Ash's acoustic rabbit hole

[ADFinlayson]

Heat blanket arrived today, still waiting on the spring steel and the press screw to complete the bending machine. But obviously I couldn't resist having a bit of a play this evening.

I spritzed a bit of the walnut binding I made with a bit of water, switched the blanket controller to 100ºC and OMG that was so easy, after maybe 20 seconds of holding it in place, I clamped the centre block down and it just bent perfectly. Stuck a bar clamp on each end to told it on to the form, left the blanket on for 5 minutes before stitching it all off. 

Took it out after about another 30 mins and this is what it looked like. Bit of spring back but not a lot, I can hold it against my sides  and it conforms pretty much perfectly. 

I did a bit of radiusing of the top of the sides for the limba build, Following the driftwood method - I folded a piece of paper a few times and placed it under the heel block to prevent sanding the front so I can keep that area flat. It was quite a slow processes sanding the solid area of the arm bevel and I had to be careful how I applied pressure to prevent the other side disappearing, spent about 20 minutes and got bored, it's about 2/3 of the way there.

Back to bracing the top, got the rest stuck on apart from the sound hole reinforcements and did a bit of carving. The tone bars and the wings were a doddle to cave but the x braces are not proving to be as much fun. Weird because it's nicely quartersawn with uniform straight grain but they really don't want to be carved. Those little ebony pieces you can see off to one side are offcuts from the bridge plate, they're 2.5mm thick and I'm using them as a guide so when I taper down with the chisel at the ends of the braces, the bevel of the chisel rides along those and I know I need to notch the sides out to 2.5mm at the braces.

With any luck the other bits of the deck and the ebony strips will arrive tomorrow or sat, otherwise I'll carrying on with the top.

[Muzz]

Really enjoying watching the craftsmanship here, hope the supplies arrive on time.

[ADFinlayson]

On 9/23/2021 at 10:32 PM, Muzz said:

Really enjoying watching the craftsmanship here, hope the supplies arrive on time.

Thanks Muzz

[ADFinlayson]

Made a bit more progress on the bender. The press screw arrived a couple of weeks ago. It didn't have any holes in the base so I had to drill and countersink some. Pretty easy to drill through on the press so I assume the base is only made of aluminum.

Centred it on the outer mold for the waist and marked holes with a centre punch so I could make accurate pilot holes.

To make the sides I cut up some ply I had left over from the workshop insulation project. Pinched my dads jig saw because I have nothing that I can cut down bit sheet materials with. Roughed out both pieces then finessed one with the spindle sander 

Once I had the first one shaped, I screwed the two together and used the first as a template for the second and routed it to match. Then I changed bits and put a roundover on the outside of both pieces just to take off the sharp edges.

I needed a channel running down the middle so I used the same bit I would normally use for a truss rod channel, clamped a straight bit of wood down as a fence and used my trim router to make the channel in both pieces. 

Then I drilled a couple more screw holes so I could align a couple of blocks between them to screw it all together. 

I made a slight cock up here, my screw holes are in the centre of the two cross sections but not thinking, I used the line that should denote the bottom of the form, so the form is currently sitting 10mm too high against the sides. I was going to glue a couple of pieces to the bottom of the form anyway to stop it moving about while in use. So I think I'll just notch 10mm out of the bottom of the form where the cross sections go so it sites 10mm lower and in the correct place. 

Here's where it's at now, starting to look like a bending machine! I need to make a cross section for the top and drill a hole in the right place to take the press screw, then I need to get some springs and make a couple of blocks up that will make up the outer spring clamp things. I haven't taken into account how/where I am going to fit those on the sides so I think I'm going to have to take it all apart again so I can get the holes for those in the same place on both sides for even clamping.

My ebony binding has finally shown up now too so I'm excited to try and bend some wood!

[ScottR]

Wow. You've kept quite busy whilst I was out traipsing around the high country.

very cool and informative build(s).

SR

[ADFinlayson]

59 minutes ago, ScottR said:

Wow. You've kept quite busy whilst I was out traipsing around the high country.

very cool and informative build(s).

