Building up the riser from thin laminations

[arachnid]

Hi guys.

Say I want to build a KennyM style R/D. Can I laminate thin strips of wood to get the riser shape instead of sanding it into shape (I mean only the curve thats facing the back. the inner fades and feathering will need to be sanded), or is there any structural problem I`m missing?

Thanks

[KenH]

Weight more than structural, I suspect.   If you're using typical bow making scrap -- pieces of laminations from .03 to .10, you'll be using a lot of pieces of wood to build up a 2" deep block, and a LOT of glue, which is relatively heavy.  If you're talking using 5 or 6 pieces 1/4" to 3/8" thick, say, glue weight won't be an issue
....

[bamboo]

if you are thinking of clamping it into your form to get a "perfect" fit--there will be springback--figure that in and it would work

[Pat B]

The riser on my Jeffery's takedown recurve is multiple layers of thin lams. It was lamed together first than shaped.

[arachnid]

Originally posted by bamboo:
if you are thinking of clamping it into your form to get a "perfect" fit--there will be springback--figure that in and it would work

Thats what I thought of doing and I know there will be springback.
I was thinking about 2 options:

1) use thin lams so the springback will be minimal. cutting the first one 18" and going down in length with the rest (say, each one will be 1" shorter the previous, so I`ll get a sort of "fade").

2) If there will be some springback, I think that once clamped and glued with the bow lams to the form, it`ll take the right form.... but I could be wrong...

Your thoughts plz...

[Mad Max]

I don't think any spring back on this one.


http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=011972;p=1

[LittleBen]

Originally posted by arachnid:
 

Originally posted by bamboo:
if you are thinking of clamping it into your form to get a "perfect" fit--there will be springback--figure that in and it would work

Thats what I thought of doing and I know there will be springback.
I was thinking about 2 options:

1) use thin lams so the springback will be minimal. cutting the first one 18" and going down in length with the rest (say, each one will be 1" shorter the previous, so I`ll get a sort of "fade").

2) If there will be some springback, I think that once clamped and glued with the bow lams to the form, it`ll take the right form.... but I could be wrong...

Your thoughts plz... [/b]

I've done this numerous times for the same reasons you mention and it works fine. Yes there will be some spring back, but the riser will also bend right back to shape once you clamp everything back up for glue up of the limbs.

[arachnid]

Originally posted by LittleBen:
 

Originally posted by arachnid:
 

Originally posted by bamboo:
if you are thinking of clamping it into your form to get a "perfect" fit--there will be springback--figure that in and it would work

Thats what I thought of doing and I know there will be springback.
I was thinking about 2 options:

1) use thin lams so the springback will be minimal. cutting the first one 18" and going down in length with the rest (say, each one will be 1" shorter the previous, so I`ll get a sort of "fade").

2) If there will be some springback, I think that once clamped and glued with the bow lams to the form, it`ll take the right form.... but I could be wrong...

Your thoughts plz... [/b]

I've done this numerous times for the same reasons you mention and it works fine. Yes there will be some spring back, but the riser will also bend right back to shape once you clamp everything back up for glue up of the limbs. [/b]

Thanks Ben. Seems like you always have the solution for my problems.

How thick where the lams you used for the riser? What the max thickness I can use so I won`t get a ton of springback?

[LittleBen]

That's a very subjective question. Depends on the curvature and the wood. I've done it with 1/4" thick or as thin as 1/8".

Let's put it this way, if you can get the lamination to bend once to glue the rise, you can get them to bend the second time even more easily becaus you will shape them down. So as long as you can get the riser glued up to the right shape, you're good.

Only the ends of the riser will spring back. The thicker portions won't move at all.

[arachnid]

Great info everyone. Thanks very much.

[Mad Max]

Like ben said
Let's put it this way, if you can get the lamination to bend once to glue the rise, you can get them to bend the second time even more easily becaus you will shape them down. So as long as you can get the riser glued up to the right shape, you're good.

Only the ends of the riser will spring back. The thicker portions won't move at all.

[Robertfishes]

This riser has at least 26 layers of fiberglass in it..I glued it up in the form and it was not fun.. but it came out really nice in the end. I put the back glass and 002/inch tapers in the form, covered them with plastic, then started adding the layers of glass. It was really challenging due to the slippery smooth on, I added the top pieces of wood after the smooth on cured in the glass lay up.    

[arachnid]

Thats a very good looking riser Robert.

[Robertfishes]

Thanks, It's a KennyM design that I built back in 2011, I made it 66" instead of 64"    

[arachnid]

Looking at such nice bows makes me want one.... Damn mail... the FG I ordered should have been here by now...

[kennym]

Love that riser Robert, bet it don't flex!!

[Crooked Stic]

Robert I have done risers like that but the glueup on the riser parts  was before going into the form. I like that look. Bomb proof to.