Chapter Log

Step 0 - Materials
Status: Completed 
Est Time: 26.00, Actual: 0.00
Est Cost: $ 500.00, Actual: $ 1753.82
Date Completed: 00/00/0000

The plans call for the following materials for this chapter:

• 14 MS24694-S54 Screws 24 yds BID RA5277
• 15 yds UNI RA5177
• 2 gals MGS-335 epoxy
• 2 qts MGS-335-fast hardener
• 2 qts MGS-335-slow hardener
• 1 pc. 1" x 12" x 12" urethane
• 2 sheets 0.75" x 24" x 48" H45 PVC foam
• 1 sheet 0.25" x 36" x 39" H100 PVC foam
• 4 sheets 0.2" x 12" x 48" 18 lb. Last-A-Foam
• 1 pc. 0.25" x 24" x 48" birch plywood
• 1 pc. 0.25" x 2" x 4" 2024-T3 aluminum
• 1 gallon cotton Flox
• 1 gallon glass microspheres

Step 1 - Front Seatback
Status: Completed 
Est Time: 0.00, Actual: 4.50
Est Cost: $ 0.00, Actual: $ 0.00
Date Completed: 01/27/2004

When I bonded two pieces to make a large enough sheet of form for the seatback, I didn't do as good of a jointing job as I should have. While one side has a perfect joint, the other had a bit of a crack. I filled this with micro when I micro'd the rest of the piece. It took some experimentation to figure out how much micro I needed for the whole step - I ended up mixing three cups by the time I was done because I kept being too cautious with trying to avoid large batches and exotherms.

Moving on, I also screwed up when I did the actual fabric layups. I'm trying to figure out a good ratio of Fast to Slow hardeners and don't yet have the experience to know what ratio is ideal for different work sizes and types. I kept mixing batches that were too small, and by the time I got to the peel ply step my last batch literally exothermed in my hand. That's a fun learning experience: "Hey, honey, why is my glove smoking?" "Because it's melting, dear." It was actually a small batch, but I didn't need nearly what I thought I needed - I was just touching up a few resin-starved areas with a brush, and didn't get it out of the cup quickly enough.

I ended up taking off the peel ply at knife trim to see what happened, and I'm glad I did. I had a roughly 2" long ridge where the fabric had formed a large air bubble under the peel ply. Earlier, I had to stop wetting out the peel ply halfway through when my last batch of epoxy started exotherming in my hand and the rest of the epoxy was setting up. The peel ply had lifted the fabric right off the foam in this spot.

Fortunately, this is the only spot I think I have to fix. There are still more of the tiny bubbles present than I would like, but not an unacceptable amount for quality control purposes. There are also some small (0.75" dia) air bubbles on the back (BID) side, but they are in the overlap area PAST the 1" margin (I overlapped more than I needed). None of these should significantly affect the structural integrity of the piece.

You can see the ridge roughly in the center of the picture below. The unevenness of the surface coloration is from the micro, not the epoxy - I didn't get my coat quite even and some of it was curing as I mixed new batches (see above). I don't think this is an issue - I tried to delaminate each edge and couldn't, and this is the only thing I can think of that could be a problem.

I AM however happy with my edging job. I do a lot of woodworking veneer work and got my edges "just right". Of course, almost none of these edges will actually be visible in the finished project, but what the hey, some pride in one's workmanship is important, no?

Step 2 - Forward Bulkheads
Status: Completed 
Est Time: 0.00, Actual: 10.50
Est Cost: $ 0.00, Actual: $ 0.00
Date Completed: 02/16/2004

I ran into a bit of trouble edge-joining the Last-A-Foam for F22 because the 5-minute epoxy dried faster than I worked. I ended up with a slight joggle (1/32") but I was able to sand and micro to correct it. In the future, I will make large joins with MGS-285 and Fast hardener, despite the wait this involves for working cure. I'm just a methodical worker and I like to take each step slowly. Another builder suggested a sandwich bag with the corner cut off, which certainly helps make a clean bead.

Cutting the rest of the pieces was straightforward. I traced OUTSIDE the line on the plans, then rough cut TO the line with a Dremel and straight cutting bit. I then used sandpaper on a block (or on my fingers, for inside curves) to remove the traced line, and was left with a perfect match. (Old veneering technique.) It took about an hour, which was faster than I expected.

The layup went fine, now that I've learned to use only slow hardener for this step. I made way too much micro, even after reducing the amount to allow for the fact that this foam is dense, and doesn't require much. I also am improving my technique at cutting fabric the right way - I kept forgetting which way to lay it out when unrolling. Cutting it into actual rectangles helps! (I used to leave the triangles and cut them off later.)

Everybody seems to have their own option for weights to keep layups like this flat. Since I am nearly finished drywalling my office, I have a lot of end pieces. Drywall is heavy - 60-80 lbs per sheet, depending on how thick it is - and I have enough ends to put about 160 lbs of weight on a single layup, which is more than enough to keep it flat on the table. I couldn't figure out a way to weight down the bevels on the F22 doubler, but I don't think it's important - there's enough local pressure right around the bevels to hold them flat.

