Bamboo question.

[wood carver 2]

A few days ago I planed some bamboo slats and scorched them for use as belly lams. Out of the three I scorched, two have developed cracks that have made them useless. It was cold the day I burned them and I'm wondering if going from freezing to burning and then cooling down rapidly in the cold shop might be the reason why. I have never done this in real cold weather before and it never happened before. When I scorch bamboo, you can see steam rising from the ends and I always leave them to re-hydrate for several days before finishing planning them down or bending them. Is it possible that the freezing conditions prevented the slats from re-hydrating?
Dave.

[macbow]

Sounds pretty feasible .
I know the bamboo I use has a high moisture content.
For backings I usually put it in a hot box to bring it down after flattening.

Were these natural bamboo backs or slats like used in glass type bows?

Eventually I'd like to make a trilam with bamboo belly.

[wood carver 2]

These are natural. I saw a bamboo tri-lam with a scorched belly and I had to have one... well, more than one. I've built three now and I'm still learning. I don't have room for a hot box, but it looks like I should try and make some. I guess for now I might just wait for warmer weather before scorching any more slats.
Dave.

[macbow]

Dave, I've been waiting for it to warm up too. My last BB Cumaru splintered on the belly. I think it was too dry because it was so cold our humidity was way down.

Do you have any pictures of your successful bamboo belly bows?

[wood carver 2]

Here are some pictures of my first two all bamboo bows. The bow in the first two pictures is my best, both for looks and performance.
 
 
I don't have a picture of my third one as it's only half done and due to an error on my part, it came out really heavy.
Dave.

[carpin'mark]

beautiful bows, really like the turkey head, great job, did you free hand that?

[wood carver 2]

Thanks. I drew the turkey using water based art inks.
Dave.

[David Flanrey]

Dave, very nice.  

[wood carver 2]

Thanks David.
Dave.

[macbow]

I like those .
Would you want to share your stack formula?

[wood carver 2]

Unfortunately, I don't have a reliable formula.
I plane the backing bamboo to 1/8 inch in the middle tapering to 1/16 inch at the tips. Cut the back to shape before final planing to get the ends thin. The belly lams are also planed really thin and the core is just over 1/8 inch with no taper. For the core, I planed a natural bamboo slat to thickness , but flooring bamboo could be used. I also used a power lam made from jatoba about 3/16 inch and 2 inches or so past the fades.
I use a blow torch to blacken the belly lams after I get them planed flat, but not too thin. Then I leave them for a few days before final planing. Torching bamboo makes it cup towards the outside, so be careful planning. I find this lets you get them nice and thin as the crown flattens a bit.
The problem I had with the third bow is that I used osage for the core instead of bamboo and I didn't taper it, so it came out very heavy.
 One thing I like about these bows is that they draw smoothly and are nearly silent. The burnt bamboo looks really cool too.
Good luck with your build and let me know how it turns out.
Dave.

[macbow]

Thanks Dave.

[wood carver 2]

No problem. I hope it works for you.
I'd be eternally grateful if anyone has a working formula for an all bamboo longbow that they would be willing to share.      
Dave.