Author Topic: First attempt build a long !  (Read 1967 times)

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Offline Stick Bender

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First attempt build a long !
« on: October 21, 2017, 04:02:29 am »
I have read BowEds thread on horn prep , read and reread Adams book ,watched a ton of utube and been studying composites on and off for a year now and still a little nervous about starting this project given the expense & rarity of good horn but figured I would post my question here instead of PM so as others in the same boat can learn ,I got these horns a while back they are flattened one side & now need to be thinned but at the thickest part they are 0.30 they also have some what I would describe as pitting on the surface so I need to get them thinned to find out how much width is available so my question is at this point being the thickest part is 0.30 should I try to heat straiten the horn for ease of flattening or thin them more ? I have thought about using double back heavy duty carpet tape and forcing them flat on a dead flat milled board in order to flatten more but there still just a bit strong for it ?
« Last Edit: November 16, 2017, 06:53:35 am by Stick Bender »
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Offline Stick Bender

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Re: Prepping horn ?
« Reply #1 on: October 21, 2017, 04:03:15 am »
Pitts
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Offline BowEd

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Re: Prepping horn ?
« Reply #2 on: October 21, 2017, 05:20:21 am »
That pithing on 1 side shown in the picture is just the natural grooves on the outside of the horn.A lot of that can be sanded away by crowning the horn on that side some.Then you will find how wide of horn you got too.Starting with 1 side or the inside flat to begin with.
The horn widths and thickness taper on my bows were 1 and 3/8" wide mostly.Narrower towards the tip end.Starting out as wide as possible is good.Tapered in thickness 1/32" every 6" of length on type of bow I made.Regular horn bows I don't think have as much thickness taper at least from the fades to midlimb because of working area and shorter length.
A person can slowly heat bend that horn then or before to a nice slow not too abrubt arch and flat with no twist.I use the heat gun very carefully and hold it in place to cool.Remember less thick less heat needed while using dry heat.Matching the pair in profile.It can be done steaming too with the way yours are thickness wise and clamping to the shape you want till cool.Some prefer to do it that way.This can all be done even with an 18" belt sander and a file.You want the thicker end towards the handle.It can get very thin out towards the tip too.
From there you can either groove the horn in a jig or glue it flat too.
« Last Edit: October 21, 2017, 05:38:13 am by BowEd »
Beadman
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Ed

Offline Stick Bender

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Re: Prepping horn ?
« Reply #3 on: October 21, 2017, 10:20:50 am »
Thanks Bud you brought it together for me as usual Im hopping to pull 1 3/8 width on this one My maple stave is 61 in. trying to make one similar to your current hunting bow just a bit longer and a bit lighter draw , hey Ed how much reflex where you at before sinew after you took it off the form cured ?Right now I will take them down to 3/16 & see where Im at on width after straitening them a bit more!
If you fear failure you will never Try !

Offline BowEd

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Re: Prepping horn ?
« Reply #4 on: October 21, 2017, 10:24:03 am »
I gave it 8" and it came off the form with 5.5".
Beadman
You got to stand for something or you'll fall for anything.
Ed

Offline Stick Bender

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Re: Prepping horn ?
« Reply #5 on: October 22, 2017, 01:39:29 am »
Ok thanks Ed I need to make one of those forms like yours I believe yours was a Torges style form if I remember right, I found a padded adjustable leaver type clamp that can be screwed to a board and making some shims to put under the horn for straitening , if I can get this horn more strait & double back tape it to a flat board would any body see any problem running it threw a conveyer type drum sander ? I could at least get them closer with one side flat it would follow that thickness or maybe use hot glue to glue them down & then file to final thickness kinda like the way the guys that make lam bows do it ? Also need to pick up some rubber bands or old bicycle tubes but other then smooth on I have every thing else I need I think , Ed when you used your belt sander did you remove the stop so you could use the whole belt ? From my best guess at this point looks like I can get 16 in at 1 3/8 width or 17 1/2 at 1 1/4 width . Thinking 45-47 lb at 29 1/4 ! Might be able to split the width difference 1 5/16 won't know tell I get them down !
« Last Edit: October 22, 2017, 02:04:33 am by Stick Bender »
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Offline BowEd

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Re: Prepping horn ?
« Reply #6 on: October 22, 2017, 04:58:11 am »
Ritch....A 1 and 5/16" wide is enough.If you can cover at least 3/4er's of the width of the belly you should be ok.If you can get more length then that's better yet.If not the length sounds ok too.You might need to butt joint on the ends somewhere where it's not working too much to get more length.
I know a fella who used a drum sander thinning horn.It did work but I would'nt reccommend it really.I prefer to do it more slowly on the belt sander if that sounds good....lol.An overall crowning of the surface is what you should have too and a drum sander does'nt lend itself to that very well.All that should be done by hand with a fine file or sand paper.Getting a strong 1/8" thickness maybe 3/16" for at least a 6"to 8" length should do the job.Feathering out to 1/16" thick on the thin end towards the tip.
I should mention performance wise Marc has done closely these types of bows without horn but either way a pristene piece of wood should be used.A good compression strong wood should be used then if that narrow.Without horn the core should be wider.
For the type bow you want there I'll send you a diagram of dimensions in the mail tomorrow & you can call me anytime too.
« Last Edit: October 22, 2017, 05:29:56 am by BowEd »
Beadman
You got to stand for something or you'll fall for anything.
Ed

