Hey fellas,
It's been a while since I've been on the site. I am on my third homemade longbow, using Bingham's plans. My first bow turned out beautifully, and without a hitch except for the finish that would not dry on the cocobolo riser. Thanks to some helpful suggestions from you guys, the problem was solved with a lot of sanding and a little superglue to seal the wood first.
1.) Anyway, my buddy asked me to make him one, just like mine. Everything went well with the laminating process, cut the limbs to shape, cut some nock grooves and left it strung for a week, while drawing it several times -- no problem. I cut the riser with a jigsaw rather than my bandsaw because the blade was too dull. I rasped it to shape -- approximately 75% finished, strung it up, drew it back probably 18" and POP! The glass just above the sight window was split about 4" up the top limb, and it looked like the core lams opened up. Not sure which happened first. Is this delamination?? I thought maybe the up and down motion of the jigsaw contributed to this, and maybe caused the lams to open up. Yea or nay?? This is the only thing I did differently than the first, except laminating it outside rather than in the kitchen.
2.) So, after being out $190, I ordered more materials and started another. The first two bows, I used Epon Versamaid epoxy -- fairly thin and runny, and very messy, hence no kitchen layup on the second. Third bow, I used Smooth-On, which I found to be much thicker, but did thin a little when mixed. I layed this bow up without the help of my wife to tape it up while I applied pressure, as I did on the first two. This time I used spring clamps after cutting slots into the form. Three clamps along the limb(reflex/deflex)and one in the center on the riser. Everything seemed to be going well, my clamp idea was working and preventing the lams and riser from sliding everywhere. I used the filament tape to tape into place, but the process took a little longer by myself. I noticed that the epoxy began to thicken up a little during lay up. I was interrupted for about 15 minutes by my two and four-year-olds (one disaster averted). Also, keep in mind that the temp outside in Northeast GA was a little over 100 degrees with a fairly steady breeze. I placed the hose and top of the form, pumped to 60 PSI and baked for 4.5 hours. When I took it out and off the form, I noticed that the lams were not all sandwiched tight together on the belly side of the fadeouts and in a couple places down the limbs. UGH!! Another waste of time and money! Do you guys think that the combined heat, breeze, and increased time, before the hose was applied was sufficient for the epoxy to begin curing making it thicker and less able to be compressed? While I was taping, it was difficult to tape and apply pressure without cutting the tape on the pressure strip, but I felt like I was getting it. I use every bit of the epoxy on one bow, so as not to under glue it and hopefully decrease the risk of delamination. It is terribly messy. Is there a better way that you guys use. I noticed on the T-N-T video by Black Widow that they apply epoxy with a roller -- very clean and quick. Me with my packaging lamination as a spatula, takes much longer.
As I lay awake disappointed last night, I was going over everything in my mind. The riser shape was the same, same form, same everything, except the conditions, duration of layup, type of epoxy. I don't know what went wrong. Did I just not apply enough pressure while taping it?? But I thought the hose takes care of that.
Any ideas? Another question, is it possible and safe to use this bow. It's not like there is open space between the lams, it's filled with epoxy. Could it be salvaged? I would say the widest gap is 1/32" in the limbs and 1/16" on the fadeout at the top of the curve near the handle. There shouln't be any flex right there right? But the limbs?? Is it destined for the wall of shame?
I realize this was an exhaustingly long post, but I am in dire need of some help, anecdotes, advice, ideas -- anything. I really enjoy building bows, and thought I had it under control after my first was a success -- it shoots great and looks beautiful, but it's looking like I was terribly wrong. Maybe the first was just beginner's luck. I don't have the time and funds to go through anymore trials!!
Any information you guys could provide would be GREATLY appreciated!
Thanks and sorry for the length,
Jeremy Holzberger
Topic: Questions for all you bowyers (Read 318 times)
