Primitive Archer
Main Discussion Area => Bows => Topic started by: NTD on June 26, 2011, 04:06:24 pm
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Would bamboo that is planed flat possibly become crowned after sitting for awhile and losing moisture in a drier enviroment? It's the only thing I can think that might have happened. I got some bamboo from someone that always has top notch stuff. It sat for a couple months. Well I glued up a BBI last night and when I unwrapped it this morning it's a disaster. There are large gaps on both sides the whole length of the bow. At one part of the limb the boo is cracked where the bicycle wrap was trying to pull it flat to the ipe. I checked the other piece of boo and it also has a crowned belly. The only thing I can think of is that the boo dried while sitting in my dry climate and it pulled the sides of the boo up and crowned it. I guess the moral is to always check before you glue it up ::)
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O bummer, that is too bad Nate. I'm about to build both a BBO and BBI. Hope that doesn't happen to me. ???
George
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Nate, you might be better letting the boo acclimatize first before final thinning. I think it would be less likely to crown or crack like that.
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Pat, this wasn't your boo, this was glue up ready boo....
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I guarantee it will roll up on the sides, I have had it happen to me several times. It is a real bummer.
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I guarantee it will roll up on the sides, I have had it happen to me several times. It is a real bummer.
Thanks Justin,
When I get the glue up ready stuff I'll have to remember to glue it up sooner rather than later, and if not to check it and knock the crown down, it's a shame that a whole power lam, core and boo back are now firewood....
I'm thinking of sticking to stave bows for awhile....
Good luck with your glue ups George.
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Nate, what glue did you use?
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Weldwood plastic resin, there's no delamming this and trying again Pat ;)
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The moisture in that glue might have affected the boo. I've used Weldwood Plastic Resin with good results on bows but we aren't near as dry as you guys out west.
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Pat,
That's why I mentioned that I checked the other piece, it has a crown as well. I've used this glue several times before for BBO's and BBI's, never had a problem, and the other piece being crowned tells me it wasn't the glue.
Yeah, we're dry out here....It's a different world. It's 9% RH outside right now....and dropping, just went to 8% as soon as I posted this.
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I WILL STICK TO URAC RESIN 185TO ME IT,S THE BEST AND I HAVE MADE ALOT OF BOWS
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Yeah Wytetale, you have and you make some nice ones, but this isn't my first rodeo, and it sure the heck wasn't the glue.
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I USE URAC 185 TO ME I THINK IT THE BEST ALLROUND GLUE AS FAR AS THE BOO I DON,T THINK IT WAS TO DRY MAY BE THE WRAP WAS,T TITE ENOUGHT
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Nate, I believe that your real problem is that it's been far too long since we've seen any of your work. The only solution will be to make more bows faster, so that you use up your materials before they decay on you. :P
Just kiddin. That's a crappy deal. What a waste of materials and $$!
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wytetale, Weldwood Plastic Resin is about as close as you can get to Urac and not be it. It is also a urea glue but it comes in powder form and mixes with water. Once cured it is hard to tell them apart. ;)
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wytetale, I've used Urac as well, but there is not much difference between the weldwood resin and urac. They are both Urea resin glues.
The point is, if you read my whole post, the other piece of boo has the same crowned belly. It wasn't that the clamping pressue wasn't tight enough, I know how to glue up a blank. The fact that the piece that has not touched glue is crowned should be proof enough this wasn't a gluing issue of a clamping issue.
Justin, Thanks for the reply, I think you're the only other one on here that might understand what an arid climate is.....
Thanks Cam, but I think I might be done for awhile.
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That sucks. I've had boo do the same thing. I always stick it in the hotbox for a while now, and then I re- flatten the belly on the belt sander before I glue it up.
Yeah, I'll be checking the boo before glue up from now on. I also may build a humidor type chest for my bow wood/boo etc.
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Nate, I'll bet if I sent you a seasoned osage stave from here it'd crack like crazy there. It's 47% RH here now at 95 degrees. I've had trouble sending wood to the north all year splitting once it arrives. Low humidity can really play havoc with stave bows too.
George
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Oh definitely George, I don't doubt that but at least with staves there are less working parts to worry about ;)
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Scott,
That makes sense in theoy but I've never had it happen in practice here. Every boo strip I've gotten from the east coast in the past was glued up within a fews weeks of receipt and if it was going to crack because it couldn't curl after I would think one of the many boo backed bows I've made would have had that happen. I'm not saying you don't have it happen, just that I haven't seen it here.
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Hey NTD not sure who you bought if from but I sell a tone of bamboo ready to glue planks. after glue up did you stick the blank in a heat box? Most people dont know it but once you have the bamboo almost perfect the way you want it you have to cure it in a heat box at 200 degrees for 5 hours. once that has been done the bamboo will gain a crown and then you have to re flaten. if they did not do that and you put it in the heat box that is where the problem is. I have made tones of boo backed bows and every time I take these steps I have never had a problem. if you did not use a heat box but had it in a garage or attic or somthing like that where it stays hot all day long, that will do it to. never heard of a dry climate doing it but I guess anything is possible. if the person you got it from has there shop set up right to sell items like that it sould be as dry in there as where you are. I keep mine around 10 to 12% humidity levels and heat treat all my bamboo and re flaten before selling and always have good results. I hope this helps.
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BowNut,
A bit drier than your hotbox ;) ;D
(http://i95.photobucket.com/albums/l144/NDanforth83/WeatherBug.jpg)
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Nate, my skin would crack with humidity that low. Don't get discouraged, and press on man.
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BowNut,
To clarify, my point about how low my humidty is was to illustrate that I don't expect anyone to prep their boo prior to shipping it to me to handle RH's as low as 5 and 6% and 110F temps in my garage. He may very well have done the hot box, intentionally had the edges lift and then flattened it, but the extremes here may have just re-bowed it. That's my fault for how I'm storing and not the seller's fault. The guy I got this from is beyond reproach IMO.
Lombard, You acclimate...some...