Chapter Log

Step 0 - Materials
Status: Completed 
Est Time: 0.00, Actual: 0.00
Est Cost: $ 0.00, Actual: $ 0.00
Date Completed: 01/06/2004

The education section includes three "confidence builders" - a flat layup to practice making light layups, a reinforced beam to prove the strength of the construction method, and a bookend that combines several techniques into a more complex shape.

I will be purchasing materials for the education section and Chapter 4 at the same time, so this section focuses primarily on the workshop-related expenses.

Step 1 - Workbench
Status: Completed 
Est Time: 6.00, Actual: 8.00
Est Cost: $ 100.00, Actual: $ 70.64
Date Completed: 01/19/2004

I had intended to make two workbenches in 6' sections that could be bolted together for large layups (wings) or used separately for smaller layups (bulkheads), in a more convenient (that is, not the garage) location. For the time being, I decided to reuse a work surface I had made for another project as the second workbench, and just build one. The two are the same height and about 13' long, although I will do something to fasten them together securely when it comes time to use them as a single unit. I'm so happy with the new table, though, that I may build TWO more and use one to replace my current woodworking bench!

The new workbench is built out of ACX plywood (slightly better than utility grade - a better top surface and core) in quasi torsion box style. I used 1/2" plywood rather than 3/4" to save weight, although I regret not using 3/8". That would have been more than sufficient, and as it is this table is still quite heavy (the top is about 80-90 lbs). The base is extremely rigid and glued/screwed throughout with dadoed joints for added strength and rigidity. The exception is the two long cross bars, which are only screwed in place and stiffened with L-brackets. This allows the base to be removed from the table and disassembled for transport. This is an excellent workbench, and when the project is completed I will likely replace my woodworking bench with it. At some point I'll add a sheet of utility-grade plywood across the legs to create a storage shelf.

I designed this project to use glue as the primary fastener, like a true woodworking project, so the vertical plywood ribs inside the table have 3/4"x3/4" pine ribs at the top and bottom to provide additional long-grain joint area. This basically makes them look like "C" beams. I used brads to hold everything together while the glue dries. Screws are fine too, but brads are much smaller and less likely to interfere with something I'm nailing down. They're also a lot faster to install if you have an air nailer. With a project like this, don't be tempted to use screws "for strength" - a proper glue joint is stronger than the wood it adheres to, and screws allow the wood to flex around it, creating a looser joint.

I did NOT install the hinges as planned on the legs, since the top was heavy enough as it is without permanently attaching the legs. So, with some minor modifications, this project required:

1. Four 2x4s ($2.39 ea)
2. Two sheets of 1/2" ACX plywood ($26.96 ea)
3. Four L brackets ($1.29 ea)
4. Glue and screws (est $2.00)

Step 2 - Fabric Cupboard
Status: Completed 
Est Time: 1.00, Actual: 2.00
Est Cost: $ 20.00, Actual: $ 22.00
Date Completed: 01/20/2004

I planned to make my cloth box wall-mountable, but for the time being I will be working out of my new office, and I didn't want to mar the walls (as you can see I'm still taping - I didn't have the heart to put four NEW screws into it!) I opted for a solution similar to that of some other builders (Dean May, Jeff Wilson, et. al.) and just made a few minor modifications.

First, I only have one leg at the moment - this is a temporary support while I figure out where I'll ACTUALLY be building the next few years, at which time I will be designing the table to drop down and hook onto a work table, giving me a bigger surface to cut fabric on. The sawhorses are also temporary.

Second, my front lid is mounted slightly offset from the bottom of the box. This allows it to fold down flat on the sawhorses I currently have it on, or whatever shelf/table it may sit on in the future. This prevents me from having to have the box flush with the front lip of a shelf.

Finally, my latches are two chest latches on the top of the box to help keep the cheap-a** utility-grade plywood from warping and exposing the cloth to dust. I cut notches into the top of the lid that the latches hook onto.

I intend to eventually install a paper tape measure along the edge of the lid to make measuring things out faster, or simply install a self-healing cutting mat for rotary cutters, as these have markings on them already. Building this project required the following:

1. Three quarters of one sheet of utility-grade 1/2" plywood ($15)
2. Three small hinges ($0.50 ea)
3. Two small chest latches ($2 ea)
4. Glue and brads ($1.50)
5. Scrap for the leg

Step 3 - Epoxy Hot Box
Status: Completed 
Est Time: 2.00, Actual: 1.00
Est Cost: $ 25.00, Actual: $ 27.27
Date Completed: 01/22/2004

My epoxy hot box is quite simple - just a simple frame of rigid foam insulation screwed together with LONG screws. (The front cover is not shown in the picture below.) There is absolutely no strength in this structure but that's fine because I don't move it around and it bears no weight. I installled one light bulb as a heat source for now - later this will be two bulbs and a thermostat. Currently I must monitor the temperature of the box and make sure it doesn't get too hot - I just only turn on the bulb an hour before I plan to use it.

You must be VERY safety-conscious if you follow in my footsteps. The aluminum foil is conductive, so the light bulb is actually mounted to a junction box that contains the wiring, and there are no sharp edges for wires to catch on. Don't let it get too hot, either. This type of insulation is flammable if exposed to flame or extensive heat (somewhat more than wood). Finally, note that one side is more reflective than the other (a stamping on the board indicates which) and should face INTO the box.

I have a very accurate digital scale for measuring my epoxy, and I plan to work by weight rather than by volume. I purchased the set of cheap-o West Systems epoxy pumps (I am using MGS 335) with the intention of doing as other builders had done and keeping the epoxy in Hefty gallon-size freezer containers (see Jeff Wilson's site, et. al.). However, I could not find suitable containers, and in the end discovered that the pumps fit the MGS bottles just fine if you don't mind the resin pump not actually screwing on. I also intended to work by volume and make the modifications to the pumps' depth controls discussed by others, but discovered that measuring by weight is so much easier (and more accurate) that it's not worth the effort and risk (of making a mistake).

