Lamination problems

[Nikodemus]

I ve got somethimes little bubbles looks like your foto and I think it´s the veneer
My problems only  when I use a special veneer (Wenge ist very bad /Zirikote +-0 /Maple never problems ).some wood is full of "porus" and the glue takes his time to penetrate .
If I glue the veneer first of all and then
temper with hot air for a short time the bubbles all comes up and after this procedre you can do the usual lamination without any problems .
Nikodemus

[talkingcabbage]

it's coming.  I managed to shoot some CA glue in a lot of them before I cut the tapers.  Now I'm just waiting for time to get a hypo needle so I can shoot some more in the tighter spots.  I'm gonna try to get as many of them filled before I go bending them too much.

Had a question, though.  Maybe it's totally normal, but when I hold the limb against my leg and try to bend it ( I was just testing the limbs to make sure they weren't showing signs of delamination), they seem really stiff (like way mroe than 45#).  Is that normal?  Will it feel different with a string on?

[grizz]

Mister Cabbage, just my nickels worth. The limbs will feel stronger till you get a string on the bow, just make sure you listen for a creak or crack when drawn for the first time. Now back to the air bubbles, at first I experienced some and then I started making sure that I wrapped the saran or plastic wrap around the glued up mess so that none could leak out. Also fold the ends up and over to keep the glue "in". And of course the obvious, be sure that both pieces are coated with the glue very well on the laminations. I use 80 to 90 psi on the air hose. Save that "new piece of glass for another limb, as Jack Harrison stated, "Don't throw good money after bad!"

[talkingcabbage]

Grizz,
Those were my thoughts as well, as far as them feeling stronger till I string them.  This is my first lam bow, so I just wanted to make sure.

I did wrap them with plastic wrap, just like you're talking about, and had both pieces coated real well -- well, maybe not well enough.  You know the saying, "Hind sight is 20/20"?

[razorback]

I'll just start by saying I have no experience with laminated bows. That being said i would think that since many use dark glass cold this be a "problem" that is way more common than anybody knows and if such is it not a problem at all, (from the mechanics side of the issue). If it is just from the looks why waste too much energy on it. Shoot it and make another one with the experience you have. Just my 2 cents worth.

If you are not sure, just paint it and give it to an old teacher, ex girlfriend/wife, boss, etc etc etc.

     

[talkingcabbage]

Razorback, if the bow was for me, I could care less.  But my brother bought all the supplies, so I'd like to give him something decent.  Right now I'm just trying to get something in the air gaps to get the color of the wood to come through so it looks a little better.  My father in law is a doctor, so I'm pretty sure he can get me a couple hypo needles to squirt some glue in those gaps, then at least it'll look good!

[BigJim]

Cabbage- That appears to be Zebra. I have had a few zebra lambs come up with small air bubbles as well as leopard wood and cocobolo. Irritates the crap out of me since I can't sell them that way.  As long as it is not excessive, it will be fine. No way you will replace that glass with out problems. Also tipical to only get bubbles on one side. If they are on the back side, it is common for bowyers to put snakeskins on or the sort. If on the belly side, there is no good fix except camo dip or live with it. I guarantee that those using colored limbs get this all the time and never know it.
The temp of the glue/or room can be a problem. Be careful in warming up the glue though since this will make it set faster. Also warm glue touching cold laminations is a fairly mute point. The instant it starts turing cold it thickens and back to loosing pressure during heat up and sqeeze out.
During 10 months of the year hear in the south, I won't hardly ever get bubbles, hot all the @#$% time and no AC in my shop. The other 2 months we can get some cool weather. If I don't take the time to get the room warm enough, and the glue warm enough, I get bubbles. I also force the glue into lams with heavy hand pressure and then put another thin coat on top of the coat force in.
Good luck, BigJim

[talkingcabbage]

That's all good to know BigJim.  It is zebra, and most of the bubbles are on the belly side.  When I do this again, I'm just gonna clean the crap out of the lams and warm the glue with the lams like you suggest.  Thanks for the tips.  

I'll try to post more pics this weekend.  I've got a lot of the bubbles filled already.  Like I said earlier, I really want these to look nice since the bow is for my brother, so I'm gonna get a hypo needle and try to fill a few more before I continue.  I should be able to get the limbs bolted to the riser blank and check for twists this weekend.  

