Search found 931 matches

by Alan Carruth
Wed Jan 08, 2020 2:50 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Bolt on issues
Replies: 12
Views: 807

Re: Bolt on issues

I fit the joint, and then drill the holes for the cross dowel nuts in from the heel. I use one most of the time these days, but sometimes two. Careful measurements and allowance for a little gap make it fairly easy to get it/them in and drill the holes from the end of the tenon into the fittings. To...
by Alan Carruth
Fri Jan 03, 2020 1:54 pm
Forum: Glues and Finishes
Topic: Drop filling
Replies: 9
Views: 870

Re: Drop filling

I copped a roll of Teflon 'spaghetti' when I was helping a friend salvage some stuff from a shut-down lab at MIT years ago. It's fine tubing they use to insulate wires, such as the leads on a transistor, when building a prototype board. I think the stuff I got is #26: it just fits in the spout of th...
by Alan Carruth
Fri Jan 03, 2020 1:45 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Gluing surfaces
Replies: 10
Views: 734

Re: Gluing surfaces

Wood that has been sitting around for a while can have low surface energy. The spritz test will tell you. If the water tends to bead up, then some sort of surface dressing is in order. I like to scrape lightly, as it leaves a better gluing surface than sanding, but light sanding with not-too-coarse ...
by Alan Carruth
Thu Jan 02, 2020 3:12 pm
Forum: Other Stringed Instruments
Topic: Banjo neck angle
Replies: 5
Views: 413

Banjo neck angle

One of my students is working on a 'minstrel banjo', based on a fair amount of research and an existing wreck. The problem is that the books he's got are by music historians, not builders, and the scarf joint of the rim on the wreck has come unglued, so it's hard to tell just what the neck angle sho...
by Alan Carruth
Thu Jan 02, 2020 3:02 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: REPAIR
Replies: 8
Views: 495

Re: REPAIR

Another way is to use the baking soda and CA to build up the nut from the bottom, and then file the other slots down. Use tape to make a dam around the bottom of the nut, spread on a layer of CA, and put on some baking soda. Allow that to harden, and sand/file it down level. It's visible, of course,...
by Alan Carruth
Wed Jan 01, 2020 2:33 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Gluing surfaces
Replies: 10
Views: 734

Re: Gluing surfaces

Brent Tobin wrote: "The only adhesive that I know of that recommends scuffing is epoxy." Much of the information I got on surface energy came from an article in the Experimental Aircraft Association's 'Experimenter' magazine, which focuses on construction issues. It was from a detailed article on as...
by Alan Carruth
Sat Dec 28, 2019 6:44 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Gluing surfaces
Replies: 10
Views: 734

Re: Gluing surfaces

I was told that the 15 minute limit for a really 'fresh' surface comes from research done back in WW II by the Forest Products Lab. They also found around that same time that machine planed surfaces glued better than sanded ones. Aside from leaving dust behind, sanding chews up the surface and leave...
by Alan Carruth
Thu Dec 19, 2019 4:12 pm
Forum: Tools and Jigs
Topic: Steam generation
Replies: 8
Views: 598

Re: Steam generation

I got a regular stove top pressure cooker that works fine. I just run a line from the pressure valve stem to a basketball needle, using a couple of small hose clamps. I put in a cup of water or so and heat it on a hot plate, which I already had.
by Alan Carruth
Fri Dec 13, 2019 11:08 pm
Forum: Tools and Jigs
Topic: Thank You Alan!! (Ultimate Scrapers)
Replies: 14
Views: 1347

Re: Thank You Alan!! (Ultimate Scrapers)

There's no reason why the skate sharpeners can't work, but the edges may not hold up as long. I usually touch them up at least once after the initial edge is lost. Lap the face as per usual, then stand the scraper up on it's edge on a fine diamond stone and hone small flats on either edge. This help...
by Alan Carruth
Fri Dec 13, 2019 5:51 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Tap tone on the closed box
Replies: 5
Views: 397

Re: Tap tone on the closed box

The 'tap tone' that you perceive is generally the 'main air' half of the 'bass reflex couple'. The air and the top (and the back as well, usually) work together to alter the 'natural' pitches that each would make in isolation. Generally on flat top and classical guitars these end up about an octave ...
by Alan Carruth
Wed Dec 11, 2019 12:58 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Hmpf
Replies: 6
Views: 459

