Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: EwokArcher on January 08, 2017, 01:25:00 PM
-
Welp. Live and learn. So I was lowering poundage on this here Kenny m that turned out at about 65 pound at 26 inches. New belt on my sander took off glass way quicker than I was expecting and here is the result...
(http://i1077.photobucket.com/albums/w466/tyrelljrutledge/Mobile%20Uploads/20170108_121600_zpsuryipary.jpg) (http://s1077.photobucket.com/user/tyrelljrutledge/media/Mobile%20Uploads/20170108_121600_zpsuryipary.jpg.html)
(http://i1077.photobucket.com/albums/w466/tyrelljrutledge/Mobile%20Uploads/20170108_121625_zpsuidqmm3p.jpg) (http://s1077.photobucket.com/user/tyrelljrutledge/media/Mobile%20Uploads/20170108_121625_zpsuidqmm3p.jpg.html)
Now this is all clear glass went with desert camo lams and handle all about 120$ worth of material. This is a bow for myself.
I have a couple ideas in mind to maybe save it.
1- sand off my tip and prep the end so I could be shingle on a new piece of glass that would cover the whole end of the bow and then put on a new tip.
2- use my smooth on and glue down a lil piece of glass into my mess up then sand smooth.
3-ignore it and hope it goes away.
I appreciate your input, total length 61 inches currently 60 inches NTN.
-
Ouch Ty!!
# 3 ain't gonna work.
#2 probably won't either.
# 1 "might" if you make a long scarf joint on the glass. You will be relying on mostly glue strength on a narrow area.
Personally, I wouldn't trust it, especially if somebody else ever shot it. Actually if only I shot it.
When one blows up in hand, you never forget it...
-
well...
i would cut that piece and make the bow shorter. i know it is going to increase the power but better to stay safe...
best.
-
I propose option #4. Make a mixture of wood flour and epoxy and fill that divot. Scarf joint the glass but grind that tip off first and run the new glass from the scarf to the tip. Glue a piece of thin black glass on top of the scarf all the way to the tip then reconstruct your tip. Make sure the black glass completely covers the scarf. It's what I would do and it may not work but I hate to give up to and hope it helps. If you do this you may need to approximate the same modification on the other tip.
-
5. It's ruined. Pitch it. Start another.
Stay away from aggressive power tools when doing delicate things like glass bow weight reduction and tip shaping.
-
It's not ruined, grind the tip overlay and glass off(carefully) scarf joint another piece of glass to replace the end piece, glue on another piece of glass to cover the glass joint underneath and replace your tip overlay.
You would be way better of to round the edges to loose weight than grinding the surface glass, maybe tuck that away for next time.
Good luck, let us know things work out for you.
Regards.
Bert
-
as big Bert says- round edges and trap to help drop weight- i would glue on overlays like Bert says- then narrow the tips- so almost like a Holmgard type bow.- just do both tips the same!
x2 whqt Bowjunkie says about power tools- we have all faced the wrath of the runaway sander/grinder :D
-
cut the tips right off- and z splice in some static tip recurves, and maybe a nice neat epoxy saturated wrap over the join- might as well try something funky!- but that will add poundage too!
-
Take this for what it is wort as I am NOT an experienced bowyer. I would make sure that I learned from my mistake. I would hand sand all the fiberglass from that limb to the center of the riser, replace that piece of glass, and cover joint on the riser with an overlay.
It might not work, but by the time I was done I will have learned my lesson, and only be out another $5-10 for half a fiberglass lam.
-
I feel your biggest issue is that there is a chance of delamination... If you are bent on salvaging it I would do what Bert and Pago suggested... But to keep from delamming and to strengthen the joints I would put that top layer of glass about an 1 1/2" pass the scarf joint and feather it to nothing... Take some epoxy and wet out the area to be wrapped with cotton... Take cotton thread and start wrapping your limb about a 1/4" before the end of the F/G taper and wrap it up to about a 1/2" past the scarf joint... Saturate the cotton well with epoxy... Could probably use ea-40 if it is warmed up enough so that it is on the thin side... Or just wrap with the cotton and saturate later with thin super glue... Might work... There are no guarantees... That is a heavy bow...
