finally started my newest selfbow

[Pat B]

I got the other limb heated and clamped to the form this morning. I'll post pics a little later.

[Flem]

Does the heat allow permanent deformation, or is some lost over time?

[Pat B]

It should be permanent but sometimes you have to reheat to get it to do so. As cold as my basement is(lower 40s) I may not have gotten it as hot as it should be. That why I'll double check and repeat if needed. Also I think that by using oil when heating not only helps to prevent scorching but I believe it helps to distribute the heat more evenly and help hold the heat longer allowing it to go deeper. No scientific proof of this but in my experience it does these things.
 I have put recurves in limbs with dry heat, just like this and they stayed permanently fixed. Heating and bending wood has been around as long as people have used wood for tools. Even Neanderthal used this method to straighten out their throwing and lunging spears they used to hunt the megafauna of their times.

[Pat B]

I flipped the stave on the form to work the other limb. Not much to do with this limb but add some reflex...


...and remove a little tip twist...


I started by oiling and heating the limb. I hold the heat gun about 1" above the belly and move it back and forth over about a 6" area until the wood is too hot to touch then add a clamp and move on to the next 6".  The dark spot on the limb is a shadow. I don't like to scorch the limb as I make adjustments. After the limbs are straight and at a later date I will go back with the heat gun, without oil and heat treat(temper) the belly, scorching it as I go.


When it's too hot to touch I clamp that area and move on to the next 6" and on out the limb...


next it's time to remove the twist from the tip. I place a wood pad under the down side or the twist and clamp the other side to twist the tip the opposite direction while I'm heating. You can see the pad under the limb edge just beyond the clamp...


more to come...

[Mad Max]

This is going to be a nice How To Pat

[Pat B]

Thanks Mark. I've done a few of these over the years but photobucket are most of them. 

[Roy from Pa]

Looking good Pat.

[Flem]

I'm starting to think twice about all the twisted wood I have in my shop. Might have to get out the heat gun!

[wood carver 2]

Does the oil you use to help bend the limbs affect the finishing later?
Dave.

[Mad Max]

I've used cooking oil too on osage and buy the time you get the bow ready for finish you can't tell the oil was on there, Osage is a oily wood anyway but doesn't seem to matter.

[wood carver 2]

Thanks. Just something that I wondered about.
Dave.

[Pat B]

What Mad Max said. I'll be putting a rawhide backing on the bow with hide glue so I'll degrease before I do that.  A good scrub with Dawn and warm water and rinse with boiling water. That will remove the natural wood oil, fingerprints and any cooking oil that might still remain.

[Pat B]

Did a little more today. I took the stave off the form after working the second limb. One limb took less reflex than the other. I won't worry about that now but will take care of it later...


...but I did get the twist out of the limb tip...


I also developed the back profile starting out at 1 1/2" at the fades and out 4" before tapering to 1" about 7" from the tips then tapering to 3/4" for now.


Now it is time to put in temporary string nocks. I put a pencil line on the side of the tip at 3/4" at the back and 1" at the belly...
 

and cut the groove with a chainsaw file to about half the diameter of the file...


...making sure I go on to the belly side to guide the string...


...I put a string on just a bit longer than the bow for a tiller string and put the stave on the tiller tree...


and after a little short exercising I do a pull to check the initial tiller...


more to come...

[Mad Max]

I call that a long string Pat , I see some people with really long strings

[Pat B]

Mark, that string was hanging on the pegboard above the bench. Loop on the top limb, bowyers knot on the bottom so I can adjust the length. That's how I make all my strings. As soon as I can I will go to low brace of 3" to 4". From there it should be all down hill. 

[Roy from Pa]

Looking very nice, Pat.

I like the unbraced profile.

[Mad Max]

 

[Pat B]

Hope I can keep most of that Roy and Mark . I'll be heading back to the basement soon so I should have more pics later today or this evening.

[Pat B]

I did a little more today but my camera ate the pics.  I'll get more done tomorrow.   

LOL

[Pat B]

Well, maybe the day after tomorrow. Anyway I got back in the shop today. One thing I do in the early stages of tillering is to continue to check the limb thickness along each edge of both limbs and again use my hand and a pencil to scribe a line showing areas uneven in thickness. You can see the line here where the limb edge is thicker.


I continue this pencil line through the handle area from limb to limb to insure the thickness is consistent through the tillering process.


After a little more belly scraping I exercise well first then I can also get a good view of how and where the limbs are bending. Here I am at 17" on a loose string. It bow is pulling 50# at this point so I have plenty weight to loose while adjusting the tiller.


I decided to pull out the good ole tillering Gizmo. This is my tiller stick. It has 3 settings, 4.5", 7.5" 11.5" and 14" at the top. I use it very little, only when using the Gizmo. Looks like I'm at 11.5" on a loose tillering string in the pic.


Here is the Gizmo in action. You can see the pencil line where I need to give it a few scrapes.


...more to come...