| 27 |
Phone John at Europa to check if FWF kit will fit in an estate car - he says no problem. Biggest thing obviously is the cowl which needs to fit the width of the tailgate. Bend a wire coat-hanger into shape for a handle for the dowel. Drill the ends of the dowel 4mm and then enlarge to 5mm to allow really free rolling on the wire. First attempt to get it inside the wing shows it's much too big, so shorten, try again and shorten much more drastically. It will now go in (although handle has to be assembled to dowel inside as the whole thing is still the wrong shape to go through the hole) and can be positioned satisfactorily at the lower corner of the repair area. Countersink the holes in the end of the dowel so it's easier to assemble when inside the wing cavity. Mark the pitot & static tubing with insulating tape and re-connect to the dummy fitting inside the wing; tuck it out of the way. That gives a better view into the wing without the tubes in the way. Measure up again for the BID needed inside the repair and decide that 300mm x 180mm would be better than the previous smaller size. Cut a piece of BID and roll it onto the dowel, leaving the selvedge edge at the outside to minimise unravelling problems. Temporarily hold in place with a rubber band while tying a slipknot in a piece of sewing thread. Remove rubber band. 17C, 82% RH; turn on both fan heaters to thermostat setting 4. Spend some considerable time abrading the inner surface with the sanding drum on the MiniCraft tool. Need to prop up the LED light with various wedges to get light where needed and some areas need a mirror to check fully. Eventually satisfied that the whole area is sufficiently abraded. While pausing for a break, e-mail Matronics to find out what's happened to the servo governor order. Vacuum out as much dust as possible from inside the wing. Now 20C, 65% RH, so turn fan heaters up to 4.5. Check epoxy pump spouts and valves are clear. Mix 3 strokes and brush on to inside of repair area. Quite tedious as each brushful needs my arm wriggled in and out of the hole, and I can't load the brush too heavily or it will just run back down onto my hand. When area appears fully covered, insert dowel with BID and fit handle inside wing. Fiddle round until positioned for start. Roll it gently back and forwards slightly to get the end of the BID wetted, then pull the thread to release the slipknot. It starts to go slightly low but manage to correct the angle. Problem arises about halfway across when my arm fits tight in the hole and I have to wriggle to get it further in. Can't keep the dowel firmly in contact with the skin while doing that and the BID starts to unfurl a bit, but manage not to lose control completely, and roll it the rest of the way to the top. Seems to be sticking OK to the wetted area, so pull my arm out and dismantle and extract the dowel and handle. Alas! By the time I look inside again the BID has peeled off and fallen down. Drag it out and discard it. Paint pretty much all the rest of the epoxy onto the repair area in the hope it will wet out better next time. Cut a new piece of BID (no selvedge edge this time). Clean off dowel and roll BID onto it, securing as before. Insert into wing, position and roll on. Same problem as before at half-way, but manage to keep it fairly straight. It was a good idea to use a bigger piece of BID! Visibly better wetted out this time. Dismantle and extract dowel and handle. Mix another 2-stroke batch of epoxy. Stipple BID with epoxy-loaded brush to complete wetting-out. Have to discard gloves as they keep getting torn going in and out of the hole. Brush the outside of the inner prepreg layer with epoxy and fit the pre-cut piece of BID into the recess. Stipple carefully to help it adhere to the inside BID, trying to eliminate all bubbles. Gently push BID from inside to restore flat surface in central hole. Paint back of brown foam pieces and insert into the recess in turn, ensuring full contact with BID and avoiding bubbles. Again check profile of BID inside, stippling BID while holding foam in place on outside with other hand. Mix remaining epoxy with flox to non-slump consistency and butter into small damage area. Paint outer surface of foam and surrounding prepreg with epoxy and lay on pre-cut piece of BID, covering both damage areas. Mix another 1-stroke batch of epoxy and wet out BID. Cover with some conveniently-sized offcuts of peel-ply and stipple them on. Now 24C, 49% RH. Leave heaters on for cure. At bedtime, 25C, 44% RH. Epoxy seems well-hardened, turn off heaters. Note that a small area on the edge of the inside patch nearest the access hole has puckered up - will need to be cut away and patched over. |
1306.8 |
| 31 |
Grind off puckered areas of repair inside wing with sanding drum on MiniCraft tool, and abrade surrounding area for at least 50mm all round. 18C, 74% RH. Turn on fan heaters to setting 4.5. Remove peel-ply from outside surface of repair. Mostly looks OK but one small area is slightly proud of the contour, so will require more filling work. Cut a piece of BID 150m square on the weave and a slightly larger piece of peel-ply. Wet out BID on polyethylene sheet with a 1-stroke mix of epoxy. Lay peel-ply on top, wet fully then lay polyethylene sheet on top. Turn over, trim edges and peel off polyethylene sheet that was originally on the bottom exposing BID. Bend into a U-shape to fit through access hole and press onto the abraded area, keeping weave in line with that of prepreg. Once convinced it's sticking well, peel off polyethylene sheet and stipple down with brush. 24C, 55% RH. Leave to cure. At bedtime turn off heaters. 25C, 55% RH. |
1308.0 |
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