Akula

11 minutes ago, LFlab said:

Looks great! Like yourself not sold on the Warwick headstock, and also, I think it is preferable to have the tuning machines not parallel but have them taper so the run from tuning machine to nu is straight. At least, that's how I designed in my parametric model, Especially that middle string on a 3+2 headstock is often at a severe angle.

Wouldn't mess with a compound scarf joint, just make it straight and solve it in the volute, as long as your glue joint is neat, the extra line is not too noticeable (and you could always put veneer on the back of the headstock)

Thanks! Yep I definitely like a good straight pull on the strings past the nut - my 6 string headstock, like most modern designers, is built around a straight pull. I designed around the tuner holes, not the shape. A re-design is in order. I shall, however, be messing around with a compound scarf joint. It's in my nature to try something I've never done before, however I shall be messing around with spare stock before I do it on the actual neck blank. Nothing like a badly scarf-jointed knotty pine neck to put myself off the idea and follow your advice!] There'll be time to experiment before the real thing.

11 minutes ago, Bizman62 said:

A Crimson video about the subject looong ago revealed that plain soaking won't dye the veneer thoroughly. A vacuum chamber might help. Another option might be using a pressure kettle but boiling the veneers may cause them to disintegrate in the manner they make cellulose for paper.

Righto! I picked a darker coloured timber just in case. There is a luthier supplier this side of the world who does "black veneer sheet" for about five times the price of raw timber veneer specifically for this reason. I'll deal with not having jet black accent stripes, they look just fine to me.

 - Jam

Here's a rough outline of the thing. I'm still not sold on the headstock - I've been sitting down every night and moving bezier handles by a bee's.

The scale lengths are 863-876mm. I briefly went over this in the original post, but the idea is to extend the lowest string a bit while allowing for standard hardware and pickups. I'm going to have issues with the nut, though. I can't use the adjustable nut I currently have, and will need to make a new nut, yet I want the adjustable feature. So, I'll try my hand at machining a multiscale adjustable nut from brass. The idea is mechanically simple: a normal nut, slotted and shaped, riding upon two pins and sitting hard against grub screws on a brass plate, which is either screwed or glued to the shelf at the end of the fretboard. 

I've been working on a spreadsheet to calculate the weight distribution of the instrument. I figured, knowing the density of the building materials by weighing them in a known DAR format, I could use CAD to measure surface area times thickness, subtract any cavities and roundovers or carves, then do the same calculation for the neck profiles as a cross section, averaged, and times the length. The headstock was actually the easiest to calculate: surface area x 0.014m, minus 5 x Pi R^2 of 0.005m. Throw these into a centre of mass for both sections, and I've got a fairly good predetermination that the instrument will lean back into the strap quite nicely.

Next item on my list of mathematical endeavours is the neck dimensions. I've drawn up plans at a 1'and a 2' neck angle, and I've decided a smaller angle will allow for less grain run-out on the neck blank, and also letting me sit underneath the standard timber sizes here. Another degree could mean buying a 75mm thick board instead of a 50mm one, and wasting a lot of it. However, this means my neck blank won't allow for a straight run into the headstock, and shall require a scarf joint. This is interesting to me because of the nut angle - I'll have to attempt a compound scarf joint. The concept is really simple, but the execution could be rather hard with a multi-laminate neck blank. If the laminations won't line up, and I see no logical reason why the would, then I'll probably throw a veneer slice into the mix to distract the eye from the aesthetic issue. You'd see a shoddy line on a scarf joint, but throw in a dark veneer line or two between the joint and I bet you'd skip over.

I've ordered the veneer for accent lines on the laminated neck and scarf joint. It's a species called Dillenia. Looks quite dark, takes glue and stain well, fairly stiff. I'll try my best to soak veneers with black stain before gluing up, to add to the effect, but if it affects glue ability or won't soak uniformly through the fibres then I'll deal with having brown rather than black. Also got some carbon fibre rod in the post, plus a truss rod and some jumbo SS fretwire. 

Thinking of timbers for the build. Maple neck is a given, but the 5-piece laminated neck gives me some options to throw some other wood in there as well. I was thinking Wenge for lams number 2 and 4, but I may just go for maple all round with the accent veneer. Wings will be walnut, as I've been in love with that particular grain pattern and feel for a few builds now. Top? I'm thinking flamed Tasmanian Blackwood like my DC build a few years ago. I'd like to have at least one or two proper Australian woods in the mix, and I simply adore the look of blackwood. Tiger Myrtle is another option, as is fiddleback Redgum. Fretboard will be either Sheoak or Wenge, depending on the particular pieces on offer.

