Cowiche Archery

Sorry I've been so long in getting to the meat and potatoes of this thing.  I had to build the bow first, and run back and forth to the Doctor.

Lord willing and the creek don't rise, I will get this bow build page done this week.

Anyway, here's a sneak preview of the bow we will be building.  It is 60" knock to knock design with a Bamboo backing.  It has a Red Elm core lamination and a Black Cherry Belly.

The riser and tip overlays are Walnut and Purple heart, (just enough Purple Heart to make you want more).

I guess before we get to the nitty gritty we should talk a little about woods. I strongly suggest, if you haven't already, to invest in the Traditional Bowyers Bible volumes 1-4.  These books are a difinitive source of information about the art of primitive and traditional bowbuilding.  Anyone seriously considering getting into bowbuilding needs to have this resource.  They cover everything from wood and it's properties, to bow design, to shooting, stringbuilding, arrowbuilding, and basically everything you ever wanted to know about building a wooden bow

They are available from Bois d'Arc Press, and are in most good bookstores, over the internet, and from all the major traditional archery suppliers.  Get 'em, you'll need 'em

Now, without spending a lot of time on all the various woods that will make a good bow, (and there are many),  I will mention first the characteristics you want in bow woods.  The backing strip must be a type of wood high in Tension strength (stretching) such as Hickory, Osage Orange, and Bamboo (really a Grass).  There are other materials that can be used to back a bow in place of wood; one of the most used is Rawhide, (one of my favorites), also various fiber materials such as Sinew, Linen, Flax, and Silk can be used. Again, I strongly direct you to the Traditioal Bowyers Bible for further information on this subject.  I will be focusing on the use of Bamboo.

There are many varieties of Bamboo available from many sources, some are really good, like Madake and Tonkin, and some are not so good.  With some experience most can be used, once you understand their properties.

Next, your core woods should be strong in compression strength, (bending).  The core lamination and the belly lamination, when the bow is drawn, tend to compress the wood fibers causing string follow in the bow which in turn causes the bow to lose cast or strength.

I like Hickory, Osage Orange, Bamboo, Black Cherry, Ipe, Walnut, Red Elm, & Hard Maple for my core and belly woods.  The bow in this building tretise uses Red Elm and Black Cherry.  Like I said there are many other woods suitable for this and many other resources available for you to discover them.  Experience being the best source of information about different woods.

Above all else try to get or make laminations with parrallel or straight grain.  When looking at the wood it should look more like end grain that flat grain.  The grain lines should run as near parallel to one-another as possible, not running off the edges or in islands. 

The wood should be dry.  Between 9% and 12% water content.  We'll talk more about that later, so for now let's get our feet wet and look at the mechanics and processes of bowbuilding.

Here are the individual pieces that go together to make up a laminated Bamboo Backed Bow

At the top, a photo of the roughed out bow blank with a full sized Walnut riser. (the bow we will be building has what is known as a bulbous handle, more on that later). Underneath the bow is an 8/4 piece of Black Walnut from which the riser section and the tip overlays are cut.

Next are some different type of woods, Cocobolo & something else, I ended up using Purple Heart for these pieces, for the "Power Lam" that is layed up between the riser and the belly lamination.  The riser is 12"x2"x1 3/4"   The Power Lam is 14"x 1 3/4"

Next the Belly lamination: Black Cherry,  tapered @.002 per inch, .190 at the thickest end and 62" x 1 3/4"

Next the Core Lamination: Red Elm, .130 thick x 62" x 1 3/4" This is a parrallel lamination, no taper.

And finally the Bamboo Backing strip. It is 62" x cut to the layout of the bow shape, and planed level on the glue side.         ( More tomorrow)

I'm no architect, but here is the design for the handle I am using in this bow construct.  It's called a "Bulbous Handle."  It is thickest in the middle and tapers to the fadeouts, and then widens to full limb width, (in this case 1 1/2"), at the end of the fade out.  Between the handle and the bow belly there is a power lamination layed up; it extends from 1 to 2 inches from either end of the handle.  The effect of the power lam is to lengthen the distance between the limbs, increaseing what is called the "dry fire rate" of the bow.

This is a design element used in flight bows and increases the cast of the bow as well as giving you a little more transition from the fadeouts to the working limb.

Bows store their power in the fadeouts not the Limbs. This is one of the most important design elements in building fast and durable bows.  Most of the stress in a bow is in the fadeout area.  Dont give it enough transition or make the fadeout too short, and you will soon discover the joy of blowing up a bow!  Learn this lesson well!!

The diminsions of the hadle,incase you can't read them are: 1 1/2" at the center and 1 1/4" at the begining of the fades.  Mark them in on your template with a compass.

Here's a drawing of the bow design you can reproduce and use.

This bow is 1 1/2" wide, 62" overall, and 60" knock to knock.  It is an homogenous design incorporating elements from Eastern plains Indian, Korean Horsebow, ancient European (Holemegard Bow), and modern day Howard Hill type bows.  It's a design that has evolved for me over the years of building many different types of Primitive and Traditional bows.

It has proven to be a durable, asthetically appealing, and high performance design.

The bow is built with 1 1/2" of deflex and 4 1/2" of reflex. Depending on how well you follow instructions, pay attention to detail, select and cure the wood, the bow will retain approximately 1 1/2" to 2" of reflex after being shot in.

As mentioned in the above section on wood you will need 1 strip of Bamboo backing cut to length and final bow deminsions. One core lamination cut to length and 1 3/4" wide by .100 thick, and 2 belly laminations 36" long, 1 3/4" wide by .190 thick tapered ,.002 per inch.

