Binding Lamination and Wrinkling

First off, I want to thank all the builders for the discussion that takes place here on Mandolincafe forum. I've been "lurking" here for years gathering information to help me in my Mando builds. There is a wealth of information. I'll try and add to the knowledge base in the future. THANK Y'ALL!

I'm currently working on F style mandos 6 & 7. Since Mando #2, I've bound the mandos using the 2 step process; w/bk or iv/bk thin purfling followed by the thicker ivoroid binding. I feel like I could get better miters if bound in one go. I was inspired by the Andrew Mowry mando binding article in the Spring 2013 American Lutherie and decided to try and bind 6 & 7 in one pass.

I purchased binding from Bill James at Axiom Inc and used a homemade laminator patterned after the Stew Mac laminator to create some strips. I've discovered that you need to be generous with the acetone to get a really good weld. I let the binding cure for 3-4 days and then started on the scroll area. In the tight curves, the thin iv/bk purling binding would de-laminate from the thicker ivoroid and/or wrinkle . I've switched to a hybrid one pass/two pass installation. I'm doing the scroll curves with two passes and using one pass in the less tight areas.

My questions; Have others had problems with this? Any methods to help prevent? Does the pre-laminated binding (iv/bk/iv) from Axion Inc perform the same way?

Thanks for any advice!
Bryan

I've used both the prelaminated IBI and also made up some fancier bindings using the StewMac jig. Yes, you need to use a healthy amount of acetone to get them to bond. I have had no problems with delamination when bending with either method, but it's a lot easier to use the IBI from Bill James.

How are you heating up the binding to bend it? You can use a heat gun but that is dangerous with celluloid because it tends to ignite. I do it this way: I have a frying pan with small glass beads, basically very fine sand, that you can get from Santa Fe Jewelers Supply. That sits on a hot plate. Heat the sand/glass up and put your binding in it for just a few seconds (you'll have to experiment) and it's ready to bend on either a form or on the binding channel itself. Because the binding is pretty much out of the open air, it doesn't ignite and you can heat up 6-7" at a time if you wish.

Yes, it looks like it may be partly an issue with the heating technique. I use a heat gun, but I try to warm the binding gently. You can also try heating the outside of the binding more than the inside, so the inner layers can't wrinkle like they have in your photo. If you only heat the outside, the outside lamination will streatch around the bend while the inner layers retain their structural integrity.

I've had the same problem in the past. I've found it's best to install the binding as separate pieces without pre-laminating. For the piece your showing for the scroll, you can do an inch or so starter to get your joint done, but then leave the strips separate.
As you glue it you add glue between the strips as well as in the rabbet. Then you don't have the tension and wrinkling problem. If you ever get a chance to see Bob Bennedetto's video you will see him doing this with about 5 laminations threaded between his fingers.

That looks to me like a combination of too much heat and the acetone was not "cured" out of the binding enough. That will make those little holes.
I use a few shaped channels cut into teflon cutting boards and shape my laminations with a heat gun, or sometimes boiling water. I'll tack a few start spots on the scroll area with super glue. I build the rest up on the instrument as separate layers all at once using white tinted super glue. Miters get wiped with acetone and sometimes a goop of acetone and melted ivoriod binding scrap.

Wish I had been smart enough to think of Andrew's idea. So obvious.

It sounds like I've tried all the usual stuff. I heat the binding with glass beads (actually Harbor Freight ground glass sandblasting media) and with a heat gun as necessary. Mostly the ground glass, as it seems to heat the entire piece more evenly. It seems that the binding strip is wrinkling internally in a tight bend as there's no where for the inner binding piece to go unless it compresses. I've also tried this with a piece that was laminated and allowed to rest for a week with the same result. I tried slowing the process down, but maybe try slower or let the newly laminated piece rest for even longer.

I have also used a jig cut into a PET cutting board to help form the bends, along with right sized ratchet sockets. I initially tried to laminate the bindings while held in the cutting board channels; I shaped them and then dropped acetone between the two layers. This was unsatisfactory as the laminations were easily broken apart. I've been using ivoroid/acetone goop as the glue with good results.

It sounds like the experimentation will continue...Andrew - thanks for commenting. I've been religiously studying the GAL journal binding article. Wonderful resource! Also thanks for the terracing templates from your website.

Thanks, I'm glad they were useful! As an experiment, I'd try heating only the outside of the binding with a heat gun when you make the initial bend, because the inner layer won't compress if it's not softened. The outer layer does get a little thinner when you do this, because it's stretching. Once you've made the initial bend you can reheat the whole thing to make final adjustments.

I will try the outside edge heating trick. Thanks!