So I have slowly been working on this bow. Had some scraps of wood in the shop and figured it would be a good way to get some ideas worked out.
After HOURS of work.. I was going to do a quick tiller and noticed this:
(http://i383.photobucket.com/albums/oo273/timberwolf177/Trad%20Bow/20110814172932.jpg)
(http://i383.photobucket.com/albums/oo273/timberwolf177/Trad%20Bow/20110814172925.jpg)
You can see the gap at the glue line when pulled back half way (about 22 in draw) I played with it a bit and it looks like the Walnut is flexing to much.
(http://i383.photobucket.com/albums/oo273/timberwolf177/Trad%20Bow/20110814173002.jpg)
So any ideas? It is only pulling about 35 lbs.. it is a 64".. I am sooooo bummed. I have not had a problem like this before. I am just worried that maybe the walnut is not strong enough wood.
Here are some pics of the bow. I was trying out some new design ideas on this bad bow
(http://i383.photobucket.com/albums/oo273/timberwolf177/Trad%20Bow/20110814173057.jpg)
(http://i383.photobucket.com/albums/oo273/timberwolf177/Trad%20Bow/20110814173109.jpg)
(http://i383.photobucket.com/albums/oo273/timberwolf177/Trad%20Bow/20110814173132.jpg)
So.. looks like I am going to have to build another riser. Maybe using maple as the main and walnut as the accent.
If anyone has any ideas of a repair, let me know.
Thanks,
Brad
I snapped a walnut riser not to long ago but I had the lam thickness wrong so I am sure I over stressed the wood. What kind of glue did you use?
I built a walnut riser bow and it failed to. So from now on if I use walnut it gets a I-beam with phenolic. Sorry for your bow she's a beauty.
Shawn
I wouldn't use walnut in such a load bearing role; I've had it fail on me before as well. In decorations and accent strips, it seems fine, but it's a bit brittle and doesn't like flexing too much. At least, that's been my experience with it.
beautiful bow, shame it's giving trouble.
edit: same goes for mahogany.
Thanks guys.. I used smooth on. I always cut a center rest shelf, so the maple I beam portion got cut away.. leaving only walnut.
Live and learn (NOTE to self .. DONT use walnut as main wood! LOL
I have used maple, ash, dymond wood, walnut/maple laminate, purple heart and yellow heart.. with no problems (as the main wood)
Well.. at least the limbs are still good.
Second bow I saw on here today with a failure at the reverse swoop on a footed riser. Tons of stress trying to pull that joint apart when the bow is drawn.
Very cool bow though!
Total amount of wood at the area of the separation is small, real small, looks like about 1/2 inch by maybe 2 inches. You have a huge site window cut out that looks like well past center cut and very tall. If you cut clear through the "I" beam it no longer functions. It is a fine line between a "clunky" riser and a weak one. The good news is you can build another riser for those limbs.
I just had a riser crack in the site window a few weeks ago. I used CA that is the consistancy of water and is made to fill cracks. I have shot it several times and left it strung with no problems.
Yehbut Ricky, U had "professional" help.
you hit the nail on the head Shaun.. .55 wide and only 1.45 deep. I knew this was only going to be around 30 to 35 lbs, so I pressed the limits. Just was not aware of the walnut being so week.
All the smooth on in the world can not keep a softer wood and a harder wood together with the stress difference.
I will super glue the bad parts and put a couple coats of tung oil on her.. use it for show and tell. I like the lines of the riser.. she looked sexy! So will repeat with another but with the stronger woods. And will give a little more beef at the window line. I like the large windows personally... so has everyone that shoots my bows.
why not glue a lam on the riser cut out for the arrow shelf...that should thicken it up and make it no flex at all.
May not be "centershot" anymore but it shouldn't break
but it is bending at both ends? So what is your thought.. just in the window?.. or elsewhere as well
Thanks for the idea... I am all ears, but don't follow just yet
This comes under the not normally done category for bow risers,
but why not put a 2 inch screw from the light into the dark and plug it, (drill a screw hole, fill it with smooth on run the screw in (counter sunk of course) and then put a plug in each end, Might save your 35 lb bow
unless I misread something.
Nice looking work.
I actually was thinking something along those lines.. but I am still worried that the thin part of the walnut will give way. Maybe drill straight down and glue in a steel rod? strengthening the walnut. Might work.. I will give it some thought when I get home
You got the riser way too thin there in the crack area plus walnut two bads. Make another riser loose the walnut except maybe for accents. beef it up a bit more in the thin areas. Not a biggy just part of learning.
I wouldnt try and fix it unless you are the only one shooting it then its on you if you get hurt if/when it fails. .02
Terry
You might try drilling a hole and pegging it with some dowl material and Urac? Since it's a project bow anyway, may not look all that great but I bet it would hold it together. Just a thought.
I see Mike was already headed in the direction I was thinking. Great minds think alike.
I'd get some good quality dowel or make your own and make the hole just a few thousandths bigger than the dowl so you have plenty of room for the epoxy and peg that sucker.
My bow is doing great by the way, I love it! :thumbsup:
It is a bit thin (and I knew I was pushing the envelope), but I think it would have held with maple. Especially since it is low poundage.
Just never thought walnut would have acted this way. But it is all good.
I will just finish up the riser for show and tell. I will use the limbs with another riser. Gives me something to do.
Semo.. glad to hear it bud!
That is why this bow was NOT a commissioned bow.. had some scraps and figured I would try some new tricks.. I still have my standard pattern for any bows going to others.
With those 3 pc take downs, it's best to limit the glue lines in the riser as much as possible.
Limit the glue lines? I thought laminating was always stronger. It has got to be done right though.
So, it's stronger with glue joints than a solid peice of hardwood without glue joints?
That is the perception. I work in the flooring business, and engineered wood (laminated) is stronger than pure hard wood. Reason being that the layers give strength to the overall board.. less twist and warpage.
That being said, the laminations do have to be done right with the right glue.... flooring or bows. And that would go for I-Beams in bows.. not the decorations in front or back.
I am sure there are test done out on this subject. Would be interesting to see what results are.
With that light of poundage I'd fill it with a good CA glue like ZAP or Hot stuff. Get the water thin style and put some in the gap prior to clamping then continue to apply around the area until the wood stops taking it in. The glue will fill the gap and pores and strengthen the walnut. I've had a similar problem, or 2, on thin accent stripes and they have never failed yet.
I have chosen to never build another riser without at least one strip of glass running along the back of the riser. I have never had a riser crack or fail since. It is pretty cheap insurance.
Not an expert by any means but looks to me like you could drill and dowel it. Use a contrasting hardwood and make it an accent?
Bill
Cracks like that is the reason I will not build a bow without glassing the back of the riser. I too had a walnut riser crack on the back of the riser in the grip. Since then I always make a form and glue glass to the back of the riser. Best to be safe than sorry.
Troy
Could you dowell it with a soild fiberglass dowell(old c/b antenna,tent pole)or a piece of all thread( bolt with head cut off) then over lay the hole with thin maple and walnut.