Finished Pics! Dreadnought acoustic (guitar) for me?

[Andyjr1515]

7 minutes ago, Jabba_the_gut said:

Interesting build this one. I like the offset rosette - nice touch!

Never could get things straight  

[LukeFRC]

1 hour ago, Andyjr1515 said:

And tap tuning has begun 

Rather than me trying to explain how it works and what you do, this is one of the best explanations I've seen.  For those who REALLY want to know why and how - at quite a detailed scientific level - watch the whole thing.  For those who want to see - and hear - exactly what he does and what difference it makes to the sound, start at 30' in.

 

Anyway - he knows what he is doing and he does this for 8 guitars a week.  I don't and this is my 3rd acoustic 

But it's started and it's made a difference.  Mine doesn't sound like his, though 

Here's where I started:

And this is after slimming the struts to rough arch shapes (It's OK - it will be eventually sanded properly):

 

And since then, I've done a reasonable amount of tap tuning.  It's having the under-bridge plate glued at the moment - when that's set, I'll take a shot so you can see where and how I've tweaked the braces.

 

That, and the video was really interested and explains the question I was going to ask about brace shape compared to the triangles in my acoustic. 

Im quite lucky, I sold a takamini acoustic I had and then missed it - found a eBay advert for an unbranded guitar local to me, and based on one photo of the binding and the quality of Ebony used in the fretboard bought it... when I went to pick it up it’s a beautiful hand built early Martin om clone made by someone semi famous - and sound absolutely beautiful - it’s resonant and alive - and that videos just told me why! 

[Andyjr1515]

Well - I really don't know what I'm doing.

Actually - I half know what I'm doing but I have no idea at all in terms of how far I can safely go!  I've gone through cycles of pleasing tap tone, varied tap tone, mono-harmonic tap tone to this, which is back to a number of distinctly differently pitched notes, each with resonant harmonics.  Maybe I could go much further...but I don't know, so I'm stopping here:

I'll leave it overnight and see what I think tomorrow - then finalise the preparation of the kerfed join line ready to glue the top to the sides.  Which will, of course, change the tap tone anyway.  Told you it was black magic! 

[Andyjr1515]

OK - a bit more info for anyone who might want to build an acoustic.  Why all this fuss about the kerfing strip joint line?

Well - for a start, remember that the top is spheroidal.  Therefore, the kerfed strip surface isn't going to be square to the sides - it's going to be at a slight upward angle from the edge of the guitar sides.  Wouldn't just sanding it flat be OK?

Well - no.  Remember that this will have binding fitted.  And therefore after gluing the top or back, this much (dashed blue line) is going to be routed away!

So it is just as important that the inner surface of the kerfed strip is flush with the (curved) top edge as the edge.  In fact, arguably, more so.

What you are after, as well as a closed joint at the outside, is for the inside to be also tight like this:

Note, by the way, that the structural braces on the right - the X brace and the front cross brace - go through the kerfed strip to the inside edge of the sides and form part of the structural integrity of the sound box.  The tone bar braces peter out at or before the join.

The other tip is to not glue the top until you've done the same fit job on the back - otherwise it's impossible to see if you've got a decent internal fit!

And so with the top now fitting internally and externally:

 

...it's time to tidy up and brace the back (this will be a 15 foot spheroidal radius) before I go through the fitting process - which is actually more complicated because the depth of the sound box slims as it approaches the neck joint.

But while I've got a flat piece of joined back wood to work with, I need to put in the decorative strip hiding the join line.  

I use a Dremel and precision router base.  Normal stuff - always try out the set up with some scrap:

 

...and next job is doing the full length rout on the back and gluing in the strip.

 

[Andyjr1515]

And another one for the Andyjr1515 bloopers DVD.

It was looking so good:

 

...until I overdid the still-a-little-damp strip with the scraper:

So - having routed it all out again, a second strip is currently being glued.  I'll leave it to properly dry this time!

 

[TheGreek]

This is looking complicated...

I'm not feeling as guilty about my build requests on my Psilos bass now. 😉😉

[Andyjr1515]

And second attempt.  Prior to scraping, mind, so there's still plenty of time for me to c**k it up again 

 

[LukeFRC]

Like we kinda knew this anyway, but there’s a real art to acoustic instruments- I look on solid body builds and think “yeah I can do that” 

i look at this and go “wow”

i guess also the difference between mass produced and hand crafted/tuned acoustic instruments must be way higher than that of solid body instruments. 

[Andyjr1515]

13 hours ago, LukeFRC said:

Like we kinda knew this anyway, but there’s a real art to acoustic instruments- I look on solid body builds and think “yeah I can do that” 

i look at this and go “wow”

i guess also the difference between mass produced and hand crafted/tuned acoustic instruments must be way higher than that of solid body instruments. 

First of all - 'Yeah!  You CAN do that'

I agree  - given a specific and identical set of woods, dimensions, shape and electical componentry, then there is less scope for building in a little bit of extra sonic excellence on a solid body.  Loads of scope in terms of feel and finish, but less so in terms of actual sound. There is, of course, always scope for tailoring those factors to an individuals needs and taste.  

