Primitive Archer
Main Discussion Area => Bows => Topic started by: webrx on March 08, 2015, 09:56:58 am
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Hey all,
I had a 66" red oak long bow that was fully tillered and shooting ok, albeit a little light 30# @ 28
Decided to try and reflex the tips mostly to see if I could
The reflex went ok, but it looks like I developed a couple tension cracks on the belly from the heat and bend process. Thinking it was on the belly so it was less fatal than if it were on the back, I filled the cracks with super glue and let it set for a bit. I was then was able to string an shoot it, and it seems ok, but, I am not sure i trust the bow at this point.
My question of the experts here is.....
Should I patch it differently? Add some linen or silk to the belly, wrap it in rawhide and super glue at the crack area? Burn it and make coffee?
I am open to advice on this one. It is not a big deal if it is a goner and just needs to turn into firewood for the coffee pot, but, I figured it would be a good learning experience if I ever run into this again on a bow I have more time in.
Thanks
Dave
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Scraping it down flat and adding an extra layer is the best option. Wrapping it is just hiding it.
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adding some pictures
(http://www.pbase.com/webrx/image/159372221/medium.jpg)
(http://www.pbase.com/webrx/image/159372198/medium.jpg)
(http://www.pbase.com/webrx/image/159372218/medium.jpg)
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Looks more like it's at mid-limb than tips. Toss it.
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yeah, kind of what I thought, I did superglue it and have actually put about 50 arrows through it after that, this bow only pulls 30# but my fear was that the biggest one (on the bottom limb belly) would eventually let go.
I thought about superglue and a rawhide wrap that expanded 1/2 inch past the tension crack on each side to give it some additional support, but, at this point I think the best case is it lets go easy and not catastrophically, worst case, is it lets go at the worst time and I get hurt.
Not worth the risk I think. Guess I'll burn it.
So, any advice on what I did wrong that caused this? Can you not bend a red oak board bow with dry heat? Did I heat it too much, bend it too fast? not tilt my head the right way?
It had a nice smooth snaky bend to it when i took the clamps off so I would like to try this again with a new board so any advice would be appreciated.
Dave
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How deep is the crack?
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the two on the top limb are not deep. The one on the bottom limb was maybe 1/32nd.
I glued them up with superglue before i released the clamps and I actually shot 60 arrows through it starting with half draw and working my way up. I didnt hear any cracking or creaking while doing this.
My thought was that since they were tension cracks on the compression side of the bow, the superglue would hold. I also added more superglue 1/2 on either side of the crack and wrapped them in 1/8 inch rawhide 1/2 inch on either side of the crack to add a little more safety after that, but have not shot it since.
Was thinking gloves, motorcycle helmet, leather jacket and pull it to full draw and see if it breaks.
Dave
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Well,
Here is the repair, shot a couple dozen times at full draw, no creaking, cracking etc. Seems to be holding.
I did a larger area on the lower limb crack because it was a bit deeper.
Still not sure I trust it, it may become just a lean in the corner bow and I definitely would not let anyone else shoot it.
(http://www.pbase.com/webrx/image/159373983/original.jpg)
(http://www.pbase.com/webrx/image/159373984/medium.jpg)
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FYI - Shot another 60 through it today, still holding up, no noise no issue, but again it is 66" long and only 35#s at 28
Asked this question earlier, but it was kind of buried in other stuff...
Any advice on what I did wrong that caused the belly to crack?
Can you not bend a red oak board bow with dry heat? Did I heat it too much, bend it too fast? Thoughts?
It had a nice smooth snaky bend to it when i took the clamps off so I would like to try this again with a new board so any advice would be appreciated.
I have a couple nice boards but don't want to ruin them, or another bow, if dry heat is not going to work.
Thanks
Dave
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U should of steamed it, woulda worked outa a little better maybe
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Those cracks should be no problem, though your wraps are no help. The belly is entirely in compression. Bows have been made with pieces of bone just butted together on the belly and they work. The wrap is no help because leather, rawhide, silk, etc, adds no compression strength.
As far as what you did wrong, among the possibilities are not enough heat, heat not applied to the whole area you tried to bend, a growth ring at a bad surface angle and more that don't come to mind.
When you make perfect bows every time, you will lose interest. Not many of us have lost interest. :)
Jim Davis
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I only wish I could make perfect wood bows.
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Thanks for the replies, and I will be the first to admin i have yet to make a perfect bow.
Next time I will try steaming vice dry heat for red oak.
I actually thought that the cracks being on the belly were less risky than on the back, and I wasn't really trying to add compression strength with the wraps, more just trying to make sure I had superglue in and around the crack so if it did let go it wouldn't be as catastrophic.
I appreciate the information and advice.
Dave
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I have dry heated red oak. My opinion is you either heated it too fast, or not enough before bending. If your wood is making noise while bending it is bad. Heat bending is a long process.
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Thanks
I decided that I would junk this bow and build another. I will try to reflex just the tips this time and go slow. I think I have an old lobster pot somewhere I could possibly boil water in and heat the tips that way. But I will try dry again on some scrap and see how it comes out. Maybe I heated too fast, I dont recall hearing any noise but maybe my old ears missed it.
d
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There's a board bow buildlong on my site. You can rip the board the board to 1 3/8" for 45-50# or you can leave it 1.5" for 50-55# provided you tiller well.
Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/boardbowbuildalong.html
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Thanks George, I actually have spent a lot of time on your site.
d
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Chances are that the red oak you got was kiln dried and kiln dried wood is more brittle when it comes to heat bending (dry/steam/boil). That's not to say it can't be done it definately can. You may find that a lot of the shapes you heat into a self board bow may pull out during tillering so that's another thing to bear in mind. If you can get a thin lamination cut you could bend your main piece to a fancy shape and then glue a backing strip onto it. This will help you keep your reflex/shape.
A few tips for bending - soak your wood for a few days for extreme bends. Round all tension edges well. Dry heat for small bends, then steam for medium bends then boiling for sharper bends. Use a steel strap for the very sharpest bends. Ideally work the tension side to one growth ring.