Post by: kennym on March 30, 2023, 10:42:08 AM
Custom build …
Post by: B-JS on March 30, 2023, 10:47:16 AM
Looks Like my 50" Rover.
Pain in the A*** to build.
You'll need 45/45 Carbon to get it stable.
Post by: kennym on March 30, 2023, 10:56:47 AM
The top form will have to be two pieces to get in and out . :tongue:
Post by: Longcruise on March 30, 2023, 11:11:30 AM
Post by: Stagmitis on March 30, 2023, 12:14:39 PM
Post by: onetone on March 30, 2023, 03:33:52 PM
Post by: kennym on March 30, 2023, 04:22:55 PM
If you mean tip to tip straight line , I'll have to measure that too... :biglaugh:
This is a big dude, says he draws 32"
Post by: Mad Max on March 30, 2023, 05:29:42 PM
Bottom form
(https://i.imgur.com/E603irc.jpg)
Post by: onetone on March 30, 2023, 05:35:09 PM
But he could slide the “top” form in from the side and not have to do cut it in half.
Thanks for the info Kenny. Just wanted a general idea of scale.
Post by: kennym on March 30, 2023, 08:20:52 PM
Post by: onetone on March 30, 2023, 09:00:05 PM
:scared:
Post by: Kirkll on March 30, 2023, 09:13:21 PM
Pulling your lams into that tight of an inside radius is going to take ratchet straps, or some seriously heavy duty , large zip ties.... You can find those heavy duty zip ties on amazon, and they work pretty good..... But man that is doing it the hard way with that form IMO.
Post by: Crooked Stic on March 30, 2023, 09:22:29 PM
Post by: Mad Max on March 30, 2023, 11:13:41 PM
Yes you have a lot of work on the form you need to start over.
Those tall recurve ends on the form will warp/twist (or warp when the air hose is inflated) and string alignment will pull your hair out.
Trust me on this one :thumbsup:
Sorry
Post by: kennym on March 31, 2023, 07:30:00 AM
Trust me on this one :thumbsup:""
I'd been thinking that too after getting it cut out. Point taken... :thumbsup:
Post by: Mad Max on March 31, 2023, 08:53:39 AM
Post by: Kirkll on March 31, 2023, 10:40:41 AM
Pushing lams into an inside radius it a bit tougher to do, but the pressure pushes the end into the stops real well if it’s done properly.
When bending these around a radius, the process is easier to do, but the lams can easily pull away from the stops in the limb form if you are not careful and use enough zip ties in the wedge area.
There are also advantages to having both a top and bottom form that is held straight with steel straps, or even smaller angle iron pcs. Holds everything straight and Kills the twist as you air up the hose….
Of course with a form like the one Max showed above, that one would be pretty tough to twist…. Kirk
Post by: Kirkll on March 31, 2023, 10:52:35 AM
Kenny That needs to be the top form.
Bottom form
(https://i.imgur.com/E603irc.jpg)
I’m curious if you use any heat and load your lams into this form dry to pre- bend the lams before laying it up on this radical lever form.
That is a seriously tight radius. I can’t imagine trying to bend .040 glass that tight without heat…. I can think of a lot of different wood types that wouldn’t bend that tight without fracturing either. Even milling it pretty thin…. :o
What is your procedure for pulling this off successfully?
Post by: Mad Max on March 31, 2023, 01:28:55 PM
No heat
2-1/2" radius
HR maple and boo flooring will work, could always have a parallel on heaver bows to keep the lams thin out there.
I use zip ties and work my way out on both sides to the recurve, push it down around the recurve and zip tie the last 2 on each side and use a cheep ratchet strap Horizontally around the form to pull them in tight. I have about 2-1/2" more length past the nock to cut off later, that helps too.
Also I pin (1/4") all the way threw the stack and (riser 1-1/16" thick) into the form. I've done it both ways with and without a top form.
I like the topless form best but the key for me is to mule tape loose so the fire hose doesn't wrap around the edge so I can see the stack closed up and flush to the sides of the form.
Trying to bend a lam around the form can crack it, but bend the whole stack works.