Quite looking forward to having all the bits and bobs in front of me. First cut is going to feel great.

 - Jam

33 minutes ago, Asdrael said:

Are you going to leave the very top flat to install a bridge or keep it radiused with single saddles?

The entire top will be radiused. The bridge is recessed, and that routing procedure will be done the same way as the pickup bays - with a flat template riding on shims either side to produce a flat-bottomed route on a curved surface. It's gonna look sick - probably!

 - Jam

Thanks @Asdrael! If I can get this build anywhere near the precision of your builds, I'll be a happy man.

@Bizman62, I am preparing myself to bend timber for the top if I can't improve the radius jig. I've found my issue - the concave shape of the convex jig, if that made any sense, is deflecting with pressure from the router. I'll maybe fabricate another one with thicker timbers and more bracing. The deflection is resulting in all of my mathematics being thrown out the window, and for the top and body to not quite fit together. Even worse than that, the top is now not a uniform thickness across the curve, as the inside and outside curves now have different radii! Check this:

I'd love to aim for a total body thickness, perpendicular to the arc, of 40mm, and therefore I've left enough meat on my pine demo to try and give it another go. Here's a quick CAD view of what I'm really going for:

As you can see, machining the top to fit the body perfectly will be a good solution, but only if my jig can accurately reproduce an exact radius. Otherwise, it would be simpler to create a curved surface on the bottom of the body, match that radius on the top of the body with planes and sanding, then bend the top to match. 

17 hours ago, LFlab said:

Do you have a drawing of what you are planning to do?

I do indeed! They're not finalised yet, but I can send the unfinished plans in a PM if you'd like?

I've got a new bandsaw blade in the post, and a rather large sheet of clear acrylic for templates-making. This build will succeed or fail upon the quality of it's templates and the preparation of it's operations. 

 - Jam

Time for another rabbit hole of a build.

Four years ago, in the grip of a covid lockdown, I built my first all-in guitar after nearly ten years of hiatus. A five string bass guitar modelled after a popular high end model, and with it's flame maple top it was quite a beauty! In the time since, I've built about two dozen guitars, and I'd like to think my skillset has improved just a touch. Back in those days I was building in the garden on a folding trestle table, using a jigsaw as my main apparatus. I foolishly left all my tools in England a decade prior, and I was still months away from owning a bandsaw or even a plunge router. The instrument that resulted has done well, but there are so many things I could've done better... So it's time to strip it for all it's parts and hardware, and do a complete rebuild.

Three major differences from my original build. Firstly, I want to experiment with a curved radiused body. This means the body and the top will both have convex and concave surfaces, and fit together for the glue-up. It alleviates the need for a gut carve or an arm carve, and looks damn cool. Secondly, I will be doing a multiscale, with the parallel at the bridge line. It's a smaller difference in scale length to the usual, which should result in less of an angle on the nut, and the parallel at the bridge means I can use standard hardware and pickups. Really, it just allows me to have a slightly longer scale length for the bass strings, for a little less flabbiness. And thirdly, I changed the body shape and plans for this build compared to the last one. It was just a little too similar to the popular brand-name guitar for my liking - those on this forum who know me know I like to take influence but not carbon copy. My instrument is going to be longer, thinner, wider at the hips and smaller at the waist, and just all around sexier.

In short: a 5-string, chambered, radiused body, multiscale bass guitar. Not decided on timbers yet, but I'd like to see Walnut and Tasmanian Blackwood. I'd opt for a maple neck laminated with some other accentuating species, possibly purpleheart if I can source it on this side of the world.

Lacking a CNC machine, I figured the best way to impart a radius onto the body would be using a router sled. Here's what a bunch of pine sticks and plywood got me.

I made two sleds, one for routing a concave shape and the other for a convex shape. I had to crack out the math textbook to work out radii for drops in thickness over a chord length of the circle... Then the added depth of cut for the router bit, plus a bit of wiggle room. The good thing about working with timber as opposed to something like solid metal is that wood has a little bit of bend to it. If I can get both surfaces within a millimetre or two of each other, good glue and clamp technique will take care of the rest. I would prefer precision, however, to alleviate any future tensions on the workpiece. 

Here's the other sled, with a pine-and-ply demonstration body being worked.

Nearly a good fit. The jig needs a little fine tuning. 

