Band Form Help

[EvilDogBeast]

Couple questions for you guys regarding building on a rubber band form:

1. Is it better to cut everything to length before or after glue-up (I would assume after for a first-timer)

2. How tight am I wrapping these bands around the form during glue-up, as tight as possible without breaking them?  I have 100 1" rings knotted into figure 8 bands and 2 91" bands to go serpentine style over top of those.  Overkill or just right?

3. How important is heat with Smooth-On?  I have seen this question many times and I know it can work both ways, but will it affect the longevity of the bow if its not heated?

Thanks in advance for the information!

[Bvas]

1. I precut so that I have a full inch past my string grooves to work with.  So a 60" bow, I cut them 62".

2. I don't do the rings.  I clamp my riser in place then I just serpentine wrap as tight as possible.  Start from center and work toward tips.  I will do two passes on each limb, criss crossing the first pass with the second.

3.  Cant say.  I heat, but only to about 120.  First couple bows I heated higher and had a couple bands pop.  Now I let form set at room temp for a couple hours so glue can start to set before putting in the oven.

[monterey]

Trying to understand the 100 figure eight thing.   :confused:  

What are your bands made of?

[EvilDogBeast]

Bands are made from bike inner tubes cut cross-sectionally into 1" wide rings.

[mwosborn]

Never used a band before so can't help there.

Here is the link to what they recommend for EA40..

 https://www.smooth-on.com/tb/files/EA40.pdf

If you scroll down a ways they address bow making specifically.

It will cure at room temperature in 24 hours.  Curing at higher temperatures supposed to make it more resistant to heat after it has cured.

[monterey]

Ok, now I get it.  I cut mine length wise around the bike tubes so each strip is equivalent to the circumference of the tube.  I go very tight crisscrossing and do occasionally break a narrower band. It's necessary to have the form firmly clamped down or in a vise while you work. It's easier to work with more narrow strips than fewer wider and stouter.

I've cured bows at 180* in the bow oven, at about 110 to 120 in a hot car in the summer sun and on the floor with a light blanket over it and a space heater blowing through end to end and maintaining 90 to 120. All three methods seemed to work just fine.

[OkKeith]

I used heavy duty rubber bands from the office supply:

 https://www.staples.com/Staples-Economy-Rubber-Bands-Size-84/product_831636

They seemed to hold up in the hot box well. I will probably have to get some more. Its been a while since I used them.

OkKeith

OkKeith

[EvilDogBeast]

Thank you all for the information.  I went to the hardware store and it seems an actual hotbox will cost me about £80.00 in supplies that I'll need to get rid of in August when I go back to the States.  I'm going to try the blanket/heater combo and see how it goes.

[Roy from Pa]

Doesn't the heat cause the rubber bands to stretch more?

[Forwardhandle]

I cured a bamboo backed hickory bow with 2 folded over electric blankets about 2 months ago lifted the blanket and used the laser thermometer max temp 135 Deg F at the form .

[OkKeith]

Roy-

I didn't have any problem with them getting looser. If I remember right, rubber is one of those weird substances that contracts when its hot and expands when its cool. From my reading before I built that bow many years ago, the thing to watch was not to get the rubber bands over tight before they went in the oven. If they contracted too much they could cause "glue starvation" or break.

       imgur    

I thought I had a pic of the bow in the form but can't find it... This is a pic of the form. We started from the middle and worked out to the limbs tips working a band up over and across at each set of pegs. If I remember right we put two bands per peg set. One square over and one figure eight.

Chris... As Yellowwood suggested, before I had a hot box we made several backed bows just wrapping them up in plastic and then an electric blanket. We then wraped that in one of those annoying space blankets. None of them failed (because of the glue anyway).

OkKeith

[EvilDogBeast]

I don't have any electric blankets, but I do have a spare bedroom and a few space heaters.  Yes, I am totally going to build a blanket fort in there and cure a bow  :D

[OkKeith]

Chris-

I think we are gonna need pictures of that... with you peeking out from underneath!

Good luck with your bow project.

Okkeith

[JamesV]

I use a farm tractor or big truck intertube, spiral cut into 1 1/2 inch wide strips. I start in the middle and spiral cut each half. Last one I cut, I got two strips over 75 foot long. The big tire dealers throw away lots of used intertubes.

James