Hot Stuff for binding question

[Brian Evans]

I'm about to do my first binding job on an archtop. I have the channel cut and cleaned up, I have the plastic binding material and laminating tool on order from Stewmac, but I couldn't order their binding cement because it couldn't be shipped to Canada for some reason. Weldall 16 and Duco is essentially unobtainable here, probably down to abuse of airplane glue by youngsters. I read copiously in the archive and was struck by Bill Moll commenting that he does amazing binding jobs using Hot Stuff, which I understand is a very quick setting and very thin viscosity CA glue. I can get it by mail order.

Here are the questions. Bill Moll says he fully tapes the binding tightly and then wicks in the glue along the seams. He then goes back and does the bits covered by tape, and uses another method for mitres, not sure what. Does this actually work on top bindings to softwood? How perfectly must the binding fit into the wood, since I understand that CA glue is poor at gap filling?

Second, there are a million brands of CA glue. Is Hot Stuff unique, accept no substitutes, or are there other brands available at big box stores that would be another good choice?

Brian

[Pat Foster]

I've used CA, similar to Hot Stuff, with good results. Main thing to remember is to seal any parts of spruce that where the glue will be to avoid bleeding and discoloration.

Up side is that you can get all the binding/purfling in place like Bill Moll, check every spot, and only then wick in the glue between the pieces of tape and going back over it after the tape is removed. Contrast that with adding white or similar glue as you go, taping as you go.

Cleanup is much easier with the white/AR glue, and if things turn out really poorly, it's easier to remove bindings with a little heat.

Since I started bending the binding in the x, y, and z planes, fitting the binding is much easier, so I'm back to Titebond I.

Pat

[Brian Evans]

Pat, how do you seal the spruce? Would that be lacquer, shellac, tape? One of my big questions was clean-up of excess glue, since you are just kind of putting it on there and letting it find it's own way in. I am going to be staining the top after, and sealing just the edge might cause issues with that. My top, fwiw, is redwood and the sides and back are mahogany. My kind of plan was to sand back after glue to clean up excess.

Thanks for your comment.

Brian

[Pat Foster]

I use shellac, 1 lb cut. I don't know if redwood gets stained by some CAs the way some spruce does or not. Anybody?

Pat

[Barry Daniels]

After glue up, you should use a scraper to level the binding and remove glue residue on both the sides and the top/back plate. Whether you are using Hot Stuff or Stew Mac superglue, make sure you use the thin glue to get maximum wicking effect. Shellac is the best for sealing endgrain in the binding channel.

[Michael Lewis]

Be very careful with tape on raw wood, especially soft woods, as it can pull fibers and splinters when it is removed. Also be very careful when applying CA, as it can wick to places you don't want it to go.

CA is great at gap filling, it's just not strong in that condition.

Make a habit of making your joints fit well so there are no gaps. Also keep in mind that better fitting joints are stronger. The more you try the easier it gets.

[Barry Daniels]

The other type of binding glue that Bill Moll used is a homemade concoction used strictly at butt joints. It is made by dissolving binding shavings in acetone. The glue makes binding joints virtually disappear.

[Brian Evans]

Thanks for all the comments, folks. The shellac wash-coat to seal the binding groove end grain was a brand new idea for me, prompted some additional research and found that it probably is a better bond CA to shellac than CA to porous wood anyway. My concern with staining will probably be alleviated since I will be using an alcohol based stain that will work with the shellac sealing coat.

Brian

[Barry Daniels]

Also, you will remove the shellac from the surface during scraping and sanding prior to finishing.

[David King]

Redwood is particularly susceptible to staining from CA glues. Redwood and spruce are also quite acidic and will slow down the curing of the glue which will allow it to wick in even further. There's nothing special about Hot Stuff. It works well but so do most of the other glues. Bob Smith Industries (BSI) sells rebranded CA of excellent quality to many small hobby shops around the country. The blue bottle stuff is thin, fast setting and quite reasonable.

[Barry Daniels]

When I was doing a lot of plastic binding with CA I had a test to determine if the glue was "hot" or fresh enough. I put a small squirt of the glue on the slick side of the binding and then wiped it off after a couple of seconds with a paper towel. If the glue is "hot" it will melt into the surface of the plastic and leave a slight etched impression. Over time CA will lose this property and it can be wipe off cleanly. This glue can fail to penetrate and bond to the plastic sufficiently.

I also took the precaution to rough up the surface of the binding with sandpaper to give the glue something to grip.

[Todd Stock]

Looks like LMI ships international on their binding cement - might call them on whether they have some unpublished restrictions on Wendall, Duco, and their FCA to Canada. The FCA LMI contact cement is for mixed wood and plastic bindings (see other strategies below) - awesome stuff. but with some annoying limitations.

For complex schemes that have lots of angles (think Florentine with lots of purfling layers), CA works well - use just enough CA applied with a fine tip micropipette to tack into place, strip tape, then carefully go over the guitar section by section and use gravity to control things. Sealing the top within a couple inches of the edges avoids drips on raw wood (already mentioned about yellowing, and yes - redwood can show color change) and makes the top wood much less likely to tear out when stripping tape.

I like the new Ultrathin CA from the GluBoost folks (distributed by Jescar as well), StarBond 2-3 cPs Ultrathin, and have used thin Hot Stuff, but just about any thin CA down around 2-5 centipoise should do. Fine tipped micropipettes are your friend, as is GluBoost accelerator.

On sealing, two or three coats of thinned 1 lb shellac will do a better job than a single thicker coat of 2 lb, and avoid forming a film in the joint. Also worth sealing end grain on light-colored bindings where the butt joint will be noticeable, such as on curly maple, holly, etc.

