Kevin lives! Well, almost.
I had solid weekend in the shop working to finish the enclosures. First thing to tackle was the foam. In hindsight I should have simply stuffed them but the material was already purchased and I wanted to get moving. I ended up using 3 full queen mattress toppers. A ton of measure, cut, spray glue, watch the foam fall off, then staple. I really like the 3M spray adhesive but it’s not so great when you have to spray the foam and not the wood. The foam absorbs the glue and it dries very quickly.
Next step, the face. These are massive drivers so I’ve elected to go with two 3/4” sheets. The first cutout supports the lip and the second cutout adds depth to come closer to flush with the driver.
Cutting a precise circle is pretty easy with a router and jig. I’ll run through the process for those interested. Using any spare sheet material, grab a piece longer than the radius of the circle you’re cutting and about 3” wide. I like 3/4” material for increased stability. At the end of the strip cut a circle roughly the size of the base of your router. You end up with something like this.
The router base likely has a removable plate attached by a couple of screws. Remove the plate and use the mounting holes to attach it to the jig. You’ll likely need longer screws than those that come with the base due to the thickness of the jig. Drill out holes the same diameter of the screws. Because the head of the screw will be on the underside, they’ll have to be recessed. Drill out the holes using a bit the diameter of the screw head, stopping when the depth of the hole is enough to bury the screw head - don’t go all the way through. Forsner bits work really well for this. Then drill a hole through the center of the jig to accommodate the router bit.
All set. Measure from the outside of the bit, the radius that you need and use a screw as the pivot point.
Here are a few tips that I’ve learned over the years.
1.) When cutting MDF, DUST COLLECTION!!! This stuff spews fine dust like nobody’s business. Keep a vacuum hose at the bit of the router while you cut as well. This will keep it out of the air but will also make it easier for the bit to rip through the wood.
2.) Use a sacrificial piece under the sheet that you’re cutting and attach both the sacrificial and good piece to the bench. I use a sacrificial piece roughly the size of the work piece and attach them both to the bench with clamps. Then attach the router jig to both the work and sacrificial piece. The reason for this is two fold; first if the work piece is elevated off the bench then the dust has an easy exit and it’s very difficult to collect it. Second, if you’re not mounting the jig to something other than the work piece, when the circle being cut let’s go the jig is now free to move and it will gouge the work piece.
3.) Take it slow. Don’t jam the router through the full width of the board and expect a smooth finish. 3/4” MDF can take 3 or 4 passes with small incremental depths.
The first sheet
And the second
To finish the face off the foam was added. Dropped in place, the large opening made it easy to reach in and trace out the location of the bracing to remove the foam.
And the test mount!
Still some work to do; flush trimming and round over of the edges, cutting out the port openings and of course paint but we’re getting closer.