honza992

While the glue malarkey kafuffle was ongoing, I cracked on with the sides. First job, trim the kerfing back with a spokeshave. The best job in luthiery. It's like popping bubble wrap but much better The back is dome shaped, with a radius of 12 feet. So that same radius needs to be sanded into the sides & kerfing. Straightforward to do on the radius dish, even if it takes quite a while. Any time I'm doing sanding I try to do it inside my hi-tech sanding cubicle. A quick n easy downdraft table. Or sidedraft I suppose. Works a treat. Next I need to carve channels through the kerfing so that the braces sit nicely inside. I used a dremel, again in my sidedraft cubicle. (I must get that patented, pronto). The idea being that the ends of the braces go into the kerfing, like this: The gaps will get filled with epoxy when the back gets glued onto the sides. And here they are, not glued yet as there's another job to do first......(ooh mysterious!)

Thanks JPJ, a very good suggestion! But the mixing pot was the same. There's something odd about the hardener. It's got a skin on the top which I've never seen before, despite years of using exactly the same epoxy. Anyway, it's in the bin and new ordered.

This morning the glue is hard. Hurray! That was close to being very annoying. 36 hours to cure is a loooong time though. I'm throwing away the containers, and have ordered more West System. It's a good reminder to measure exactly the two parts of the epoxy mixture, and to stir them together really really well. It's also a reminder to keep the mixing pot so you can check each batch has hardened. I use a paper espresso coffee cup. Phew😅

Yeah, getting the ratios right is key, as is stirring...a lot. Epoxy has got lot's of advantages. It's got a long open time, so you've got lot's of time to set up clamping etc. it's incredibly strong, it doesn't creep, and it gap-fills better than wood glue. Also, it's not water-based meaning that I'm not introducing moisture and possible warping into my very thin piece of wood. The disadvantage is that if it doesn't cure properly....yer buggered. Up until now West Systems has been spot on.... I generally use Titebond for most things. But for critical joints and anything designed to never come apart, epoxy is great. It was suddenly colder last night, but this is Italy, it's not the arctic....Cold for us is anythng below 15C !! Fingers crossed tomorrow morning it will be rock hard and all my hair pulling will have been for nothing...

Ok this is a bit frightening. The epoxy hasn't completely hardened. It's hard but I can still push my finger nail into it. I've had failures before with epoxy, but never with West Systems and my way of measuring out exact amounts with syringes. Fingers crossed it just needs more time. This is why it's always good practice to keep the mixing pot so you can check it's completely hardened. We'll see how it is in a few more hours.

I've started on the bracing. The blanks I've got are very oversized, so by cutting some off at the line I can end up with a brace which is almost perfectly quarter sawn: Putting it onto the platform, I use a biro sticking through a Gibson selector switch washer to mark out the shape of the top onto the blank. You can chose either Rhythm or Treble depending on whether you want thundering lows or blistering highs.....It also means you can get a pretty much exact contour. Because the top is arched in both directions I mark both sides of the blank. With a spokeshave I then carve down to the line... ... My makeshift 'go-bar deck' is ugly but very effective. I find myself using it all the time either for gluing or just holding stuff down. Here I'm using it for both. The brace get's held in position on top of a piece of sandpaper (150G). You can adjust the go-bars very quickly so they apply just the right amount of pressure so the brace is held in place but you can still slide the sandpaper back and forth to get good fit. Finally the brace can be glued down in the same way. I use West System epoxy. I use the Ken Parker method (as usual). Which is wet the brace, put it onto the top, then remove it so you have an imprint: The idea is to let the epoxy soak into the wood as much as possible. I've got a silicone brush which I use to go back and add more epoxy to any parts that soaked it up. Finally, clamping in the go bar deck. One of the (many) good things about epoxy is that it needs very little clamping pressure, just enough to stop anything moving. Squeeze out I clean up with a cotton bud soaked in acetone. Tomorrow, brace number 2...

Sides are nearly finished. The final kerfing was glued in this afternoon....

Top carving continues. I've hummed and ha'd long and hard about final thicknesses. Ken parker thins his tops to between 2 and 3mm, he mentions D'Aquisto tops were 2.5mm to 4mm thick. Obviously those were guitars but the string tension is actually very similar. The arch is a bit flatter on mine and the wood is certainly cheaper...so plugging all those variables into the scientific calculator, my finger in the air came back with the following: 4mm around the bridge, 3.5mm around that thinning to 3.2mm at the periphery. I don't know if you can read any of these numbers, but here we are, getting close:

Post #2 in my world's uggliest jigs compilation.... I'm planning on thinning the top till it's quite flexible. Holding firmly without cracking it is therefore a problem. I've taken Ken Parker's beautiful work holding platform which takes several hours of video to explain, and made my own version which took about half an hour to make. It's basically a 6mm sheet of MDF, with a 15mm piece of ply with the shape of the guitar cut out. Some more scrap pieces of 4mm MDF on top of that cut to the shape of the top ensure that the top goes back in the same position. Because the top is still slightly oversized it can sit upside down on the rim. The thing is as it get's thinner an more fragile it really needs support from below. Sooooo......I then filled the space with 3.5-5.5mm polystyrene balls - the ones you use to fill bean bags and such like. So far it's worked really well. The balls are soft enough not to scratch or dent the top, but it seems for the moment to provide enough support. We'll see as the top get's thinner how it works out, but so far I love it!