SR

I'm not familiar with the high country, is that a mountainous region in Texas? But snap, I've been away this week trotting around and making sand castles on the beaches of Cornwall in south of England, we've had fantastic weather over the last week or so which is not normal for the south coast in September and it was nice to take our daughter to the seaside, especially as we weren't allowed to travel anywhere last year.

[MiKro]

3 hours ago, ADFinlayson said:

I'm not familiar with the high country, is that a mountainous region in Texas?  >snip<

High country in Texas can refer to two regions that I am aware of. The panhandle area in North West Texas or the Mountainous area in the Big Bend area.

The Hill country area is South of DFW and encompasses a large area including Austin and surrounding areas. It starts around Hico.

 

Also, When using a heat blanket put it on the inside of the wood side wall, otherwise you may have ribbed pattern show up in the wood that is very hard to sand out.

MK

[ScottR]

3 hours ago, ADFinlayson said:

I'm not familiar with the high country, is that a mountainous region in Texas? But snap, I've been away this week trotting around and making sand castles on the beaches of Cornwall in south of England, we've had fantastic weather over the last week or so which is not normal for the south coast in September and it was nice to take our daughter to the seaside, especially as we weren't allowed to travel anywhere last year.

 

26 minutes ago, MiKro said:

High country in Texas can refer to two regions that I am aware of. The panhandle area in North West Texas or the Mountainous area in the Big Bend area.

The Hill country area is South of DFW and encompasses a large area including Austin and surrounding areas. It starts around Hico.

 

Also, When using a heat blanket put it on the inside of the wood side wall, otherwise you may have ribbed pattern show up in the wood that is very hard to sand out.

MK

Well, I went through the hill country on the way in and out, but I was referring to the Rocky Mountains. I spent a few days a little north of @killemall8's neighborhood in Santa Fe and Taos New Mexico and then headed up to my son's place in Denver after a stop in the Great Sand Dunes National Park. I'm pretty sure that wasn't a national park the last time I was there. We took the grand kids to Rocky Mountain National Park and the next day headed back down hill. We came out of the mountains across the llano estacado, (staked plains.....don't know why they call them that, most folks would call them the high plains) then down off the caprock and through the hill country and finally into the coastal plains where I live.

SR

[MiKro]

12 minutes ago, ScottR said:

 

Well, I went through the hill country on the way in and out, but I was referring to the Rocky Mountains. I spent a few days a little north of @killemall8's neighborhood in Santa Fe and Taos New Mexico and then headed up to my son's place in Denver after a stop in the Great Sand Dunes National Park. I'm pretty sure that wasn't a national park the last time I was there. We took the grand kids to Rocky Mountain National Park and the next day headed back down hill. We came out of the mountains across the llano estacado, (staked plains.....don't know why they call them that, most folks would call them the high plains) then down off the caprock and through the hill country and finally into the coastal plains where I live.

SR

Like I said some refer to the panhandle as High country, it has always been high plains to me and drops off the caprock as you said. Llano is around the Austin area and South of Hico. If any one ever says that the caprock and highplains is flat I laugh at them because they have never walked any of it. I can show you a place at the Matador Wildlife management area in the Northwest back corner that is at min an 800ft elevation change in less than a square mile of distance. LOL

mk

[ScottR]

The Palo Duro Canyon comes to mind as well along with the breaks of the Canadian.

SR

[ADFinlayson]

1 hour ago, ScottR said:

 

Well, I went through the hill country on the way in and out, but I was referring to the Rocky Mountains. I spent a few days a little north of @killemall8's neighborhood in Santa Fe and Taos New Mexico and then headed up to my son's place in Denver after a stop in the Great Sand Dunes National Park. I'm pretty sure that wasn't a national park the last time I was there. We took the grand kids to Rocky Mountain National Park and the next day headed back down hill. We came out of the mountains across the llano estacado, (staked plains.....don't know why they call them that, most folks would call them the high plains) then down off the caprock and through the hill country and finally into the coastal plains where I live.

SR

Sounds like a great trip. I hope you came back to some fully cured lacquer 

[ADFinlayson]

A bit more progress on the bender. I notched out a couple of rebates in the underside of the form so it would sit on the cross sections of the machine. Did it the old fashioned way because I didn't want to run the risk of routing into a screw. It was quite funny actually - When a chisel hit's chipboard, the chipboard just explodes and I was covered.