It took 4.5 hours just to get to this point. It's amazing how much time and work can be described in two paragraphs.

I peel-plied everything and now actually regret this decision. First, I had an issue with epoxy-starved (sharkskin) surfaces in some earlier work so I overcorrected. Now there was so much epoxy that in combination with the weight, it squeezed out through the peel ply and against the plastic I used under the weights. It's just thick enough that I couldn't get all the peel ply off! Second, I'll need to do some cutting and sanding work to trim the overhang from the F22 doubler, because this fabric hung down enough to contact, and join with, F22 itself. The peel ply hid this from view until it was too late to correct except by lots of sanding.

I'm not entirely unhappy, though - this is a complex layup that went fairly well, overall. Sanding the peel ply layer off sucked, so I broke out the random orbit sander and a finer grit of sandpaper, and was suddenly much happier - I got the peel ply layer off with NO damage to the layer below it. This piece is probably too epoxy-heavy, but I'm not making one piece over to save a few ounces. I'll learn and move on. And the back side, which I thought would be much harder because of all of its layers, went by very quickly - three hours. I had to glass F28 separately because it was too late to do both at once, but all went well, otherwise.

Areas for improvement:

1. When cutting cloth, especially BID, lay it out on a separate work surface in the way it will be put down on the foam. This makes it easy to keep track of multi-layer layups.
2. Cut the peel ply at the same time as the cloth. I keep forgetting to do this.
3. Find a cheaper source for peel ply. I spent about $20 on a bunch of it and it's not lasting as long as I'd hoped. It would be nice to cut this cost in half.
4. Throwaway paintbrushes are GREAT tools. I no longer use a squeegee except on large layups. You can spread out reasonable amounts of epoxy (instead of pouring it on), stipple, AND squeegee excess epoxy to the edges all with the same tool. Now, I only use a squeegee for micro and on top of plastic when using peel ply. This also greatly reduces cleanup.
5. Make smaller joins when edge-joining foam, or use MGS instead of the 5-minute epoxy.

Update: Still working on this. I can't afford the Fein yet and I'm regretting it. I missed knife-trim on the back side, and cutting through all of these layers with a coping saw is a bear. I've trimmed most of it, but I'm moving on to the next step and coming back here to trim the pieces when I can afford the Fein.

Step 3 - Instrument Panel
Status: Completed 
Est Time: 0.00, Actual: 16.00
Est Cost: $ 0.00, Actual: $ 0.00
Date Completed: 03/22/2004

I got a little too fast in a few spots while cutting the various holes and ended up with a few small gouges, but nothing that can't be fixed. Both layups went fairly well, and I'm learning to conserve BID by cutting just what is needed and overlapping segments, rather than cutting enormous sheets that have a lot of waste hanging off the diagonal edges and internal spaces. Nobody will see the bumps on the back, and I'll almost certainly use an aluminum or wood overlay on the front. The bumps aren't that big anyway.

I made a mistake but it wasn't related to this step. Because I spend a lot of time doing layup preparation, I decided to do the 22-ply hardpoint layup at the same time. Somehow I mixed too much Fast hardener in the batch and when I got to the 4th ply it started gelling on me. Rather than try to recover it, I just scrapped those four pieces and decided to wait until the next day to do the hardpoints. It was late, anyway.

The first picture below is of this mess. I'll save it for something - jig material, paint tests, etc. It's actually pretty strong and most of it got wet out fully before it gelled. I'll think of something. (Yes, I'm a Yankee, but there ARE many uses for fiberglass panels that aren't structural such as pieces to make mounting brackets out of, covers for storage compartments, scraps for paint tests, etc.) Incidentally, the sheet underneath it is the back side of a sheet of drywall. Drywall cutoffs make perfect surfaces for this type of work. It stopped the layup from picking up the imprint of my cheap plywood table surface, and they're heavy as heck, so they make great weights for the tops of layups. And they're worth almost nothing - a 4x8 sheet of 1/2" drywall only costs $5.

The instrument panel turned out OK, but I made a few errors on the back (forward) side. You can see an example of this in the second picture. Basically, I didn't weight down the back side very well, and I didn't use peel ply at all. The plastic lifted up in a few spots and left some thicker epoxy "hills". It's no big deal, aside from being a bit epoxy-heavy. Lately I've discovered that I'm better at getting epoxy out, and a smooth surface, with just plastic and no peel ply at all. It certainly saves the agony of trying to find good, cheap peel ply. Plastic is reusable and cheap as hell if you don't mind dealing with the wrinkles. I'll save my peel ply for critical join areas and the wing surfaces.

