Building a take down long bow.

[bassmatt72]

Going to try another DIY follow along on building a take down long bow. I have done a youth take down recurve and a regular recurve. Here are the links to those.

http://discussions.texasbowhunter.com/forums/showthread.php?t=484345

http://discussions.texasbowhunter.com/forums/showthread.php?t=378494

This thread will be very similar to those. These have all been Binghams designs and plans with just a few personal changes here and there.
So, just like with the others this is my first of this style so we have to build our forms. These plans call for 12" X 33" X 1 1/2" plywood form. I used 3/4" Ash cabinet grade plywood but it wasn't going to be a full 1 1/2" thick so I have some phenolic material that I sandwich between the plywood and got it to a full 1 1/2". Lots of Titebond glue and screws. Of course trying to not put any screws where the form will be cut later.

[bassmatt72]

I did something a little different next from what I've done before. In the past I actually cut my blueprints up to where I could tape them down and draw the lines through them.

This time I taped the whole plan down and used the round curved end of a pick to press the lines into the form.

This way my prints stay in one piece and its easier to store them, and use them again. Here is a close up of the lines "transferred" into the wood.

[bassmatt72]

In this way of building bows we use thin pieces of wood called laminations, or lams, fiberglass, and laminate them together with a two part epoxy. We use heat over a period of time to cure the epoxy, that's where I am now. Can't really do any more work on it until epoxy is cured and cooled. So, its a good time to catch up on the DIY thread.

[bassmatt72]

Well, I did run into a snag already.....bandsaw quit???? A little searching and discovered burned contacts in the on/off switch. Cleaned them up, reassembled switch and I'm back in business!!

[arrowsmack324]

In for this one!

[TMiddleton]

Following this one Matt!

How thick is that phenolic you have there? I'd be interested in buying some, if you have extra.

[bassmatt72]

Ok, saws up and running time to finish forms. Lines transferred from plans to form, and cut close to the top line for the top half of form. The top half doesn't have to be real perfect but the bottom...its got to be exact!

[bassmatt72]

Following this one Matt!

How thick is that phenolic you have there? I'd be interested in buying some, if you have extra.

I'll have to check. It was some seconds/rejects from a local manufacture. I have some extra I'll give you. I was originally using it to skin deer stands.

[Dry Bones]

Going to follow along here as well. Pretty awesome building your own. INCLUDING the form!! My hats off.

[bassmatt72]

Ok. The bottom of the form....this is what gives the limbs their shape. If it is wavy, your limbs will be also. Crooked, yep, limbs will be too. Twisted, you guessed it, limbs will be too! So, it needs to be a smooth curve to the shape, and it needs to be square to the sides. Being square to the sides is how you know there shouldn't be, and helps prevent us "building limb twist into it".
Oh my! How do we get this form all smooth, squared and a nice sweeping curve to it?!?!? Here's how I do it. I cut close to the lines from our plans with the band saw but not to the lines.
Then I'll make a thin pattern and temporarily screw it to the form. It is much easier to cut and sand this to a smooth graceful curve.
I use a pattern following straight router bit, it has a bearing that "rides" along the pattern. Here you can barely see the pattern on top of the plywood form. There is the bearing right on top.


The router bit is not long enough to get it all in one pass, so we lower the bit and use our first pass as our new pattern and finish the job.

[bassmatt72]

Going to follow along here as well. Pretty awesome building your own. INCLUDING the form!! My hats off.

Well, I don't do any of the "thinking" on these builds. I call Binghams and tell them what poundage I'm trying for and they figure the thickness of the lams for me. I build off of their plans, which anyone can order, and order my supplies from them. I'll do a few personal "tweeks" to the bows but pretty much just follow their instructions.

[bassmatt72]

Ok, checking the form for square.... we're good!!! I checked multiple places all the way down the forms.

Well crud!! I use my hands a lot when I'm doing sanding to "see" imperfections, sometimes I can feel a spot but not see it very well. While I was checking square I ran my hands over the form to feel for any waviness. Found a spot on each form in the same locations. My pattern must of had a little wave in it.

I normally will use bondo to fill low spots in my forms but I didn't have any and these are really shallow.....two part 5 minute epoxy! Put a thin layer in the wavy spot, let cure and hand sanded to smoothness.

A couple other little things, add closing hardware and..Ta Da! Two completed forms!

Yes, we could do this and only build one form, but that means we would have to glue up one limb and put it in the hot box for several hours, cool down for several hours then do it again with the second limb! Now I can just go a head and glue up, and cure both limbs at the same time with only one curing process.

[bassmatt72]

Remember I said we use heat and time to cure the epoxy? Here is a pic of my "Hot Box". It is big enough to do full length one piece longbows and recurves, and anything shorter. Since this picture I lined it will foil backed Styrofoam insulation, indicator lights and a small internal fan to keep the air circulated and avoid any hot or cool spots. It has an inline thermostat set at 180 degrees.

[bassmatt72]

Ok! Ready to see the choice of materials???? This bow is for a coworker and he decided on Dessert camo action wood for the riser and Burgundy camo flat grain under clear glass for the limbs. He said he wanted a little "craziness" to it?



What's the difference in edge and flat grain?? It has to do with how the material is cut. Edge grain is where it looks like the side of plywood, you can see all the laminations, flat grain is where it looks more like a board with wide, broad grain patterns.

[bassmatt72]

Binghams plans has a very shallow grip and the limbs are sitting out on the back (the side that is furthest away from the shooter) of the riser.

This doesn't give it a very clean appearance.....
I don't really like the riser/limb pad design, might have to change things up a little?????