Acoustic Guitar Construction

Will. Me thinks it's looking pretty good. I figure bending that thick a binding is going to be difficult. You may want to try bending each strip first then gluing them together, or glue them together as you glue them into the channel?
This is a fine effort your making to do the repairs.

01/08/24
Ah, Kevin, timely advise. Promptly broke the teak purfling – which I was mindful might happen.

I planed the combined purfling/binding strips down to .180” wide this pm with my cobbled up binding planer. This is an old Harbor Fgt. Laminate trimmer with the bit depth adjustment broken. The bit projection is assured by a screw-tightened automotive radiator clamp. On the left, is a piece of .250” drill rod above the work to prevent the binding from flopping around on the outfeed and the infeed down pressure is from a finger made from a bent piece of former binding on the right. Vacuum pickup from above for sawdust.

Hot pipe is a piece of 3” diameter auto exhaust pipe. I was in Menard's one day and found an electric heating element for starting charcoal briquets for $10, squeezed it into a tighter loop to fit in the pipe with the vise on my welding bench.

I do waist bends on the hot pipe and then upper and lower bouts on my home-built approximation of a Fox bender using 3-200 w bulbs.

There isn't a separate, shallower, purfling rabbet, so now my dilemma is how to add the purfling and binding. I found 4 pcs of .250” x .100” maple, surplus bindings, but they're only 30” long. Might just work if I accurately locate the waist bend. And I had 3 extra pieces of the cherry I can use for the purfling.

I 've always used Titebond, but just glued up bindings. I think gluing binding and purfling before bending, like I just ruined, might work, but I'd hate to ruin a second set. If I glue purfling by itself I will need to shim under both ends of any bars clamping as the purfling isn't as wide as the rabbet.

Soliciting more advise here. The more the better. Feel free to jump in.

Can I clamp up both purfling and binding in sections and get in enough thin cyanocrylate to glue both at once? Is this a thing? Should I try the same thing with the far more messy Titebond? What do you use to glue bindings?

I made a similar bending pipe using 3" aluminum pipe and the charcoal lighter. I put a dimmer switch on it to control the heat but found I always left it on high to get the needed heat. Used it on my first 5 guitars.
Then I built the fox style bender using, like you, 3 x 150 watt bulbs. It slow heating but would reach 300 degrees. I found a digital temp reader with a wire and probe on it for $12 at Walmart and stuck the probe in the sandwiched sides and SS slats. Worked pretty good. Then after about 5 more guitars I bought a silicone blanket and made up a control box. This took the bending to another level. Now with the blanket AND the light bulbs I heat up to 270 degrees in about 3 minutes. The bend is done at 300 and about 5 minutes.

I have been taping in my bindings and purflings making sure the fit is good, then wicking in CA around the top first, then on the sides. Let it dry a few minutes, then pull the tape and wick in the CA where the tape was. So far on probably 7 guitars it's worked great. No rushing to get everything set right before the Titebond starts to get too tacky and sets up. I prefer this method now.

You won't be able to steam off bindings later if necessary but I never plan to have to do that anyway.

I think .180 is too thick to get clean bends especially in the waist. I say bend them separate and tape them in the channel together and us the CA.

Good luck with it mi friendo.

01/10/24

Yet again, against excellent advice from a guy whose expertise I respect, I decided to use Titebond. I did take Kevin's advice and bent the binding and purfling separately. I agree .180” wide is too thick to get accurate radii from.

My logic was:
1) I've got Titebond on hand and for most of my builds, have used bindings only at .100” wide. Lots of experience gluing that slowly, utilizing multiple clamping setups.

2) Not much experience with thin cyanoacrylate, and what little I have may be close to 10 years old. Don't know what its shelf life is.

3) Mindful of Kevin's admonition that heat won't release cyanoacrylate and how nice it did with my new heat gun.

4) I need to go to Ann Arbor with Pam tomorrow for appointment with her cancer doc, so lose that day of work, and next Monday and Tuesday its projected to be a high of 8 and 6 degrees respectively. Shop heats with pellet stove, 1-40# bag/day at speed two of five keeps it 30 degrees below the outdoor temp, but if the temperature gets down to single digits, then probably 40 degrees, but too cold to glue.

I glued the first clamping setup this afternoon at the waist on the bass side. It appears that the 30” pieces of maple will just barely meet at neck and lower bout without having to piece in a scrap. TBD.

The work was surprisingly identical to gluing just bindings, no real increased difficulty.

02/10/24

By Friday, 9 February, I finally had the bindings all glued up, planed, scraped, sanded. Back, and sides as required, stained and wiping satin urethane applied. New maple bridge fabricated, glued down.

Today I unfastened the fixture clamping the bridge, 24 hours after gluing it, countersunk the bridge pin holes, notched them with a saber saw to provide string relief, and reamed the holes to fit the existing pin set. Attached the neck. Also cleaned the pellet stove in the shop and restarted it.

Restrung with the original strings, now 3 years old. I need to order another box of 10 D'Addario phosphor bronze light. I could make another sound file but it sounds to me just like it did before self-destructing, albiet with the old, mostly unused, strings.

And, yeah, the 30” maple bindings were just a leetle short at the neck heel (photo) – I could kintsugi it up but probably won't.

Also, I did carefully cut around the old bridge with an exacto knife before removing it but somehow during the top refinishing managed to lift a chip just above the bridge, close corner in photo. Ignoring that, too – wabi-sabi. I think I'll keep this one.

Love it! Holy Modal Rounders, anyone?

She looks great Will
That is a neat saddle.