I've been monitoring the mass of this demo-body quite closely. I can use it to work out the surface area of the guitar body, and extrapolate to the density of the hardwood timbers I'll be using for the actual build. Throwing in a good amount of CAD means I can plan against the neck dive which plagued my previous attempt. 

In all the fun and games, I broke a bandsaw blade. Damn! Get back to you guys in a coupla days.

 - Jam

I went for wiping poly as a top coat. Given my unlikelihood to be bashing this on the stage at the next punk rock show, I figured a light poly would sufficiently seal the timber and provide a bit of protection. 

The headstock took finish spectacularly. The grain filler sucked up the stain and went jet black, really cool look, considering this timber cost me less than a case of beer. If keen eyes spot an issue with my tuners, just remember that I successfully removed 8 cheap tuners from circulation in my spares box!

Think we've got a mandolin here!

Well, that was fun! Last job - learn to play the bloody thing...

 - Jam

I dig it! The simplistic angular style works perfectly with that finish and colour. And I just adore those triangular knobs.

15 hours ago, ScottR said:

Jumbo frets on a mandolin!

Distance between frets 23 and 24 is something like 5mm, and the fretwire is 2.5mm crown width. There's very little wood showing between them! Of course, playing a mandolin up to two octaves is rather pointless, too, I just had enough fretwire for 24 frets and figured I'd see if I could do it.

I made a little boo-boo while routing the mortise at an angle - the template slipped. I'm better than this. Anyways, I routed away the mistake to the dimensions of the neck tenon, plus extra on both sides, then glued in some offcuts. Clamping was fun, had to stick some quick-grips in upside down, which had me flinching anxiously.

Then I installed some faux abalone binding to hide the fact that I'd screwed up. I reckon this'll look alright once it's all done.

Oh yeah, I did something new with the pickup mounting. I didn't want to go for a pickup ring, or even a pickguard, so I figured a way to direct mount from the rear. I glued a plug to the end of some aluminium tubing, drilled a hole in it for the pickup screw to go through, then mounted those to the rear of the mandolin. It works exactly the same as a mounting ring or pickguard, but from the back. 

The pickup, obviously, is slanted on quite an angle to catch all four courses of strings. It looked really strange on the design but I'm warming up to the aesthetic now.

Binding, and stain.

And the neck is set.

I'm stuck on the choice between tung oil or wipe-on poly for the finish. Poly will be more shiny, I guess, but oil just feels great. I've read a lot about how oil finishes dampen the free vibration of a soundboard, and why not to use them on acoustic instruments, but my hollowed-out chunk of timber doesn't really count as a "real" acoustic instrument. Or, I could go get some shellac flakes and try my first french polish.

 - Jam

Got some work done on this one, despite trying to keep the shop fairly dust-free for finish work on that mundane strat. 

I used up a few bits of spare binding, white for the fretboard and faux abalone for the headstock and eventually body too. New tricks I tried out include tucking the headstock binding underneath the fretboard binding, and including the fretboard binding around the nut. Had to slightly trim the bone nut to fit - used the bench grinder and it stunk out the whole place for hours. 

Semi-hemi fret ends on a bound fretboard. The fretwire is some huge jumbo nickel wire I had left over from another build. This whole thing is basically a way for me to use up leftovers while consuming some of my idle time, with a very small budget. I spent about $35 on the timber, ten bucks on a bridge, five bucks on a nut, etc.

 - Jam

It was frightening! I mean, think of it this way: if something goes so badly wrong with a plunge router that it comes in contact with your groin area, chances are your denim workpants aren't going to save you. But still, routing with your nuts hanging out - that's a hell of a scary moment!

I glued up and cavitied the body blank. Here be a shot of the underside of the top half before the back was glued on. I'd like to point attention to the alignment dowels in the neck and tail blocks, they helped align the outside body shape template with the inside cavity template. There's a 12mm R roundover on the outside and a 6mm R roundover on the inside, so I needed a way to ensure they matched perfectly. Excuse the mess on the underside of the top - I foolishly routed away much of the surface area for the router to ride on. A lot of that fuzz got cleared up with scrapers to leave a flat and uniform top.

Top half got conjoined to the bottom half, routed to body shape with a template riding on the alignment dowels. Then I did the roundover, and after that a binding channel. Binding won't be added until a little bit later on, but I wanted the groove done sooner rather than later.

Stacked neck heel, scarf jointed headstock, and the tiniest little fretboard I've ever slotted. 

And there we go, two components of a stringed instrument. 

 - Jam

Ok, I wasn't really going to post anything about this, or the rather mundane strat-type I'm working on at the moment. But something radical happened to me in the workshop yesterday, and if I post this build then it's a good excuse to share my anecdote with the fine people of Project Guitar.