Did a test fit and it fits nicely, not too snug but there isn't a lot of play so it shouldn't move around when I'm screwing the press down.

and importantly the routed slots that will guide the press line up perfectly with the centre of the waist

To make the top, I used a bit of pine that came off the old work bench and cut it so that it would fit inside the two sides, clamped it in place and used the holes that I had already drilled into the sides to pilot the pine as I'd be drilling into end grain.

Then I drew a couple of lines corner to corner to find centre, the press screw is 3/4" so I used a 20mm forstner bit as that is the closest size up I had, drill a pilot hold first then drilled through half way from each size with the forstner to prevent tearout

Then I installed the press screw using a couple of wood screws with washers

And as if by magic it works! the blanked it 6" wide which is the dimensions I worked to for the form and the machine inner width, but the spring steel (which I got from Rall Guitars in Germany) is metric at 15mm wide so there is a bit of play with the steel but the blanket first nicely without moving around. 

I just need to get hold of 4 springs and screw hooks now to make the clamps for the ends, 

 

[ScottR]

2 hours ago, ADFinlayson said:

Sounds like a great trip. I hope you came back to some fully cured lacquer 

In fact I did. That's when the trouble started.....

Very impressive fixtures you are making. They seem to be more work than the actual guitar.

I hope you get dozens of gorgeous guitars out of them.

SR

[Andyjr1515]

Impressive stuff, Ash.

Andy

[Dave Higham]

I gather you'll be using an inner and outer  steel slat when bending. Can I pass on a little tip someone gave me when it comes to taking the sides out of the bender?

As you're taking the pressure off the ends and the waist, the inner slat tries to straighten out and break your sides.

Make some little clips like these. Thes are made from plastic coated fencing wire.

They slide into holes in the bending form near the waist and the ends, the flat part going between the inner slat and the wood. Release the pressure on the ends and the waist just enough to insert the clips.

You can the safely take off the outer slat and the blanket and the clips keep the inner slat in place.

If you already knew all that, please forgive the intrusion

[mistermikev]

really inspiring seeing you work thru this one.  not inspiring enough to make me think I'll try it any time soon (hehe) but inspiring none the less!  you rawk.

[ADFinlayson]

19 hours ago, ScottR said:

In fact I did. That's when the trouble started.....

Very impressive fixtures you are making. They seem to be more work than the actual guitar.

I hope you get dozens of gorgeous guitars out of them.

SR

uhoh, I hope it all turns out alright. Yes well making the form for it was a time consuming PITA but as you say, I will hopefully get several builds out of it and hopefully it's not such a pain to make the same machine work with other shapes too.

[ADFinlayson]

2 hours ago, Dave Higham said:

I gather you'll be using an inner and outer  steel slat when bending. Can I pass on a little tip someone gave me when it comes to taking the sides out of the bender?

As you're taking the pressure off the ends and the waist, the inner slat tries to straighten out and break your sides.

Make some little clips like these. Thes are made from plastic coated fencing wire.

They slide into holes in the bending form near the waist and the ends, the flat part going between the inner slat and the wood. Release the pressure on the ends and the waist just enough to insert the clips.

You can the safely take off the outer slat and the blanket and the clips keep the inner slat in place.

If you already knew all that, please forgive the intrusion

No intrusion at all. I had watched an Eric Schaefer video where he talked about just that issue and he drilled a hole in his inner slat to hook something through it to prevent the sides popping up and putting pressure on the side. Your version looks a lot better though, I like your design too, being able to easily remove the top assembly is a good idea. I've got an 18" press screw so it should be tall enough to be able to lift the side up and out without having to work it around the form but I'm definitely steeling your idea for keeping the spring steel down. Thanks.

[ADFinlayson]

2 hours ago, mistermikev said:

really inspiring seeing you work thru this one.  not inspiring enough to make me think I'll try it any time soon (hehe) but inspiring none the less!  you rawk.

You do love a good jig though!

[mistermikev]

40 minutes ago, ADFinlayson said:

You do love a good jig though!

lol... wut u tryin' a say??!  ok, i do.