This will give you a bow somewhere in the 50 to 60# range, depending on the quality and final thickness of the Bamboo backing.  Due to the varying thickness of the ground bamboo strip (it can be from .070 at the edges to .170 in the center of the lamination), the bow will require some hand tillering to bring the bow limbs to final weight and tiller but we will discuss that further along in the tutorial.

(more later, gotta tend to other issues). Have a good day!

Laying up the laminates is pretty straight forward.  If you are doing your first glue up I reccommend you do a mock up first.  With all the laminates on the mold and clamped down just the way you will do it when you've got the glue on.  The glue is very slippery and you will need to tape the glued laminates in place before you clamping them down, or they will slide out of alignment.  Take no shortcuts here.

Types of Glue:

on the left is a bow epoxy called Bow Grip 1000.  It's a glue that can be used without a curing oven, the viscosity is light, and it spreads easily.  It has a tendancy to flow everywhere, so only experience will teach you how much to use.  It is available from http://www.rudderbows.com/.

Next to it is the old standby in the bow building industry SmoothOn.  It is available from almost all the archery suppliers online.

It takes about 1 cup of glue for one bow.  Bow Grip is mixed in equal parts by volume while SmoothOn is equal parts by weight.

I have used Tite Bond 2 and 3 to lay up bows with some success but really reccommend using one of the epoxies with a curing oven.

Cover your mold with Saran wrap to prevent glue from sticking to it.  I also put a coat of paste wax on all surfaces of the mold before laminating.

After laying out the laminates in the order they go on the mold, using masking tape, tape the sides of the laminates that don't receive glue.  In this case that will be the surface of the belly laminate and the back of the bamboo backing strip.  Apply glue evenly to all other sides of the laminates and lay them up in order.  If you are using a back up mold begin with the Belly, then the core, and finally the Backing laminate.                                                                                                                                                  

After you get the laminations glued and on the mold in the right order, you'll want to tape the laminates in place before you apply the clamps.  Again, the glue is very slippery

Once you've got the lams and the mold taped down, begin applying the clamps; spaced approximately every 1 1/2." Tighten the clamps just until you begin to get a little squeeze out between the laminates.  Don't over tighten the clamps.  If you do you will squeeze all the glue out and end up with a dry joint that will blow up on you the first time you stress the limb.

           Lay up comeplete

 With all the clamps in place you are now ready to put the mold and the soon to be bow of your dreams into the "oven."

This is the curing oven.  Built from 1/2" plywood, 80" long, by 18" deep, by 1 foot wide.  It is lined with heavy duty aluminum foil and has 4 200 watt light bulbs wired to a 150 degree thermostat and an on off switch.

The glued up and clamped down bow blank and mold go into the oven for 4 hours at a temperature of 150 degrees.

After 4 hours I leave the bow and mold in the oven, I just cut the power and let it come back down to room temperature before removing the bow from the oven and the mold.

This is a good time to make sure you've got something to hold your interest for 4 hours while the bow is curing.  Don't keep lifting the lid every 20 minutes, Let it cure!

After allowing cool down time, (cool down is when it is cool to the touch), and if you cut your Bamboo Backing to finished bow deminsions before layup, all you need to do next is cut the bow out following the lines of the Bamboo backing.

Don't cut right up to the edge of the bamboo leave a little room to file or sand down to final deminsions.

Here's where the beauty of using a pre-tapered belly lamination and a fixed thickness core lamination prove their worth. The major differnce being that there will be very little hand tillering to do, whereas with a bow stave the tillering process can take hours if not days to comeplete.

With the tapers and thickness pre-done you can go from this stage to finish tiller in around an hour!

Working from the center of your bow limb blank, lay it over a 13" riser block, (in this case Walnut), and trace the curvature of the handle and fadeout areas of the limb blank onto the riser blank.

Cut the blank just to the pencil line and then file, grind, or sand down to the pencil line; making sure to keep everything square.

Once you have done this, the handle should fit perfectly to the Bow limb. 

Using your epoxy, spread glue evenly on all gluing surfaces, clamp up, and place the bow with glued and clamped riser block back into the curing oven for 3 more hours.

When all is done and cooled, using the riser template cut out the fade outs.  The handle or grip section is 2" on either side of center and the

fadeouts are 4".  Oh, almost forgot, don't forget to glue your 14" power lam in.  It goes between the handle and the bow limb. (See the purple between handle and limb in the photo)

Next I install the tip overlays.  Remember, Mass weight is critical on the last 1/3 of your bow limbs.  Get 'em too heavy and you get handshock and poor cast  I use, as a rule, a combination of the woods used in the riser block and the Power Lam for the tip overlays, especially if I am going to use D-50 bow string material.  If I want to use Fast Flight or some of the newer lightweight - non-stretch string materials I will use a piece of Linen Micarta in the overlays.

These new string materials can saw the tips right off a bow if they are not built to withstand the sawing effect of Fast Flight and some other non-stretch string materials.

(personally I dont get the rush to get two or three feet per second more out of a bow by using potentially damaging string materials.  Oh well, each to his own).

I cut my overlays 2" long by whatever width, just as long as it is wider than the bow limb itself.  And glue them up with Sure Shot Super Glue.

Clamp them down evenly for about 1 hour, and then you are ready to cut them to shape.  look at some other bows to determine your favorite tip shape.

Trimimg the tip . . . .

Ok, now were ready to tiller the bow.

(Please see the tillering page)