Need Help and suggestions for first fiberglass laminated longbow

[Stephen B]

Hello Everyone Was wondering if there is anyone that could answer a few Questions for me. I have been Building Longbows for about 5 or 6 months now and have built about 6 bows, But have mainly just used Hickory and Bamboo maximum of 3 laminated pieces. I am now looking to attempt a multiple laminated longbow with Fiberglass back and Belly of the long bow. I am looking at using a black .50 fiberglass piece as my back then a set of Coreflex Action Bamboo 1.00 jointed on center line then Riser block and the another 1.00 tapered coreflex action bamboo then a tampered Black Walnut of 0.60 then a Clear .50 Fiberglass. I was wondering is this layout ok or should I move the Second Set of Coreflex Action Bamboo underneath my Riser block and alter the scarf Joints on my Center line and just use the Black Walnut and Clear Fiberglass on top of my Riser block. Thanks in advance for any help or Suggestions.

[Bowjunkie]

On my longbows, I put down the glass for the bow's back, then three core lams, then riser, then a .040 or .050 parallel lam, then the belly glass... similar to your second scenerio.

I like the main wood lams running behind the handle, and besides, it would be much harder to bend those thick butt ends of the lams down into the fadeout radius on the belly side. When I HAVE seen it done that way, with the butt end of the taper on the belly side of the riser, the bow is designed so that area is considerably flatter... as in some forward handle designs.

If you decide to put that middle lam on the belly side of the riser, do a dry run first to see if it'll make the bend.

[Robertfishes]

For the longbow I build I try to keep belly laminations under 0.075"..any thicker and it has a hard time running up the belly side riser ramp.

[Robertfishes]

Stephen. Welcome to the Bench.. by the way .50 glass is 1/2 inch thick. I know you meant .050 sometimes I type it without the zero too...

[7 Lakes]

What style longbow are you building, the stack is much different for a straight limbed hill style & a radically refelxed bow.

I'm assuming at this point you know to move your decimal one point to the left for all glass and wood measurements.  

What made you decide on .050" black glass for a back instead of .040 ??

[Bodork]

I agree with the others. I use thin lams down the fades because it hard to bend the thick ones. Another tip: don't let the glass or lams stick above the belly side of the riser block. The air hose will be against it and cause the glass and lams to lift off of the riser fade.

   

[Stephen B]

Thanks everyone for suggestions and help, and yes see what your all are saying about using thinner laminates on the belly to match up to your riser, I attempted to lay one of the coreflex .100, then the .060 black walnut, and the .050 clear fiber glass piece and there no way to get it to lay down unless I was to cut the riser angle to allow it to lay down at a much lower angle, and then it just would not look as nice. Also my first bow is going to be a 68" straight longbow, and second is going to be a 64" reflex/Deflex long bow.

 I was wondering about my lay out thickness also with what I have planned I will be at.360 which is at 40lb for a 68" long bow, I may have to cut it down to 66" to hit my desired 45lb draw, Luckily I also order 2" laminates because I am fairly new at building bows, so I will have room to play with if I make mistakes while cutting out the limbs so hopefully it will draw at 45lb with the ticker limbs, if not I can take 1" off of both ends and hopefully get my 45LB draw.

[Stephen B]

I epoxied everything together last night and it came out pretty good but I have a few Air bubble under my clear fiberglass laminate. I tried to get a even coat of epoxy on both the black walnut and clear fiberglass was wondering is this because of too much epoxy or too little epoxy or some other reason. Luckily it is along the edge of my limbs so Hopefully when I cut it out I can remove the majority of these bubble but would like to know what I did wrong so I can correct the issue on my next build.

 https://www.facebook.com/405581672878355/photos/a.416609558442233.1073741831.405581672878355/418957458207443/?type=1&theater

Sorry could not get the image to add to post so had to use link to my Facebook page where photo is.

[fujimo]

So here is what the folk on here have told/ taught me.
1.Put your glue cans in the hotbox, while you are pre heating the oven, that will get the two parts nice and thin before you mix them
2. When you inflate , put in about 10 pounds of air, give it 10 mins. Another ten ponds, more time and so on till you hit the 60 mark. That time will allow the air bubbles to slowly squeeze out without getting trapped.
Cheers
Wayne

[Crooked Stic]

The walnut will soak up a lot of glue. Here is what you can do. Butter one side of the walnut pretty heavy and lay it aside. put glue on the rest of your lams and let the walnut soak to be sure any dry spots don't show up. Of course you will have to do both sides the same. And warmer glue is better also.

[Stephen B]

So finally got some clear weather this afternoon and got to sand down edge's and clean all the excess epoxy from the limbs and cleaned the fiberglass up to see how bad the air bubbles where. This bow is not going to be savable, but going to finish it to get the practice of working with the fiberglass, and One thing I have learned from building bows no matter what a bow looks like on the outside does not keep a bow from shooting nice. Some of the first bows I made looked like crap but they ended up shooting really well, and I still pull them out of closest and shoot them.

[fujimo]

why is it not usable- small air bubbles wont hurt it- will it!!