With acoustics, every piece of wood all has it own physical characteristics.  The experts in this field not only choose specific pieces of wood ( which the good mass producers also do) but then are able to tweak things to make that piece of wood do the best that it's physically capable of doing.  And the difference that can make is quite large, as you can hear in the back end of the video.  Bear in mind that his top was starting where my top has finished. So the guy in that video would be able to absolutely transform the way my own build is going to sound.  And conversely, an amateur like me is capable of actually making it sound worse than when it started.

The mass producers of acoustics therefore are looking to consistent woods, machined to a high standard to produce predictable and replicatable tones.  Having said that, surely it can't be far away that someone directly links a vibration spectrum analiser to a cnc router to mechanise the present realm of the craftsman?

[Andyjr1515]

The bracing for the back is much simpler.  The back provides the volume rather than tone and so the braces are just there for strength and to hold the 15' radius of the back - yes...another radius dish!

First of all, sorted the radius for the braces to sit nicely in the dish in their respective positions:

 

Then the bit I've always struggled with - carving the parabola shape.  Most guides seem to indicate that you glue first and then carve, but I found that much more likely to end in damage.  So this time, I decided to carve their shape first.

But how?  They have a radius bottom and are not easy to hold (which is probably why everyone says carve them afterwards!   ).

After a few abortive attempts with a dovetail cutter on the router table and an angled jig on the bandsaw, I came up with this:

i.e., bung a plane in the vice, wear stout gloves and push/pull the brace wood across the blade.  To my great surprise, it worked a treat!

So out with the go-bar-deck, this time with the 15 foot radius dish and the braces are being glued as I type! 

[TheGreek]

1 hour ago, Andyjr1515 said:

The bracing for the back is much simpler. 

He says....not all of us have your toolkit, experience or skills. 😃😃

[Andyjr1515]

Back braces in place and looking OK.  



The back of the back, though, isn't so good.  If this was for a customer, it would be a scrapper - and therefore scrap of the matched sides!  The problem is the massive tearout at the top end!  It was bad to start off with and I tried to improve it and made it much worse (that DVD might have to be a boxed set )!




For my own use, this will be fine, though.  I will fill it with a slurry of sandings and tru-oil and, because of the irregular patterning of the lacewood, it won't be too obvious 


Next job is trimming the sides to get a good fit for the back to eventually be glued to.

[Andyjr1515]

And onto final preparatory jobs before gluing the top and back on.

I put the soundhole braces in place and double checked that the hidden pre-amp of the Shadow Doubleplay will actually be hidden!

Then double checked the basic fit of the top:

 

And the back:

 

Then checked how well the spool clamps would secure during gluing.  Now then 'you can't have too many clamps' and this is no where near enough.  This is dry fitting:

While it is actually giving me a tight fit all the way round the kerfed strip, the wood will tend to move about during the wetting from the glue.  So what I will do is cut some shaped plywood cauls to spread the load round the curved and allow me to use some metal clamps to supplement the gentler spool clamps.

Also got to add a sliver of veneer on top of the heel and tail blocks to then chamfer in and give it a fit with the radius of the top.

And THEN I can glue it

Certainly, by the end of the weekend, I am hoping to have a sealed body, ready for the scariest bit of the whole build (as far as I'm concerned) - routing the binding channels and routing the neck mortise!

It's a long way to have come with still a huge opportunity to completely wreck it - but that's acoustics for you!

[Andyjr1515]

And the top is on and gluing!

 

[RichardH]

When I glanced at that photo I thought it was a cake with candles on at first!

[Andyjr1515]

3 hours ago, RichardH said:

When I glanced at that photo I thought it was a cake with candles on at first!

If it all goes wrong candles might come in useful...

[TheGreek]

3 hours ago, RichardH said:

When I glanced at that photo I thought it was a cake with candles on at first!

+1

[Andyjr1515]

Once the back is glued on is no time to remember that you've forgotten something so this is a time for a pause, note the remaining jobs, do them, pause again.

Hopefully, I've paused enough times! 

First there's the cross-grain maple strip across the join line.

Because the back has a double curvature as it slims from the main chamber to the neck, I let the glue for the strip set while bending in this direction by using a fillet underneath  at the bend axis of the panel:

Then the all important label

 

In the past, I've marked the top at this stage or similar and - because it's pretty much final thickness, those can be difficult to get out.  So for the clamping, I cut out a comprehensive set of clamp cauls, chamfered so that the edges don't dig in (fingers crossed!):

 

And then - after one more fit check - the 'well, it's too late now' step : 

 

 

[Andyjr1515]

Well - huge amount still to do, but definitely at the end of the beginning!

 

The next bit on the body is getting a router out and routing the top and bottom binding channels.  I might spend time on the neck before getting to that terrifying prospect!

Edited August 25, 2018 by Andyjr1515

[Andyjr1515]

Been doing other stuff most of today but found an hour to do two things neck related - one I've done before and one I've never tried before:

 

When it's all dry, I shall reveal both - unless they haven't worked, in which case I'll quietly bin them and do it differently

[Andyjr1515]

OK - so far so good.