If you hear any creaking or cracking that is probably the F/G delamming... The wrap will probably buy you some time so the bow does not blow without warning...
-
If shortening the bow isn't an option I would not chance a repair. Chalk it up as a 120.00 lesson and move on. Way cheaper than any hospital visit! And no matter what anyone tells you , you can't replace an eye! Lol.
I would never sand glass to try to reduce weight. I'll sand on the belly to adjust tiller but never as an option to drop weight. Trapping and rounding will shed some weight but only so much.
-
I've messed up bows too. I've patched some up that held together. But it was always in the back of my mind shooting them, that what if it lets go and I get hurt or someone else does. So I finally cut them into pieces and moved on. Is it worth the possible consequences?
-
Do away with the divot. Cut the tips off at the string grooves. Sand flat to divot depth & taper in. Replace the tip spacers to cover past the area and reinforce it. File the string grooves in only a 1/2 or so back from where they were. End up with slightly shorter tips,slightly longer tip spacers with out increasing the weight so much. leaving no splice. Reduce weight from sides and or trapping. Just thinking out loud. good luck Ken
-
Either pitch it and chalk it up to experience or pike it and find someone who can pull that much draw weight.
Whenever I need to reduce weight, I narrow and/or trap the limbs towards the back. I've always been too afraid the sand the glass. It just doesn't seem like a good idea, although that's how some do it.
-
Hard lessons stick the best I guess. I'm gonna sand it out flat and scarf it. I think this tip won't have any trouble handling it as there is no bending going on there. I'll post pics and give it a good stress test on the tree before I shoot it. Now black glass so I have a stark reminder or clear to camo my mess up... hmmm...
-
Shorten it or junk it. You can sand the belly glass BY HAND with a flat block count your stroke on each end. really rounding the corners or trapping. By hand is slow but more safe from screwing up. :knothead:
-
just a comment in general and not pointed at anyone particular...I advise against sanding glass to remove anything more than an pound or two. If you need more than that, then trap the back but don't sand the glass to lessen the thickness. you ruin the glass to core ratio and really hurt the shooting characteristics of the bow. not to mention the fact that unless you are really good, you'll get some areas thicker than others and that could lead to disaster. again, just my opinion.
-
(http://i1077.photobucket.com/albums/w466/tyrelljrutledge/Mobile%20Uploads/20170109_154350_zpsjwgcfp8c.jpg) (http://s1077.photobucket.com/user/tyrelljrutledge/media/Mobile%20Uploads/20170109_154350_zpsjwgcfp8c.jpg.html)
That's about 6 inches of clear glass with smooth on covering the area. I'll smooth the joint down to something pretty after its all dried up.
-
I've got my start in making self bows so managing tiller shouldn't be an issue. However I completely agree this was a dummy mistake and it was haste that led to my fail.
-
However I completely agree this was a dummy mistake and it was haste that led to my fail.
Oh I know how that goes.. :)
-
Originally posted by Bert Frelink:
It's not ruined, grind the tip overlay and glass off(carefully) scarf joint another piece of glass to replace the end piece, glue on another piece of glass to cover the glass joint underneath and replace your tip overlay.
You would be way better of to round the edges to loose weight than grinding the surface glass, maybe tuck that away for next time.
Good luck, let us know things work out for you.
Regards.
Bert
X3 for berts plan.
Or cut it up and throw it in the bin,
-
Well this thing is too dang pretty to cut up, worse case scenario(if this scarf thing doesn't pan out) I shorten it Polish it up and have a 75-80 pound wall hanger.
I do appreciate all the feed back guys.
-
If you don't feel confident in the scarf patch, instead of just shortening both tips, how about trying to make it a two-piece takedown bow with a new limb to replace the one you sanded into too much? I've seen other posts where guys will take a good limb from a bow that failed and make another limb for it. It's a little more expensive than your current solution, but I think it would be better to do that than to make wall art out of the bow.
