Da plan . . B, er..G at this point. A first for me (pics)

[Prarie Bowyer]

So I learned the hard way that Lyptus is not for making bows at all (4 broken bows).  No part of them aparently.  I'm working on a few bows.  This one is more of a fantasy inspired bow.  I'm going tro try and sandwich the the riser and core in bamboo. 

In the images below I made my form "backwards with the intention of making bamboo backed bows and gluing on the riser in a second stage.  Turns out it will work well like this also.  I've done a dry run to check the fit of my parts.  The laminations are currently Maple but I'm going to redo them in Hickory I think.  Riser is maple.  I'll actualy lace the form with nylon rope and use wedges to tighten the lams.  Prelacing the form solves some of the problem with poor gluing between the nodes and I think I can fine tune with small wedges or toothpicks.

I need to get a bit better fit on the riser.  I'm thinking of gluing it to a lam and then sanding the transition  from the other side to get it feather thin then gluing up the rest of the bow.  The bamboo belly will run the length of the bow.

I'd like to get some decent weight out of the bow so I'm considering two hickory lams between the two bamboo.  I'm wondering if I could put the riser between the two hickory or infront or behind it?  I get the best fit if I put both behind as shown in the pic but then I think I could see the stress on the fades being an issue.   Putting them all in front makes a sort of sense also.  Or centering the riser between the two also seems sensible.  Which is best?

Oh.  I have heard from skimming on here that "toasting" the belly can be done agressively and will increase draw weight and reduce string follow?  How agressive is agressive?

Bow will be about 68" long and ?# at 28"  No arrow shelf I'm thinking.  Shot off the knuckle.  I'll add some tip overlays to curl the tips around a bit more.  It's a fantasy inspired bow.

[gstoneberg]

That looks a lot like the form I used to use to build glass laminated bows.  Maple will work fine as a core, most glass bows use hard maple laminations.  You are correct in that the fade-out on the riser will make or break the bow (pun intended).  You must sand it well enough that there is no perceptible gap in the transition from riser to limb.  I would also worry with a form like that that you would not get even pressure on the boo in between the nodes which is facing the form.  Hopefully others will be along that have done boo/core/boo laminates with good advice.  Those limbs look pretty deep to me, you might get more draw weight than you think.

Good luck

George

[Prarie Bowyer]

gstoneberg~  I prelaced the form with a narrow guage rope and it seems to help alot.  I'll also put wedges under it.  The maple I have has iffy grain.  I have no real sense of the weight I'll get so I'm not certain how many laminations to use,  if the riser is too long or what else I may be missing.

I'm mostly looking for guidance on how to arrange the riser and laminations.

[gstoneberg]

In my laminated bow making days I never thought it mattered much whether the laminations were in front of the riser, in back or one on each side.  I think with that riser design I'd put them just like your picture has them.  I never curved a mold through the handle though so I could mill the riser flat.  Your sanding will have to be very precise.

Using boo on both the belly and back should reduce the impact iffy grain has.  However, if it were me I'd use good wood too.  Too much effort goes into building a bow to risk it.

Somebody else will have to help with how much core wood depth is required for a given draw weight.  You might as well resign yourself to making more than one bow since you can only narrow the bow to tiller/lower draw weight.  It may take 2 or 3 before you get what you want.

George

[Prarie Bowyer]

Doing some more searching I came up with this.
http://www.tanasibows.com/plugins/albums/slideshow/ss_9fg2Rt03G184YUJHGcKkjX1iLcY_gn3bS2z4ywE.html?bgType=3&bgStyle=000000
He seems to be putting them infront of the riser.  It's a fiberglass bow but the principle is the same.

[dragonman]

Hi PrarieBowyer, good luck with your project, I understand your difficulties because I've been working on the same project the last few months , theres no way in the beginning to know how thick the core should be without time consuming experiments. I did ask one well known bowyer who makes these but he gave me too thick core measurements for some reason and I couldnt even bend the bow, but that was a starting point,yours looks a bit similar from the pics. that bow will be very strong.
on my last bow like this the mid limb maple core thickness is about an 1/8" on a 60" bow...1 3/8" width at the fadeout, with 1/8"(or just under) thick boo, the belly boo was mildy toasted though, and this bow pulls 55#, hope this helps

Dave

[Prarie Bowyer]

It helps!

so you only used one lamination? 1/8" thick?  How did you toast the belly?  Can the charing be scrapped off to get a clean look?  How long did you make your riser?  did you put the lamination in front of the riser?

[mikekeswick]

Regarding the heat treating - obviously you will have to do it before glue up! I'm just saying in case you hadn't thought about it! Once it's done you should leave it well alone - no scraping. The maple will be fine, dodgy grain or not, as it is simply acting as a spacer and not doing any real work. Save your hickory for backing strips.
My guess is 65lbs @ 28.
Good luck with getting a shooter first time.

[dragonman]

Prarie, I used one single boo lam on he belly toasted on the inside not the rind side BEFORE glue up, and 2 seperate backing lams for the back, one for each limb. Total riser length is 16". Thisis just the way I did it, not saying it is the only way or the best way,  good like . I like your jig set up....

[Prarie Bowyer]

Mikekeswick~ it will shoot.  The question is what and how far.

By dodgy grain I mean it's got runn out on two sides with in 3" on the same face.  "Dodgy" . . . ha, ha, ha you must be English.  Oh man I could go for some serrious fish and chips.  Sorry, about all our coming pollution.

Well I set this asside for a bit becasue my main project finaly dried.  Some kinda long bow flat bow reflex/deflex hybrid.  I just want a cool looking shooting bow.  I think I got it.

So for this bow I'm gonig to toast the inside of the belly by using the heat gun till it starts to darken.  I'll go ahead and use the maple (cringe) and put the one lamination under the riser.  I had it nearly perfectly fitting on the photo side.  1/8th gap that would squeze out mostly on the other side.  I decided it should be fixed.  Now I have 1/16" gaps everywhere.