The latest installment of my progress on the set of loudspeakers for my bro: Woodwork on the cabinets has been completed! I used woodglue and screwed rectangular 3/4″ strips to the inner edges to hold it all together. Tip for the speaker builder: when putting screws into MDF, always drill a pilot hole beforehand, because MDF really does not want to accept any screws. Also, when screwing into the unfinished ‘side’ of the MDF (as opposed to the finished face), be careful to stop once the screw gets as far in as it needs to go. Continuing until the screwhead contacts the wood will split the wood, as MDF is simply made of many composited layers. These layers can easily be split apart from the side.
As I was putting it together, I used silicone sealant to cover up all seams on the inside. My previous designs used caulk instead. I think I like the silicone a little bit better. It seems to ‘flow’ more and it’s easier to move around versus caulk. Although it does have a nasty odor… which probably promotes the growth of new, more powerful brain cells, I’m sure. Still, it’s supposed to be more resistant to cracking than caulk, and if these suckers are going to be pumping out jams for at least a decade to come, longevity is good.
Last weekend I got outside with my router and a dustmask to try out my roundover bit and smooth off the edges. I used a belt sander to get rid of any imperfections in how well the boards lined up (some of the edges stuck out, maybe 1/16″ or so), and then I used wood putty to try to fill up any seams that were left open. I used a half inch roundover bit to curve the edges, which worked well. Since the MDF thickness was 3/4″ I thought about going out and getting a 1″ bit, which might’ve helped camoflage the joints (in theory?), but the close proximity of the woofer hole to the edge nixed that idea. Just one little juncture in this art of compromises.
I’m very pleased with the roundover bit. I first tested out on a spare piece of plywood and it cuts a very smooth curve which is pleasing to the hand. Something tells me this sucker is going to get some use in future projects… These routering and sanding steps were probably the nastiest part of the whole process. When you use either of these tools on MDF, it emits a large amount of superfine dust that gets everywhere. It’s a serious mess. I used a mask to stop myself from breathing it, and did my work in the driveway with the garage door closed. When I came inside, I immediately put my clothes in the washer and took a shower to get it out of my arm hair, my eyebrows… everywhere. MDF, while an ideal material for loudspeakers, is a pain to work with. Oak might be a better choice, if you’re open to spending a little more money.
That evening I put on an initial coat of paint. White primer. That’ll prepare the surface to accept whatever tone he chooses (update: emerald GREEN!). I could veneer them, but eh… my main speakers have veneer and I’ve seen over the last decade how easily it peels back as it ages and chips off. Maybe I didn’t do the best possible job applying it, but still. I think paint and some kind of sealant (still deciding) should produce a more resiliant finish that will stand the test of time. I doubt I’d ever use veneer again, after moving these monsterous mains many times. (It’s really moving when they’re susceptible to damage. And they WILL get damaged, no matter how careful you think you are being).
Stay tuned for updates. The next time you see these, they will be a vibrant emerald green…