I also made my first major modification in this step. Marc Zeitlin was kind enough to give me a ride in his and one thing I discovered is that lifting the bottom of the instsrument panel a bit would be a nice touch. I took the plunge and lifted mine a full inch. It's amazing how much easier it is to get in when you do this. I've done the measurements - if I don't make the electrical wire channel I can still BARELY fit two 3.125" instruments vertically in there, and I can always reroute the wires if necessary. But, I'm going with a glass panel, and THAT fits great. Note that you can get regular instruments all the way across if you're willing to cut (gasp!) the stiffener ribs... Can anybody say "aluminum overlay"?

Step 4 - Landing Gear Bulkheads
Status: Completed 
Est Time: 0.00, Actual: 10.50
Est Cost: $ 0.00, Actual: $ 0.00
Date Completed: 03/21/2004

The hardpoints layup originally didn't go well (see Instrument Panel comments) because of an exotherm, but I just threw out the four layers that got wasted and cut replacements. I also started using a rotary cutter and self-healing rubber mat. This is a DREAM to use. It cuts perfectly straight lines, and doesn't touch the BID fibers at all.

Like some other builders I chose to use spacers to make sure this piece comes out exactly 1/4" thick. I cut them out of the same foam that the hard points will be inlaid into to make sure they come out perfectly. You can see them under the bottom of the stack of the drywall weights in the picture below. This didn't do quite what I hoped, see below.

I don't have a band saw, and my jigsaw is broken, so I decided to use the table saw as much as possible to cut the hard points out. I'm glad I did because it saved a lot of time. A 60-tooth combination blade produced very clean and perfectly straight cuts. I made my panel a bit oversized (9" wide) so I was able to change the layout of the pieces on the panel from what the plans depict. That let me make straight cuts between the pieces. You can see what I did in the second picture below. (The edges aren't really curved, that was just how I was holding the camera at the time.) I finished the rest of the cuts with a coping saw.

The third picture shows a foam cutting technique I stumbled across while working with this foam. It only works for thinner (1" thick or less) foams but it works so well I intend to use it wherever possible. Basically, I just use a hammer to tap a razor blade into the foam along the cut line. This produces a perfect cut that requires no sanding, and it goes faster than you'd expect because of the width of the blade. I've also done this with 4" long snap-off-tip blades for long straight lines.

The other things I've tried include:

1. Using a coping saw to rough-cut the shapes, then sanding to the lines. This is still my preferred method for curves but it's much slower for straight lines.
2. Multiple passes with a long razor blade and a straight edge. For really thin foams this is OK, but at the bottom of the cut, especially on thicker foams, it's hard on the hands. (I have arthritis.) And it's still slower.
3. A Dremel and a spiral-cut bit goes through foam like butter, but it's hard to get perfectly even lines that way so I still usually cut a bit oversized and sanded to the lines. This also produces the most dust.

The layups went about to plan. But, I had another piece of good luck - my Fein Multimaster finally arrived, and BOY is this a great tool to use! Unfortunately, it's really only good for straight lines, but it goes through hardened lauyups like butter. This completely ends my issues with being there when it's time for knife trim. I had saved final trim on some of the other bulkheads until this arrived, and I went back and did them all in about an hour, including some final sanding for smoothness. The best part is, the Fein blade (still using the one in the kit) didn't dull at all. My coping saw blades got dull basically every piece I cut.

Step 5 - Firewall
Status: Completed 
Est Time: 0.00, Actual: 3.25
Est Cost: $ 0.00, Actual: $ 15.95
Date Completed: 03/25/2004

I had less 1/4" fir plywood on hand than I thought, so I delay the creation of the dummy firewall until Chapter 6, where it is used. It's easy enough to make from the real firewall pieces with a router, straight cutting bit, and template guide bearing. I did include its cost here, though.

Creating the firewall went well enough. I prepped the aluminum engine mount inserts with Alumiprep followed by Alodine. Some people have made larger inserts to accommodate some movement in fitting this, but I decided to stick with the plans. I'd rather adjust the engine mount for a correct fit than the firewall for a badly welded engine mount. I may have a local welding shop do the work for my rotary, and if it don't fit, I'se a gonna send it back!

Some people have had problems with the plans method for keeping the blind screws from turning, and I've seen all sorts of schemes for preventing this, from using piano wire and other things soldered into slots in the head to replacing them with ClickBonds. I elected to go with the plans method (grind two flat sides on each screw head, and fill the countersink with flox) for two reasons:

1. I know a better trick to avoid having blind screws turn. First, don't over-torque the nuts. Second, if a screw STARTS turning, just grind a slot for a flat-head screwdriver into the END of the screw. You need a wrench instead of a socket driver, but it works perfectly. This is sometimes done on concealed screws in furniture.
2. Some builders are using bicycle cable guides as a replacement for these pulleys. I haven't decided whether to do this or not - I'll test each option when I get to that step. But at least I have a Plan B.

Chapter 4 is finished, hip hip, hooray! I learned a lot, made some mistakes but nothing major, and on we go!