Using inside spanners in forms

[buckhorn]

Spanners are suggested in both of Siminoffs' books when glueing up rims. I've never been comfortable with this method because I could never get the proper pressure in the right places to make a good rim fit.. After the first several tries, I came up with what I think is a better method.. I drilled holes in the most stressed areas of my forms and used clamps to help shape the rim parts to the forms. I will mist the rim parts and let set, clamped in the forms, for a while before glueing.. They are so tight that I sometimes have to hammer the new rims out of the forms.. Hope this helps others out... Keith

[Parker135]

Certainly helps me! I'm very early in learning to build, and ideas like these are very helpful.

[Tavy]

I just make the outside of the form the same shape as the inside (so it's effectively a 1" thick rim) and then I can place clamps wherever they're needed.

But yes, damp down the rims before inserting and clamping and they "set" very nicely to the shape of the form.

[buckhorn]

I use two different forms to do F style rims and one for A styles. My first form used 1/2 inch plywood while the second is 3/4 inch thick. The first is a two piece, split in the middle with threaded rods at each end. The second is solid plywood, not split and no threads. Though both work just fine, the solid form just seems to work better. I've seen lots of forms that form from the outside, but this method works for me.. I try to pre-form parts before trying to clamp and glue. If you have to tweak a little before final gluing , the parts bend a little easier... Oh .. another secret

[HoGo]

I use four piece form made out of 30mm plywood. I cmamp against outside of the form if needed and I use spanners for gluing the back and top so the ribs are following the outline perfectly. I made a base board to which I pin and bolt the formto prevent any deformations of shape. After the back is glued I can loosen bolts holding the four pieces together and remove the form. For clossing the body I typically use two or three split spruce "go bars" inside to hold the rim tight again after closing body I use long nose pliers to brek the sticks into smaller pieces and pull them out through f hole.

[John Bertotti]

Seems a lot of people use inside forms and I always wondered why people didn't just bend on the outside of a form with a heating pad or similar.

[Marty Jacobson]

They do. Google "Fox Bender".

[John Bertotti]

I have some silicone pads and fully intend to use them.

[buckhorn]

Most any rim will relax a bit when it's removed from the forms.. Therefore, I always glue the kerfing on while still in the forms. Don't take the rim out of the form 'till after glue is cured (couple hours). And if you store the rim a bit, stretch a rubber band between the scroll bout and the 2nd point.. Just enough to keep pressure on the rim till you are ready to use.. The 2pc form I first made was hardly ever separated to remove the rims, just tap out with a mallet. More complicated then needed.. I did give the inner edges of the form several coats of sealer, keeps glue from sticking.. The 3/4 inch form (as apposed to 1/2 inch) does help cut down on twisting of the pieces, and they almost always try to twist... Good luck and keep trying …. Keith