Step 4 - Flat layup
Status: Completed 
Est Time: 2.00, Actual: 3.00
Est Cost: $ 0.00, Actual: $ 0.00
Date Completed: 01/21/2004

Some advise you to dive right into the first real chapter, but I wanted to proceed with the confidence layups for three reasons:

1. I wanted to show them to family members.
2. The plans say the flat layup (six plies of BID) can be useful later, and I believe them (grin)
3. My first few feet of the BID were warped beyond my satisfaction for actual use, despite the ability to reshape BID. This gets them out of the way.

I am now using a roughly 30/70 mix of Fast and Slow. Since I am measuring by weight, my process is not rocket science. I place an empty cup on my scale and zero it. Then I fill the cup with as much resin as I think I want, by eye, allowing for the fact that hardener will join it. I weigh this, and look on my chart for the closest matching weight, then add a drop or two of resin if I'm not on an exact number. The chart gives me a final weight with the hardener, so I then just add equal squirts of each type of hardener in the ratio I want until I reach the target weight. I can get 1 drop at a time out of the pumps if I'm careful, or accuracy to a third of a gram (one drop's weight) in the entire batch.

This is a really easy and fast method of measuring out epoxy. If I want it to cure a bit faster, I lean more (or all the way) toward Fast hardener, and vice versa for more setup time. And there's basically no cleanup involved - the pumps don't drip or leak, and if they get gunked up over time I'll just replace them. The only drawback is that my scale only goes up to 500g, or about 17.6 ounces. That's about a medium cup full of resin - a 16 fl. oz. cup would contain more than the scale could measure. This is OK with me - I don't intend to work with that much at a time anyway, for fear of exotherms. I would rather mix 2-3 smaller cups to get the desired quantity.

My flat layup turned out to be 10.5 ounces, which is on the lighter side. I don't attribute this to an excellent layup but rather to the higher amount of tiny bubbles present. I don't really have any large air bubbles to speak of. However, I did have a large number of tiny bubbles that none of the pictures show well. There's enough there to be a concern (15% or so, I'd say) but the opacity isn't all from that - I peel-ply'd one side and that's the cause of the milkiness.

I also have some fabric dings I made with the squeegee while doing the layup, and some embedded aluminum foil bits and streaks on the back side where epoxy crept underneath the gap between my two sheets of foil (I laid foil over the plastic on my bench to see how well it peeled).

None of these issues justify doing this layup over again. In the future, I will focus on my stirring technique for the epoxy mixing step. I believe this is where the tiny bubbles were introduced. Also, I have rounded the corners on my squeegee to prevent them from catching the fabric. Finally, I'll only use plastic instead of foil.

Step 5 - Confidence Layup
Status: Completed 
Est Time: 2.00, Actual: 1.25
Est Cost: $ 0.00, Actual: $ 0.00
Date Completed: 01/21/2004

In all, this is a pretty basic layup, and it went by a lot faster than I expected. I incorporated my changes from the flat layup. This time, I stippled with a brush to remove all visible bubbles, even the tiny ones present in the epoxy due to mixing. I also incorporated a trick suggested by several other builders, that you not only use plastic underneath the layup to protect the bench, but also on top of the peel ply. The plastic allows you to perform a final squeegee step to remove epoxy and air bubbles and prevents air from being reintroduced. This worked very well... for the top surface.

Well, you can see the results. The 4mil plastic is actually not all that malleable in terms of compound corners, which this layup contains. I discovered the hard way that it was difficult to bend around the edges without it pulling the top surface off the foam block, or lifting the peel ply right off the layup.

This caused all sorts of problems. First, by picking the peel ply up it created a peel ply air pocket. That's not a big deal because the peel ply doesn't stay there, but it DOES mean there is an area where peel ply didn't touch the layup, so I would have to sand this spot and I would also expect extra epoxy buildup here. This area is circled in red.

More important, I found it very difficult to actually do the squeegee work in the lower portions, under the complex bends. Because of this I ended up with much more epoxy on the top of the peel ply than should be there, and it became impossible to remove - epoxy doesn't stick TO peel ply, but a 0.5mm sheet of it on top of the peel ply with fingers down through the mesh sure HOLDS it there. I'd have to sand the excess epoxy down, then sand the peel ply off to be sure it was fully removed before doing another layup.

In all, I think I will leave this trick to flat layups or areas where there are gentle curves and great benefit to be had, like on the wing surfaces. Nonetheless, the layup was a success - it's epoxy rich and ugly as hell, but it easily held my weihght, and I don't think I really need to practice sanding - I'm moving on.

During the layup I was also reminded of a complaint I forgot in all the fuss in the flat layup - loose fabric strands. These get all OVER the place if you let them get onto your brush, gloves, or squeegee. I think in the future I willl simply take the hit and add an inch or two to each cut to keep these away from the areas I'm working in during the layup. I could do a temporary selvedge with masking tape or similar, but because the BID is so malleable, I keep having problems with my 4" cuts becoming 3" strips, even when I roll the fabric; cutting things oversized will prevent problems there in the future as well.

Step 6 - Bookend
Status: Completed 
Est Time: 2.00, Actual: 0.00
Est Cost: $ 4.00, Actual: $ 0.00
Date Completed: 00/00/0000

I started assembling materials for this step, then put it on hold because I wanted to practice/evolve my flat layup skills on the bulkheads. I may return to this step at some point.