So I was routing out the pickup bays in this dreary strat. I've got the template taped and clamped down to the body, and I've drilled a bunch of holes to remove material before routing. Nonetheless, it's still a wise idea to spin the router up and plunge it into the timber, so it doesn't catch and tear out upon start-up. I got into the "woodworker's stance" - feet a shoulder's width apart, legs slightly bent, hips locked, then I started up the router and bent my knees to keep my body locked in position to brace the powerful router in my hands.

That's when my belt buckle popped and broke. 

Now, I don't know if you've ever held a fearsome machine in your hands, spinning a sharp cutting tool at high speeds, with your pants dropped around your ankles, but it's quite the experience! Needless to say, I stopped the machine safely, put my skinny ass away, and hobbled back to the house to find another belt. If anybody is considering becoming the Naked Chef of Luthiers, I don't recommend it.

Anyways! Now I've gotten that off my chest, I'd like to share this non-guitar build of mine. I'm going to build a mandolin. 

I'll be taking a rather unorthodox approach to the construction, notably by avoiding to bend the sides. I'm a selfish luthier - the guitars I build for myself, I build it because I want it, and this time I want a mandolin. What I don't want is a ton of specialised acoustic-building equipment, namely bending irons and gobar deck, in my tiny workshop with limited space. Mark my words: I shall soon invest in all this stuff, build an acoustic guitar, and become part of that particular club. But a mandolin is probably too fiddly and challenging an instrument to begin my acoustic journey with, and so this mandolin will be what electric guitar builders call "chambered".

I've got a bridge, nut, and a rail pickup in the post. A lot of stuff like fretwire and tuners I have in the spares drawer. May even try my hand at fabricating a tailpiece from steel sheet. I've picked up a board of Meranti, and resawed it into body and neck blanks, and I'll resaw an offcut of maple to make the tiny fretboard. I've been working on my CAD skills, too, I haven't even drawn this on paper not once! 

 - Jam

9 hours ago, Bizman62 said:

That would tie up with the other damaged mirror acrylic parts. Is the mirroring surface easy to scratch from the bottom side? If so, scraping the mirror off for your logo might look interesting.

Yep, that's the direction I was going as well. The backing is easy to scratch off, I'm thinking if I do it with a Dremel it'll have a clouded look on the underside of the acrylic. 

My headstock design is rather slim, too, and it doesn't leave a lot of room for a large cover, so the logo will be quite small. 

 - Jam

Oil's cured. Wax, assembly, electronics, strings, fretwork, strings, and setup. Normal story - guitar's far from normal.

Just need to make a truss rod cover with my logo, and this atrocity is complete. Shall I make it out of steel sheet like my other builds, or do it with mirror acrylic?

 - Jam

On 1/3/2024 at 1:08 PM, tjiscooler said:

I love this!

HOw did you size the fingerboard to the neck? looked like you glued the full blank onto the neck, but a router wouldn't make it past the body?

Thanks!

Yep most of the fretboard was trimmed flush with a router, but you are correct, the router won't follow past the point where neck meets body. For the last little bit, I used a chisel.

On 1/4/2024 at 8:16 AM, ScottR said:

This definitely needs to be a prop in a horror movie!

 

It's so creepy it's cool.

SR

One day it might be

 - Jam

42 minutes ago, henrim said:

Acrylic cracks easily. Counter sinking the holes may help some. But better alternative is to use polycarbonate for clear parts that are fastened with screws.

One of my first experiences working on live TV was screwing in an acrylic facia to a riser during a changeover, and I went too hard and cracked the corner off. About thirty seconds to air, back from an advert break. Camera tape saved my ass, but I learned all about how easily acrylic can crack!

Polycarbonate would indeed be a better solution, but acrylic was easier to source, and it's a known material to me - sometimes it's all about the devil you know.

 - Jam

Whilst waiting for a bunch of tung oil coats to cure, I figured I'd make a jack plate and pickguard. I had previously made these items, but then I screwed them in using 2mm screws in 2mm holes, and cracked them. Whoops!

So I cut the jack plate using a hole saw, and carefully removed the "plug" to reveal a mostly round-shaped mirror object. Attached an M6 bolt, nut, and washer, stuck it in the drill, and wiped it on some coarse sandpaper at high speed until it was rather circular. Got my bevel done in the same way.

