Primitive Archer

Main Discussion Area => Bows => Topic started by: OffTiller on August 26, 2014, 08:07:17 pm

Title: question on backing
Post by: OffTiller on August 26, 2014, 08:07:17 pm
Hey guys, i am starting on a hickory backed black walnut flat bow. I have a thin strip of hickory from last bow but it varies in thickness. If i hand plane it even, how perfect does the thickness need to be, and do i need to worry about anything lifting if i use a hand planer. and what can i use to smooth the backing to keep anything from lifting.
Title: Re: question on backing
Post by: Pat B on August 26, 2014, 08:15:07 pm
Sanding might be easier if you have a belt sander. If you have to plane it be sure you go with the grain.
Title: Re: question on backing
Post by: OffTiller on August 26, 2014, 08:20:01 pm
thanks, and obviously use the sanded side for the glue up?
Title: Re: question on backing
Post by: DarkSoul on August 26, 2014, 08:20:05 pm
As long as the backing is quarter sawn or rift sawn, you can sand or plane it even after you've glued it to the walnut. A thin and flexible strip is difficult to reduce by hand. Just make sure you have one flat surface so you can glue it to the belly wood.
Title: Re: question on backing
Post by: OffTiller on August 26, 2014, 08:23:11 pm
makes sense, I was thinking 1/8" thickness. should i also trap the backing if using BW? and if so how do i do that with BW?
Title: Re: question on backing
Post by: Pat B on August 26, 2014, 08:29:09 pm
You'll want to trap it after glue up too. Then, trap it from back to belly with the belly being wider. You can probably bring each side of each limb in 1/8" or slightly more on the back.
Title: Re: question on backing
Post by: OffTiller on August 26, 2014, 08:30:44 pm
great, that gives me a great place to start. really grateful to both of you.
Title: Re: question on backing
Post by: OffTiller on August 27, 2014, 02:25:16 pm
so i took the clamps off my boards today and on one side of the bow past a fade the glue has shrunk and caused a gap on edge of the boards. to get a better idea, lets say it's the top limb on the right side (as an example) my goal was to do an ALB but if i cant figure out how to fix the gap, i feel i might have to cut this into a pyramid bow and hope the gap doesn't run to the middle of my glue up. any suggestions? thanks.
Title: Re: question on backing
Post by: bubby on August 27, 2014, 02:41:49 pm
Heat it up, take the backer off, clean it up and reglue, get some bike innertubes and wrap vs,.clamp
Title: Re: question on backing
Post by: Pat B on August 27, 2014, 03:44:26 pm
2x
Title: Re: question on backing
Post by: OffTiller on August 27, 2014, 05:16:27 pm
so obviously TB3 shrinks as it dries. would another glue be better for backing with woods?
Title: Re: question on backing
Post by: DarkSoul on August 27, 2014, 05:27:38 pm
No.
Nothing wrong with titebond 3.
It has just been improperly clamped by you. You need at least 30 clamps to make them work, but a much better technique is to use bike inner tubes as elastic bands.
Title: Re: question on backing
Post by: OffTiller on August 27, 2014, 05:34:57 pm
so just cut em' to length and use a square knot? since tighbond need air maybe wrap around every 4-6 inches. would that be enough
Title: Re: question on backing
Post by: John D on August 27, 2014, 05:43:53 pm
Your glue up needs even distribution of clamping force more than big gaps for air.  Little gaps between the wraps of bike tubes is enough.  Do a search for bike tube and see how some of the other guys use em.  If I was gluing on a backing that was 1/8" thick, I would leave gaps no bigger than 1/4" in my bike tube wraps.  Hope that helps.  Leave em long and tuck the end and start another.  In my opinion, air will get in there. 

John D.

Boise
Title: Re: question on backing
Post by: OffTiller on August 27, 2014, 05:58:39 pm
i have seen those set ups before, just didn't stick and now i'm kicking myself for it, i'm gonna give it another go. thanks.