Humidity + sinew

[Axes bows n knives]

Hey guys i am planning on backing a bow with sinew and I know humidity and temperature has an effect on sinew. I live in Florida where it is humid and hot.. well not so bad now. Anyways I was wondering what precautions I should take with doing my sinew backing. Will shellacing a finished sinew backed bow help keep the moisture out enough to not effect cast?

[broketooth]

first id have to say where you live it might not be a good idea to back your bow with sinew. its been told to me that high humidity makes a sinew backed bow draw like a wet noodle. 2nd, you are leaving out the specs of the bow. what is the length of your bow? its also been told to me that a bow thats a good candidate for sinew will have a length of 60" or less. that being said, you need to tell us more about your bow . as fare as using shellac to seal your bow over sinew, im not sure i would use it. i would get a better sealent for your bow. some type of urethane sealant would be a better choice. im sure there will be others to offer up thier opinions. ruddy

[Art B]

We have climate control today so you can pull it off where you live. Be smart about construction and selective about using your sinewed bow.

Several good choices out there as far as finishes like spar varnish or spar urethane. Or snake skin over hide glue/sinew. Sinewing using the Tite-bond 3 waterproof gule is another option for your area. Good luck..Art

[hova]

i was thinking the same thing art. i have been wondering myself about hickory and sinew. i was wondering if it would be a good idea to cure the sinew or hickory near a de-humidifier , or maybe a "bow humidor" , where you can control the RH a little better either with a light bulb / fan , or just some desiccant packets in a cardboard box...

[Art B]

Hova, do you have a humidity/temperature monitor? If not, then you can pick 'em up for as little as 7 bucks at Wal-mart. That should be the first and foremost tool any bowyer should have. For winter time us a humidifier and summertime an air conditioner to help with climate control. Last thing you want to do is suck moistue out of a sinewed bow to quickly. Just let things dry out normally at first. Once your sinew is dry keep in the proper R/H that your particular wood requires. For most woods that around 8% MC or between 40-45% humidity. For hickory a little less is fine.....Art

[KellyG]

I was truely wondering about a bow Humidor myself. Once the rains stop here this place is going to dry out. I am going to post a tread about it latter though so I dont hi jack axes thread.
Kelly
Sorry Axes for the brief interuption.

[Pat B]

You can not prevent moisture from entering a bow if the R/H is high. You can slow down the hygroscopic rate in a controlled environment and/or with a good finish.
  In high humidity environments you should probably not use your sinew backed bow for any length of time. Over a few days you will notice a drop in poundage and performance. Once the R/H goes down again the M/C of your bow will go down as well and the draw weight will go back up.
  There is no finish that will prevent the increase or decrease in the M/C of your bow. It will follow the R/H as it raises and falls. All you can do is control the rate somewhat at which the M/C will change.

[John Scifres]

I have made a bunch of sinew bows with hide glue and Titebond 3.  I prefer TB3 for its ease of use but I haven't seen a whole lot of difference in the rehydration/dehydration dynamic.  My bows still lose and gain weight from season to season.  As much as 10 pounds.  I keep my bows inside but do not control hmidity intentionally.  I should for many reasons but don't yet.

I have used shellac and plastic finishes and haven't really seen much difference between the two.

If it were me, and I lived in a high humidity area most of the year, I'd try my best to avoid sinew.  I don't like shooting sinewed bows in the summer here in Indiana becasue of their sluggishness then.  I go to Cloverdale in June and my go to bow from the past, a sinew-backed static recurve, was noticeably slower.

[Art B]

As I mentioned earlier, be smart about design and construction when it comes to these sinewed backed bows for your area. Goobs of sinew and glue does nothing but causes problems due to changing weather/enviorment conditions.

Choose a narrow limb design where less sinew/glue is required. Reduce it's width even futher by trapping it's back. Try two layers of sinew instead of three and see if that meets your needs. Sinew only the working portion of the limb rather than the whole limb.

Perhaps a pyramid design over a retangular will help also (next on my list)
 
For a hickory bow you can heat treat it's belly and that'll allow you to narrow it's limb width. Sinewing itself will also allow some limb width reduction. Plus, I think heat treating helps prevent to some degree, moisture absorbtion back into the wood......Art

[Axes bows n knives]

The specs of the bow are 49 inch osage. I am still early in the stages of making the bow but I thought I should ask about sinew ahead of time. Is there anything that is as good as sinew and doesent care for humidity that I can back it with? or should I just put sinew on it anyways or just try to leave it unbacked. I want to back it because of its length

[John Scifres]

In that case, back it with sinew.  What's the draw length?

p.s. I make my kid's bows 51"  

[Axes bows n knives]

I have no idea yet I am stil laying out the bow shape right now. I will repost something when I have all the specs of the bow but right now its sitting in the garage as a stave. thanx for your advice tho guys.