A short scale acoustic bass guitar experiment.

[Dave Higham]

The third piece of wood had two triangular pieces cut out of it and these were glued to the first two pieces to strengthen the joint between them.

The surface to be glued to the sides is profiled on the belt sander.

Then finished by rubbing on sandpaper fixed to the mould in the same way as the tail block.

So that's the neck block finished.

 

[Ben Clarke]

A huge factor of why the Taylor works so well is the decision to use those nylon core strings.

I've played probably a dozen or so acoustic bass guitars over a few decades, and other than a short scale Gretsch which was a bit more than ok but not great, none of them got at all close to how well the GS-mini works.

And I should add that I had a significant bias against Taylor because of their bread and butter acoustic guitars (some based in my actual preference, some based in snobbery).

 

[Dave Higham]

A huge factor of why the Taylor works so well is the decision to use those nylon core strings.

Thanks for the input Ben.
I'm planning on the Pyramid flat-wound strings that I think are made with the GS Mini in mind.

 

[Dave Higham]

this looks like a very interesting concept, my only objection so far is the pin bridge. I don't like'em!
subscribed!

I've been thinking about that. What would you propose instead? (I have a couple of ideas)

 

[dlmarquez]

I'd have 2 possible options:
An acoustic guitar style bridge with the strings thru the bridge anchored at the back. Breedlove for one uses this system.
However my preferred type of bridge these days is a suspension bridge, like a Jazz archtop uses with a stop type tailpiece or some such arrangement. The Takamine TB10 uses something like this…it brings to mind an upright bass!
being primarily a fretless player, I don't really get interested in the modern bass bridges with 150 parts and 16 adjustments. I really like a simple bridge. I actually like the old Gibson EB0/1 1 piece bridge with only up and down and back and forth adjustment. If you play fretless and you always use the same strings, it really simplifies what's needed for a bridge

 

[Ben Clarke]

Thanks for the input Ben.
I'm planning on the Pyramid flat-wound strings that I think are made with the GS Mini in mind.

I was reminded of these basses a couple nights ago, and pulled the trigger on one priced really well. Hopefully it shows up and is as described, but if it does, I'm considering those Pyramids as well. I used their regular flats on a Stingray and a Les Paul Jr type guitar for a while years ago, and really liked them. I believe the Pyramid for the GS are also nylon core.

 

[honza992]

Dave, very nice project, up to your usual very high standards!

I've been playing around with the idea of top damping for a while, though for the moment I'm still focused on optimizing the acoustic sound of my acoustic basses, so it's never gone beyond background mulling....

Like @Bruce Johnson my thought was an extending damper that could be retracted for full acoustic. Stewmac sell these Prop-jacks that I wondered if they could be repurposed:

StewMac Prop-Jack - StewMac

Spring-loaded for easy one-handed positioning deeo inside of acoustic guitars and instruments. Provides controlled, sturdy pressure to hold a cracked brace or bridge plate in place while the glue sets.

www.stewmac.com

(Edit: I've just read you're putting the top damping idea on hold....Let us know if you do it in the future).

With regard to strings, Aquila do a nylon core flat wound ph. bronze string that is designed for your string length. Just as an alternative:

Flat Spirals bass strings | Aquila Corde Armoniche

aquilacorde.com

 

[Dave Higham]

With regard to strings, Aquila do a nylon core flat wound ph. bronze string that is designed for your string length. Just as an alternative:

Flat Spirals bass strings | Aquila Corde Armoniche

aquilacorde.com

Hi @honza992 (what's your name?), I had noticed the Aquila strings but, at around €82 a set, they aren't something you'd want to try and then be disappointed with.

 

[honza992]

Hi @honza992 (what's your name?), I had noticed the Aquila strings but, at around €82 a set, they aren't something you'd want to try and then be disappointed with.

It's John.

Yeah, they are comically expensive. I've got a 34" set, but haven't yet put them on anything. If I do I'll let you know!

 

[Dave Higham]

Now it's time to move on to the sides or ribs. A couple of the acoustic guitars I've made were 'deep-body' models. OM size but with bodies about 12mm (1/2") deeper than normal. It brings out the bass notes on a guitar so it seems the obvious thing to do for a bass.

But a deeper body means it's less comfortable under the right arm so it will have a wedge shaped body, i.e. shallower on the bass side (under your arm) and deeper on the treble (on your knee). The body is built with the sides perpendicular to the top and the back swivelled about its long axis. They call this the 'Manzer wedge' because master (or mistress ?) luthier Linda Manzer was the first to do it. If you've never heard of her, Google 'Linda Manzer Picasso guitar'.

Finally, for maximum comfort, I'll put an arm bevel on the bass side lower bout.

Most people build acoustic instruments in an outside mould and this is an old photo of mine. It's sitting on a 25ft radius dish and I'm tracing a line to get the actual profile of the sides.

These are the profiles. Some luthiers leave the sides parallel and cut off all the surplus after bending. I prefer to profile the back edge before bending as there's quite a lot to trim off and I've even been able to use the off-cuts sometimes as bindings. If you trim them after bending, all you have is shavings.