Re: Hmpf

I think a well defined top tap tone is probably a good thing. Maybe not so necessary on the back: the top and back have different jobs, after all. A lot probably depends on why the tap tone is 'tight' or not.
by Alan Carruth
Tue Dec 10, 2019 1:29 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Hmpf
Replies: 6
Views: 459

Re: Hmpf

Cutting the binding rabbets does two things; it loosens up the edge a bit, and opens a lot of air holes. I'm pretty sure its the leakage that has the most effect on the tap tone sustain, and the pitch, particularly for the 'main top' and 'main back' modes does drop. The 'main air' mode should rise i...
by Alan Carruth
Wed Dec 04, 2019 1:55 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Small (very) acoustic archtop design questions
Replies: 15
Views: 1239

Re: Small (very) acoustic archtop design questions

The arm angle is the whole point about the wedge, of course. The depth of the box along the center line is the same as always, and so is the box volume, it's just easier to reach around it.
by Alan Carruth
Tue Dec 03, 2019 12:52 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Small (very) acoustic archtop design questions
Replies: 15
Views: 1239

Re: Small (very) acoustic archtop design questions

The 'Manzer' wedge (actually patented by Smith) is probably just what you need. 1" of sideways taper (make the treble side 1/2" deeper and the bass side 1/2" shallower), is the equivalent of reducing the width of the lower bout by 1", more or less. It's easy to do, too. My most recent archtop was ba...
by Alan Carruth
Tue Nov 12, 2019 2:46 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Renaissance vihuela de mano
Replies: 1
Views: 229

Re: Renaissance vihuela de mano

And now you know where the viol da gamba family came from!
by Alan Carruth
Fri Nov 08, 2019 2:14 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Resonate Frequency Problem ?
Replies: 14
Views: 589

Re: Resonate Frequency Problem ?

That would be characteristic of a resonance issue: it's linked to pitch rather than, say, buzzing on a particular fret. Any musical instrument will have several different resonances. Often, particularly in the lowest pitch range, these will be most strongly affected by one or another par of the inst...
by Alan Carruth
Thu Nov 07, 2019 6:23 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Archtop as a concept for acoustic bass guitar?
Replies: 23
Views: 7385

Re: Archtop as a concept for acoustig bass guitar?

Various people measure the arch height in different ways. I'm used to just taking the height of the peak of the top above the bench, so a normal violin top would be about 15mm. If you're taking the difference between the low point of the channel and the high point, it's 12 or so. That's for a nomina...
by Alan Carruth
Thu Nov 07, 2019 6:18 pm
Forum: Flat-Top Acoustic Guitars and Bass Guitars
Topic: Resonate Frequency Problem ?
Replies: 14
Views: 589

Re: Resonate Frequency Problem ?

It does sound to me like the classic guitar-type 'wolf' note. There is a strong resonance (on the guitar the Helmholtz-like 'main air' resonance) at that pitch. It pushes on the top and vice versa, so it's strongly coupled to the string. All of the energy 'leaks' out of the string in a hurry, and is...
by Alan Carruth
Wed Nov 06, 2019 1:14 pm
Forum: Archtop Guitars and Bass Guitars
Topic: Archtop as a concept for acoustic bass guitar?
Replies: 23
Views: 7385

Re: Archtop as a concept for acoustig bass guitar?

My two cents.... I'm not sure box volume is as important as top area . The 'Violin Octet' is very successful acoustically, and the basses are long and broad, but not deep. They started out making them deep, but cut the depth down significantly later, which helped a lot with clarity: the deep ones te...
by Alan Carruth
Tue Nov 05, 2019 1:05 pm
Forum: Tools and Jigs
Topic: Source and Band Saw Blade recommendations
Replies: 10
Views: 994

Re: Source and Band Saw Blade recommendations

I've been getting resaw blades from Infinity that have been pretty good. I get 1/2" 3-4 tooth blades for my 14" Jet saw with a 4" riser. They are the straightest blades I've seen, and it's hard to find the weld. They last pretty well and make a reasonably smooth cut. I was able to get four good slic...