Apr 21

Neoplastic fun

A while ago, Stewart Furini was playing around with colouring a wooden bowl in a neoplastic fashion (think Mondrain) using paints and stains. It looked like fun so I thought I’d give it a try.

Turns out, it’s a little harder than it looks. I started with a miniature bowl blank because it was the first thing to hand.

Very simple shape (the idea was to part off at that thin line about an inch in from the chuck jaws so the proportions of the final cup wouldn’t be horrible). The colouring should be simple – airbrush with the lightest colour, then mask off squares with masking tape and airbrush successively darker hues and finish off with black lines on top (you’d do it the other way round with paints, in the same way that the order you paint with oils is the opposite order to that for watercolours). And obviously, because we’re not limited to the three primary colours this isn’t really neoplasticism, but roll with it, I’m just having fun πŸ™‚

Two quick problems – firstly on such a small piece the curvature on the surface is fairly tight and you might not know this but 2D geometry on a curved surface is non-euclidean (eg. the three angles in a triangle on such a surface do not add up to 180Β° but to more than that) – which means that masking off perfect squares gets a little weird when the square is large compared to the radius of curvature. But okay, I can just squint and ignore that.

The second problem was a doozy. Turns out, masking off spirit stain on a surface with cheap lidl masking tape is a non-runner. Does not work at all, and the darker stains for some reason show that up the most.

Bleuch. But I had some fancy frog tape, which is supposed to be the best thing ever for masking for painting.

Nope. Still no dice. I actually gave up on this blank at this point and just sprayed it with ebonising lacuqer and thought I’d just make a little cup from it with the red/black urushi colouring scheme and come back to the neoplastic colouring later on.

Yikes. Good news is, the faceplate still works. I still haven’t found the missing third of the piece though, it rattled off my head and went flying somewhere in the shed and has resisted attempts to be found since.

So if the small piece bounces off your head, the first thing to do is try again with something much heavier πŸ˜€

And this time I had much better luck, because I gave up on the tapes designed for masking when painting houses and switched instead to tape designed for masking when doing small scale modelling (you know, airfix kits and the like). Meet Tamiya tape:

Stocked in any model making shop near you. I couldn’t recommend it for housepainting unless you’re a millionaire, but for this sort of thing, it’s just astonishingly good.

Unfortunately, it isn’t perfect and there are things you have to do when using it.

So first off, whatever was in the black chestnut spirit stain, it just ignores tape entirely. No matter the tape, no matter how I burnished it, it wasn’t staying in its lane for anything. So I just didn’t use it after this (I turned off the surface on this bowl about four times trying to get it right).

Also, if you’re masking off a square with the tape, you’ll have vertical sides and horizontal sides and one of those is going to be going down over the other. You have to burnish both sides heavily, but you have to pay special attention to the point where the top layer of tape meets the bottom layer of paint. You have to burnish that like it owed you money, because if you don’t, you leave a very small gap where the horizontal line meets the vertical line and the tape has to rise up off the wood to layer over the vertical line’s tape; and the spirit stain will wick into that gap through capillary action and spread waaaaay further than it has any right to and you’ll have to turn off the surface of the bowl and start over again.

And do I even need to mention that you have to airbrush from a ways back, use light coats and take time to build up the colour you want because if you get too close to the surface the air will blow the stain into any little gap to get out from the tape otherwise?

However, with enough time spent burnishing, and some care airbrushing you can get nice results.

It’s still not perfect, but I like the effect. I might come back and use it for something else in the future. I also liked the simple shape and the foot that I got on this bowl, I must try to do that again but better.

Dec 20

Well, poop.

Was bound to happen sooner or later I guess.

So I was mucking around experimenting with some colouring on spalted beech:

Just picked a funny shape because I was experimenting with that as well. Then some yellow stain…

And then some royal blue…

Hm. Potential but maybe not. Sand it all off…

BTW, that’s why I picked this blank – that black line isn’t spalting, it’s a crack. Not sure if this would survive hollowing, so it’s a learning blank πŸ˜€

Now, purple…

Eh. Not quite. I mean, it’s okay, but I’d want it lighter. Maybe some gold embellishing wax (or buff-it, since that’s all I had to hand)…

I dunno. I don’t like it much. Too dark. If I’m going to colour wood, I want it to look brighter than that. Personal taste I guess, I always preferred lighter-coloured woods even without staining.

