nobody has ever had a properly constructed straight-grained bow break on them?

If anything it would be the bowyers poor judgement that broke the bow. Not necessarily the materials.

[Acheulean]

I'm curious. I'm going to build a butt jointed bow.

[Bryce]

I've butt jointed two lams of horn mid-limb. But not wood, I have a sneaking suspicion that the ends will crush and leave an ever widening gap when unstrung and eventually be a pain.
Now a butt-joint in the handle I've done many times more often than not with a stiff handle and a power-lam

[Acheulean]

Butt jointed bow challenge anyone?

[Ballasted_Bowyer]

Butt jointed bow challenge anyone?

I believe it can be done.

[willie]

a more practical challenge would be to rip and laminate what usable wood you can get out of the erc boards. then apply a backing

[Hamish]

I thought in the context of this question the "straight grained stock = no issues "was pretty self explanatory to anyone with a modicum of common sense.

You won't have any issues associated with relating to the scenario that I had explained in my posts, and the posts of other guys answering your question.
Nothing can be done if the design, workmanship, glue up prep, or tillering judgements are bad. That's pretty obvious dude.

[Acheulean]

I thought in the context of this question the "straight grained stock = no issues "was pretty self explanatory to anyone with a modicum of common sense.

I know what you meant. The statement is still a fallacy. 

[Del the cat]

I'm curious. I'm going to build a butt jointed bow.

I look forward to seeing it. I'd suggest a reasonably thick Boo or Hickory back, with a nice thickish tapered belly lam that is cut into blocks before glue up... maybe 3" or 6" blocks?
Del

[Acheulean]

I was going to go with hard maple, because it's what I've got. How thick are you thinking on the back and the belly?

[gfugal]

I'm all for trying new things. Just know going into it that it's an experiment, and prepare for failure. As long as you are okay with that, I too look forward to seeing if you can get it to work.