-
The scarf repair scares me, I am afraid it Will lift and... Could you pike it and narrow the limbs? I did repairs on 2 D/R longbows for friends where tips were smashed in doors or tail gates. Both had to be piked, narrowed and new tip overlays glued on..I did not enjoy these repairs.. Most guys only sand the belly side to reduce weight or adjust tiller. I think someone here on TG peeled the back glass off and replaced it with new glass on a bow..maybe it was JamesV?
-
It's not a recurve, I feel like there should be near zero limb movement this close to the tip which will work in my favor.
-
Well good luck.
-
Well good luck.There is bending there thin part of the limb.
-
I hate it when that happens.
-
(http://i1077.photobucket.com/albums/w466/tyrelljrutledge/Mobile%20Uploads/20170111_160023_zpsnpnmlwvw.jpg) (http://s1077.photobucket.com/user/tyrelljrutledge/media/Mobile%20Uploads/20170111_160023_zpsnpnmlwvw.jpg.html)
The old boo-boo is about where I'm pointing and the overlays is about 3 inches on either side of the joint. Gluing on a new tip and I'll start putting it through some testing on the tillering tree
-
Looks good. but the glass butt joint there will be you problem eventually. I could be wrong though.
-
I would never trust that.
-
On one of the first bows that I made my bottom mdf form gave way at the riser during glue up and the glass had a gap mid way up the bottom riser fade. I ground the glass off from the top of the riser ramp until I got to the glass that was glued down. Glued on about a three inch piece of glass and blended it in. You could barely see the splice-until it failed after a Few weeks of shooting. Learned 2 things. mdf does not make good form material and the fades flex a lot higher than I thought they did! Mike
-
Your repair looks really good. However I would cover that butt joint with glass or something similar. If you do that, you could feather the top layer as you move away from the butt joint underneath.
-
Bow failed. But it was actually in the riser when I was stress testing the bow. Looks like the glue didn't bond well at all to the desert camo stuff where I mixed it with osage. Maybe I should have degreased it better or something.
-
(http://i1077.photobucket.com/albums/w466/tyrelljrutledge/Mobile%20Uploads/20170111_173609_zpspdsfdetl.jpg) (http://s1077.photobucket.com/user/tyrelljrutledge/media/Mobile%20Uploads/20170111_173609_zpspdsfdetl.jpg.html)
Also... after dissecting the corpse the clear glass that was intact with the desert camo lams just peeled right off. Super weird. All other glue surfaces were just as strong as normal. What did I do wrong here?
-
The glass to veneer bond is not nearly as strong as any wood to wood bonds. The epoxy just doesn't soak into the glass as it is very dense. It is not surprising to me at all that the glass peels right off after the bow broke. It you ever cut out longbow limbs on a bandsaw then take the scrap pieces and you will see that you can peel the glass off but you can't get the wood to wood pieces apart.
Your original fix for the bow should have been to grind off any overlays on the back of the bow. Then using a heat gun heat up the glass on the tip enough to get a knife between the glass and veneer. Heat the glass enough to loosen the epoxy as you work the knife between the glass and veneer all the way down the bow. This is a five minute job as the glass comes off easily. Then use 60 grit sandpaper to hand sand the epoxy off the veneer being carefiul to keep it flat and not rounded off or dished. If you want a reduced weight on the bow then get yourself a thinner piece of glass. Butter up the veneer and glass and put it back on the form. Cure it at a lower temp. About 110 degrees for 4-6 hours is about right. Leave the pressure on for 24 hours. Carefully profile the glass so you don't snag it and peel it. The bow will be as good as new.
I've done this on a half dozen bows that had flaws under the glass. These bows have been used and abused by myself, family and friends for years and are just fine. BTW I have never sold one to a customer just because, but feel confident that the bow is as strong as original.
Chad
-
I appreciate the feedback back. Good to know about being able to remove glass so easily. Thanks all. I hope we can all learn from This a little.
-
Did you clean the two pieces in the riser with acetone? Acetone will bring any oils in the wood to the surface and can cause an inferior bond.
Just a thought I had when I saw the pic
-
No acetone, I prepped the pieces by blowing them off with an air hose then wiping them down with paper towels.