Tillering --Humidity --Hot box

[Mad Max]

Tell me and every body else about tillering and humidity and string follow??

Can i put my bow in the hot box over night and tiller the next day??
and what tem.??

I have a hot box    3-40W bulbs is 120*,   1-40W bulb is 90*

[Slackbunny]

Humidity makes wood more prone to taking on the shape that you form it to. Certain woods are more prone to it than others, such as hickory. If you live in a high humidity environment then some woods will feel sluggish, and may be more prone to string follow. There is really nothing you can do about it aside from choosing humidity resistant woods and sealing them up well.

I would not tiller for at least 2 days after the hot box. I typically wait 3 days. If the wood is too dry then it becomes brittle and prone to fracture.

[Pat B]

You can put your bow in a hot box between tillering. Be sure your hot box has a hole at each end, one up one down, so the moisture can escape. I would not go over 90*. Give youer bow a few hours to cool completely before stressing it.

[Mad Max]

You can put your bow in a hot box between tillering. Be sure your hot box has a hole at each end, one up one down, so the moisture can escape. I would not go over 90*. Give youer bow a few hours to cool completely before stressing it.

Pat B     I have a ash stave that was 10% moisture last Thursday ,   today I had on the tillering board  and put a 3" brace on it and did "some" tillering , when I took the string off it had about 3" of string follow.   do i need to wait until November befor i can finish it.
I am in mississippi , very humid
Can i put in the hot box over night 90* until i get it tillered or just wait until it is not so humid???

[Chadwick]

3" of string follow is a lot. If you have it in a hot box, it should be drying out, not embracing humidity. I'm lucky to live in a dry environment: if I have 3" of sting follow, it's because of horrible tillering. I haven't seen bows recover from sting follow, but bowyers do.

[Mad Max]

3" of string follow is a lot. If you have it in a hot box, it should be drying out, not embracing humidity. I'm lucky to live in a dry environment: if I have 3" of sting follow, it's because of horrible tillering. I haven't seen bows recover from sting follow, but bowyers do.

It has never been in a hot box,,          I am asking what should I do.   as soon as i took the string off it had 3", it might be less in the morning .
Thanks,      tell me more.

[George Tsoukalas]

How did you get that 10% reading? Was that measured on the full stave? Did you use a moisture meter.

That 10% may have been an external reading. Once you rough out the bow, next time keep checking the moisture content.

Jawge

[Pat B]

Max, heat treating the belly(to chocolate brown) of woods like ash, elm, maple, hickory, etc will help prevent string follow if you do your part and I think help prevent some moisture absorbsion.
 At 10% M/C you are probably overstressing your ash bow to get that much set. You don't want it much dryer. 9% to 11% is ideal M/C for most bow woods.

[Mad Max]

My dad has a moisture miter at his plant.
The stave was saw cut   3" from back to belly, 2 1/2" wide ,      you may be right.
I don't have the meter with me.

[Mad Max]

I have never try ed to toast a belly before.
But today I put some reflex? on it and Toasted?  it some , don't know if i did it right.

[briarjumper12]

I been dealing with hickory throughout my bowbuilding experiment (4 years). It loves moisture as everyone knows.  I keep it in my well designed hot box throughout the construction process.  About 90 to 100 depending on the weather outside.  I take it out an hour or two before I want to work on and let it cool. In my earlier bows I was getting them finished with around 1 inch of string follow or less. Then I would quit storing them in the box. After a couple of months of shooting they where taking more set progressively.  I began storing my finished hickory bows in the hot box and the last few bows I've finished haven't taken the progressive set that the earlier ones had.  I always tru-oil to finish, and do it good at that. But I think, in my humid enviroment, the bows were just getting back to equilibrium with the enviroment and for hickory the MC was too high. Storing the hot box seems to allievate that problem. Of course, you have to let them cool good before stringing and shooting.

I'm no expert, but that's my experience with hickory.

[Mad Max]

Thanks jumper

[koan]

Im in complete agreement with Pat. Atleast its been my experiance... Here in Mo. I have purty high humidity and ash seems to be just as hydroscopic as hickory.. Sounds like your wood is just wet so hopefully there aint any damaged wood yet. The last ash bow i built took 7" of string follow but it turned out it had just re-hydrated not damaged the wood cells. I put it on the caul, toasted it, then back inda hot box for a couple weeks. It is bout 60" long, 47# @ 26" and has less than 1" of follow now... Sometimes ya get lucky .. I have personally found that bringin your stave inside the house dries them better than my hotbox.. Central airs basic process is to take moisture out, imo

[Mad Max]

Koan   Thanks

[mikekeswick]

I make sure that ash is very dry before bending it much. 10% is a bit high for ash in my experience. Ash is also massively strong in tension and not great in compression.
The rules to follow for a low set ash bow are 1) Start with dry wood. 8%     2)Trap (narrow) the back a lot!    3) Heat treat the belly.
These things might tip some woods over the edge tension-wise but not ash. Ash is great bow wood!