 

[Dave Higham]

The first thing to do is sand the sides down to 2.2mm thick (about 0.090").

Then profile the back edge of each side.

A part of the profile of the front edge is cut at each end so I know where to glue the neck and tail blocks. The rest of the front edges are left straight. It makes it easier to place the sides squarely in the mould.

 

[Matt Liebenau]

This is the home-made bending rig with the silicone heating blanket and controller.

View attachment 7398744

Each side is placed in a sandwich consisting of:

A spring steel slat
Aluminium foil
Damp kraft paper
The wood
More damp kraft paper
More foil
Another steel slat.
The heating blanket
Yet another steel slat

The centre screw is wound up and the sandwich inserted . The heat is switched on and when it gets up to the required temperature the screw is wound down. Then each end is pulled down and tightened. There are wing nuts on the end of the threaded rods. Then it looks like this. There are no action photos because I'm a bit busy doing all that.

View attachment 7398746

The sandwich is heated up to about 320°F, kept at that temp for about 15-20 minutes, then allowed to cool down to room temp. The heating process is then repeated after which I let it cool down completely overnight.

When it comes to getting the bent side out, the spring steel slat nearest to the bending form will try to straighten out and break the side, so I made these clips. They are plastic covered wire (for garden fencing) with one end flattened.

View attachment 7398748

These are inserted into the form and prevent the innermost slat from straightening out; two at each end and two as near to the waist as possible.

View attachment 7398749

View attachment 7398752

Here's the first side bent and fitted into the mould to prevent any tendency it might have to straighten out again.

View attachment 7398753

Both sides bent, ends trimmed and fitted into the mould.

Bending sides is always a bit stressfull, especially if you don't do it very often. Some wood doesn't want to bend at all. I've had sides where the bend in the waist has come out tighter than the shape of the form, which doesn't seem possible, but walnut has always seems to behave itself and this time is no exception. This is Claro walnut, by the way.

View attachment 7398755

Interesting. Ted on the twoodfrd YouTube channel is building a cello acoustic guitar and mentioned heating and bending the sides, letting them cool then heating them again still on the bender. I don't remember seeing that before.

 

[Dave Higham]

Can anyone see the photos in my last post (yesterday), because I can't? Where there should be a photo there's just the file name but if I click on 'Edit' I can see the thumbnail photos at the bottom of the page as if I hadn't inserted them, although I did. I tried to insert them in 'Edit' but wasn't able to.

 

[honza992]

Can anyone see the photos in my last post (yesterday), because I can't? Where there should be a photo there's just the file name but if I click on 'Edit' I can see the thumbnail photos at the bottom of the page as if I hadn't inserted them, although I did. I tried to insert them in 'Edit' but wasn't able to.

I can't see them

 

[Dave Higham]

I can't see them

OK I'll try to delete it and post it again.

 

[Dave Higham]

This is a repeat of the post which should be before Matt's post #32 because, for some reason, the photos weren't visible.

This is the home-made bending rig with the silicone heating blanket and controller.

Each side is placed in a sandwich consisting of:

A spring steel slat
Aluminium foil
Damp kraft paper
The wood
More damp kraft paper
More foil
Another steel slat.
The heating blanket
Yet another steel slat

The centre screw is wound up and the sandwich inserted . The heat is switched on and when it gets up to the required temperature the screw is wound down. Then each end is pulled down and tightened. There are wing nuts on the end of the threaded rods. Then it looks like this. There are no action photos because I'm a bit busy doing all that.

The sandwich is heated up to about 320°F, kept at that temp for about 15-20 minutes, then allowed to cool down to room temp. The heating process is then repeated after which I let it cool down completely overnight.

When it comes to getting the bent side out, the spring steel slat nearest to the bending form will try to straighten out and break the side, so I made these clips. They are plastic covered wire (for garden fencing) with one end flattened.

These are inserted into the form and prevent the innermost slat from straightening out; two at each end and two as near to the waist as possible.

I'll make the post in two parts, in case it was too big.

 

[Dave Higham]

Here's the first side bent and fitted into the mould to prevent any tendency it might have to straighten out again.

Both sides bent, ends trimmed and fitted into the mould.

Bending sides is always a bit stressfull, especially if you don't do it very often. Some wood doesn't want to bend at all. I've had sides where the bend in the waist has come out tighter than the shape of the form, which doesn't seem possible, but walnut has always seems to behave itself and this time is no exception. This is Claro walnut, by the way.

 

[Dave Higham]

So (for me) the photos are visible this time. We'll see if they stay that way.

 

[Matt Liebenau]

So (for me) the photos are visible this time. We'll see if they stay that way.

I can see the pictures. I'll admit I couldn't see them in the first post you deleted but I knew what side bending jig you were talking about. I'm pretty sure it wasn't you, there's been several posts yesterday and today in all the areas I look at that have done that.

 

[Dave Higham]

The next thing is to glue the neck and tail block to the sides, starting with the tail block. Even though I've sanded the blocks to match the mould, there might be a slight difference between the blocks and the sides so I use epoxy to glue them.

I use 30 min epoxy but leave it a few hours before taking the clamps off and then gluing the neck block.