Shiver me timbers . . .

Excruciatingly long layups (six hours per), but a pretty simple chapter. Make a rectangular box out of foam, put a kink in it, sand two troughs...

3-Jul-08
I made the spar jig out of "everyone's favorite", 3/4" MDF. Dado'd the back piece for the 'table', and the 'tables' for the support legs. Everything screws together, maybe someone in the area can use it when I'm done with it. I used my trim router with a piloted flush cut bit to trim CS1 to the width of the jig.

CS2 and CS3 were sanded to final dimensions as a pair, sand a bit proud of the jig, then balance a level on the sanding block and sand to the top of the jig. Since I cut the foam blanks on the table saw, the bottom edges were very square. I didn't use the 'sticks' mentioned in the plans.

I sanded the relief areas at the end of CS2 and CS3 with the sanding block. Nail 0.7" (or 0.3") shims on the table, and sand to it. Finish sand to a pleasing shape.

6-Jul-08
Nothing exciting on the interior layup's. Slurry, micro the corners, add glass, pour on the epoxy, squeegee. The glass on the sidewalls will tend to flop in, slap some epoxy on the walls and plaster the glass back on. I did run into a bit of a snag with the interior bulkheads though, I pre-cut them a bit loose. SInce the interior layup is done in one session, it might have been better if I made the bulkheads a bit tighter, then used a clamp between the jig and CS3 to hold them in position as I glassed both sides of the bulkheads.

Locations for the alodined interior wing attach hardpoints were pre-marked on the foam. Keep in mind they're measured on the BL. Extra length BID and three ply UNI at these hardpoints was done just as the epoxy was starting to set. Micro (why micro instead of flox is beyond me) these hardpoints in position, a bit of micro around the edges, add peel ply and some poly, a board across the hardpoints, then weight for cure.

Glassed one side of the precut CS4 front cover pieces, peel plied the edges, applied the three pieces to the spar box with micro when cured. Don't ooger a pile of micro along the outside corner/edge, this corner will get cut off later.

Cutting the spar cap troughs was a non event. Made a small sanding block three inches wide, nailed a strip of plywood on one edge to follow CS1 or CS4 depending. You can see it in the background in the third picture. Sand down until this jig hits the H-100 foam. You did remember to acurately slice the thin strip off per the plans didn't you? Basically the depth of this strip sets the spar cap trough depth. Note the spar curves/tapers on the outboard top side, and therefore the spar cap trough and outside edge will too.

11-Jul-08
Next step is to embed the LWA4 and LWA5 slugs into CS1. For kicks I used an old (but expensive at the time) 'stud' finder to find the edges of the interior slugs. I was a bit surprised when the meter picked up the edges of the interior UNI reinforcements :) That done, four crossing plies of UNI over the aft side, around the corner (radius it with the router first), and up to the spar cap ledge.

15-Jul-08
Epoxy from Wicks and spar tape from ACS arrived, so here we go. I Bondo'd the dams on, then ran a real fine bead of medium wet flox next to the dam to prevent any epoxy from oozing down the side of the spar. Popcicle stick and blunt end of a wood match worked to pack the flox into the corner. I pre-cut just the full lengths of the spar tape, set them off to the side. Made a 'toothed' squeegee by notching a vinyl squeegee with a pair of dikes. Make it about 2.75" wide, and make sure the cut edges are smooth so it doesn't grab the filaments making a total mess as you comb through each layer.

I hung the roll of spar tape on an old broom stick, which was clamped to the front rails of my six foot step ladder. Tip: Set the roll up so the colored 'release' strand is away from you. Makes pulling the cross threads much easier.

I did the bottom spar cap first, I think the plans say top first, the bottom has fewer plies just in case everything started to set up early. It didn't.

My trough measurements were off, the spar tape was thinner than advertised, or I squeeged real good. Both sides took two full length plies over what plans called for. Tip: order plenty of spar tape.

Two day cure, strip the dams off, and sand any remaining Bondo off. A couple of high spots on the spar caps were smoothed by hand with the block sander.

Top trough was easy. Nothing to see here, move along...

I made a small jig out of two small scraps of MDF to sand the 1" x 1/2" bevel (30°). Stick the sandpaper on one face with Scotch 77, sand away. The H-100 front face didn't seem to mind being used as a guide for the sanding block.

Layout and notch the urethane and sliver of H-100 for the shoulder harness hardpoints, micro in. An Xacto knife and 3/4" chisel worked fine for me. Hit them with the sander jig, mentioned above, once cured.

Move the spar off your build table for the last four ply UNI shear web layup, unless you have a narrow table with access to the other side for layups. Regardless, you'll need to elevate the spar off your work surface slightly. I used a couple of paint cans set on overturned 5 gallon pails on the floor. Precut the UNI to width, I needed 10 strips with an eleventh 'just in case'. I also sprinkled a liberal amount of planer shavings on the floor to catch epoxy drips. Don't forget the LWA hardpoints!

25-Jul-08
I made a template out of MDF to cut the access holes on the front face. Four boards about 4" wide. Cut two exactly 5", the other two longer than 18". Glue them up flat to make a rectangle with a 5" x 13" (4 1/2" x 13" in my case) inside opening. Rough cut the spar opening with a 1/4" straight router bit and a 13/16" guide bushing in your router. Follow up with a 1" top bearing pattern bit to get a 'pleasing' radius in the corners. Lastly, remove the template and use a piloted rabbiting bit to get a nice and uniform 3/8" rabbit for the glass/glass bond. I should have enough room on the flange for nut plates, in case I want to make decorative covers to befuddle the DEA/TSA/FBI/ATF/MOM. Sand a bevel on the square edge of the foam for a smooth glass transition. Two crossing UNI plies, lapping onto the 30° bevel.

The last step is a bit anticlimactic, cut a 2" hole near the ends for outer wing bolt access; flox corners on the end bulkheads, cover with one ply BID covering. Hanging from the ceiling (the spar!) you can pick out the Bass Monster speaker cutout and the outer wing attach access hole.

Comments
Remove the tape you applied to protect the urethane foam just after you finish the spar cap layup's, don't wait till cure.
Consider making a rabbit or flange for the outer wing attach bolt access hole. As in make a shallow recess 2.25 in diameter, and the through hole at 2". This will allow for a recessed cover at the finishing stage.