Oryx horn belly, pictorial

[John Sturtevant]

I’ve had some people ask in the past how to prepare Oryx horn for use on the belly of a bow, so last winter I started taking a few pics when I was messing with some.

With the Torges/Bowyers Journal challenge being mulled over some people have been toying with the idea of using horn on their “contender”, so this might be a good time to try and post these.  

Keep in mind I’m still experimenting with all of this, and I’m certainly not claiming I’ve got it all figured out.  
Started with adding baleen to the belly, until I ran out of my supply and tired of the high price of material….and the legal issues.  
Tried using Gemsbok horn as a substitute and it seems to work OK, although it takes a little work to prepare.  
It’s fun to fiddle with as an alternative, although the jury is still out on the actual benefits with the type of bow I normally build.  

For those of you considering a bow for the challenge mentioned above, keep in mind that at one time baleen was used as a backing material.   I believe horn would be more durable then baleen on the back of a bow.  
Someone might consider building a 58” horn bellied and backed bow, perhaps somewhat styled after some of the short hybrids that seem to be kinda popular.  
Based on a comparison of horn to fiberglass, suspect the core laminations would be key.

Anyway, I’ll try to get these pics up with a few comments and maybe someone will get some good out of them.

[John Sturtevant]

 The horn blank.   Gemsbok, Oryx.  Ebay is a good source sometimes.   Try to get male horns.  (thicker) and get them as long as you can.    Make sure they are somewhat fresh.   I’ve been burned on some old relics that are unusable.

[John Sturtevant]

The horn needs to be split.   It saws easily,  just stinks a little.

[John Sturtevant]

The horn after splitting.   Note it is hollow for most of the way, and will need to be flattened with heat.

[John Sturtevant]

Before flattening, it’s a good idea to grind the ridges off the outside.   Easier to flatten.

[John Sturtevant]

A heat gun works great.   I sometimes start by using a very special horn flattening tool to open up the horn.   You can pass this step if you trim the horn a little more on the sides.

[John Sturtevant]

After the round horn is partially flattened using the very special caul; you can finish in the vise.   Must be hot enough to bend w/o cracking.   I heat until my finger sizzles a little when I touch it.   You might gauge the correct temp by wiggling the unheated section of horn around as your applying heat.  You can tell when it’s getting rubbery and ready to bend.

[John Sturtevant]

The butt end partially flattened.   Keep working your way up the horn, flattening 4-5” at a time.

[John Sturtevant]

Horn after being flattened with heat.  Next step is to grind the horn to the initial thickness and clean up the edges.   I normally like to leave the horn a little thick during glue up, easier to apply uniform clamping pressure then with a thin piece.   .100 - .125 is about right.   Plan on thinning down to at least  .060 to .080 during the final tillering process.    I’m starting to think thinner is better, but I’m still experimenting.     Added horn to 4 bows over the New Years weekend that I’m trying to thin the horn to .040 -.050.    I have high hopes for something better as a result.

Note, when sanding you’re going to make a stink, and it will linger for some time.   If you’re shop is in your home you might be in trouble.   If a neighbor stops by that you’d rather not visit with, you’re in luck.

[loyd]

John i have a pair of them , been wondering what to do with them, your shop is way to clean for me to work in. loyd

[John Sturtevant]

Sometimes it needs to be straightened sideways.   Do not pull into place when gluing.   A little heat will allow it to line up properly.

[John Sturtevant]

Prior to glue-up, the horn should be shaped to match the limb.   Trace it out and grind to shape.

['46]

John, thanks. I'd like to see those bows (works of art) when your finished. You are waaaay too modest my friend.

[John Sturtevant]

Back of horn after grinding.  The ridges will be removed after it is glued to the bow.  Looks bad now, but when finished it will be wonderful.

[John Sturtevant]

Two blanks ready to glue to bow belly.

[John Sturtevant]

Another view of both horn pieces ready to glue on.   (Timo, I think this is the carp backed bow blank)

[John Sturtevant]

The bow blank the horn will be glued too should be flat tillered to aprox 6-8# under your target weight  This will vary depending on how thin you want your horn to end up, and how much you radius the belly.   I’ve been trying to get the horn thinner now then I did on my first attempts and hope the end result is a better shooting bow.  
  Belly of the bow and the gluing surface of the horn must be flat or very slightly concave.  

  I prepare the surface of both with 36 grit just prior to glue up.

[John Sturtevant]

 A trial run before glue up is helpful.   On this bow, the horn will not run all the way to the tips.   The bow blank is also left wide, and once the tips are narrowed all will fall into place.  Probably.

[John Sturtevant]

 Messy glue up bench.  Many clamps.   I’ve only used Smooth-on or G2.    Heard Urac may work, but I haven’t tried it yet on horn.    Back in the hot box to cure.

[John Sturtevant]

During the glue up, I use ¼” Polycarb as a pressure strip.   I like to see where the horn is positioned, and since its clear this is helpful. (also get it free out of the trash)
If it’s a BB backed bow make sure you have adequate padding between the clamp and the BB.   I’m  starting to suspect some of the BB failures that people are experiencing are the result of denting/bruising the BB during glue up.