[Stephen B]

Yes Fujimo it is still usable but was building this one for a friend, and not going to present him with it if it does not look nice and shoot nice, will have to try again and keep this for my own use.

[Stephen B]

Ok so have another question for you guys, When sanding the fiberglass what grits and how many times do you sand the fiberglass laminates. I started with a 220 grit on my dremel multimax and removed the protective coating on the black fiberglass and the clear fiberglass, then went to a 320 grit and sanded once by hand, then moved to a 400 grit and did once in strait motion with limbs then a second time in a circle motion, then moved to a 600 grit in circle motion. I did not apply a lot of pressure just enough to remove previuos sanding, but after the 600 grit sanding I cleaned with Acetone and there is a light white film on fiberglass it is not to bad but was wondering is this normal or should I sand again with the 600 grit, just do not want to sand to much so thought I should ask before going any future, other than that bow has turned out really nice there is a few small air bubbles but if not looking for them you would not see them just have to file grip into shape and apply finish coats of polyurethane. I will post pics or link to pic when I have finished it up, I am pretty happy with the outcome with it being my first time using Fiberglass and multiple laminates to build a bow.

[Stephen B]

Here is a couple photo's of riser and limbs I will post more once I get all 3 coats of polyurethane on bow and it is finished completely.There is several small flaws in it, but I am happy with the outcome since it is my first time working with Fiberglass, and multiple Laminates.  [/url] [/IMG]

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[Robertfishes]

I use a rubber block sander and 220 grit paper on my back and belly glass, no power tools on glass surfaces for me. No need for finer grit.. alot of guys use 180 grit. The white haze on the sanded glass  will disappear when you apply the finish

[Stephen B]

Thanks for info Roberfishes, I went a little overboard with the sanding on this one it seems but now know to stop at 320 grit, I have few other question for everyone, does anyone know of any good how to DVD or books that teach how to make bow strings, I want to learn how to make my own strings.I was also wondering if anyone has used Koa wood for laminates before, I was thinking of using it under a clear fiberglass on the back or belly of a reflex/deflex, might just play it safe and use on the riser instead unless some has used it before on limbs, as says it its ok, wood is $$$ here in Hawaii and a piece for a riser would run anywhere from $50 to $100 dollars depending on the grain pattern and look.

[Robertfishes]

3Rivers should have a string making DVDs.

[Stephen B]

Hello everyone I almost got bow finished up and finally got correct lenght FF string for it, so went out to shoot some arrows through it a few days ago and It has bad hand shock. So I checked the form and took most suggestions and removed some of the excess matherial from my tips and checked tiller and it seems to be drawing evenly, and I took about a 1/8 of material off of the limbs since bow was drawing in at 49lb and was looking for it to be at around 45lb. So finished sanding down went back out and tested it again and the hand shock got worse, I was only going about half draw to test the limbs so after about 3rd arrow went back to full 28 draw and when I release it felt like a mule kicked me in the shoulder, it was bad I had to put the bow down the pain went up my arm from elbow to top of my shoulder, and today shoulder really sore.
 So I was brain storming today trying to figure out what was up with this bow, and realized I had shortened the riser length instead of 16 1/2 it is 14 1/2, I took 2 inches of the riser before I marked it up and cut it out, I was going to use the walnut wood as accents for the tips so it would blend in nicely but I did not think about it after I laminated it together and cut out my arrow shelf, I have a foam board template i use to mark up my arrow shelf and it is  marked up to 16 1/2 riser so i lost 2 inches of my grip arrow. The bad part is I took the two inches from riser to use for tip overlays, and did not even use them as tip overlays I ended up using some white tip overlays i had because it made bow look better. I have attached a picture of the grip and way my hand fits on the grip and bottom palm of my hand is right on edge of where my belly laminates ties into my riser Is this possibly what is causing the horrible hand shock, and if so is there any way of fixing.
 I am stuck on ideal of how to fix it the bow turned out really nice and don't want to scrap it but not going to send to friend if it is going to hurt him to shoot it. I am going to start on a reflex/flex bow Saturday got to build a form for it but got my plans from Kenny a week or so ago so going to attempt a 62" R/D glass bow but going to drop a laminate on this one only going to use one 0.100 bamboo coreflex and two maple laminates at 0.60 on back and belly with two clear fiber-glasses at 0.50 on top of them so it should come in around 40lb. any suggestion would be greatly appreciated on idea as to how to fix current longbow it is a 66" top riser where riser laminates meet is 1 1/2 and tip is now at 5/8" I was thinking of taking tips down to 1/2" but if the riser being to small is my issue then no need to if it would not change anything.

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[fujimo]

narrowing the tips to 1/2"is a good idea, and maybe even thinner too- but remember when you shorten the bow( cutting off the tips!!) you ADD to the draw weight!!!- not reduce the draw weight,
look thru the last page or so here on the bench- and look for the thread on limb timing- or talk to Roy, or Bow junkie- cant remember who else- but there are a few of them that have the limb timing thing down- with vertical lines drawn on their tillering trees to help. its a great system, and i am going to use it on my next bow- as a geuss , i would say you have a limb timing issue. some full draw pics will help with tiller advice from the guys on here!!