I have built six bows with no issues like this. I used some Paduak for the first time and got the following results. I am using smooth on epoxy and the bow is in the oven for 4 hours. I only had the lams in the oven for about 15 min prior to glue up. The bow comes out looking great and when I get to the point of drawing the bow I hear slight creeking noise and the lines begin to form on the back of the bow. The Paduak is some wood I purchased from a local shop and cut and ground myself.
Any thoughts on why the development of this new issue?
(http://i1073.photobucket.com/albums/w394/cunruhsurf/Bow%20Making/th_25dc7ab33633caba83524a8f717c171b.jpg) (http://s1073.photobucket.com/albums/w394/cunruhsurf/Bow%20Making/?action=view¤t=25dc7ab33633caba83524a8f717c171b.jpg)
Did you grind on both sides? It kind of looks like saw marks..
I am watching responses here. I have had LOUSY results with padauk. Tried twice to put it in a lam stack as a sort of racing stripe on a BBI but BOTH times it just tore in half..literally. Broke my heart cuz it looked totally COOL
I made a padouk limb bow many years ago to workes fine. Its not the wood.Did you let lams cool off to room temp before spreading glue? Was a heat source near that spot.Did you sand lams with at least 50 grit paper? Many questions no answers wish I could help.
The padauk I bought was very wet/oily, may be an adhesion problem. I used a block of it to prop a form in the oven and when I took it out, had a run of oil an inch long down the side.
Sold a pc of it to a guy who reported it checked to heck too, replaced with something else.
I also made my wife a bow with purpleheart limb veneers, similar results to yours except only little marks along limb edges
Sorry for the slow response - long day at work.
I did not let the lams cool from the preheating time...I typically take a lam from the oven to the bench to apply glue. Elmont from Bingham mentioned that the lams needed to be sanded with 30 grit I believe he said and I did not do that. He also mentioned that this wood is very oily.
I am guessing that this bow is unsafe to shoot...is that fair to say. I still get little cracking noises when I attempt to draw back to full draw...makes be a bit nervous.
I am going to layup another bow with bloodwood to see if I get a clean bow. I am getting different advise on preheating the lams some say it is not necessary and others say mandatory. So I put them in for 15 mins to split the difference.
I would say the paduak was either still green, or most likely just an oily piece. If you continue to get those cracking noises I would guess it will delaminate.
If you think the Paduak was oily, wait until you deal with the Bloodwood.
Built one riser using Bloodwood and swore to never use it again.
Never seen a wood gum up the drums on my spindle sander and belts on the edge sander so bad.
Troy
I feel the only time you need to stick lams in oven is on super humid days.Maybe five min. time lams are thin no need to dry them that much. If lams were hot when you started gluing you are starting to kick glue. Epoxy works faster with heat.I have seen spots that look like crystalized. sand paper should be 36grit,40grit,or 50grit. looking for trouble with less.I am from Old Master Crafters with 38 years.
Thanks everyone for your input...I was worried about the next bow and a little hestiant to start another one. I don't have the disposable income to keep buying glass and have the bow sit off to the side unusable and ugly. Not the kind of trophy you want to hang on the wall.
Thanks also for the heads up on the bloodwood...I think I will pick a safe wood to rebuild my confidence.
Dont know if its worth your time but you could pop the glass off and re-do it.
How is that done? I have not heard anyone talk about that process. I would consider giving that a try if it was safe.
Looks like either moisture or got too hot, did you use a hot box or heat strips? Heat strips getting too hot will do that to glass in a heartbeat.
Dave
I looked up some other threads on the process of removing glass and applying a new piece. Rather than let this bow go unused - I think I will give it a try.
Peel off the glass .
You will be surprised how easy it is to do.
Use an old wood chisel and a hammer to start to lift some glass at the tip then continue by hand. ;)
The pattern looks like form/hose issue to me.
Make sure all of your pressure strips/hose/rubber and such are laying flat and making good contact.
60-70psi of air.
I just went and purchased a heat gun and I ground down the nock overlays back to the glass. I heated up the glass at one nock end and peeled up the glass then proceeded to slowly pull of the glass while heating the portion directly below. The glass would release from the wood and pull right up.
I had a couple of little splinters of the wood pull up and I am glueing those sections back down with TB2 and I will now order a piece of glass - sand down the wood with some 40 grit paper and prep for a new glue up.
I just went and purchased a heat gun and I ground down the nock overlays back to the glass. I heated up the glass at one nock end and peeled up the glass then proceeded to slowly pull of the glass while heating the portion directly below. The glass would release from the wood and pull right up.
I had a couple of little splinters of the wood pull up and I am glueing those sections back down with TB2 and I will now order a piece of glass - sand down the wood with some 40 grit paper and prep for a new glue up.
When I glue up the new glass piece using Smooth-On should I let it cure for a longer period of time out of the oven? I don't figure it is a good thing to put the bow back in the oven causing the existing laminations to come apart in the heat. Will Smooth-on set up ok without the heat of the oven?
If it's in the form under pressure then putting it in the oven won't be a problem- it will also dry without heat in 24 hours.
When you ground your limb laminations what grit paper did you use? I've seen that adhesion problem with 120 grit and above on heavier bows.
Good point 7 lakes. I like 36 to 50 grit. Added insurance that that the glue joints dont get starved.