Advice on reflex adding forms.

[Minuteman]

I started down the seemingly smooth path of laminated bows a while back and as I've walked along I've manged to figure out its not as smooth a trail as I'd expected. Bit more to it than I thought.
 I've made two separate forms now since I've started. The first one induced 2 1/2" of reflex in a 70" bow (we are talking Hik backed Cherry Lonbows here)But all of the reflex was in the outer 20 or so inches of the limb the center part was flat.  Don't really know why  just did it that way. What I found was that where the transition from reflexed to flat occurred I couldn't get a good glue joint no matter what I did. There was always a little bit of a thicker line there where it made the transition.
 My second one , which has my third ( first two are kindling) Hik backed cherry longbow on it 'till tomoprrow evening, was a bit more radical. It is a complete arc, no straight section to it at all. Even the thick part where the handle is has bend in it. Don't know how it'll turn out or what kinda gaps I'll have under the backing strips with this new one.
 What I'm looking for is maybe a good discussion of the finer points of making a form for reflexing a laminated bow, or maybe pics of your forms and why you made them the way you did. Whatever you experienced fellas think is important to understand.
 I'll certainly appreciate the info. Tired of breaking wood.
 Chris
 

[WTK]

Chris I do a dry run when I make mine. Put everything in but the glue. This lets me see any area that isn't being compressed completely so I can add additional material above that area so there's more pressure there. I like to place some thicker wood strips across the fades and use clamps to pull that area tight.

[Pat B]

Chris, It is possibly your clamping method rather than the form. I have a hard time getting good glue joints also. I'm also interested in seeing what others have to say on the subject. I know some have very good sucess with rubber bands or tire inner tubes. I use spring clamps with the Dean Torges type of form.  Pat

[Minuteman]

WTK, thats not a bad idea with the dry run. I did put clamps over the area that I had been having trouble with. This afternoon I'll find out how I did.
 Pat, don't know what a Torges style form is but mine is one where the back goes down first and the bow limbs are pulled down to the form . I've been using rubber pond liner strips. I guess I need to cut some that are all the same width so I get even clamping pressure. I just wacked these out with a pair of scissors. They are anywhere from an inch and a half to 3/4" so that may be part of my problem. I'm a carpenter and O don't have enough clamps to do a bow! Don't see buying enough either. Good clamps are expensive.Bet you'd need a good 30 er so for a 70" bow.
 Any one else wanna put in there 2 cents worth?

[Justin Snyder]

OK, I think people are getting sick of seeing my forms but I will post it anyway.  If you are tired of seeing it, you should have posted yours quicker so he could see it.    I do NOT like to do a glue up reflex on a form that the back goes on first.  I have tried it that way and I had air bubbles.  If the form isn't perfect it does not put pressure on the entire back.  Also the nodes of boo will hit and prevent the even pressure you need.  I like to clamp the riser in the center and push the limb tips up.  You can adjust the amount of reflex by adding blocks under the uprights. This also allows me to get all the way around the limb and see what I am doing. As for clamps, I am the rubber band guy.  I cut some wood blocks from scrap pine. They are about 3" long 3/4" wide and 3/4" thick. I then go to the office supply store and buy a bag of 1/4" rubber bands for $3.  You put the wood block on top of the back and slop the rubber band over the end of the block.  You then stretch it down as tight as you want. Pull it under the belly and wrap it around the block on the other side of the bow. Then back under and wrap the other side of the block. When you have the rubber band wrapped until you just have the end left, you just slip it over the end of the block.  On the problem areas you pull the rubber band tighter, or use a second rubber band after the first one is wrapped.  It works great on wood backings with water based glues, because it holds the edges down where it would want to roll up from the moisture.  After I clamp the bow and apply the glue and put the backing in place, I like to put plastic wrap on to keep the glue off my clamps and rubber bands. If you still have a problem area you can use one or two clamps on the wood blocks to squeeze the area harder. But if you check the glue up first you should never have that problem.   Justin

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[huntersim]

One thing that might help you, is to use a very slight concave surface where both back and belly meet. It allows the joint to sit tight on the edges vs rolling up at the edges like a flat gluing surface might with a lot of clamping pressure.

[Coo-wah-chobee]

   JUstin dude !----you are so NEAT and you are clean too ! Wow-must be the better half's influence or maybe demands . I know mine demands and then I pay no attention of course ! ........bob

[Pat B]

A good pressure strip of wood or metal helps to keep things consistant and especially with hickory backing, unless you glue it up with the backing down on a solid form, the pressure strip will keep the backing from curling up when the moisture from the glue sinks in.
   I prefer spring clamps over screw clamps. I have had screw clamps loosen while in the hot box. Whether the clamp loosens on its own or the wood shrinks when it heats, I don't know.   Pat

[DBernier]

Justin, nobudy gets sick of this stuff. Excellent use of natural resourses, and you could do it on the kitchen table its so clean. Your clamps are #1

Dick Bernier

[Minuteman]

Justin what kind of wood are you gluing that backing to in the pics? Did it hold up with that knot in the limb? Looks like cherry?

[Minuteman]

Well ,the third one came out looking real good. No un glued portions and nice even, thin glue lines. I did take the bow down to shape prior to glue up this time. Before I had been glueing them together when they were still at there full 1 1/4" width. Think that helped me out some as well as the form not having any transitions from flat to curved.
 I started another thread on the bow that just came off the form. HBCLB follies; episode 2
 Chris