Pickguard was pretty easy to cut, three straight lines and a bunch of sanding on the edges. This mirror acrylic stock has been lying around in the shop for a few years, and the backing has definitely detiriorated in that time. Heads up - mirror acrylic will get damaged if you leave it on the sheet stock shelf for long enough! When I wet sanded the sides, the watery gunk flowed over the face of the pickguard and made these awful stains that I can't seem to remove with metho. These imperfections almost made me order some new stock, but when I screwed it onto the guitar in question, I realised that it would fit the style nonetheless. 

Interesting thing about the jack plate, spinning it lathe-style against sandpaper gave it quite the thermal shock, and it cracked, but just around the edges. Same argument, I figured the broken mirror effect sort of fits the corpse-filled guitar look. It's staying. 

I masked off the sides leaving just the router-milled surfaces of the tops and backs exposed, then sanded the machine marks away. I could've gone much higher with the grit numbers, but the cloudy finish gives the impression of some sort of binding. If I wanted to go super glossy I could've flame polished the edges, but I didn't want to risk the glue joint opening up.

Here we are, all rigged up with another coat of oil to cure. 

I've done four coats of this tung oil, and I'm thinking I might do one more tomorrow and call it quits. The horns and edges of a guitar are normally the main points to protect, but the timber doesn't see any of these parts. And I'm aiming for a satin finish at the most. So yeah. One more coat, assemble, show the world my most insane creation.

 - Jam

Here's a quick cross section of the idea I had a few years back. The view is a cross section viewed from the strap button, looking at a slice of the body, down the neck.

I've accounted for a 12mm body, standard humbucker at 23mm total height, and a 5mm fretboard. Springs go between the pickup ears and the body, as usual. The drawback being, clearly, you've got the butt-end of a humbucker poking out through the back of the guitar, as in, the pickup route will be quite literally a hole through the guitar body.

Solutions include making the body just thick enough for a pickup, but just in the area underneath the pickup. Think like the camera "bump" on a modern super thin smartphone. Or you could look at some ultra thin pickups, I think Lace Sensor make a super slim model.

I'm really interested to see this one come together! Following intently.

 - Jam

I dig it! Keen to see how the pickup mounting idea works, I investigated a similar idea a few years ago which didn't pan out, I'm sure you have much better ideas.

That inverted strat-jack is genius!

 - Jam

On 12/27/2023 at 9:17 PM, Bizman62 said:

That's the issue with long haired women, be they wives or dolls. Yesterday I had a strand of female floss in my salad. And pulling a hair from under your foreskin has to be done delicately...

Hahaha duuuude! 

On 12/28/2023 at 5:18 AM, woodfab said:

My wife hates Barbie.

Mine too! That's why she pulled all their heads off!

Right, so that WeldOn glue is pretty strong. After taking the clamps off, I couldn't twist or squeak the wings at all. They've formed a triangular box section, so geometrically they should be very sound. I routed the tops and backs to the exact profile of the sides, and while routing acrylic always sucks, it came out pretty good.

Now it's time for the finishing phase. This comprised of sanding all the exposed timber until it was glassy smooth, and staining it black. 

The stain seems to raise the grain a little, but I'm always reluctant to sand it again and risk going through. I tried something new - I burnished the wood with a scrap of MDF, and then with a rough rag. The maple ended up glassy smooth, once again. Now it's time for a few coats of Tung oil - well technically it's a product sold as "kitchen oil", and it's made for benchtops and cutting boards, but a look at the data sheet tells me it's basically just Tung oil.

I'm going to do a few coats of oil for sure, I think a matt finish wouldn't fit the aesthetic as well as satin towards gloss. 

 - Jam

https://docs.google.com/document/d/1MXq1XGZaBv-wqxqv53c0wFu2QgLKi2Kzzp5NUSPhdNA/edit?usp=sharing

https://www.projectguitar.com/forums/topic/55163-jam-winter-builds/

Here's a documented, day-by-day progress log of my last Tele-inspired build. The link for the forum post is underneath, includes two other builds in the same thread but mostly the same processes. 

Hope these help! 

 - Jam

I document all of my builds from start to finish, including times for processes and labour costs. Part of my quotation includes a full bill of materials. When I get on the PC later I'll post an example

I'm guessing you're talking about materials and parts, as opposed to order of procedure, labour times and tools required. Order of procedure really depends on the builder, people like to do things in different order. Labour times probably vary wildly - I'd bet I do my fretwork a lot slower than most professional luthiers!

 - Jam

The whole expanse of maple will be stained black eventually, so I did the sides of the core now, so I wouldn't have to much around with masking off the insides of the hollow wings at a later time.

