Finished Pics! Trini Lopez Semi Tribute

[Andyjr1515]

I'm 5/6ths done carving the back braces.  Like the mahogany sides of the wings, the bottom faces of these will be curved to fit the radius of the dish in their respective positions.

Using a jig called a go-bar deck, I will use these, glued on their bottom faces, to force the walnut into the curve of the radius dish

[ScottR]

I'm enjoying the mental gymnastics and problem solving involved, to take the requested parameters, through in the tools and jigs on hand and come up with a workable plan  to build what promises to be a phenomenal instrument.

Carry on!

SR

[Bizman62]

21 hours ago, Andyjr1515 said:

a jig called a go-bar deck

Why is that called go-bar? I know what 'go' means and I know a couple of meanings for 'bar' and even may have a clue why the beverage serving place is called a 'bar' but in this case I have no clue. You aren't going to a bar with your jig, aren't you?

[Drak]

1 hour ago, Bizman62 said:

Why is that called go-bar?

Google Go-Bar Deck Mr. Biz, all will be explained.

Its primarily for gluing up curved (arched) bracing to a curved (arched) acoustic top or back.

Primarily...it has many other uses, but that's its primary purpose.

[Bizman62]

1 hour ago, Drak said:

Google Go-Bar Deck

I know what it does, I was asking why it's called that. I found a thread asking for the origin but there was no answer. Go go bars are a different thing...

[Andyjr1515]

I've no idea where the name comes from @Bizman62, but it's pretty much universally called that.   

[Andyjr1515]

4 hours ago, ScottR said:

I'm enjoying the mental gymnastics and problem solving involved, to take the requested parameters, through in the tools and jigs on hand and come up with a workable plan  to build what promises to be a phenomenal instrument.

Carry on!

SR

Which is a very kind and polite way of saying, "He's making it all up as he goes along, AGAIN!!"  

Which is not an long way from the truth...

[Bizman62]

6 minutes ago, Andyjr1515 said:

it's pretty much universally called that

That's what I've learned. Thanks.

[Drak]

I figured you had to have known, but nothing in your post alluded to the fact that you did know.

[Bizman62]

10 hours ago, Drak said:

nothing in your post alluded to the fact that you did know.

Ahh... I thought the first sentence would have hinted that way by asking "why is that called go-bar?". Hadn't I known I would have asked "What is a go-bar?" or "How does a go-bar work?". Guess I'll have to continue the over-explaining I've tried to get rid of.

 

[Bizman62]

I guess I've found the answer: It's from the old French 'Goberge' which means 'Pollock' (fish) but also bed slats according to Wiktionary. It may be a corrupted spelling of 'écoperche' which translates to a scaffolding pole.

Here's some pictures and explanations: https://www.popularwoodworking.com/woodworking-blogs/felibien-fantastic-goberge/

[ScottR]

On 8/14/2021 at 3:36 PM, Andyjr1515 said:

Which is a very kind and polite way of saying, "He's making it all up as he goes along, AGAIN!!"  

Which is not an long way from the truth...

That's a perfectly valid way of doing things .... I do it all the time!

SR

[Andyjr1515]

Bit more progress.

I thinned down the walnut for the backs and sides down to acoustic guitar levels - around 1.9mm

The long-reach calliper I had was difficult to use because of the flat pads - it meant that it was only accurate if the wood was completely still and dead level...not easy when it's a large sheet of walnut in one hand and the calliper in the other! 

I rummaged around my 'general bits that might come in handy one day' box and found these from a set of old mirror fixing screws:

Ideal.  I ground out the centre screw, got out the epoxy and problem solved

 

Without access to a sander-thicknesser, I always struggle getting sheet down from the supplied 3.5mm down to the 1.9mm.  However, the last few times, I've found the easiest way is using my block plane (don't know why, but much more effective for this than my other planes) and then levelling it all out with the Mirka:

For the sides, like on an acoustic, I find it easier to pre-cut the unintuitive shape of the bottom edge.  I made a card-paper template first from its position in the radius dish:

Transferred that shape to the sides blank:

And then started bending:

After sitting in the mould overnight to fully dry (which helps to avoid the bent wood to relax) I have a bent side...

...and a florentine end cap:

 

The cap will be cut to size and fitted after assembly of the topless box.  I will be cutting a piece of swamp ash or similar as a shaped front block to support the florentine and the cap will be fitted to, hopefully, have a nicely fitting and decorative - but not structural - function.

I'm growing in confidence that this method might actually work!   

 

 

 

 

[Bizman62]

59 minutes ago, Andyjr1515 said:

I've found the easiest way is using my block plane (don't know why, but much more effective for this than my other planes)

As you already may have noticed, I'm curious about things like this and spend quite some time pondering... To the nuisance of others who'd like to go on!

Anyhow, is this your only low angle plane? They seem to be less destructive on delicate or otherwise challenging surfaces. A scraper plane with a vertical blade might also work for the same reason. The effectively chewing angles on regular planes may not be the optimal choice in cases like this where tearing would mean a catastrophe.

And I'm just guessing here, of course based on what I've heard, seen and done.