So, next day, I turned all the colour off and made it into a simpler shape, and laid down a few coats of royal blue and a little white to lift it and even a touch of yellow to give it some hue variation.

Still not wild about it, but it’s not terrible. So I hollowed it out and then took the round-nosed scraper to remove the worst of the toolmarks from the bowl gouge and the hollower…

…and I removed the bottom of the bowl as well as the tool marks. Structural toolmarks? Oh well. I guess I had to join the funnel club sooner or later, and at least it was a learning block πŸ˜€

Oct 20


So there’s a podcast I listen to here in Ireland called TortoiseShack (I guess they’re more a channel than a single podcast these days, they’ve spun up dedicated special-interest podcasts), which has a lot of voices we don’t get to hear on RTE much. Longer chats with data protection experts like Simon McGarr (which is how I got interested in them), talks on green politics with people who know why you can’t have a forest of walnut trees, discussions on the homeless crisis with Peter McVerry, that sort of thing.

I’ve been throwing the price of a cup of coffee at them for a while now on patreon, but I was reading how one of the two guys who does the podcast is running 2,020 miles this year for charity (he finishes next week) and I had the idea to make them a desk ornament because if you look at their logo, it’s almost like it was designed to be made as small bits on the lathe and joined together:

I figured, the head is just an egg, the legs and neck are just slightly curved cylinders, the tail is just a cone, and the top and bottom shells are just unhollowed bowls. Sure, there are tenons and mortices and the neck hole of the top shell might need a holesaw but I have those, and maybe that angle at the front would be a cut on the bandsaw with the table at an angle, but all that’s doable. So over the last week I did it.

First five minutes went well, I missed a flaw in a bowl blank because it was painted over (what idiot thought that was a good idea?) and it bounced off my faceplate (remember, Norm was right). But the rest of the turning was easy enough, and I put a small tenon on the back of the bowl where the woodscrew was holding it (and a little undercut) for reasons that show up later.

Nice grain pattern really. Wish I had brown stain to match the logo better but oh well. You can see the lower shell on the lathe there in the top left as well, the yellow stain isn’t very evident there though. I think I’d have needed to go full-on Furini with an airbrush to get colours that matched the logo though, so I’m settling for just evoking it rather than replicating it πŸ˜€ I’m also skipping the plates for the same reason – I could dremel them out but the design on the 2D logo doesn’t actually translate to 3D well when you try to figure out what the shell would look like from the top, so I’ll leave that bit out so long as it’s still recognisable at the end.

There’s a tenon on each piece here which is why the gap between shells is so large. Next up, the head, neck, legs and tail…

The green stain looks a lot nicer here, but it doesn’t stay that pronounced through sanding alas – here I’d stopped sanding at 120 hoping to get deep penetration of the stain, leave it overnight then hit it with sanding sealer when the stain was fully dry and sand to 320. This didn’t work – the sanding acted like the stain was still fresh and a lot of it came off. But that aside, this part went quickly – I did the head and legs over one lunch hour and the tail and neck in an hour that evening (the legs all came from one blank I’d made to make a toolhandle from but I wasn’t using it, so they were very fast to get to this stage).

Yes, I know. Go on, laugh away, get it out of your system…

That’s everything drying at the end of the first day. Everything from here is just fiddling and fettling really.

Right so we need tenons and mortices. The legs, neck and tail have tenons already, and to drill the mortices I have this new famag 1″ forstner bit and a drill πŸ˜€

The neck and head were easy enough, and the mortices for the legs go in the underneath of the shell. At which point I discovered one of the tenons was not like the others…

Whoops. Much smaller, way too loose. No way glue’s going to cover over that much of a gap, there’s a good 1-2mm on either side between tenon and mortice. So…. grab one of the other bits of spindle blank I’d made up and the #04…

Make a few shavings, moderately thick…

…wrap the tenon and glue the shaving in place…

Not perfect, and if I was less lazy I’d remake the part, but it’ll fit and hold now.

