Primitive Archer
Main Discussion Area => Bows => Topic started by: DustinDees on October 21, 2012, 09:51:49 pm
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I returned home from a 1 year deployment in may to LOTS of extra work, so i finally got around to putting together a new bow about 3 weeks ago. I have a friend that wants a BBI ELBish styled bow. Started with the first one 1 inch wide and 70 inches tall, got it to brace height and it was shifted a good 4 inches to one side. I didn't like that at all, all the tension was being taken by one corner of the hickory backing so i heated to straighten.... duh, the glue let loose and the bow blew. My fault entirely, but i noticed the hickory released along the entire bow when i pulled on the backing. I made sure to sand and clean the surfaces with acetone... time to try again. Glued up the same thing and made sure i shaped slower and deliberately. No side bend on this one. Got it to brace height yesterday and worked on it all day, beautiful bend, perfect weight when i got it to 60# @ 26" it blew, this time it released 3/4 the way to the top nock and the ENTIRE backing released. I made sure it was sanded, clean, and oil free before gluing up. The glue took to the hickory but released clean from the ipe. Used TB3, not expired and recently purchased, it hasn't been frozen or even under 60degrees, the glue line looked phenomenal . *sigh* next time im going with a hickory backing with something else.. ANYTHING else. Is there another way to remove the oil deeper? Any advice at all would be very much appreciated. Thanks.
Sincerely,
Dustin D.
*edit* wow i really put that, i meant HBI not BBI.
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i am going to be doing a hickory backed ipe, and from what ive heard, tb3 may not be the best for ipe, just what ive heard......
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ya i think your glue might be the problem i would try urac 185 or smooth-on epoxy
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I understand that epoxies like bowflex and the like are accepted by many bowyers, but i don't want to rely on something not readily available for glue ups, i think i will be transitioning towards staves only here shortly. Thank you for the reply.
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i use tb2 on epe with no problems, now finding a good pc of epe when ya cant see the grain, that's what gets me, Bub
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On Ipe I plane the surface, then scuff with 150 grit, wipe down with Acetone, glue with tb3. No failures. Moderate clamping pressure.
VMB
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On Ipe I plane the surface, then scuff with 150 grit, wipe down with Acetone, glue with tb3. No failures. Moderate clamping pressure.
VMB
What counts as "moderate clamping pressure"? Inner tubes?
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tubes are what i use, Bub
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Thank you for the replies. I will have to try that again... eventually. I'm just disgusted that i have broken that much wood in just a couple weeks. I know bows break, but this is the first time i have had 2 back to back. Its just really disheartening.
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If you can peel off the complete backing (or if it broke in such manner), there's something wrong with the glue-up procedure. TB3 has been used countless times for BBI's, so that can't be the problem in itself. It's probably either too much clamping pressure (resulting in a starved joint) or inproper surface preparation. Myself, I make sure both the backing and the ipé are 100% flat using a thickness planer. The planer leaves the surface too smooth and compressed for my liking, so I always sand the planed surface. I take a sanding block with 80 grit sandpaper and create a flat and even surface using loooooong strokes with the sanding block. Sanding takes only a few minutes, since I don't want to remove a lot of wood, but just need a fresh layer of wood. I use a brush and cotton rag to remove all dust.
By the way, check your bottle of 'acetone'; is it really pure acetone with nothing else as contaminant? Did you make sure all acetone was evaporated before you did the glue-up? I intend to wait at least half an hour after I put on any solvent for degreasing. I never degrease the backing, and only occasionally degrease the ipé. It's not necessary by all means.
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I use oven cleaner on Ipe and never had a problem.
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Its just really disheartening.
I understand that feeling. I once busted three bows in one afternoon. But we bowyers are a strange lot, not enough sense to quit while we are behind and have a mounting pile of low grade tomato stakes outside the back door of the shop. Then when we do make a decent bow, we don't know enough to quit while we are ahead, and ever single piece of standing wood is now threatened with a chainsaw wielding maniac!
Try a hickory backed hickory bow. You can add reflex as you glue it up to increase a little cast and give yourself a chance to work on glueing up.
Relax, it's only wood.
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The first time, if the bow was shifting 4 inches to one side I would suspect the straightness of the original straight line down the bow or maybe the way the glued up bow was reduced. It is possible to glue a straight set of backing/belly into a curve or also to induce a real problem in the way we file or rasp the bow. Not accusing, just saying what may be a potential cause.
If the glue line keeps going I can only assume that there is a problem at the glue line. It can't be the woods as these have been used with success many times. What I have seen and experienced is that it is really important to follow the instructions. Prepare the surface, apply the glue, join the surfaces, apply the pressure, waiting just as the instructions say! This may be obvious but I know of cases where enormous aircraft hangers have had flooring paint put down where they painted part A n the floor without mixing it with part B as instructed!
My personal preference is for Resorcinol glue. This seems to be fairly forgiving, gives a long open time and if bound with rubber inner tube strip works really very well.
Glues can fail for many reasons. Too much pressure. Too little pressure. To small or big a gap. Too much or too little a gap. Too smoth or too rough surface. Too hot or too cold. Glue going off too quickly before joining, or the opposite. Use the right one (and there are many good ones) in the way that works for you and all will be OK.
Good luck,
Mark in England
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I use alcohol instead of acetone and I generally do not have a problem in straight glue ups with ipe. The only problem I had was in trying to add reflex by clamping a few inches from the tips and starved the glue joint. 2 failures in a row that didn't show up till final tillering. What a bummer. Been doing straight glue ups since, but will soon have a smooth reflex board to use. I use bicycle tubes, too.
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Lets see. The first one i glued up before i left so i really do not remember times but i used electrical tape in lou of tubes. Glued in reflex and it held fine until i heated the limb and the hickory released just in the areas i heated. the hickory was warped about 1/2" in 12" of released backing, so im assuming i glued the backing in with a bend to straighten the grain, putting stress into the glue up causing the warp. the second one i had the backing planed and sanded. i sanded the ipe with 100 and cleaned up the ipe with plain Klean-strip acetone, let it dry for about 10 min at 65 ish degrees (now i know not long enough) and glued up with approx 28 spring clamps, 4 pipe clamps and 2 "C" clamps. i let the glue dry for 1 week before shaping began. when the backing let loose it held a good glue line to the hickory but the ipe was bare. the glue side of the backing was slightly brown but had no wood grain stuck to it. I have done quite a few hickory backed bows, a hickory split with an ipe center, oak, hickory, im over 30 bows now and i know there is always more to learn but its disappointing when you set it down for a while and forget basics. again thank you for the input.
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Glued in reflex and it held fine until i heated the limb and the hickory released just in the areas i heated.
To quote the guys from Mythbusters, "Well, THERE'S your problem." At last for the first one.
Anyway, better luck on the next attempt!