One of the things I've done before a few times is, in adding a couple of strips to bind the fretboard, I've used acoustic banding - rosewood with a b/w/b feature strip.  This gives me a couple of advantages as well as the binding itself.  It gives me a faux veneer feature demarcation line - which I always find to be a pain to do without any wavy lines using three pieces of actual veneer:

The other advantage is that, before I trim it to the fretboard radius, it gives me a flat surface to use for the Dremel router base when I do the pair of 12th fret swift inlays (a job for this showery afternoon)

 

The second thing is one I've never done before and might not work.

Because the neck is an offcut, it isn't as deep a blank as I would usually use.  As such, the heel needs three pieces to extend from the top of the body to the bottom.  Three sections of maple stacked up is, at best going to catch the eye.  At worst - eg with a tiny bit of offset of one of the walnut centre splice positions - it could look awful!

So I'm trying with a section of decorative wood sandwiched in the middle:

To make it look like I meant it to be there, I added an angle to that and the adjoining bottom block.  I won't know if it really works until I rout the tenon and shape the heel - and there are a few things I need to do before I tackle those jobs - but it will be an interesting experiment  

 

Edited August 27, 2018 by Andyjr1515

[Andyjr1515]

OK - major scary bit number 1.  Routing the body binding channels.

Why is it scary?

Well, as far as I'm concerned

- because it is using a router

- because it is using a router on a pretty much finished body with all that work already done and a top and a back pretty thin and pretty much thinned to within 0.1mm of it's final size

- the above, then remembering that the top is dished, and varying radii to the dish centre all the way round

- the above and noting that the binding channel is as deep as the sides are thick

- the above and then remembering that it is the BOTTOM of the routed slot that has to be accurate all the way round the body

Other than that, it's a walk in the park

 

There is a rig that the multi-acoustic builders sometimes invest in which is a large, complicated and quite expensive rig for a Bosh trimmer router - but I don't build many acoustics so can't really justify the cost and, besides, it's too big for my tiny workspace and storage area.

Then there's this from Stewmac to fit onto a Dremel:

 

Hmmm...the general view of this amongst builders I know is that it is rubbish.  I've used one before - and I got away with it.  But the risks of serious eyesore digs and unevenness in the binding joints is high to very high.  And when I used it, there was quite a bit of judicious gap filling needed.

The problem is that the top is dished.  So the front edge of the jig doesn't (mustn't!) run along the edge of the guitar body - instead the back edge of the jig must.  The Dremel - top heavy and while hitting the hard wood of the sides at 40,000 hits a minute - must be kept vertical (assuming the top is the other way up to the photo above - which is pretty impossible to use as photo'd) MANUALLY in both planes.  When it tilts - even a smidgen, it digs in and that affects the depth and you get wavy lines at both join lines.

So I had a think about it last night.  And got a couple of strips of binding and some super glue out and stuck it on (honestly!)

 

 

Could this act as a visual guide that the rig is parallel to the sides?   Would it stay on long enough to prove the concept and then, if it helped, how would I stick it on properly?

Well - and here you could knock me down with a feather.  Because the concept worked:

And it's even stayed glued for the full multi-pass rout of the back!!!

 

And, it is even and wavy line free with only the very slightest amount of tidying up.

 

OK - now it's time to wreck the top! 

[Andyjr1515]

And the top is successfully routed, including the additional slot for the b/w/b purfling lining strip:

So I declare my unofficial mod to Stewmac's dubious tool A SUCCESS! 

And now there is no excuse but to start the tortuous binding process.

Luckily, the purfling - which is applied first - is fairly easy.  It's bendy enough to fit round the perimeter and be held by tape while the titebond is setting.  Note, by the way, that I've given the top a couple of coats of protective varnish.  This keeps the dirt from soaking in, stops the scratches and dints to an extent and - most of all - allows tape like this to be used without the risk of pulling the top surface away as the tape is removed.  In their sanded state, the tops are very delicate things...:

 

The binding is quite another matter.  It will need:

- pre-bending, just like the sides

- a long length of joined together bicycle inner tubes

- luck

- a following wind

Luckily, I'm tied up tomorrow so have a day to build up the courage

 

[SpondonBassed]

23 minutes ago, Andyjr1515 said:

- a following wind

I suffer a bit from that sometimes too.  Maybe ease off on the Jerusalem artichokes?

[Andyjr1515]

I'll do an update in a little while, but just checking imgur - anyone had any issues recently?  Yesterday couldn't log in at all, and then today, I can get in but a number of images missing and it stalls when I try to add a new image.

Just posting this old image to see if it actually posts OK (this is the binding strip I'm in the middle of adding to the body:

 

OK - that worked....

Anyway, for the post, I'll download the images directly.  Back in a bit

***Post post - just found an imgur status update on twitter.  They have done a major maintenance exercise and there are issues at the moment updating new images - so it's not just me.

 

Edited August 30, 2018 by Andyjr1515