This is Brent Rudolph's 50" Sheepeater Sprit bow
Post by: Kirkll on March 31, 2023, 02:11:51 PM
I think this is your secret to success... That and using .030 glass....
I was building some canes a few years ago with 2" outside radius at about 3/4" -7/8" thick stack using various types of wood. So the inside radius was pretty tight. I used steam on some of the thicker lams and laid them up dry first just using a single form like your form above.
Then i tried using thinner lams and wrapped the whole stack tight with shrink wrap before bending in the form with the epoxy in one shot. I used an inside and outside form on that and it worked well with very little grain lift. But i eased the edges of the outside lamination with a small round over with a palm sander..... Some wood bends much easier than others do.... Kirk
Post by: Kirkll on March 31, 2023, 02:21:06 PM
Finished photos
https://photos.app.goo.gl/SKamdSmmGMoyqv6F7
Post by: Mad Max on March 31, 2023, 05:44:53 PM
That's why this forum is so good, people sharing a lot of different ways to do things.
I would not go any tighter than 2-1/2" radius on the back of the bow.
Like kennys new form, been there, done that, don't try :thumbsup:
Post by: Kirkll on April 01, 2023, 11:33:40 AM
http://www.eaglewingarchery.itgo.com/custom3.html
He has a design called the “Talon” that has a pretty tight little curl on limb tips. Hence the name The Talon…. I remember back when he was first prototyping this limb, he had a tough time bending .040 glass that tight without his tip wedge sliding around. I believe he pinned it with something in the end game.
I believe he used to post on TG years ago…… but….I kind of lost touch with Steve. He is a gifted craftsman and bowyer of many years. We were pretty tight years ago. Kirk
Post by: Mad Max on April 11, 2023, 08:12:59 AM
Post by: kennym on April 11, 2023, 09:11:32 AM
Post by: Mad Max on April 11, 2023, 09:13:22 AM
Purty slow on it, I'll take pic today. I think it be better this way. Will 3/8" steel pegs hold it?
I would think so :thumbsup:
Post by: kennym on April 11, 2023, 05:05:13 PM
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Post by: Kirkll on April 11, 2023, 08:26:57 PM
Did you seal that real well with shellac or some kind of sealer? How many layers of plywood, and what grade did you use?
That one should be fairly easy to check for twist with a straight edge diagonally. I sincerely hope she stays stable
Post by: kennym on April 11, 2023, 09:40:45 PM
Post by: Mad Max on April 12, 2023, 07:20:18 AM
Post by: onetone on April 12, 2023, 03:49:21 PM
Post by: Kirkll on April 14, 2023, 10:04:46 AM
Did you use cabinet grade plywood? 7 lam perhaps? Kirk
Post by: kennym on April 14, 2023, 09:04:10 PM
Post by: Kirkll on April 15, 2023, 02:34:31 PM
Plywood was the best fir ply they had without going to oak or birch cabinet stuff. I prob shoulda priced it tho, as much as this cost!!
If you can find decent looking A/CX. the stuff is typically pretty decent if you get solid core.
The problems with a lot of the cheaper plywood, and even expensive stuff is the blows in the laminations from knot holes falling out. The old days of clear vertical grain plywood are over. Often times going to a marine grade plywood for forms isn't a bad idea.....
I gave up on plywood myself and stick with LVL material now.
Post by: Longcruise on April 15, 2023, 06:54:19 PM
I used chipboard T&G once on two forms. One was stored in a shed for a couple years and swelled. It did stay straight though. Nice thing about it is that the stuff i had was true dimensions. No fiddling with spacer stock.
Post by: Crooked Stic on April 15, 2023, 08:01:13 PM
Post by: kennym on April 15, 2023, 08:18:09 PM
Thanks!
Post by: Crooked Stic on April 15, 2023, 09:31:54 PM
Post by: OldRawhide42 on April 15, 2023, 10:04:40 PM
Post by: Crooked Stic on April 16, 2023, 02:28:54 PM
Post by: Kirkll on April 16, 2023, 02:46:14 PM
It really kicks up the draw weight compared to gordons E glass. But.... It's also heavier in mass weight, so performance was mitigated .... I don't know whether they even sell it any more.
Kirk