I just don't know

[Kopper1013]

Well I just glued up my first glass bow... Nothing but trouble! During glue up my riser just kept sliding around, finally got that to stay, got it at taped and started to inflate my air hose. All that did was slide my glass all around and off to one side, I deflated my hose moved stuff around and upon re inflation the top half of my form split at about 50 psi so I quick deflated again and screwed 2x4's all down the side of the top of the form in order to try and salvage anything. I got the hose inflated again this time making it to 60psi and put it in the oven. I pulled the bow out 6 hours later only to find the glass had slipped again now the best I could have is an 1-1/4" wide limb will this even work. I'm so defeated right now guys. Do you guys have these problems, are air hose forms really this hard to work with?  Can I salvage this?  I got into this cause I love traditional archery and though hunting with something I build but be so rewarding, but man am I frustrated right now.

[kennym]

Bummer!

The first one is usually the worst, there is stuff you learn every time, and still forget from time to time...

A 1.25" limb will work fine on most longbows, on a recurve it will be tuffer to keep limbs straight..

There are lots of little tricks that help during glueup.


Here are a couple if I may...

1- clamp the riser, then tape it before laying rest of stack on.

2- Have something to hold lams and glass in place side to side. Fender washers, cool wellmade sliding holders, or a pc of plywood screwed to form side. The most important on a one pc is where the fades of riser are about 1/4" thick on both ends of riser. And about mid limb, the ends will be fine, you're gonna take the edges off to the nock anyway.

3- Ummm, the form breaking, I'm not sure, maybe a different form material would be in order, I like plywood but hear LVL is great too. MDF I have seen several pics where it broke in the bolt hole, usually while cooking.

4 - Add air 5 or 10 # at a time to give the glue time to squeeze and not move lams and glass.


What type bow do you have going? Narrowing will reduce weight, but you can still make a shooter most likely.

Sorry to hear all the trouble you had, but don't give up, taking game with YOUR bow is about as good as it gets!

[Bowjunkie]

Put keeper plates on the sides before you inflate to keep the lams from shifting to the side.

I dont do it, but I know guys who cant keep the risers from sliding around and they drill the riser in the area of the sight window cutout and pin it to the press. Plastic wrap will let it come apart afterwards.

The first couple glueups are stressful and mistakes are common and part of the learning process. Dont let it bother you too much. You'll get the hang of it.

What kind of wood did you use for the press? It should not have broken. Only press I ever had break was particle board.

[Kopper1013]

Thanks for the info guys, my form was built out maple 1/2" plywood that broke when I first put the hose in to glue down my Formica strip, so then I cut another one out of a 2x8 that's the one that split during glue up. They seem to keep breaking where I send the bolt through to hold top to bottom form. I know the pine 2x8 is some what weak but didn't figure 50psi would split it so quickly.
My "mess" was/is an attempt at a 64" r/d longbow, I was aiming for mid 50#s but went heavy with my stack at .423 with a .003 taper. Figured I can always take weight off hard to put it back on.

[bowhntineverythingnh03743]

Check out my form build a long.... Should help you! I want to build one form and have it forever so I'm going all out for this one

[kennym]

I think you have plenty of stack to get mid 50s there. Stay with her, I think you  will have a shooter, and maybe just what you want!!

[Kopper1013]

Bowhntineverythingnh03743 I've been watching your build along very nice BTW.  Kenny thanks for the info. At this point I gotta stick with it just to see and if nothing else learn from it might just have to step back for a day or two and regain some composure. I really hope I can save my first attempt. Think I'll try an LVL beam for the top on the next one. Could I have possibly used to much glue? Would that creat all the sliding problems I was having or like you said before did I just pressurize to quickly and not give enough time for glue to squeeze out? I posted a question before "what makes a lam bow fail" everyone said Not enough glue so I used a lot of glue stupid newbi

[kennym]

You probably can't use too much, it will squeeze out when you air it up.

On the other hand, lot less messy to use just a little more than stays in.

The glue will be like grease when you put it together, and way too heavy could make stuff move more if you don't air up slowly.