On the repair side, worth looking for non-fume/odor-free CA if rebinding instruments finished in lacquer, John Arnold's tip of using the Gold non-fuming CA is a good one - much less burn-in on lacquered surfaces.

The challenge with mixed plastic and wood/fiber binding materials is getting one glue to hold them all together. CA will hold just about any combination, including ABS and vinyl, as will LMI's FCA contact adhesive (it works well, but have short shelf life and is a little pricey. Always an option with ivoroid, tortoid, and other cellulose nitrate binding materials (but not ABS/Bolteron) to use an acetone primer on the binding and use AR/PVA glue like Titebond to attach binding and purfs to wood. Wipe the cellulose nitrate plastic with a single pass of acetone or lacquer thinner, then set in the Titebond with purfs. This works really well with mixed materials (cellulose nitrate binding and fiber/wood purfs), but is a PITA for multiple layers of cellulose nitrate found on some guitars like the Country Gentleman. I have not tried this with fish or hide, but I suspect it won't work.

[Randy Roberts]

Brian,

While I have not used plastic bindings, I do use thin CA for wood bindings. A few hard earned tips:

I also get my CA from Bob Smith industries. It may be the identical stuff in some other brands, as he makes it for a lot of private label companies. He is great at answering questions, and I know I can count on it being fresh, where as with store bought, who knows how long it sat in a warehouse or the shelf. If you buy a number of bottles, you can freeze ( unopened) it, and according to their studies, it keeps indefinitely ( when I asked 5 or 6 years ago, he said they have saved frozen samples from original batches 17 years prior and when tested showed no problems). Once opened it keeps best at room temperature, storing it in the freezer after opening causes a strange wicking of the glue to the top of the bottle where it then slowly sets up. Barry's test for plastic being etched by the CA is a great idea.

Pipette applicators or 3cc syringes with 25 gauge needles allow exact placement. Only apply a few drops at a time, and press the binding firmly into the ledge. I don't just count on the tape holding it firmly. The CA will wick itself into the interface well no matter how hard you are pressing the binding to the ledge. If you apply too much at one time the heat when it sets off can boil the glue, causing a white foam when it sets that can't be undone short of routering it out. You want the binding absolutely flush before you apply the CA because, gap filling or not, the gap you leave will show.

I usually just press the binding against the shelf with a finger while the glue sets. A drop of accelerant while holding speeds things up. I've also found a quick swipe with white paper towel( away from the top) will accelerate the glue. I'm guessing the paper towel is very basic or alkaline and so sets it off. Another option is a light dusting of the ledge with baking soda will set the glue off when it wicks into the ledge.

A couple swipes of shellac on the surrounding wood surfaces will greatly lessen problems with tape pulling out wood fibers when removed, as well as protect against misplaced glue soaking into your top etc. It also makes cleaning up by scraping easier. A small artist's brush works best for hitting the binding ledge to prevent CA wicking up the pores of the top. I do 2 coats of 2lb cut, but doubt the cut is a big deal.

If you are going to be staining, alcohol based or not, you want to scrape or sand off all the shellac before applying the stain. Test on scrap to see why.

Crap, Todd posted as I wrote this and I could have saved the repetition...

The fumes of CA aren't toxic, but are extremely irritating to eyes and nose. A fan on low blowing across your work does a good job of blowing the fumes away from your face.

[Todd Stock]

As I was reading your post, I was thinking that those were some really good tips, Randy. Not much overlap, and what there was is worth repeating!

[David King]

We could use this thread as a "sticky" on CA and binding.
Has anyone determined if the gluboost products are any different from any of the dozens of other CA choices. They would need to be significantly better to justify the 2x price. One claim on their thin and extra thin is that they " are luthier-tested, purer, safer (carcinogen-free), fresher, and "surface insensitive," so they will work on all woods and substrates, while being stronger than any involved substrate."
Those are significant claims if they are truthful. Is the cure time for redwood or Douglas fir the same as it is for cocobolo or spalted maple?

[Todd Stock]

Big difference on accelerator; pretty sure the glues are mildly tweaked Mercury or BSI stuff, based on packaging and similar handling characteristics. While the glues have some minor advantages as a system tweaked toward better usability with accelerator, GluBoost is unlike anything else - to the point where I drop $80 every month or two for 6 cans of the stuff, which is pricey, but a fantastic value.

Bottom line: The Finisher does a slightly better job on deep repairs and the ultra thin is just the right viscosity for padding on touchups (on polyurethane or polyester finished guitars).

[Bob Gramann]

I like the GluBoost products because of the bottle design. It's easy to push the whip tips over the end of the bottle, easy to scrape the tip of the bottle clean, and the pin in the cap unclogs the bottle every time it is closed. I get to use the whole bottle of glue before it gets so bouggered up it's useless. And, then there's the accelerator. The products a worth the money to me just for the ease of use. (But I still do wood bindings with hot hide glue.)

[Dan Smith]

I've read that when using CA, lightly wet the channel to speed the CA cure.
I have not tried this yet, but the idea of using CA instead of Duco or Weldon 16 seems easier and cleaner.

[David King]

Excess moisture will interfere with the CA bond. If you want to speed things up then mask the channel and spray lightly with accelerator, let that dry for 2-5 minutes until you can barely smell it. The time it takes to mask and waiting for it to flash off usually overcomes the time saved in the cure but it might be helpful at critical junctures.

[Brian Evans]

In researching this question I came across an excellent video of a luthier performing this exact task, in the exact manner I am contemplating. He set up and taped on all the binding as tight as possible with about 1" gaps left between strips of tape. He dripped in accelerator with a pipette, then dripped in thin CA glue right away, and then pressed on the binding with a piece of wood to seat it perfectly as the CA kicked off. 5 seconds, then moved to the next gap and so on. Quick, and pressing in on the binding seated it perfectly.