Heat with a Board Bow?

[Burnsie]

I picked up what appears to be a red oak board bow - whoever made it did a nice job.
Was thinking about putting 1-2" of back set in it using a caul I built previously.
Can oak take some heat and bending?

[Pat B]

Yes it can. Whether it will retain the backset will depend on how the previous owner handled it and what shape it is in now. Got any pics of it now before you adjust it?

[Kirkll]

Pat,

If this is a laminated board bow, wouldn’t the type of glue used to put it together dictate the use of heat being safe or not? 

Another question: 

After a piece of wood has been subject to extreme levels of tension and compression that we put these bows through without any backing, it has  compressed the belly side of the limbs wood cells , and literally stretched the cells of the wood on the back in tension….

I can’t help but wonder what this is going to do to the cells of the wood by reversing the tension and compression….

Considering that heat closes up wood cells and makes the wood brittle, and moisture allows more flexibility without damage, wouldn’t it be better to sand the existing sealer off the bow and introduce some steam to reshape it, then use a backing of some sort to hold it there after it’s dried?

  I cannot see how doing this Is going to hold at all without using backing…. What are your thoughts on this?    Kirk

[Burnsie]

Here are some pics of the bow.
It originally had some kind of old flaking and yellowing finish on it. I scraped/sanded it off and rubbed it down
with some grape seed oil.  It's a solid piece of oak - not laminated except for the glued on handle section.

[Pat B]

Kirk, I would not use heat on a backed bow, maybe before backing but not after. Most glues used for bow backings can't take the heat. Tite-Bond glues break down at 150deg(F).
 Heat on the belly will increase the compression strength but if the wood is already compressed too much it's not going to hold any reflex that is added. It's only wood after all.
 Also, after any heat treating you have to give the wood time to rehydrate because it does make it brittle. If using steam to make corrections you have to give the wood some time to dry back out or it will allow the cells to collapse when strained.

Now that I see the pics of this bow I think I'd back it with maple or elm, a little less than 1/8" and glue it up with some reflex and not use heat on it. It looks pretty flat unbraced so it was well cared for to begin with.

[Kirkll]

Thanks Pat.... My experience with board bows is minimal. I did steam and bend a lot of wood building furniture, but most of the tighter radius stuff i did, i laminated thinner strips, and of course furniture is static, and not subject to the stress we demand from these bows...

Great idea using a backing and no heat. That should get er done.    Kirk

[Longcruise]

My experience with board bows and self bows is very slim.  However,  I did find everything in the TBB volumes to be fascinating.  Especially the stuff about wood.

One thing that stuck was that the ability to form or shape wood is effected by the way it's dried.  Apparently wood dried naturally is more workable than kiln dried.  My own sparse efforts to shape wood with heat were not very successful which leads me to think that lumberyard wood has that built in disadvantage.

Would be interesting to read about actual experiences that would cast light on the comparison. 

[Kirkll]

My experience with board bows and self bows is very slim.  However,  I did find everything in the TBB volumes to be fascinating.  Especially the stuff about wood.

One thing that stuck was that the ability to form or shape wood is effected by the way it's dried.  Apparently wood dried naturally is more workable than kiln dried.  My own sparse efforts to shape wood with heat were not very successful which leads me to think that lumberyard wood has that built in disadvantage.

Would be interesting to read about actual experiences that would cast light on the comparison. 

You can go down a HUGE rabbit hole researching the different processes of air drying vs kiln dried woods. But the bottom line is air drying and controlling the humidity levels has the advantage in manipulation and bending easier, to KD woods, because it does not damage the cells of the wood as much if it’s done right over time. The KD lumber is a form of heat treating which closes the cells. The key to bending KD lumber is rehydrating it prior to bending . I’m a fan of using steam. 

The key to drying wood successfully from fresh cut green lumber to 10-12% MC levels is the importance of how it’s handled from 35% to 20% …. That’s where most the damage and loss occurs. Once you get below 20%, you are not out of the woods yet, but it becomes much easier to control.

There is a ton of info on drying wood to include how not to have it stain from mold and, and controlling the gradual reduction in mc level without letting the pores close.
It’s an art form for sure….    Kirk

[Pat B]

I prefer bow wood not only dry but seasoned, one year minimum but more is better. Air dries is better I think so that's the way I do it. One problem with store bought lumber is it wasn't cut and prepared for building bows. The good thing, especially for a novices bowyer is it is relative cheap and convenient and if properly chosen can make a damn good bow. Because the grain is usually violated in bow lumber just by the fact it was sawn and not split choosing the straightest grain is necessary with both the along the back and side grains.
 You can get air dried lumber from specialty wood shops. It costs more than big box store lumber but is far superior to big box lumber because it was treated properly off the stump.

[Mad Max]

My Thinking
Red Oak Board bows are a good way to learn and experience bow building and shooting without breaking the bank.
A tool to move on to selfbows at some point.
We hear this all the time, you get set in your bow and want to take it out some way, heat, reflex in a form and gluing on a backer, sinew and so forth.
Staves are high dollar now days, i have bought many at 35 to 45 bucks but not anymore.
Cutting your own staves and waiting for them to dry/season like Pat B said as a new bowyer does not happen mostly, They/we want a faster way to dry them and we end up with more set.
 

[Mad Max]

This is 1 of the best Red Oak board bow How to's out there but photobucket KILLED it.
I wish he would update it with new pictures.

https://www.tradgang.com/tgsmf/index.php?topic=108949.0

[Kirkll]

That one still chaps my arse what photo bucket did to so many people. I lost 100's of photos myself during that fiasco... But i was able to down load a lot of them before i cut them loose completely.

Now i'm looking at all the photos i have in the cloud on Google Photos, and am sorely tempted to down load these to a remote hard drive storage.... Just in case... We have grown way too dependent on cloud storage on the internet. I have thousands of photos that if lost would hurt me badly.

Food for thought....

[Burnsie]

Good idea Kirk - external hard drives have gotten pretty cheap, with storage capacities that were once reserved
for the big boys.
Drives with 1-5 terra-bytes (that's a lot) are not a big deal these days and under a $100.  10-15-25+ terra-bytes available for a few hundred.  For the average person you could store photos for the rest of your life with that much capacity.

I read through that board bow tutorial - it was actually pretty good even without the pictures. With pictures I'm sure it was fantastic.

[Pat B]

I lost over 100 pages of photos when photobucket screwed us all. Some pics are on our desktop or external hard drive but I lost a lot since I've been a member here. That was about when we got our first computer.

[Mad Max]

I have 1358 pictures on my photo gallery
1118 on imgur
and a sandisk 128GB removable USB stick