[Andyjr1515]

1 hour ago, Bizman62 said:

As you already may have noticed, I'm curious about things like this and spend quite some time pondering... To the nuisance of others who'd like to go on!

Anyhow, is this your only low angle plane? They seem to be less destructive on delicate or otherwise challenging surfaces. A scraper plane with a vertical blade might also work for the same reason. The effectively chewing angles on regular planes may not be the optimal choice in cases like this where tearing would mean a catastrophe.

And I'm just guessing here, of course based on what I've heard, seen and done.

Might be that - I've had my eye on a full-size low angle plane for ages and your question will probably prompt me to take the plunge   

Yes - I have a Stanley 80 scraper plane with is excellent with highly figured woods but still struggles a bit with this particular task.

 

[Andyjr1515]

While I'm logged in, bit more progress - I've cut the outline of the first supporting block.  I'll carve it to the radius underneath and then cut it to height before I start gluing the walnut and mahogany sides:

The cutaway walnut piece will be added after the main assembly of the the back and sides so that I can get the joint visually OK where it meets up with the side at the horn's point.

[Andyjr1515]

It is time to do some gluing.

As it happens, my long-reach G clamps are actually long enough for this operation, starting with the curve-bottomed side piece:

The neck-sized spacer and other side profile are there to ensure that the side is sitting in the right position in the mould which, is itself, in the right position over the radius dish.

Next was to shape the undersides of the cross-braces and glue those too.  Once dry, I was pleasantly surprised that I had a curved back that actually held its shape out of the rig:

Deconstructed, here are the main components:

And here's how it will fit together, with the addition of some kerfed reinforcing strip and an ebony top

And these will be the positions of the other components.  The Maestro vibrato is the actual one that will be fitted, the other bits are just representative for me to get an idea of the sizes and positions right:

 

 

[ScottR]

Bolt them on now. It'll be light as air.

It will still need a neck though,,,,,,,

SR

[Andyjr1515]

On 8/21/2021 at 4:39 PM, ScottR said:

Bolt them on now. It'll be light as air.

Well...I was tempted, I'll admit.

But I thought it would help with finding somewhere to put the strap buttons on to do the other side too

I also added some kerfed linings to stiffen things up:

And so, although there are many tasks to be done before I glue them, it was time to rough-cut the tops.

I chalked the optimum (only) position for the tops using my modified mould as a guide:

This was the longest/widest piece of ebony I could find - not much leeway in any direction!  Now you can probably see why I need a visible through-neck

And cut, oversize, sitting on the backs:

Clearly, there will be the weight of the through neck length to add, but, with some overage and carvings still to take off, all 4 components - 2 tops and 2 backs - are sitting at 3 1/2lbs total.  Not bad

 

 

 

 

[ScottR]

8 minutes ago, Andyjr1515 said:

But I thought it would help with finding somewhere to put the strap buttons on to do the other side too

Doh! I completely for got about the other strap button.

Still, 3.5 lbs ain't much heavier than air.

SR

[Andyjr1515]

And so I'll be moving into a 'planning before doing' phase over the next couple of weeks - not least because there are some grandparenting duties looming which means 'moving all your mess out of the way' 

But there's a lot to get right and it is worth the pondering without the temptation of cutting or gluing something before I'm sure!

This is where I'm at with the wings:

The ebony is around 6mm thick and will have a subtle top carve, following the same sort of curve as the back, a couple of diamond 'f' holes and some weight relief scoops in the underneath.  And some very careful routing for the switches.

 

Switches?

 

Yes - we're going Jaguar guitar switch system, back mounted.

 

"And so I'll be moving into a 'planning before doing' phase over the next couple of weeks" 

[mistermikev]

insane to me that you are that good at such an unconventional build.  cudos.

[Drak]

The bracing reminds me of a Macaferri/Django thing, where you want immediate volume and projection over resonance and sustain.

Kind of a ladder bracing thing.

I understand that's not really what you were shooting for, I would think basic stabilization was the key element.

If I were doing a modified centerblock as you are, I'd do the bracing the exact same way.

Django - I'll See You In My Dreams

Oh, Les Paul, I see what you did there...

[Andyjr1515]

With the neck timbers having arrived, they have been joined up which means that most of the major structural components are now ready for their respective further stages of work:

 

There are a myriad of small jobs on each, plus a few big and scary ones!

The first falls into the small jobs category - fitting the cutaway sides.

One is gluing:

 

While the other one is glued and the excess removed.  At some stage, the bottom edge will be routed for some maple binding to be fitted.  Now that will be scary...

 

[Dave Higham]

On 8/14/2021 at 6:29 PM, Bizman62 said:

Why is that called go-bar?

Hope you don't mind me dragging this subject up again. I just thought you might like to know that the French have a wonderful, even romantic, name for it. 'Le ciel de l'ébéniste' or 'The cabinet maker's sky'. Apparently they often wedged the bars between the workpiece and the ceiling.

Another thing about go-bars. You'd think that the more they are bent, the more pressure they apply. But apparently they don't. Some years ago Hesh Breakstone on the OLF forum experimented by installing a go-bar on a kitchen scale and compressing by different amounts and however much the bar was bent, the pressure stayed the same. I suppose a structural engineer would tell you why.