[Dave Higham]

1 hour ago, ADFinlayson said:

I'm definitely stealing your idea for keeping the spring steel down. Thanks.

Someone else's idea, not mine, but you're most welcome.

[ADFinlayson]

I've done a bit more in the acoustic department. Finished shaping the braces on the limba build. Though I have since taking this pic brought down the xbrace at the end of the treble side, nothing to do with tap tone, it just looked ridiculous 

Bender MK 1 is now an officially working prototype   with the missing section of ebony binding in it. Though there are a couple of modifications I need to make. I also realised after the fact that my top metal slat should probably be between the binding and the heat blanket, it's probably not doing a lot there other than looking shiny.

I made a grid of holes at 1" centres so I have options for mounting the hooks but these cheap springs I got are far to whippy - they do hold those end blocks down but barely, so I need to get some better springs. 

I absolutely need to do something like what @Dave Higham mentioned above, I was hunting around to see if I had anything suitable but I don't and I'm inpatient so I bent one of the ebony binding strips anyway. Bent absolutely fine but when I brought the press screw back up I could see the bottom slat was putting a lot of pressure on the binding at the waist, this might not be that much of an issue for sides but for a tiny bit of binding... I brought the screw all the way up and held the centre down and I released the ends but then I heard it go clink right at the waste. No biggy it was a clean break and I just superglued it back together. 

Bent this at 120ºC (according to the gauge), left the heat on for 5 mins then took it out 2 hours later. this is it after superglue resuscitation 

Then glued on to the back. The bend was clearly much better than results I was getting by hand because I was able to tape it down quite easily then wick in some thin superglue where for the previous pieces I had to put medium CA in the channels and hold the superglue in place whilst applying accelerator to fully bond the binding and my skin to the channel.

So addressing the pinning down of the bottom slat. I don't want to buy a roll of pvc coated wire, but I did see toolstation has galvanised staples which look like they would do the job. 3mm thick and 30mm long so I'll grab some of those. 

Apart from the above quirks, the bending machine and blanket work really well. Looking forward to trying out a proper side bend with it but I think that will have to wait until the limba build is out of the mould. 

[Andyjr1515]

Phenomenal work rate, Ash.  It all looks jolly splendid!

[ADFinlayson]

Well now that I've got the materials I needed, no excuse not to get back on with the walnut build, and I've learnt that scraping binding flush is my least favourite part of the build so far. probably because I had 2.3mm binding and a 2mm binding channel so there was a fair bit to scrape off. Got it all flush though then made some ebony dust to fill the gaps, That created even more of a superglue mess on the top and the back so. I spent about 4 hours on and off tonight scraping, filling and sanding.

 

This is sanded at 80 and 120, I made the mistake of getting the top, back and sides to final thickness with 80 on the drum sander so there was quite a lot of work to do. You might be able to see a little dark spot near the heel area below. That's where I dropped it on the bend when I wasn't paying attention, that's the only bit that didn't come out with the soldering iron so I'm just going with it.

The other thing that you might just be able to see in this pic is just how thin the binding is at the heel, not have a jig to keep the channel parallel with the sides definitely shows - it's about 1mm thick at the front and 2mm everywhere else, not very noticeable on the top but very on the back.

The top I was concerned about with the amount of glue around the edges, bit more work to do although it has cleaned up pretty well. keeping the ebony dust out of it while sanding is proving difficult though

I think I probably need to get on with making the bridge now, but I also really need to get on with a couple of electrics or people are going to start asking where their guitars are at. 

 

[Bizman62]

6 hours ago, ADFinlayson said:

The top I was concerned about with the amount of glue around the edges, bit more work to do although it has cleaned up pretty well. keeping the ebony dust out of it while sanding is proving difficult though

Mirka make a vacuum connectable hand sanding block in their Abranet series. I wonder if that could reduce the issues?

The basic one: http://www.mirkareseller.co.uk/abranet-abranet-sanding-blocks-mirka-abranet-70x125-tool-plus-p120-abranet-strips-p-91.html?osCsid=555rmh633nru4gtu9bbsvrdl91

And the kit with changeable curved bottoms: http://www.mirkareseller.co.uk/abranet-abranet-sanding-blocks-handblock-kit-198-velcro-p-57.html