Then I glued the backs and sides of the wings to the core. 

So there's three kinds of glue going on here. There's epoxy resin, which glues the back acrylic into the dado grooves in the maple core. I roughed up the acrylic with sandpaper so the epoxy would have something to grab onto. Then there's the Weldon glue which attaches the sides to the back. Apparently this glue has a working time of 5-6 minutes, which is total bullshit - it sets within a few minutes, but for a good bond you really want the pieces in the right spots right away. Then I'm using CA glue to hold these locating pins in place.

All of these photos look really messy. It's a combination of glue squeeze-out, the black stain bleeding, and hideous end grain scratches. All of these points will be nullified or rectified.

A little more about those locating pins. Getting the wings in the right places for the sides to line up properly... nightmare. Half a mil at the front of the "wing" could result in miles apart at the tip of the "wing". So I drilled some holes through the maple and acrylic clamped in the right spot and put some little black screws to hold them in place. However, this looked a bit unclean, so for the final glue-up I removed the screws and replaced them with 2mm aluminium tube. A drop of CA over the top and they're solid, providing a good mechanical joint as well as a clean aesthetic. They'll look great when it's all stained black.

There's a bit of overhang where the back acrylic overshoots the sides, and especially noticeable at the heel end. Once the glue has cured I'll route to profile with a bearing. I'm anticipating a fair bit of sanding drum action as well.

Tomorrow I need to fill the empty wings with their secret material - and no I am not flooding it with epoxy - and then glue the tops to the wings to close the box. I can foresee issues with glue squeeze out and messiness, as I need to slide the wings into place in their grooves. Wiring is also a problem. After filling the wings with their secret objects, how will I get pickup wires to the electronics cavity underneath the pickguard, or output wiring to the output jack? I have an idea, but we'll see how it goes.

2 hours ago, Bizman62 said:

Ahh, didn't realize until now that it's going to be hollow! Now I guess I understand the gluing problem better.

Is there going to be a straight piece of acrylic against the wooden body?

 

There's two problems with solid acrylic guitars - they sound like crap, because acrylic doesn't resonate very well, and they're heavy as hell! Making a hollow one with a timber core cancels both of those issues.... I hope!

Nope, no acrylic against the jointed face of the body, I'm relying entirely on a routed groove to hold the wings into the body. 

 - Jam

Had a right proper day in the shed.

Proper planning is key, especially when embarking into the unknown. These plans might even throw a little light upon the bigger picture here. 

Transferred the desired shape onto MDF and started making my mould. 

I cut one shape and transferred it onto six layers with the router. I banned MDF from my workshop some time ago, and will only bring it in when plywood just won't do. The mask will help my lungs, but this fluffy dust makes me all itchy. Horrible stuff. And the bandsaw hates it.

Next up, I cut the four pieces of acrylic for the tops and backs of the wings. Being that the mould will dictate the shape of the sides, I used it as a negative template. I cut all this acrylic on the bandsaw - poor machine has had the worst materials today. I'm going to have to buy my bandsaw a drink.

Used a fence on the bandsaw (poor machine) to cut strips of acrylic at exactly 32mm wide for the sides. I clamped them together and sanded the blade marks out, and measured them to be straight and true at the right width. Any deviations could introduce gaps when gluing up.

Bending! Okay, this is kind of like bending sides for an acoustic guitar, except that it's a damned sight easier. Acrylic is a homogenous material and doesn't crack or split, but it can warp and distort in planes other than the desired ones. I used a hot-air gun, affectionately known as "The Hag".

This here is just a test piece. See how the curve pulls the plastic into a concave shape? The mould helps with this, but doesn't alleviate it completely. More of note is the corresponding "bump" in the top and bottom faces, which will create gaps when gluing up with the top and back. Easily solved with sanding on a flat surface, though.

Pr

I did a few tests, then got down to bending the actual sides. Seen here is my clamping system - one pulls the interior of the mould towards the tip of the wing, and another holds it true against the long edge. To avoid any spring-back on the workpiece, I left it in there for long enough to cool down to room temperature.

Here we go - I've successfully made two triangular boxes. 

Quick mock-up. The rear end of the maple isn't shaped to it's final dimensions yet - I realised I would have to do that after installing the wings so as to get the correct angle following through from the acrylic wings into the maple.

One last job for the day was cutting a chamfer into the sides so that they marry neatly to the core.

Anyways, my shed is covered in acrylic shavings and MDF-fluff. Can I just move house and start another workshop?

 - Jam