New R/D form questions!

[Apex Predator]

I'm almost finished with a new form.  This one has quite a bit of R/D.  Much more than the mild R/D I have been building.  This one will build a 66" NTN max length bow.  At max length it will have 2" net reflex, which I measure from the back of the riser.  At 64" it will have 1 1/2" reflex, and 1" at 62".  The deflex will be 2" on all.  What are your thoughts on performance differences between these three lengths?  I included a photo of my mild R/D form for comparison.

I know you guys are shaking your head at another rubber band form from me, but it's what I know.  I have lots of confidence in getting perfect glue lines from this method.

 

 

 

 

[bjansen]

Looking good Apex!  Are you using rubber bands or innertubes?

[mwmwmb]

I have never built a bow but hope to soon. will you shape the riser to fit the form? what size dowels are those?
thanks, I think that will be a great shooting bow.

[Jeremy]

The performance differences will be tough to predict imo until you build a few of each     You should be able to adjust the taper rate or riser length slightly for each length and get identical performance numbers.

I like the profile... my forms are all rubber band forms too  

[Apex Predator]

I cut bicycle innertubes into strips for clamping.  The dowels are 1/2" oak.  I have used 3/8" before, and never have broken one, but they make me nervous.  You can get a lot of pressure from the innertube clamps.  I normally use about 12 strips on a bow.  I can put more pressure at the tighter radiuses and fadeouts with this system.

[TNstickn]

Marty your results speaks way louder than any worries anyone should have!!! Cant wait to see the bows off that new form. Performance wise, probably wont notice much difference in speed. Might pick up a little more vibration in the handle on the shorter bow, but thats a total guess on my part.

[talkingcabbage]

Apex,  how wide do you cut the bands, and how far down are the dowels, from the top of the form?  Do you have any pics of your band forms in action?

[rkmnt2]

Well it sure looks like you've asked some good questions. Can't wait til you build 1 of each and report back the results to us. lol.
   That shape looks a whole lot like the one I just built. Should have the bow shootable next week. Hope it works!

[Apex Predator]

I've got some photos of one all clamped up somewhere.  I'll see if I can find it.  I cut the rubber into strips about 1" wide.  The dowels are centered 2" from the edge.  I like them sticking out 1.5 inches on each side.

[LoneWolf]

Well Apex, you answered some of my questions too.  Next you just need to do a build along and show how you put the bands on and what comes out of that form.  Can't wait to see one of those.

[sulphur]

i think with that much reflex you will need a .003 total taper or maybe even .004.  either way you going to have a lighter limb, and you will pick up draw weight earlier.  Should result in a faster bow by as much as 5-10 fps.  really thats a guess, but i think its darn close.   I have been using the inner tube system on everyone i have made.  I just don't know about the fire hose thing.  I am thinking about going to heat strips though.  I like the idea of getting my bows off the form in two hrs instead of 6.  good luck apex.  hope it goes well for you.

[wihill]

Marty that new form looks GREAT!  can't wait to see the results off that puppy.

[Holm-Made]

What length riser are you thinking on that form?

Wood is a lot cheeper to obtain if you can keep the riser blocks under 18" I found.  Chad

[SteveD]

Nice Marty. Looks good. Can't wait to see a bow come out of that form

[Apex Predator]

Yep, a lot of wood out there 18" long.  I am thinking around 18" to start.

[monterey]

Apex, this sounds like a dumb smart a$$ question, but I assure you it is not!  What size bike tubes are you using?

I did a band form once ages ago and was not very happy with the results, but I used car tires and had the dowels much further off of the form back.  Looking at what you have done, I'm considering another rubber band form.

[Apex Predator]

I haven't found a free bike innertube that I couldn't use for clamping bows.     I just tie a loop in each end after I cut them into 1" wide strips.

[monterey]

I see, I thought you were cutting them across the tube to make a tube diameter sized rubber band.

[wihill]

Originally posted by monterey:
I see, I thought you were cutting them across the tube to make a tube diameter sized rubber band.

You're not alone - when he first explained it, I had the same thought..       I kept thinking he must have a grip of steel to wrestle those tight bands around a glued up form.

  :eek:

[Apex Predator]

Here is a visual guys.  I start by clamping the riser down with a c-clamp.  Then I start wrapping mid limb to tip, using moderate pressure.  Then back up towards the riser/fades.  Then I alternate to the other limb.  After the whole bow is wrapped once, I start to overlap with more pressure.  After I feel that I have everything wrapped pretty evenly, I will wrap some more over the critical areas like the fadeouts.  I actually use more rubber now then I did on this photo.