Chapter 5 Building Log
I received my Chapter 5 materials kit from ACS about the middle of July/08. During that time due to developing a reaction to MGS and some family vacation I had not been able to start until the beginning of August.
8/2/08 - I switched to West 105/209 epoxy and laminated the Top Longerons from the 1inchx1/4inch; Sitka Spruce stock. I used the forms that Mark Ewart had built and they are letting me make short work of this task. Also cut out the other Sitka Spruce doublers that will be added to the Top Longerons.
8/3/08 - Glued the doublers onto the Top Longerons.
8/4/08 - Checked the side forms (supplied by Mark Ewart as well) and everything checks out per the plans.
8/5/08 - Cut out the 3/8” side foam and got most of them glued up. I used a thick micro instead of the 5-minute epoxy so that I could get more working time. I also only got 3 sheets of the foam and had to adjust the layout of pieces (4 for each side instead of 2 per plans) differently from the plans to get the proper size built up.
8/7/08 - managed to get the rest of the 3/8” side foam glued up (5 minute epoxy this time) and did some filling and sanding to get it even and sanding flush where epoxy stood proud.
8/9/08- Side foams are placed on the forms and screwed into place from below.
8/10/08 - Started cutting out ¾” foam doublers on the band saw.
8/16/08 - Finished shaping ¾” foam and test fit with dry wall screws. Noticed that the fwd stiffeners on my Top Longerons are installed backwards and I will have to cut them off and reinstall them properly.
8/25,29-30/08 -Gluing the ¾ foam down to the sides and contouring.
8/31/08 - Filled screw holes and irregularities as well as adding radii corners with micro. Formed second LWX. Fixed Upper Longerons by removing blocks installed backwards and putting them back on the right way. Build the electrical channel covers. Trying to find out what the recess will look like for the Vance Atkinson Fuel gauges. I went ahead and ordered the gauges today so that I can get this right. I decided that I will be doing the Cozy Girl strakes and did not do the depression for the controls since this area will be cut away to allow access into the extended strakes.
9/3/08 - Got the Fuel gauge today and carved out the recess in the side panels. I positioned them with the lower fill hole about 1/16” above the bottom of the fuel tanks. The bottom of the tanks, or top surface of the bottom strake panel, is 9.7” from the top of the Upper Longerons per the plans. Hopefully this is correct, but I have some play in the Vance gauges and it should work fine. I also finished the micro radius and after a little sanding and clean up will be ready for the 2 uni lay-up on the inside of the fuselage sides.
11/20/08 - After a couple months of inactivity I am trying to get going again. I am sanding all filling even with the foam in prep for the inside lay-ups. This is not as easy as it sounds as the foam sands easy and the micro not so easy.
11/26/08 - Over the last two days I cut the class for the 2 plies of uni and have them rolled up and waiting. Tonight I filled the last of the dry wall screw holes that I missed and a few deep scratches in the 3/4" foam. I also drew lines on the foam where the bulkheads will be mounted so that I can apply peel ply in the right locations without having to peel ply the whole thing.
My plan at this point is to bite off this large layup in several smaller sections. The plans include parts 1-3 into a single session and I am thinking that I will run out of time.
1. Left side uni lay-ups and peel ply all joints; upper & lower longerons and all bulkheads.
2. Right side uni lay-ups and peel ply as above.
3. Upper longerons on both sides.
4. Lower longerons on both sides.
5. Aft build ups in way of the landing gear bulkheads and firewall.
The reasons for this subdivision of tasks is that I am working alone and worried that I will run out of time with only 3 hours working time with the West System 105/209. I am also right on the edge of the temperature range as West states that the temp needs to be 65F and above during application and curing. The temperatures lately have been dipping into the 40's at night and getting up into the 70's during the day.
I am going to have to work on a heating system before I begin this task. My problem is that heating and ventilation are not working together here. If I leave the garage open with my fans on to keep fresh air around than all the heat will be pushed out as well. I am very worried about developing a sensitivity to this epoxy system. If that happens it may just about end my composite building career much earlier than I want.
11/28/08 - Finished the left inside lay-up in about 3 hours today and still had plenty of working time remaining with 105/209 with temperatures around 73 degrees. West seems to have a longer gel stage than MGS(making the timing for knife trimming easy), though all my MGS work was at 90+ degrees, and that might explain it as well. I thought at first that I might have the wrong mixing ratio (from the pumps). So I decided to check it. One pump of Resin is 21g Resin and 1 pump of Hardener is 6g, this equals a 3.5/1 ratio which is perfect by weight per the manual. So it must just be the temperature and I will have to make sure I give it enough time to cure before removing the sides from the forms.
