Alignment help on BBI recurve

[Dan K]

Cool, I will have to remember this one for sure! Nice save, is that light bulb a higher watt one?

100 watts

Well done Dan .
It may be worth repeating the treatment, to over bend it slightly, in case it tries to relax back?
Del

I did and went a little too far. Had to bring it back in and let it set for a couple days to stabilize. Put the short string on and it stayed true. I'm thinking once I get the weight down it will reduce the lateral pull on the recurve areas. Hopefully it will fling an arrow!

[Hamish]

Nice save.

[k-hat]

Glad it worked for ya!!  Best of luck with the rest of the project

[Dan K]

Thanks for all the support!  I'll keep posting progress just for grins.

[Dan K]

I know some folks are out there learning along with me and wanted to share some information.  Did some research and found that when you glue up a BBI (probably any laminate for that matter) you don't want to have all your clamps on one side.  This could put your limb in a twist!  Went back and looked at my pics and sure enough...I had most of my clamps on the same side.  Can't say for certain this was the cause but makes sense.  Some others with experience can add to this but I think you should stagger your clamps side to side every other one.


Now I need some help.  My upper limb, the one with the twist that I was able to get out, is no longer symmetrical with the bottom.  In the pic you can see it lost some of the deflex and gained some reflex. 


Should I try to heat bend the reflex and or deflex to match the bottom keep tillering?

[Dan K]

 We'd some help here folks!  Not sure what direction to take with this recurve. I'm thinking I should due some more heat straightening but not sure if it may even out with tillering. ny help would be appreciated.

[cdpbrewer]

Tillering R/D bows is a tedious and iffy...   Heat bending IPE has never worked for me but it's said there are like 100 species of trees whose lumber goes by the name IPE.  Maybe the glue creeped a bit due to the heat?  Since it worked of sorts the first time, I'd try it again but on the other limb since tillering out that much difference and that much reflex in the limbs is going to be pretty touchy.

Did you tiller/thin the limbs any before you took that last set of photos?   It's counter-intutive but reflex can increase due to thinning the an area with reflex- especially with a belly that isn't tillered before glue-up .   Lots of exercise to register the change sometimes helps. 

Some tips to avoiding limb twist when glueing-up:
1) Those rubber strips used to wrap a bow can cause twist.  The diagonal wrapping can prevent the belly from evenly seating on the form.     Hopefully this is shown in the attachment.    I like 4" wide stretch wrap like shown in the attached pic. 

2) After getting a bow glued and clamped to the form, use winding sticks at different locations along the limbs to check for twist.

Please post on how it goes!

c.d.

[Dan K]

I'd like to put a close to this event, show off a little and thank you all for your help.  After I took it to full brace the twist came back.  Thanks Gordon for showing me how to tiller a twist! It worked!  I lost a little weight (the bow that is) but string aligns close to perfect and has stayed true for over 400 shots now.  Tillered to 48#@28.

[Weylin]

That's a fine looking bow! Way to save that one, Dan. Can't wait to see it in person.

[mikekeswick]

As you can see though it still isn't straight!
Lesson for the next one - make 100% sure you don't induce twist when doing your glue-up.
Also be mindful of the crown on the bamboo when preparing it.

[Dan K]

Thanks Weylin, being a lefty you can shoot this one.

Thanks Mike and you're right.  It is a bit off but shoots straight and smooth all the same.  Ill be watching closely though for any movement.  I'm happy for my first attempt and learned so much along the way to add to the next one.

[Roy]

Looks very nice, Dan.. Congrats  I'm sure you learned a lot on this one and the next bow will be even better.. Roy

[toomanyknots]

Wow, thats one sexy bow right there. Can I ask you what finish you used? It looks great! Yeah, I hate twist. Only thing I do is remove wood on the stiffer side (the side pointing farther away from the bow) until the sting is centered. Yall ever have a bow where the string is centered, but then the outer limb is twisted, to where you can't really do anything? Thats always fun too, . Very nice bow, looks fantastic!

[steve b.]

What Roy said.

I shot this bow yesterday and it flung my 650 grn arrows nicely.  Its taken just enough set to show that it is operating very efficiently.  The performance and workmanship is way advanced for Dan's experience level.

[Badger]

  Part of your twisting problem has to do with the shape of your bow, your outer limbs are pretty straight and the curves starts quite a ways in from the end and is fairly abrupt. On the next one if you can get just a slight more curve in the outer limb and make your mid limb bend just a tad gentler it wont have quite as much tendency to want to twist.