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Main Boards => The Bowyer's Bench => Topic started by: EHK on December 13, 2013, 09:53:00 AM

Title: Dry run - gaps at riser
Post by: EHK on December 13, 2013, 09:53:00 AM
Hey guys.  I'm working on my first one piece Bingham's recurve using the alternate riser.  I did a dry run last night and I have gaps at the top of the form around the riser.  Everything looks good at  the bottom of the form and around the fades.  Any idea what generally causes the gaps up top?  I probably should have taken pictures to explain this better, but naturally did not.  the glass does not come all the way up the top/back of the riser on this design - just up the curved section of the riser similar to most R/D longbow designs.

Could it be too aggressive a slope on the riser?  Too wide or narrow of a gap in the form?  I'm using an 1.5" air hose and the gap in my form is 1.25"

Any ideas would be appreciated.

Thanks...Eric
Title: Re: Dry run - gaps at riser
Post by: Trux Turning on December 13, 2013, 10:00:00 AM
Some pictures would be helpful... Until then I'd say shims could fix the problem
Title: Re: Dry run - gaps at riser
Post by: Robertfishes on December 13, 2013, 10:46:00 AM
How thick are the lams you are using there? Like Trux suggested I had to add several shims on an "experimental" riser one time..I went too aggressive on the riser and used a .100 taper where a .070 or thinner would have been the better choice for that much bend..
Title: Re: Dry run - gaps at riser
Post by: Mad Max on December 18, 2013, 01:47:00 PM
Don't glue up until you dry run looks good!
use shims
Title: Re: Dry run - gaps at riser
Post by: EHK on December 19, 2013, 11:45:00 AM
Sorry guys.  Been away for a work for a few days.  I did get it all straightened out and the curvature of the riser was the culprit.  I just had to make the slope a little more gentle near the top of the riser.

Took me 4 dry runs.  What a pain, but I guess it beats finding out it's all wrong when everything's covered in epoxy.