Oh Horrendous

[Th'Axe]

Howdy-first time posting here. Got a Carvin Strat clone under my belt, then built a chambered maple quilt-top of mahogany with a Carvin neck, then went to Dale Unger's American Archtop class in Nazareth, PA, and built a 17" Benedetto-style archtop with a Kent Armstrong floating pickup. Now retired to Washington State and starting to build again. Played self-taught since like 1968..
Building a StewMac OM rosewood kit with the "torrefied" top. Got the X-braces and maple bridge block glued in last night..in an attempt to control glue cleanup I used blue painters tape along the edges of two of the tone bars. When the tape was removed, long shavings of spruce came up with the tape..nothing real deep but UGLY. Do I get in between the braces and sand to clean up the shreds? Is there a tape I can safely use on the spruce? Or do I just need to refine my glueing and clamping techniques?
Became a member of the G.A.L. to hook up with the builders community here around Tacoma....planning to be at the convention in July. Nice meeting y'all

[Shuksan]

A simple way to ensure you don't get tear out when pulling blue painters tape off of spruce is to heat the tape with a blow drier or heat gun and then peel it of while it's hot.

It also helps a lot (even without heating the tape) to pay attention to the grain direction. You want to peel the tape off across the grain, not with the grain.

These same tips apply if you use tape while installing binding.

For the purpose you were using the tape for, you can also reduce the tack of the tape by applying it to your pants leg first, pulling it off, and then putting it on the wood.

Personally, I wouldn't bother trying to "fix" the tear out since it's on the inside of the top.


If you are looking to make contacts in the builder community around Puget Sound, you might consider the Seattle Luthiers Group. You can find them on facebook.

[Th'Axe]

cool hint with putting the tape on your pants leg first. Now I can justify getting a heat gun....spent 7$ on vacuuming at the car wash to convince the wife I need a shop vac. I DID go cross-grain on the removal, which helped, but I agree, I am not going to freak out trying to sand it out on the inner surface..
On the soundboard spruce...would it help to shoot some shellac(?) to seal the wood before gluing in binding to protect it from grain tear-out from the tape? Or do you just sand it out? I have not contacted Seattle Luthiers Group. When I worked aerospace, social media was regarded as a liability, so I never did play FaceBook. Maybe I need to start

[Shuksan]

I've never put shellac on the top. Never needed to, but I think some people may do that. I use binding tape when installing binding and that has higher tack than blue painters tape. Heating it with a blow drier before peeling it off combined with peeling cross grain has worked for me.

Another thing to have in mind is that tear out when removing the tape can indicate that there is some run out in the wood. If there is run out, and you see tear out begin to happen when pulling the tape in one direction, switching to pulling that piece of tape from the opposite direction can sometimes solve the problem.

[runamuck]

I'd suggest not using tape. Clean it up with a sharp chisel and damp rag while the glue is still soft.

[Th'Axe]

it pretty much gets down to just that, huh?

[redir]

Shellac works for me.

[Bruce Sexauer]

I don't use tape, but if I did, it would be green 233+. Also, identify the direction of the run out and peel from the downhill direction. Do not leave the tape on for longer than a day or two.

[Th'Axe]

I understand the concept of the process of artificially aging the wood, but does the treatment leave the surface "fluffier", or has it just been too long since I looked at spruce?
In any case, the linings for the sound board are sanded, the linings are notched for the ends of the bracing and bracing is carved. I confess I HATED the open notch in the X-brace, and had no inclination to embrace the old school fabric patch, so I inletted and glued and carved a small bridge into the notch. Too late in the day to start anything serious, so prepping for the sound board bonding tomorrow. I may try to figure out a way to stage the spool clamps so they are laid out ready to hand when the job gets rolling. Everything is a compromise when you build on a desk downstairs!!! And woe betide the luthier whose wife returns to the dismay of neglected cleanliness....that being said, she is a sterling woman of many talents without whom I would never have been afforded the opportunity to build this guitar. And hopefully a bunch more

[printer2]

I bridge the X gap with a piece of wood also, some say the cloth patch has something to do with the Martin sound, I still can't leave it open. You could call the wood fluffier. I think of it as more like cedar. Mind you it depends on how far along the process was taken.

[charles Tauber]

Originally Posted by Th'Axe

..in an attempt to control glue cleanup I used blue painters tape along the edges of two of the tone bars.