11/29/08 - Did the right inside lay-up today and it was colder, about 65 degrees, and this 8 degrees makes a huge difference in the workable of the epoxy. I have multiple voids between the two plys that I was not able to remove even with the help of (my daughters) hair dryer. I will have to remove about a third of this bad laminate with my belt sander and try again after I can get it to warm up. My new rule is not to do any glass work unless my shop, materials and epoxy are at least 75 degrees.
- I have spent the last few weeks trying to figure out a simpler
way to fix my oops. I have built a hot box from an old cheap foam cooler
and have a lamp light socket set in the top. I am still playing with
different wattage bulbs to balance the heat. I have a high efficiency
40w bulb (consumes 7w) now
that seems to keep near 80 degrees. The standard 40w bulb I started
with was getting everything too hot, as the top of my resin can reached almost
140 degrees. I may just end up putting a thermostat in it, but am hoping
to keep it as simple as possible. I would much rather spend time building
than jigging or support work. So this method of moldless construction
is right up my alley.
I am shopping for a belt sander for my laminate removal tool. Hand sanding will work, and I will have better control, but if I can do an almost equal job with a faster method I am all for it. Even it there is some fixing it will be easier than hand sanding. After looking closer at my work the areas with the 3/4 foam build ups are in better shape and may not need to be removed. I peel ply'ed these areas and that may be the reason for the better quality.
I have also spent some time modeling the chapters in AutoCad. I have made my living with it for several years and even though it is a poor excuse for a solid modeler it is still easier for me to use it than to learn a new program. I tried a few of the free or shareware packages and they are different enough that the learning curve would have killed a few weeks of my free time and I could be done with it by then in Acad. This helps me think through the assembly and see how things go together. Currently I have completed it through chapter 6 and will ultimately help me with the changes I have in mind like Cozy Girl strakes, nose reshaping and perhaps hanging rudder pedals.
02/10/09 - I have spent the last few weeks getting my heater unit, building a support frame for it and removing the bad glass layup on the right side lay-up. Pictures of this follow and I will be using micro to patch and fix where foam was damaged in the process, but I am almost ready to redo the layups and then its on to the longerons and finish this chapter up.
Here I am starting to peel the laminate to find out if the right side panel can be saved or not. You can see from the pic that the 3/4" foam is shearing just beneath the micro layer so I am only loosing about 1/32" of thickness and I dont think this is a problem. Though generaly it would not peel from the 3/8" base foam, except in strips or sections, and I used the belt sander to take it down. The photo on the right shows the micro patches and a new section of foam inserted around the fuel gauge window.
I am down to about 1/3 gallon of 105 and placed an order for another last night. It should be here in a few days and I will be ready for the layup by the time it does.
2/11/09 - Sanded the last of the micro patches and am ready to cut glass and sling epoxy.
2/12/09 - Cut the glass.
2/13/09 - I did the right inside lay-up today and floxed the longerons into place. Its nice to be moving forward again. Unfortunately I am off to Holland on business for a week and will not get to finish this chapter until I return. Oh, and one thing the DAR mentioned at our EAA 12 meeting this month was to be sure to include photos of me doing the work.
2/23/09 - Sanded down the top longerons. I faired the rear doublers into the main beam and will be adding fillets everywhere to ease the glass transitions. Also cut out the electrical channel overlay.
3/3/09 - Over the last week I have done the upper longeron 4 uni lay-up and installing the lower longerons. Snowflake seems to think that I am building it for her.
3/5/09 - Installed lower longeron aft doublers and glassed the wiring channel with 1 bid.
3/6-8/09 - Glued landing gear doublers and 3/4 foam fillings in place and micro'd.
3/9/09 - Did 6 bid layups over landing gear buildup. This chapter is all but finished and I imagine it will take me a week or two to get my bench disassembled and then set up for chapter 6.
3/11/09 - Trimmed ends of the panels using a board fixed at the correct angle with a cutout to fit the panel in. From there all I had to do was trim with my HF oscillating tool (better than sliced bread). After which I did the cutout for the main spar and some sanding. Done!