There was also a lot of fiddling with scribing the shoulders of the tenon to the surface of the shell, which was curved and of course the mortices are angled as well so that was fun. Hold a pencil flat on the surface, scribe against the leg, trim to that line with a chisel and undercut as well, then check the fit and fettle as needed. Fiddly, but not complicated.

And with that done, it was time to cut the neck hole in the top shell. Pillar drill, hole saw from lidl, janky-as-anything workholding setup with the shell propped up on a block at an angle and away I went, expecting it to all go horribly wrong at any moment. And it kinda did, I had to stop half-way through and use a chisel to knock off some waste because the saw was bottoming out on the top of the shell. And the second time I just took it out of the pillar drill and tried to finish the cut with the fretsaw by hand but couldn’t, so I put the holesaw in the handdrill and used the kerf of the cut so far to guide the last inch of the cut, knocking out more waste with a chisel as I went. Messy and janky and there’s about six better ways to do it that I don’t know of, but it worked and a quick cut on the bandsaw with a tilted table later and the top shell was done.

The mortice for the tail was cut by hand with a smaller holesaw (as the tail’s tenon was also too small and I figured I’d save myself another shaving trick).

Right, now I just need to turn that tenon off and make it a shallow mortice to match the lower shell’s tenon and….

oh. Shite. What do I hold the sodding thing by? There’s no tenon on the back. Well. Feck. Off I ran to youtube looking for a thing I’d seen last month that I thought couldn’t possibly work, and figured I’d take a chance.

Took a small scrap block, pinned it up against the closed chuck with the tailstock, turned it roundish, put a tenon on it, reversed it and grabbed the tenon in the chuck, faced it off, made the face concave and chamfered the face’s edge, and viola:

Glue block. You think you’re nervous now, just you wait. Put the shell into the concavity, and line it up by eye and pin it with the tailstock…

That looks very janky, how are we gluing that asymmetric unbalanced load… why are you reaching for the hot-melt glue gun?

You’re shitting me.

Oh, seriously, there is no way this works. I’m going to lose teeth doing this.


Wtf? It worked? I lived? A thing on youtube worked? What the hell…

And painting the glue line with isopropanol (or meths if you have none) gets the glue to let go a minute or three later with no surface damage. This is witchcraft.

But now I can glue up, and here you see why the wormscrews were good – the hole left behind fits a small dowel for alignment. Had to trim the tail to get a good fit but…

And now we let the glue dry. Shims are in place to keep the gap on the shell even, and the shim under the leg is because one of the legs in the logo is in the air as the tortoise is trotting. Yes, it’s a back leg in the logo. Glue-ups are hectic, okay, mixing up front and back is just a thing that can happen…

And there we go. I’ve done some pre-finishing here. The various parts have all been sanded to 320 by this point, and treated with yorkshire grit, yorkshire grit microfine and a bit of hampshire sheen, but I then put the buffing wheels on the lathe and ran up through the wheels with them to get to this level. I branded my mark into the bottom shell and sprayed with melamine lacquer and gave that overnight to cure, then cut back with 0000 steel wool the next lunchtime. For eyes, I took some googley eyes from the case of them I have here (what? don’t you have a box of googley eyes? why on earth not?) and just used the pupils. Attached with superglue, then point the heatgun at them for a minute until they soften and then mould them to the curved surface of the face. Let it all cool, give it another coat of melamine, let that cure off and then give the shell a final coat of microcrystalline wax and hand buff to a shine.

It’s not too bad I think.

I can even see it helping out with fundraising for the podcast…

“The tortoiseshack lays on its back, its belly baking in the hot sun, beating its legs trying to turn itself over but it can’t. Not without your help. But you’re not subscribing on patreon. Why is that Leon?”

‘course, now I have to make a second one for Calum. At least now I know one or two things to not do for the next one…