My horn bow build-a-long

[DC]

I'm going to start this with a quote from Gorazd from the other thread.

The thinnest part will go on the siyahs... more important is enough thickness left in the bending part of the horn - there should be at least 5-6mm ... considering that you must sand both parts to be of the equal thickness along whole length. And during this sanding you will loose some thickness...

5-6mm,, that's just enough to make me think I can rip these strips in half. Dangerous thought. That 5-6 mm, what weight bow would that give or is the weight more determined by the thickness of the core?

[DC]

Considering the trouble that Mafort had straightening his horn should I bother trying to straighten this (almost) 1/2" thick horn. It would make it a lot easier to work on if it was straight(er)

[Mafort]

My advice is to thin it. I thinned it down to a quarter inch and then soaked for 2 days and boiled. Straightened out with no issues.

[DC]

When you were thinning it did you flatten the outside to a "finish surface" and then remove the bulk of the horn from the inner surface? One of the reasons I wanted to flatten it now was to make it easier to remove material from the inside on the belt sander.

[DC]

3 of the 4 strips I got have this little white stripe on the inside surface. Is this something I should be avoiding? Maybe do most of my grinding from this side to try and get past it. It's in the future centre of the limb so my selfbow brain tells me it's nothing to worry about but I'd better check.

[DC]

I've been reading that horn is hygroscopic. Does this mean an extended drying period is necessary after boiling? Is it worse than wood?

[JW_Halverson]

Any scrap left over will be tip overlays, nock inserts, knife scales, inlays, etc! No sense wasting any of it! 

Full disclosure: I only posted that comment in order to get notifications of further additions to this post. I really don't wish to miss any of this.

[DC]

So far it's just been a series of my questions . Here's another one spawned by JW's comment. The tips of the horn strip would make good ELB tips and some overlays. The tip of the horn goes in the handle. How wide is it likely to be there? I'm wondering how much of the tip I will be cutting off. I'd rather do it now while it's still full thickness.

[DC]

So far all I've done is try to straighten some full thickness horn with limited success. I'm slowly rereading all the posts in the "Horn Bows" section and searching the web for videos. I remember there was some posted by an Slavic gentleman who was making a horn bow in his kitchen, it looked like. They were good and I can't find them now. JWB bows has a bunch but they are very short. If anyone has any links they would like to share I would be pleased.

Your bell is going to be dinging regular JW

[Mafort]

Dry heat works well as I understand. I would take it down to a quarter inch and then use dry heat from a stove top to straighten it out. Go slow and be gentle. Have a friend or someone brush on some water while you’re straightening it up. I tied mine to a flat board and it retained a large amount of the straightening. I’ve got one more session to do today or tomorrow sometime and I’ll leave them be on the board till Sunday morning and then I’ll glue it to the core wood. I had a short elm stave that was good enough for the core.

[Mafort]

The horn bow I’m making is kind of a weird one. So hopefully it all works out

[DC]

Have you found that a boiled strip takes longer to get stiff again than a dry heated piece? I have one that I boiled and after a couple of days it still seems bendier than the ones I haven't done.

[Mafort]

Dry heat plasticizes the cells of the horn which may account for the stiffness. Which I don’t mind too much. I don’t know about boiling. All I know is I had a mother set of horns which I ended up turning into knock reinforcements for arrows and overlays. They boiled for 30 minutes and they were barely straight but it’s probably because of the thickness I had them at.

[DC]

Oh that sucks. How do you know they're ruined? Symptoms?
These are a few of the things I've been trying with varying degrees of success. Sometimes there is just no substitute for more clamps. I've avoided more than 10 min boiling and more than 250°f dry heat so hopefully I'm OK. I've got one to the point that I feel I can start running it through my thickness sander. I smoothed/flattened the outside but it's still curved. I'm hoping he thickness sander will work for the inside. Somehow all the write-ups I've found seem to gloss over this part. "Boil for 10 mins and bend straight" hardly covers it.

[DC]

Another question. I've read that when you heat tiller or heat the horn/core for any reason the horn will try and resume it's original shape. This makes sense. Does that mean that the horn strips have to be oriented so that if/when they do revert they will be adding reflex? This would mean that somehow you would have to mark the horn strip so that you don't lose track of which way is which. As long as you have a bit of the horn base showing you will be OK but if you were to make perfect rectangular strips it could be a problem.