I love building guitars. I hate building jigs. It's a personality defect I know, but I resent having to do it. So I thought I'd show you a couple of my fuuuugly jigs, that seem to work just well enough that probably I'll never upgrade them. First is the top thickness guage. The guage itself was a cheapo from Amazon. A piece of scrap clamped above the table, and a piece of threaded rod going through a hole in my table. A plastic knob thingamy stops the top from getting scratched. I then write in pencil on the top what the thickness is at each point. It's pretty much a consistent 5mm, so I'm going to go back to the drill press and do another series of holes at just over 4mm. Which strangely is what I thought I did last time, but there you go. That's why you measure twice..... I should also say that pretty much everything I'm doing with this build is copied directly from Ken Parker. He's done an incredible series of videos called Archtoppery, which if you are interested and have a spare 30 hours or so, they are amazing. He's hands down my favourite builder, an absolute genius. Here if anyone is interested: https://kenparkerarchtops.com/archtoppery

I'm working on the inside carve. At the moment I'm doing it all with a gouge. It's probably a bit small (Sweep 5, 18mm in case anyone is interested), but it's an utter utter joy. The grain is tricky. The middle section (marked in pencil) runs opposite to the areas either side. I wake up sweating in the middle of the night just thinking about tearout.....

OK, the carving of the top I'm calling finished. There's still a bit of refining to do, particularly on the cutaway, but I'll do that with sandpaper once the top is on. Turning over I use the drill press to mark a 4.25mm depth everywhere (4mm mdf and a 0.25mm feeler gauge). I use a simple wood dowel with a thin piece of cork on top. Without that the top will get dented from the force of the top being pushed against the dowel. I then drill several million holes to within 25mm of the side (note to self, template #8). Several million more to go tomorrow. I'm exhausted.....

OK round one of the carving is complete. I left it 1mm thicker everywhere on purpose in order to give me a chance to see how the carving was going without risking it getting too thin. Time to get serious. I routed the perimeter down to 4mm, it's final thickness. Time to crack out the gouge and mini plane again. I'm not finding it easy planing it without getting tearout. Wood is like cats fur, it want's to go in one direction. Get it it wrong and the blade can get out under the fibres and pull out a chunk. Carving it is like butter, till suddenly it isn't. It's also a second grade piece of wood, so there's lot's of grain runout, making tearout even more difficult. So far so good though....

Thanks Hellzero for those suggestions. I wondered if anyone had put the BP100s into a bass rather than double bass, there's my answer. I may well come back to you to explore this a bit more. But it's a non-permanent install, is that right? The trouble with the K&K is that it's permanent - they're superglued to the inside of the top. These are prototypes I'm building so it would be good to know I can chop and change the electronics around. Also, I may drop RMC a line and see what they would recommend for an archtop bass. Cheers!

Ok thanks Andy, good to know. Any instinct as to whether the Ghost saddle units are less susceptible to feedback than the more normal piezo strip that goes under the saddle?

Carving in progress. I'm not sure how it's going. It's definitely going to take some practice... 😬

Does anyone have any views on what piezo pickups I should use with this one? The last one has a K&K glued on the inside of the soundboard. I want to try something different to contrast. The obvious options are: Fishman Matrix piezo element under the saddle: https://www.thomann.de/it/fishman_matrix_infinity_vt_narrow.htm or https://graphtech.com/collections/ghost-pickup-systems-kits/products/ghost-bass-acousti-phonic-kit coupled with these elements which I could fit into a handmade bridge: Any one with any thoughts? I know Rob Allen uses a version of the Fishman matrix....The Ghost, I've no experience of....

Contours done, upside down on the router table. Next, carving..

It's basically a moxon clamp adapted to hold guitar bodies. Two outer pieces of 18mm MDF, then two inner pieces of 4mm MDF held in a curve. It means the clamping pressure is applied to the edges not the top/back of the guitar. Other than the MDF it's two 1 inch diameter pieces of pipe, two flanges which I've just screwed into the table, then pipe clamps. Like all my jigs it's ugly, but works really well. Here it is holding the last build:

Yep. The total thickness of the top is 16mm. The dome will be 12mm. So dividing 12 mm by 9 templates, means each template will be used to only take off 1.3mm. Archtop guitars I think have a much bigger dome - 16-18mm, but my complete finger-in-the-air guess is that that's too much for a bass. I've never done this before though, so it will be a voyage of discovery for all of us!

