This box took me longer to make than I had hoped. Double-sided boxes are something I've been having trouble getting dialed in, likewise partitions have been proving tricky. My first attempt actually didn't quite go together right, and the box glued up wonky. So I went back and modified my code, double-checking pretty much every aspect of the sizing and tolerances. I also changed my workflow to focus on accuracy (at the cost of a great deal of speed; this box took many hours to mill).
Previously I've been using a 3mm compression bit, and cutting through the entire stock in one pass. This is very fast, but I was getting deflection. So this time I tried a 1.5mm bit (single-flute downcut as that's what I had) and use multiple very shallow passes; this gave me much better dimensional accuracy (and also meant I could use dogbones without them being nearly as noticeable), but took much, much longer. I also broke the 1.5mm bit, but that turned out to be because a connector for my spindle power cable was crap; it's one a few years old but the plastic had become brittle and the retaining tabs had snapped off. I noticed this and taped the connector ends together, but the tape apparently decided it couldn't be bothered to do its job and just kind peeled off partway through a cut, leaving the machine trying to drag a non-spinning bit through the plywood.
Speaking of the plywood, I'm not too happy with the quality. Lots of voids in the middle, and it all splinters very easily, the box finish getting damaged during assembly and sanding (in a way that feels like it shouldn't be happening). This was especially true of the box lid "runners", the tongues and grooves that hold the box lids in place. So to try to reinforce them, I added varnish first, before sanding to fit. I actually tried to apply the varnish and then put them in a vacuum pot to draw the varnish deeper into the wood, but I don't think that did anything. Regardless, I think the varnish helped to reduce the damage to the tongues and grooves when making the second box.
I wasn't too happy with some of my other materials either. My old wood glue had turned weird and yellow, so I threw it out and bought some new wood glue from the local hardware store, but this stuff... feels different. It's labelled HP Gold Synthetic Resin Adhesive, and it doesn't feel like the PVA wood glues I'm used to; it doesn't spread very well for example. It worked, but the difficulty I was having spreading it might have been compounding the issues I've been having with box glue-up.
You see, applying glue to the correct places on all the sides and partitions was taking so long that the glue would start to harden before I was done, and pieces would end up setting slightly out of place. So for my second attempt I tried applying glue to just two pieces at a time, then quickly assembling the box parts and applying pressure so that the two pieces would set in the correct positions. Once they were set I would take everything apart, apply glue to two more pieces, and repeat the process. This again took a long time, but I feel it worked better. I do need a better clamping solution though; my clamps are too big, elastic bands actually work better than clamps for smaller boxes but the ones I have are too small for this box.
I did think the resin inlays worked much better this time than in my last attempts. I applied a very generous coating of Coprabel's Easy Color wood stain varnish in Palissander 506. It's the varnish I used for my previous game box; I hoped the very dark colour would create a sort of blackline around the actual resin. After giving this a day to set, I applied a clear varnish (National Protective Coatings synthetic varnish clear) to the entire top of the lid. This was to avoid the issue I had with the previous box, where sanding the resin inlay flat created a coloured dust that settled into the wood top and refused to come out, leaving it looking slightly pink. I also wanted to wet-sand the resin as I've found it to be MUCH nicer than dry sanding (at least for resin), and hoped the varnish would protect the wood from the water.
When all the varnish was dry I applied the resin. I used gold Art Nation mica powder in ResinVentures Art Resin. The Art Resin has proven to be very vulnerable to yellowing, but I didn't feel that mattered in this case, and the mica powder worked much better than my previous attempts at using dyes or GSW metal powders. Being able to use a vacuum chamber (a relatively recent aquisition) to reduce the amount of bubbles in the resin also helped. Of course I passed a heat gun over the surface to pop the rest of the bubbles too; I think this also helped create a more organic looking pattern in the resin.
After giving the resin three days to fully set, I tried sanding the inlay using wet/dry sandpaper in a 3D-printed sanding block. While most of the clear varnish actually got sanded off the wood, and a fair bit of water soaking into the unvarnished wood on the other side, overall it still mostly worked out OK; I didn't notice any real warping of the wood or discolouration from the resin powder. The dark outline came out very nicely too, I'm quite happy with that. I did a quick polishing pass with a Dremel tool and Dremel polishing kit/compound. This did make deepen the gold colour a bit, but the wet sanding had already given the resin quite a nice smooth surface so the polishing wasn't too important in this case (I think I used a rather finer grit of sandpaper than I needed to for the initial sanding).
With the box assembled I started the final sanding (dry) to smooth everything out. Once this was done I coated the outside of the box with the clear varnish (applied by brush) and left it for a couple of days. This varnish was not very even; some areas felt very smooth, while others had a rough wooden feel. They actually felt rougher than they had after sanding, as if the varnish had lifted the wood fibres. So I applied another coat, then after giving that a couple of days to dry gave the whole box a very wet sanding. This evened out the surface a bit and actually gave it back a bit of the textured wooden feel, which I was happy about. However in some areas, where I felt the need to sand a bit more heavily as there were some thicker spots of varnish on the surface, I ran into some issues where the varnish didn't sand very well; it almost seemed to gloop up like an almost-dry PVA glue. Perhaps the water, and heat from the friction of sanding, was affecting it?
There were also some spots where the varnish didn't soak into the wood properly, perhaps because of my clumsy use of the wood glue earlier. These spots show up as pale spots and look pretty bad. Overall the final finish is not great, I actually think my previous box came out looking and feeling a bit better. The stained Coprabel varnish was much more expensive than the clear National "synthetic" varnish, so material quality might be a factor. I also dry-sanded that one much more heavily compared to the light wet-sanding I gave this box (to try to get rid of the excessive staining), creating an aged look and a more natural raw wood feel than the varnished look and feel of the new box.
Oh well, maybe the next one will be better. I want to try working with solid wood rather than plywood; I'm also hoping to eventually try using stabilized wood, which should be stronger and not require varnish. Fingers crossed.
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