Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: arachnid on February 05, 2017, 06:28:00 AM
-
Hello all.
After a few months of research and waiting for the fiberglass to arrive, I'm finally starting my first glass bow. As in the title, it'll be a 60" KennyM style. I have the form ready and already started working on the riser. I glued about 10 laminations using Elmer's carpenter's glue, then I'll grind it to shape and feather the fades.
Since I lack a lam griner (I'll get one in the future) I've made my lams with a planer and orbital sander and they came out pretty good. I'm shooting for a 40# bow so the stack should be 0.315". Converted to mm (easier for my to use) it's 8.04mm.
The glass I got is Bearpaw Powerglass, 0.8mm thick, 38mm wide. I have 1 parallel maple lam, 3.4mm thick. 1 tapered maple lam, tapering from 3mm to 1.6mm. That makes it about 8mm of total stack, which brings me pretty close. In edition, I'll use 8" long tip wedge made out of Ipe , about 3mm at the thickest point.
I plan on gluing the lams in the following order (back to belly):
Glass
Parallel+tip wedge
Riser
Tapered
Glass
That's it for now, I'll keep you posted on my progress. On the meantime, I'd like to know what you think.
Thanks,
Dor
-
Form with the riser clamped while the glue dries:
(https://scontent.fhfa2-1.fna.fbcdn.net/v/t1.0-9/16473472_1235170193239369_5251784102826438500_n.jpg?oh=ec1bd946bb7ab496cfe77ce09c1bcef8&oe=5904B8C1)
Parallel Lam:
(https://scontent.fhfa2-1.fna.fbcdn.net/v/t1.0-9/16473850_1235170199906035_5084233325644873424_n.jpg?oh=ae88abae2528b18159ab862d5dfa29ad&oe=59424A47)
Tapered Lams and tip wedges:
(https://scontent.fhfa2-1.fna.fbcdn.net/v/t1.0-9/16473473_1235170196572702_7878119533932096610_n.jpg?oh=2f59f19ff0dec9e77dbad3de9de5037f&oe=59055D42)
Tip wedge close up:
(https://scontent.fhfa2-1.fna.fbcdn.net/v/t1.0-9/16508596_1235170246572697_4048971945177072185_n.jpg?oh=26097531345ddddfd10fc30a4e4a537d&oe=58FF3582)
-
I like that riser glue up idea.Form fitting for sure.
-
I've been trying to find out where to get plans for a KennyM R/D. Can you point me in the right direction? Thanks!
-
Just contact KennyM here. Use the message system.
-
KennyM's form plans:
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=print_topic;f=125;t=011684
By the way, I'll be using the rope and wedges method for keeping pressure. So if someone has good experience with it, I'd like to know how to use it right.
-
Are you using epoxy for the bow glue up? Glass and wood glue don't work too well, I hear. Never done it.
Next thing is if gluing the riser with wood glue, don't want too much heat curing the epoxy. It kills the wood glue at ? temp.
Like your riser plan for glue up!!
-
Oh damn! Haven't thought that through... Heat can cause the riser to delaminate!
I only got the smooth-on in the mail today, that's why I used wood glue for the riser... For the glass, I'll use epoxy for sure..
Any idea how to avoid riser delamination? (I guess I can cure the epoxy at room temperature, but I rather use heat. Maybe concentrate the heat on the limbs only?)
-
I think I would research the wood glue and see if I could find the max heat it will take and then only heat the whole bow to somewhat less than that. Smoothon is supposed to be good with room temp heat so if necessary that is what I would do, or make a new riser...
-
You can cure the epoxy at room temp. I've done about a dozen bows that way without any issues. One of my personal bows has around 30,000 shots ( estimated) thru it so far.
-
Ok... That's relaxing.. I've read that heat curing cause the epoxy to have more heat resistance, lowering the risk of delamination if left in a car or in a hot climate. Since I live in Israel and the summer can get pretty hot (at 35-37 degrees Celsius), I hope I won't have any issues.
-
Next time Put half of the stack for the back of the bow on the form add plastic rap and then glue the riser on top of that.
-
Originally posted by Mad Max:
Next time Put half of the stack for the back of the bow on the form add plastic rap and then glue the riser on top of that.
This!.. Good Advice from Max...
-
Originally posted by Mad Max:
Next time Put half of the stack for the back of the bow on the form add plastic rap and then glue the riser on top of that.
Good thinking Max. Probably get a better fit that way.
-
I would cure the riser parts at room temp. then it will get the heat on normal layup using smooth-on. And the half the stack idea is a good one.
-
Great advices so far.
The lable on the EA-40 can says that the mix ratio is 1A:1:B and that the curing time is 24hr at 23*C.
HOWEVER, the label also says that by mixing 2A:1B by volume, "EA-40 will achive greater heat resistance and improved physical properties".
Anyone tried it? Is it also true when curing the 2A:1B mixat room temperature?
And while were at it, how much glue do I need for my bow (4 60" laminations + riser)? this stuff is pretty expensive and I don`t want to waste it...
-
If you have more wood you could glue up a new riser with the Smooth on..the smooth on is the right glue for building glass backed bows..I don't know about the wood glue? But I have read some where it could delam arround 145 degrees F or 62 degrees Celsius. I know you pay alot for materials and Glue..As far as cost goes it would be cheaper to build this bow once..it only costs $10-20 to make a new riser with smooth on..cheaper than having to buy one piece of fiberglass.
