MIMF

Randolph Rhett wrote:Just so I understand, by "tape" you mean just strips of cloth you cut and that you saturate with hide glue? …

Most recently I have been using green cotton bias tape that an online clothes seller uses to tie up stuff my wife buys. I have also used strips of linen from bags we got with other products. I prefer it to be a natural product rather than a "poly" something or other. The green looks amusing if you look in. I am now also putting it in before I glue the lining. Bias tape was standard item in households when people actually repaired their clothes rather than buy new. Any shop with stuff like wool, knitting needles, sewing material, etc will have plenty of options.

If you look at things such as old lutes (or new lutes for that matter), it was routine to strengthen the joints with either cloth or paper. (Remember that paper back then was not the common wood pulp stuff from today.). I built a lute some 30 years ago and each of the joints is lined with a strip of old cotton sheet. I saw a video recently of a UK lute builder doing exactly the same.

Wright bias tape is a cotton/poly blend - strength and durability of polyester fiber and glueability of cotton. All poly tapes are strong, but glue so poorly that the strength of the fiber does not come into play. All cotton tapes are weaker in thicknesses that can be buried under linings, and can get a little brittle with age, so good idea to protect both the glue and natural fibers with shellac.

I recently also gave the bias tape a try. My wife had some red stuff kicking around and I thought I would like good with the black acacia.

I like that, Rod - very cool. Have been thinking I'll do a little guitar for shipboard use...you've given me an inspiration - red tapes on the bass side and green on the treble.

I use brown bias tape (per Carruth recommendation) soak it in hot hide glue, and lay it across the side. I poke at it a couple times with a pair of fine tweezers to make sure there are no bubbles - and don't touch after that. A shellac cover is a quick lick with a wet brush. done.

scrape down the ends a bit (minimize thickness and remove shellac) then put the liners right over

Bed the tape in hot hide and use a hot, wet paper towel to get rid of the excess...no air bubbles and no excess glue. The hot water keeps the glue liquid and the paper towel picks up the excess. The blue tape trick makes this so much easier, and the edges stay straight and true. Pulling the tape after the glue sets for 30 seconds and you'll have a very clean install. The student issues I see are generally related to leaving too much glue under the tape or on the surface, which makes getting the linings down a pain. A light sanding after shellac gets rid of the defined edge and gives a good gluing surface.

I put on the shellac after the liners go in.

Used to do before, now after. My linings go in with hot hide, so shellac before makes the tapes much less likely to lift during clean up...I stop shellacking just after where liner goes on and do a careful sanding to remove what little ends up on the area that will be under the tape. Also an option to wipe from center of tape out to edges to avoid lifting the edges.

I found that if I soak the tape in the hot glue, and lift/drag it out and over the container's edge to squeegee off excess - then I'm left with a wet tape, with just the right amount of glue that lays down perfect. There is no cleanup, no squeeze out, and as the glue dries and shrinks, the tape becomes a permanent fixture on the side. Like it grew out of it.

And plan ahead for color contrast...am still kicking myself for not using a nice red tape for the pink ivory guitar I built. Something cocoa-colored is great on lighter woods, and with inspection ports (ok - sound ports, whatever) so popular, nice to plan ahead.

So the cloth tape has a certain thickness, plus that added by hide glue and shellac. So how does one glue the lining over that without having gaps on either side of the tape?

The tape is very thin, on the order of .005" in a glue line. If you use HHG to put in the liners as well as the tapes, and save the shellac for later, it more or less disappears in terms of the strength of the joint. I've never had any real problems with the liners coming loose on either side of the tape, where there is theoretically a gap, and if anything they stick a bit better over the tape.

Thanks Alan. One more question - I'm assembling some sides and I've never done this before. I'm not set up to use hot hide glue. Any chance the dreaded liquid hide glue would work for this application?

Liquid hide glue has two problems so far as I can tell: it's more subject to softening in high humidity, and may not hold well if it's not really fresh. I had some problems with it back when I started luthing, and have avoided it since then. IF you get a fresh bottle, and seal it well with shellac, it should work. If it does let go in the future it's not really a 'structural' joint (unless there's a crack), so it might be more an embarrassment than a disaster.

Titebond works OK for this. There are three reasons I don't use it, though. One is that it's harder to use: I found that the best way to get the tapes on was to dampen them slightly with water, and work in some Titebond with your fingers before applying them to the wood. It devolves quickly into a sticky mess unless you wash your hands off thoroughly between tapes. The second is that glue doesn't stick as well to hardened Titebond, so you could get a weaker joint with the liners. This should be mitigated somewhat if you sand the tapes well where the liners will glue on. The third is that, when I tested the strength of Titebond against HHG in this application the hide glue was a bit stronger. On the whole, the extra strength and ease of use make HHG an easy choice for this if you can do it. It's not really all that hard, particularly for this application. Given a choice between LHG and Titebond, I'd go with Titebond.

Hot hide glue isn't that hard to learn or set up for. I keep mine in little bottles that I warm in an adjustable baby bottle warmer set with a candy thermometer to keep the water in it just below 140F. One you figure it out, you won't go back. Learning to use HHG is well worth the effort.

I second that.

I am about to start my first guitar, and have been reading this thread with great interest.
There is another thread going, about doubling or even tripling the sides with veneer layers glued to the sides.
Does doubling (or tripling) the sides make the tape redundant, or not necessary?

Not if the center ply is crossgrain...pretty much plywood in terms of resistance to splits.

I use triple layers for my sides with the grain parallel. They can still crack, but have a bit more crack resistance than single ply. So I still add side braces since I am a belt and suspenders type.