Wish me luck!

[tim-flood]

You know a good paint job will hide a lot of stuff. remember the black " Black Widows " that were cheaper.  I'll bet ya they had bubbles too!!

[BigJim]

I'm shure thats what was up with those "black" black widows. Why do  you think people camo dip or put snake skins on.
Every time i've had imperfections, it has only been on one side. For me always on the back side which is the side away frome the hose. Perfect since this is the side to put skins on. Nobody is perfect, I just wish they wouldn't run in 3's or 4's or well you know what I mean.
The way I glue up a bow is as follows: heat up laminations to burn off surface moisture, wipe down wiht ascetone (real good for cleaning out cuts or finding new ones) mix and spread glue and use some pressure to fill any voids in laminations. Make shure no dry spots and plenty of glue to squeze out.  I use 36 grit to finish all lams, so there are quite a bit of hills and valleys to fill with glue.
I would be careful not to heat the glue too much. It would be better to heat the whole area or room. Even hot lams will cool down quick in a cold room and thus cooling warm glue.

Good luck, BigJim

[greyhawk39]

For what it is worth,I have made 3 zebra wood bow's,and have had this problem,I have a half cocked theory that this wood is so porous that I think it is absorbing the glue in places I am one of them that I put to much glue on for these instance's that I might have a dry spot and yet I have had these spot's show up.I have shot these bow's and have not had many problem's one bow I built for my cousin and it's had 2 thousand's arrow's shot through it.And nothing has happened yet or a court order being sued...lol...I just use 60lbs or pressure 180'f.These thing's haven't a factor in these particular build's...but for what it is worth hope this is some help...hawk.

[monterey]

I had one come out like that once and my solution was to camo paint the bow with flat paint and use it.

Not bein Mr. Smart A$$ here.  Sometimes things are just as well left alone.

[talkingcabbage]

I understand, monterey.  I suppose I am being overly anal about it.

I went to pharmacy to get a hypo needle for injecting CA glue into the bubbles, and would you believe -- when I asked the pharmacist for a "hypodermic needle for shooting super glue", they looked at me like I was some kind of weirdo!  Who'da thunk it!

[Holm-Made]

I'm about ready to give up on Zebrawood for veneers.  I've had this happen as well every so often and it happens to me with Zebrawood more then any other wood. Zebrawood is very pourous and sucks up a lot of epoxy, starving the joint.  It shouldn't hurt the longevity of the bow just looks bad.  I'm sure this is why most production bows are made with colored glass.  "What people don't know won't hurt them"

Any way you won't be able to fix it in my opinion so you can live with it or if it bothers you spend a little extra money and glue up another one.  

P.S. I'm still trying to figure out how you would inject super glue into the voids.     Are you thinking of going through the glass or in from the side through the lams?  Either way your going to make it worse and create a channel for moisture to get in and then your asking for problems.  Chad

[talkingcabbage]

I'm going to go in from the sides.  Some of the air bubbles have very small channels that come to the edge.  I just got the needle so I could get into smaller channels and fill what I can.  I'm not going to try to get all the ones in the middle.  I don't want to create more holes just to fill a couple.

[Bodork]

I'm a little late chimin' in but I agree with most of the points already made. I had some small bubbles on the first few bows I made using clamps. I noticed the clamps were loose when the bows came out of the oven because the heated epoxy flowed out an. An air hose fixed that problem UNTIL I glued up a bow using .030 flat grain zebra wood. It came out with the same tiny bubbles though not quite as bad. I've been shooting the bow for almost three years now and none of the bubbles have gotten worse. They sure bug me though!

[kennym]

Hmmm, I've been lucky on a couple I guess. What pressure is everyone using,and I'm sure everyone glues all sides of all lams?

[Holm-Made]

I called Elmont Bingham about this same problem about 2 weeks ago.  He said it was caused by 1 of 3 things.  Uneven pressure (could be from the airhose not laying flat), epoxy soaking into real open grained wood (most likely cause), or wiping the lams with cheaper brands of acetone which sometimes has impurities in it.  

I butter up both sides of each lam.  On the surface that is exposed under the clear glass I put a little extra epoxy and let it set for a few minutes before flipping it over onto the glass.  Before flipping it over I inspect it carefully and add a little epoxy if I see any spots where the epoxy has soaked in more then others.  Chad