I don't use tape for control of glue squeeze-out when gluing braces. I find two things that control glue squeeze-out well. First, use only as much glue as needed: very little is needed for gluing braces. Aim for a small bead of glue squeeze-out uniformly along the edges of the glued piece. Progressively use less glue until you achieve that, then you know how much to apply.

Second, if using white or yellow glue, let the glue set for about 5 minutes before attempting to remove the squeeze-out: after about 5 minutes the glue squeeze-out becomes rubbery and can be removed cleanly as a strip, rather than being smeared. A larger bead of squeeze-out takes longer to become rubbery than a smaller bead. Try a short length of squeeze-out to see if it is sufficiently rubbery: if not, wait a few more minutes and try again. Doing so, you'll learn how long to wait before removing the squeeze-out.

Decades ago, I learned a learned a technique from Grit Laskin that I still use today. Take a rectangular piece of wood bracing material or wood off-cut. Using a chisel, scallop one end of the piece of wood until it is comes to a chisel edge. The chisel shaped end can then be used instead of a metal chisel to clean-up gelled - but not hard - glue squeeze-out. The wooden "chisel" is soft enough not to cut or damage the braces, the top or the back wood. When the edge of the wooden "chisel" becomes rounded or glue encrusted, simply use a metal chisel to advance the scallop and reveal a new "cutting" edge on the wooden "chisel".

The wooden "chisel" can be made as long or as short as you like, as tall or short as you like and as wide or narrow as you like, based on the piece of wood you start with. You can also make your wooden "chisel" out of softer woods, such as spruce, for use on softer woods, or make it from a harder woods, such as rosewood or walnut, for use on harder woods.

[Th'Axe]

Charles-Thank you. I had tumbled to this method looking at video of glue-ups. Appreciate the input. Now I must deal with a weird problem. Glued in the back braces yesterday. They are shaped to a 20' radius for the OM kit I am building. I made a radiused clamping caul as suggested and left the clamp on for 6 hours, then clamped and glued the next one. This morning the biggest spruce brace is curved BACKWARD inducing a 1/10 dip in the lower bout of the back. Did the rosewood dry overnight and shrink vs the length of the spruce? Don't know whether to cut and splice or plane off the whole brace and start over. Needless to say, I am a bit less than enchanted with a totally unexpected development, but I will beat this problem, too.

[charles Tauber]

Originally Posted by Th'Axe

This morning the biggest spruce brace is curved BACKWARD

The moisture content of your wooden components needs to be maintained constant at least until after assembly. What you are describing is a classic symptom of the humidity changing from one day to the next. A contributing factor can be the use of water-based glues that add moisture to the wood until the glue is fully dry and the excess moisture has left the wood. However, this isn't usually a problem, though can be when levelling a still-wet large rosette: levelling while still wet can result in the surface being concave after fully dried. Uniform air flow around the components can be important in such circumstances as having one face of the wood against a surface while the other is open to the air.

Controlling the moisture content of the components doesn't need to be expensive or elaborate and a solution can be found for just about any situation. The starting point is hygrometers so you know what humidity level you have. Until you have a stable environment, there isn't that much point in removing the braces and gluing on new ones.


As an aside, for white/yellow type glues, one hour of clamping time is more than enough if near 70 degrees F and 45% RH or so.

[Th'Axe]

got the back clamped to the bench and block-planed the errant spruce down to 1/32 off the rosewood..COOL how that salvaged rusty little orphan shines when it needs to. Also re-educated my self with the pleasant surprise of the control and precision afforded by a well-burnished scraper. I could watch the color of the spruce darken as it was thinned above the bondline. NO damage to the rosewood..
When I first got the kit I laid out everything for a week to breathe and approach the building room humidity. The first two backs I received were not completely joined and were replaced one open at the neck end of the joint and the other open at the tailblock end. When I finally got the third completely joined and solid, I failed to give it the acclimatization time..all me. Now I need to scout around here to find a piece of local spruce to make a replacement. Tired of waiting for "GlueShack" to make good on the wood. Is the stuff at WoodCraft ever useable grade? or is runout too bad? I know they wouldn't appreciate me riving off a piece.
I am building in a corner of our downstairs in the cooler end of the house. I
may have to invest in a "grow tent" with humidity control for components to camp out overnight between work

[runamuck]

Make sure your wood is exposed to the air and thus humidity on all surfaces. If you place a thin piece of wood down on a surface it will curl up if the humidity lowers.