Self Bow Recured Tips?

[Drewster]

Is there a rule of thumb for the radius and length of recurve for "flipping the tips" on self bows?  I want to do a static recurve.  The bow I'm working on is hickory and 68" NTN.  Thanks for your help.

[mwosborn]

Not sure about a rule of thumb or not.  Here is a pic of a hackberry static I am working on.  The outside (belly) radius from tip to where it straightens out is about 6".

I just went with what looked good.  I am shooting the bow in now and it seems to be shooting fairly well with the tips seeming to be holding.  It is taking a little set though.



IMG_0103  by  mwosborn1 , on Flickr

[scrub-buster]

The great thing about self bows is that there isn't really any rules of thumb.  Each piece of wood is different and can handle different things.  I like to do a gentle tip flip on self bows.  Here is one I'm making for my daughter.

 

[Pat B]

The method of bending is more critical and depends on the wood used. For hickory you'll want to steam or boil. Have everything ready so when the wood is hot enough to bend you have the form and clamps ready to go. You only have a minute or less before the wood gets too cool.
I reflexed and recurved tips from 1" or so to long, deep recurves all with good results and woods like osage, mulberry, elm and hickory. With the hickory I did 6" shallow reflexed tips but had to add underlays to support the curves and keep them from pulling out.

[Drewster]

Pat, do you steam or boil hickory even though the stave is in the 7% MC range?  Does that work better than dry heat with hickory?

At what point in the process do you laminate the underlays?  How thick?  Any specie of wood work better than others?

Appreciate your help.

[Pat B]

I've tried bending hickory with dry heat and the bends pulled out. Steam or boiling works better. You can coat the area to be steamed(or boiled)with shellac to seal it first. The shellac can take the heat and moisture and still seal the wood. Shellac comes off easily with light sanding or scraping or wiped off with alcohol.
A thin lam of hardwood works well but almost any wood will work. It should be applied after the tips are bent. I'd pre-bend the underlays on the same form as the tips to insure a close match. It doesn't have to be thick either. Maybe 1/8" or so. The underlay and glue line makes it very strong.
Look at "4est Trecker's" post on building brush nocks. Good info there.

[Drewster]

Thank you very much Pat......HUGE help.

[razorback]

How long do hickory tips need to stay in the form before they can be removed. I was thinking of setting up so that while one tip was in the form, I'd steam the other end and switch them in the form. Just need to know how long. If they need to stay over night then not much point in going to the effort, but if they only need to stay for half an hour then I could cut my time nearly in half.

[Pat B]

Razor, theoretically only until it cools but I like to leave it in the form over night.

[razorback]

Thanks Pat, I'll ere on the side of caution and leave them in overnight. Good exercise in patience as well.

[Mark Baker]

Not really "rules" of thumb, but some common sense observations...

A static limb will effectively cut the working area of you limbs down considerably, so plan accordingly.  Also, a longer static, or any recurved tip for that matter, increases the potential for limb twist...make sense?  If you have a snaky limb or some propeller in there it will aggravate it more easily.   Just think it through.   I have had good luck so far playing with working and static recurves.   I also like flipping tips a bit on some bows.   One thing is sure, anything you do will be a learning experience....and that's half the fun of building them!

[bubby]

I like to get mine to brace before putting the hooks in, less suprizes that way

[Mark Smeltzer]

I use the same method that Pat B does. When you know you are putting an underlay on the limb you can make it thinner and it will bend more easily.

Mark