You really just need enough in there to coat each side of each pc necessary with no dry spots. I put it on, look for dry spots, then with a paddle or spatula, wipe over it one more time to get the glue smooth so it won't trap air bubbles as easily.

[Roy from Pa]

Hang in there, Greg..  It's all trial and error before we get it right. If Old KennyM can do it, so can you:)

[fujimo]

What I learnt from some of these ol geezers on here, was to drill a toothpick sized hole through the back lams and glass into the riser. And peg it during glueing, and I also mark a center line on the form and the riser, and keep an eye that those marks stay matched.

I had my first riser slip too....I know your pain mate!

[Kopper1013]

Thanks guys I really am enjoying my self so and sleeping on it along with your guys knowledge and support has give some fresh perspective. Thanks again! if I get it together I'll be sure to figure out how to post some pictures for ya'll

[canopyboy]

Originally posted by Kopper1013:
[QB]I know the pine 2x8 is some what weak but didn't figure 50psi would split it so quickly./QB]

I don't know how much longer your form is than the 64" bow you were aiming for, but a 1.5" wide form at 6' long has 108 sq.in. of pressure surface. At 50 psi, that's over 5000# of force pushing the two sides apart. With 4 tie-straps, thats 1300# per bolt hole. If you're using 5/16 bolts, that's almost 3000 psi of compression loading where the bolt goes through the wood. Stuff like pine and spruce 2x lumber doesn't like those kind of numbers.

I think people often underestimate the forces their form has to take when you use an airhose. I know I did the first time....

[Kopper1013]

Wow you know I never thought of it like that or put 2 and 2 together. My next form will def. be LVL, I don't like how my plywood held up either.
Sanded all the glue off tonight and sanded sides down till I got an even stack, looks like best case is an 1-1/4" wide LB. should of worn a long sleeve shirt cause man do I itch, you'd think I'd know better working around fiber glass insulation everyday. Oh well! Thanks again for the info feel free to keep it coming gonna be a big learning curve over here hahaha

[Todd Cook]

If you can get 1.25" wide, with .003 taper you should be fine. Maybe leave it a couple inches longer till you find out how much weight you have. You can always shorten it later.

I glued up a Hill style a few years ago for someone else. Ended up with bubbles under belly side glass on the top limb. I wouldn't sell it, so I made the guy another one. My wife talked me into finishing it( I had considered scrapping it), and I liked the way it shot, so I kept it. I've killed several deer with that bow, ugly limb and all. So you never know.

[kennym]

Originally posted by canopyboy:
 

Originally posted by Kopper1013:
[QB]I know the pine 2x8 is some what weak but didn't figure 50psi would split it so quickly./QB]

I don't know how much longer your form is than the 64" bow you were aiming for, but a 1.5" wide form at 6' long has 108 sq.in. of pressure surface. At 50 psi, that's over 5000# of force pushing the two sides apart. With 4 tie-straps, thats 1300# per bolt hole. If you're using 5/16 bolts, that's almost 3000 psi of compression loading where the bolt goes through the wood. Stuff like pine and spruce 2x lumber doesn't like those kind of numbers.

I think people often underestimate the forces their form has to take when you use an airhose. I know I did the first time.... [/b]

[kennym]

Originally posted by canopyboy:
 

Originally posted by Kopper1013:
[QB]I know the pine 2x8 is some what weak but didn't figure 50psi would split it so quickly./QB]

I don't know how much longer your form is than the 64" bow you were aiming for, but a 1.5" wide form at 6' long has 108 sq.in. of pressure surface. At 50 psi, that's over 5000# of force pushing the two sides apart. With 4 tie-straps, thats 1300# per bolt hole. If you're using 5/16 bolts, that's almost 3000 psi of compression loading where the bolt goes through the wood. Stuff like pine and spruce 2x lumber doesn't like those kind of numbers.

I think people often underestimate the forces their form has to take when you use an airhose. I know I did the first time.... [/b]

And those numbers are why MDF just don't make good forms!!

Do what Todd said and put the nocks in an inch long on each end too, cause I think she is gonna be a little overweight....