Offline Stick Bender

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Re: Prepping horn ?
« Reply #7 on: October 22, 2017, 06:43:05 am »
Ok thanks Ed  & thanks for the specs but if you want to take a pic of them & send email that would work too save you the stamp & trouble if you want, well I really got to get them thinner to find out what I got I really want to keep it one horn per limb if I can on this first one but will butt if I have to , I was in the shop this morning figuring out how to make my quick release clamp horn straitening fixture this project will keep me out of trouble for the winter...lol still have my croaker bladder glue to make too , I will use the belt sander then I think I'm taking the material stop off it so I can use the whole surface !
If you fear failure you will never Try !

mikekeswick

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Re: Prepping horn ?
« Reply #8 on: October 23, 2017, 10:58:41 pm »
Try and get rid of those cracks on the outer surface. They can run deep and sometimes you can't tell until you start working them.
No problem using the drum sander, it is a very accurate and dependable method. I actually stick my horn to a thick piece of ply with hide glue, do the thinning and tapering. Then whilst still stuck to the board I establish the centreline and do the grooving. It was one of the best ideas I ever had! You can also use a taper sled to establish the taper on the horn.
Don't worry about getting the longest possible set of horns, go for wider rather than longer BUT you really should get rid of all natural grooving on the outer surface before doing anything else, don't trust that you will be able to remove it all once glued to the core. All it takes is one hidden crack....

Offline Stick Bender

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Re: Prepping horn ?
« Reply #9 on: October 24, 2017, 10:30:25 am »
Ok thanks Mike that's a good idea whith the hide glue & water salable too ,easy to get off , I'm going to make up some ply feed tables for them after straitening at least get them close the taper jig is a good idea to get close, with needing to crown them I will do the final dimensioning by hand, I was going to pick up a commercial taper lam as a pateren for the taper matching Eds specs  thanks for the input !
« Last Edit: October 24, 2017, 12:02:03 pm by Stick Bender »
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Offline gorazd

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Re: Prepping horn ?
« Reply #10 on: October 24, 2017, 11:17:01 pm »
I   sand all the ridges/cracks away to get the flat outside  - BEFORE the cuting of the horn .... it  is easier to prepare the strips afterwards
Then I sand them on the belt to get them almost the same thickens (+- 1mm) ,
THEN cut them to the same width and length...

Then heat bend them to be almost flat...
And finally attach them to flat surface and scrap them with razor blade to get them the same thicness (on the same length positions - they are tapered from 5.5mm to 3mm at the tip - depends from horn)

Doing the final check with caliper ruler - 0,1mm !

Offline Bjoern Sofeit

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Re: Prepping horn ?
« Reply #11 on: October 25, 2017, 02:43:30 am »
Use a leather or wooden spacer with the clamp, you don't want marks or damage on the horn.

Offline Stick Bender

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Re: Prepping horn ?
« Reply #12 on: October 25, 2017, 03:25:15 am »
Thanks Fellas I also have these 2 sets that I could use the shorter ones I could for sure get 17 in. The longer ones probably 21 in at 1 3/8 in they would be more work at this point but wonder in terms of going into the fades like BowEds bow it would give me more working limb ? But would rather put the work in now then run into issues down the line ?
If you fear failure you will never Try !

Offline BowEd

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Re: Prepping horn ?
« Reply #13 on: October 25, 2017, 06:55:56 am »
The fades part that's glued down is heat bent a little to conform to better to eleviate the risk of cracking then while being clamped and thin enough around 1/8" thick prior to glueing and clamping.That's all done with a dry run clamping prior to actual glue up on the type of bow I made.Your longer horns there should do the job.
Preperation of thickness mentioned is a superb way of doing it too.
Beadman
You got to stand for something or you'll fall for anything.
Ed

Offline Stick Bender

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Re: Prepping horn ?
« Reply #14 on: October 25, 2017, 09:46:24 am »
 On straitening these horns it was mentioned some use steam with steam only being 212 Deg F  I'm wondering when I use dry heat to bend these slightly with the fixture if I apply dry heat at about the same temp will that work ? I'm just trying to use as minimal heat as possible on these horns and just bent enough to glue to the feed table ?
If you fear failure you will never Try !