-
Oh, glad you finnaly got the glass and smooth on! We are so lucky here in the States to have the bow building materials close by.. I have only used 1:1 myself or 1.25:1, I use small 2 or 3 oz disposable plastic cups to measure parts by volume
-
For a 4 lam HH style bow I use 70 grams part A to 50 grams part B. I also don't use heat on riser but do 'cook' bow to 60 c for 8 hours.
-
A little more resin than hardner is good. some do go 2-1. Another thing I do now days is leave the parts under pressure for 2-3 hours before putting in the heat box. I feel all the bubbles etc. can get out before they may be trapped with getting things hot too quick.
-
Unless it's real hot or you are real slow, you have time to mix a little more if you run out.....
-
Originally posted by kennym:
Unless it's real hot or you are real slow, you have time to mix a little more if you run out.....
Thing is I don't want to mix too much and have it go to waste.
-
That's what I mean, mix light and mix more if need be. Just have clean stuff handy to mix in if needed.
Coat each glue surface but don't get any glue on you. :biglaugh:
-
Thanks Kenny.
Any suggestions on what to use to spread the glue? Just a flat piece of wood whould do, I guess, but I`d like to know for sure.
And, should I spread a thin/thick layer of glue on each lam?
-
I use a scrap of lam about 8" long and 3/4" wide or scrap glass will work too.
The glue only has to fill the sanding marks on the lams and glass, I put slightly more on than that tho. :)
-
Well it`s been a while but I finally got a belt sander. That should make things much easier.
So, while I feather the fades on the riser block I`d like to ask about "stable core".
I got 2 strips of it in my last shipment and I`d like to know if I should use one on this bow. What will it do and how much will it effect the draw weight?
Here`s a link to the product:
https://shop.bearpaw-products.com/WebshopB2C/Bearpaw_Power_Stabil_Core_Stripes/P-3429/1?Origin=Navigator
Thanks
Dor
-
you don't need it on a kennym bow, it's more for recurves and static recurves.
-
I was very eager to continue working on my bow so I spent some time in the shop tonight. Sanded and feathered the riser, did a few dry runs and then, before I got cold feet, I went on and glued it up. Man, that smooth-on is messy stuff.
Anyway, glue-up went fine (I think). I got what seems to be a good fit with no gaps. Used the rope and wedges method and it seem to work pretty good. Got a good squeez-out of glue. I won`t have time to touch it until saterday night so it has a long time to cure at room temperature.
Hope I won`t be diappointed.
That`s my setup...
(https://scontent.fsdv1-1.fna.fbcdn.net/v/t1.0-9/17098715_1262728293816892_2174270719966536146_n.jpg?oh=bb38aee4c4a7ee1afaa3d49cf69ecf9e&oe=5927998C)
Tips with the tip wedge
(https://scontent.fsdv1-1.fna.fbcdn.net/v/t1.0-9/17103585_1262728297150225_6331045308459849477_n.jpg?oh=2149e37b79b3fcecc742085bed9aaf66&oe=593CA3AB)
Riser Fades
(https://scontent.fsdv1-1.fna.fbcdn.net/v/t1.0-9/16864564_1262728300483558_9135921916085782934_n.jpg?oh=a8a80a48a36cb8e503b0d93687626e2e&oe=592A2F23)
-
I'll keep my fingers crossed for ya. ;)
-
I did a visual check today and saw a gap on the upper right fade (right where the handle starts). It`s not a working area so I hope it won`t cause a problem (besides cosmetics...)
-
Arachnid, you are a very creative fellow. On your next bow, find some mountain bike inner tubes and cut them into strips on the vertical lines and use those instead of the rope. If you can also get a strip of phenolic 1/2 as wide as your form and put it on last before the rubber bands.
-
Well, unfortunately the bow broke when I tried to brace it.
Things learnd:
-Use smooth-on for the riser.
-Don't compromise on less then perfect glue lines.
- Don't rush things.
It's off to the next try.
-
Originally posted by Pago:
Arachnid, you are a very creative fellow. On your next bow, find some mountain bike inner tubes and cut them into strips on the vertical lines and use those instead of the rope. If you can also get a strip of phenolic 1/2 as wide as your form and put it on last before the rubber bands.
The rope and wedges worked very well. The only spots I got bad glue joints are at the fades, where I didn't gring it currently. That's where to bow failed.
-
Sorry to hear it.
Can you post some pics of the riser and the break. Nobody likes having a failure, but they are great teaching tools for yourself and others.
-
Man I hate to hear that! Study it well(looks like you already have) and figure what went wrong.
Pics would be good, like Brad said, we all can learn something from each fail.
-
As I said, it broke right where the feathered tip of the fade blended into the limbs, but there was a gap there caused due to uneven sanding (I didn't keep it totally flat). I don't have pics of the break... I kind of took my frustration on it..
My original plan was to make a TD bow so maybe I'll give it a shot before I try a 1pc.
-
Arachnid,
Please consider this. Through many years and many bowyers of trial and error virtually everyone uses rubber bands or firehose, preferably firehose at 60-70 psi for uniform pressure. I would hate for you to get another expensive learning experience trying to reinvent the wheel. Best way I know of being of helpful with what you are trying to achieve. If it wasn't a fundamental critical element of building a bow I wouldn't beleaguer the point by stating it again.
-
Originally posted by Pago:
Arachnid,
Please consider this. Through many years and many bowyers of trial and error virtually everyone uses rubber bands or firehose, preferably firehose at 60-70 psi for uniform pressure. I would hate for you to get another expensive learning experience trying to reinvent the wheel. Best way I know of being of helpful with what you are trying to achieve. If it wasn't a fundamental critical element of building a bow I wouldn't beleaguer the point by stating it again. [/QUOT
I guess it won't hurt to try... I'll keep you guys posted.