New form

[kennym]

How about this one ? Not mine , been there already ! 

Custom build …

[B-JS]

Nice.
Looks Like my 50" Rover.
Pain in the A*** to build.
You'll need 45/45 Carbon to get it stable.

[kennym]

I think he has carbon planned for it.   

The top form will have to be two pieces to get in and out . 

[Longcruise]

I came close to that......... once! 😱

[Stagmitis]

I had a friend whose mustache looked like that after waxing 

[onetone]

Big ole hooks on that one! What’s the size on that one, tip to tip, unbraced say?

[kennym]

I'd have to measure his drawing, but it will take a 76" piece of glass to put on the form surface.

If you mean tip to tip straight line , I'll have to measure that too...

This is a big dude, says he draws 32"

[Mad Max]

Kenny That needs to be the top form.


Bottom form

[onetone]

Hehe I agree with Max.

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.

[kennym]

Max for an air hose form , looks like same prob getting other half off unless you went topless .

[onetone]

Can go sideways after the hose is deflated, but would have to take the straps off one side. The idea of going topless on a concave form like that makes me more than a little nervous!
 

[Kirkll]

That's a wild looking form.... I'm with max on using that as a top form, or going topless and using the back of the bow for the form shape rather than the belly... Laying it up will be much easier.

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.

[Crooked Stic]

Yep I think  you should bend around instead of into  the curve.and yes gonna take carbon for stabilization.

[Mad Max]

I tried a static recurve years ago that way and finally burned it out in front of the bow shop and started a reverse form(back of the bow on the form) It works much better.
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
Sorry

[kennym]

""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 ""

I'd been thinking that too after getting it cut out.   Point taken... 

[Mad Max]

 

[Kirkll]

I have some pretty radical recurve forms that I’ve done both ways and there are pros and cons to each direction you use loading the lams into the form. But I’m just talking about limb forms here. Not a one piece.

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

[Kirkll]

Kenny That needs to be the top form.


Bottom form

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….   

What is your procedure for pulling this off successfully?

[Mad Max]

Two .002 lams and two .030 glass or veneers also. I'm thing .250 stack will make a 50#, I will check stack later.
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

[Kirkll]

"Trying to bend a lam around the form can crack it, but bend the whole stack works."

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