Correct. The screaming makes my tinitus go haywire.

Phew! I'm running as my 7 year old is due back from dance class in 14 minutes at which point she purloins the laptop😟 I've tried explaining to her that Basschat is WAAYYYY cooler than The Worst Witch, but her powers of negotiation a lightyears beyond mine🙄 So, I've started work on the top. My design is largely based on Benedetto's published shapes. I've stretched and squeezed it somewhat to fit my needs, but that was it's origin. I want to rout contours into the top to help with the carving. I'm not good enough to do freehand carving so I want as much help as possible. So....the incredible, the wonderful, the extraordinarily good looking @Wookiebass did some CAD jiggery to do a contour map for me. I've added a few more contours to it so it looks like this: I then cut out each of the contours and stuck them to 4mm MDF, cut them out and sanded them to shape. I now have a stack of contour templates, ready for the real fun to start! Or maybe I'll just stick a bridge onto the top of that and call it done. 🙂

Slightly out of sequence, as I did the radius before the marker dots. Radiusing I use this jig from G&W. It seems solid enough but I'm getting a few ridges so there's some slop somewhere. I'm now in the process of finishing the radius by hand. At the moment it's got 120 grit on. I'll got to 400 on the sanding beam, then probably do to 1000 with sanding sponges. The orange sanding block is probably my greatest innovation in guitar making🤣 It works brilliantly. I think I may have mentioned ebony being non-cooperative. It particularly doesn't want to have a radius sanded into it. This is going to take a while.....

The fretboard is a huge amount of work, mostly done. First I cut some binding strips off the side of the blank. This way the binding exactly matches the fretboard itself. These then go through the thickness sander: Next up fret slotting on the radial arm saw. Anyone who has slotted ebony by hand knows it's an utterly miserable job. Ebony does not want to be a guitar, thank you very much so makes sure that the fret saw gets endlessly stuck in the slots. A bit of beeswax on the sides of the saw helps, but it's still miserable. Once the slots are cut by machine I then do them all again by hand, to make sure that the fret slots are deep enough for the fret tangs. Once the bindings are on you really don't want to increase the depth of the fret slots unless you can help it... Next up, binding the fretboard and the headstock plate. First I do the white line all the way round, then go back to do the ebony. If I try to do it at the same time my head explodes. The end piece goes on first, then the side strips. If I can I use titebond, but for this end piece which is curved CA is better. (EDIT: This is what I did, end bit first then the sides. It's not though the best way to do it nor is it the way I intended to do it. Following (even my own) instructions is not my strong point. It makes far more sense to the do the sides first, then the curved piece. This way the curve is pushing the joint tight, rather than pulling it apart as I've done. Ho hum. Will I never learn....@alittlebitrobot don't answer that) d I rout the headplate to size using my binding bit. I take it veeery slowly, taking off no more than 0.5mm at a time - by changing the bearing size I can creep up on the final size. Ebony is brittle and chips easily and the headplate shape with it's curves and cross grain routing is asking for trouble. Eventually it looks like this: I can now go ahead and do the binding. Binding is actually one of the processes I like the most. It takes a long time to get all the angles right so that the joins are as near to invisible as possible. Endless tiny adjustments so that the mitres are tight. Then gluing. Many hours later it looks like this: So far the neck is made up of 23 separate pieces of wood. And there's still quite a few still to go. While we're on the neck, I've also put in the MOP dot markers. This is the sort of job that sounds easy - drill a few holes, glue in the dot. Easy. In my experience it's not though. The drill wants to wander, the ebony wants to chip, the MOP dot is just to big to fit in the hole. It's taken me a loong time to develop techniques for getting it neat and precise. First, I mark the holes in pencil, then punch it with an...awl? ....then I freehand drill a 1.5mm hole. This hole will guide the pointy end bit of the 7mm forstner drill bit. Without it, I find the forstner can wander, and a dot marker half a milimetre out of place is the sort of thing that drives me potty. If they're not on the line, re-do them. These ones look lush😊 One of the troubles with me and guitar building is that I'm bit of an airhead. Here's a good example....a mother of pearl dot superglued to the handle of the scalpel I was using to push the dot into the hole. Try to remember that superglue is called that for a reason. It's sticks, and real quick! Luckily I realised in time. A scalpel sticking out of the fretboard would not have been ideal.

Hi All, sorry this update has taken ages. Quite a lot of progress.... The back is mostly done. A bit of final sanding to clean it up but otherwise, it's ready...and the top has been joined and thicknessed.