Hi all. I've been building one piece recurves for several years and have built about 25. All the same design. Recently my own bow I built delaminated on the back between where your pinky finger rests and the fadeout. It happened very soon after it was done and I was not surprised because I could see air bubbles under the glass and was slightly expecting it. I worked EA-40 into the gap with a putty knife and compressed air and reclamped (no heat.) It lasted for awhile but soon delaminated again. Anyway, I ended up glueing three times and the last time it delaminated at full draw and created a hinge piont and some cracks in the core laminations at fade. I figured just a bad riser shape job on my part and started the hunting season with a borrowed bow that I had made for my brother about 4 years ago. It delaminated recently as well. My dad texted me pictures of his bow (built the same time as my first one I talked about) it started to seperate in the same area this evening. All the same form/jigs, all the same area delaminating, built several years apart but I haven't gotten calls from any of the guys that have bought the 15ish bows that were made in between (I'm scared.) Also, I have shot for sure one of my bows thousands of times over the last 3-4 years and it has no issues. It's a light draw (34#) and maybe there is less stress on the weak pionts. The weights of the bows that I have told ya'll about are 50#, 40# and 44#. I will post a few pictures and you guys can answer and ask questions. As you'll notice the bows are strung to show the seperation better. The one bow doesnt show delamination until braced. Thanks.
Here are the pics.
I also can send pics of my riser jigs. They are jigs that ride along a rub bearing on a drum sander
I'd make sure the glue is good, then make sure the riser is rough enough, also the lams. I run .050 zirc on my lams and 36 on riser. Mine are D/R but should be all same .
Also looks like the spot where it delammed has a dip in riser there, could that cantilever off the part toward fade and cause prob?
Just flinging ideas here...
Adding to what Kenny just posted, I think I'd take a close look at your form to make sure you have uniform pressure in that section when laying it up. Sometimes adding a wedge on top of your air hose can tighten things up during lay up.
I recently had a couple sets of limbs delaminate in the curl section of my RC limbs by not using wedges on top of my air hose like I always do... I was distracted during lay up and missed it. I've built hundreds of these limbs on this form, and always use wedges to tighten up the area in the hook. I insert the wedge tips so they overlap on top of the hose, bump the pressure to about 25-30#. Then tap the wedges in until the lams come together nicely, then pump the pressure to 55#. Food for thought.
Btw... your fade look good...
Fades look to short to me. :o
.062 at 1" and .125 at 2"
I had a couple do that to me. One my fade was too steep and the other I had gotten plastic pinched in between the lam and riser. Not saying either is the issue but maybe???