BBI R/D design help please.

[BMorv]

Sucks, but at least you weren't that far into the process.  I've had 2 or 3 ipe boards break on me during test runs before glue up.  Remember that thick ipe hates to bend; it will break; you can't force it.  And it doesn't like tension as in when you crank down on the clamps for the reflex and deflex post.
If you do another ipe, pre-tiler the ipe and make sure it's bending decently before you put in on the form.  If it's bending enough on the floor and is properly tapered, it should bend fine on the form.  Another step that I do is to round off the belly side edges and sand them smooth before the form.  It can handle a lot in compression, but is finicky when forced to bend in tension.  
 
So you want to make a tri lam with lemon as core and ipe as belly?
I have zero experience with lemon wood.

[John Malone]

I tapered it, evidently not enough. It was fine on the dry run. Even had a nice pressure strip under it. Oh well.

[BMorv]

I've never had one make it through the test run and not through glue up.  It should be bending the exact same amount, so that's confusing to me....

[John Malone]

Ive seen it before doing laminated rockers and other stuff for furniture. Doesn't happen often but not unheard off. It surprised the heck of me to.

[John Malone]

BMorv I made a bonehead mistake. I cut the midlimb post 2 3/4 tall they happened to be 2 inches wide. When I screwed them to the base I put them 2 inches tall. So I was cranking them down 3/4 of an inch further than what they were tapered to do. So that's why the dry run was good. When I glued them I was going 3/4 of an inch further and snap. Man I feel like a genius now.

[Roy from Pa]

Remember that thick ipe hates to bend; it will break; you can't force it.

Yup ipe is tough stuff.

[John Malone]

Oh I can force it all right, it went right down in thar. Only not in one piece.

[BMorv]

In regards to your midlimb post question, a good place to start is where Roy mentioned, midway between your flares and tips.  An inch or 2 one way or the other isn't all that critical, so you can adjust it to your liking on further builds.  I moved mine in a few inches in from mid because I wasn't getting enough deflex off the form.  
If you don't already have one, look into getting a .25"x 1.5"x6' mild steel flat bar.  It gives you a pressure strip on the entire bottom and it also bends nicely from post to post.  You can set the flat bar in your form with your proposed post locations and step back and see if you like the shape.

[John Malone]

Thanks BMorv, I use a 6 foot steel yard stick but its not thick enough. I got my cousin on look out for a piece of flat steel like you mentioned. Use to have one but it got repurposed for something else.
I thought yours looked closer to the riser in the pic you posted on the bow swap thread. I will go mid way, then ill know wht effect it has.

[BMorv]

The yard stick might work.  It doesn't have to be a certain thickness.  Let me double check the thickness of my bar.  It may be less than .25".

[BMorv]

And yeah, I started mid limb like Roy described, but I kept inching my way towards the handle on subsequent builds.  I just wasn't getting the deflex bend that I wanted in the handle.  There's only so far I feel comfortable going though, considering that you are putting all of that bend in a spliced lam.

[Roy from Pa]

There's only so far I feel comfortable going though, considering that you are putting all of that bend in a spliced lam.

Yup I've cracked a few before I got mart..  

[BMorv]

My flat bar is .135” thick, so I guess that’s what 10 gauge?

[John Malone]

Close, its actually based on weight. Stainless will be thicker than aluminum at the same gauge. I'm no metal expert but I remember that from some were.

[BMorv]

Here's pic of a riser I did with thin strips.  If you like the look it's easier than fitting a one piece riser, IMO.
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[John Malone]

Nice BMorv, I may end up doing that this time. I thought I had a piece of 5/4 oak but its only 4/4 it wont be wide enough. So if I have to laminate two pieces I might as well do strips. Strips would look better plus I could use that ipe I busted on the last try.