Hjem 737 Cockpit project Cockpit related Cockpit interior - Left sidewall
Cockpit interior - Left sidewall Print E-mail
Written by Vidar Fagerjord   
Saturday, 05 May 2012 20:16
Article Index
Cockpit interior
Left sidewall
Front sidewall structures
All Pages

Update 12. may 2012

I've started building the left sidewall. I'm new to the whole "stitch and glue" method, and I've never used epoxy resin before (only Polyester resin). I ran into a few obstacles, but nothing I couldn't resolve. The epoxy resin is rather "runny", and the first "glue up" got very messy. But - it worked, and the parts are now in one piece:

I taped a small piece of plywood to hold the largest part at a 90 degree angle. Two 45 degree cuts at opposite directions, and you have a 90 degree support piece. The other parts are just taped together (later I used duct tape, which worked MUCH better).

After the resin cured, I used polyester putty to create a uniform fillet with a nice radius. The fibre glass cloth does not like sharp bends, and the real world side walls has a small radius there too.

Since the first attempt did not work very well, I got better resin and micro glass balloons (a filler material made of microscopic glass balloons). The glass balloons can be mixed with the resin to create putty. I glued some plywood to the underside of the table area in order to support the walls extending to the floor, and to strengthen the joint. I then made epoxy putty and made fillets:

After the putty and the epoxy cured, I applied glass fiber tape (just a narrow strip of glass fiber with no adhesive) and epoxied it over the fillets, extending out onto the neighboring wood:

It is important to "wet out" the glass fiber, but not soaking it. It should be transparent with very little resin on top. By "glassing" both sides, this joint should be strong enough to stand on!

Here's a shot of the taped seam on the inside of the 45 degree piece on the lower wall beneath the table area:

Another method of assemble parts is to "spot-weld" the pieces together using a small piece of glass fiber epoxied in place:

Note that these spots needs to be sanded down after the inside joint is epoxied, or you will get visible "bumps". You do not need to remove them completely; when finishing the rest of the joint, you just overlap a bit on the "spot weld" piece. In the end, the whole construction will get a putty coat and sanded to a smooth surface before painting.

I epoxied the rest of the parts to the table area in two steps. The first step was to join the table area part to the frontmost part, giving me something to clamp to the work table later:

After the epoxy and putty cured, I continued with the next parts, completing the front part containing the table.

NOTAM! The drawings might have an error - the aft part on the table area was too narrow!

I order to correct the mistake, I just used a scrap piece from the plywood sheet. I made a small piece that fits between the aft and the side part.

The piece can be identified by looking for the black, horizontal line on the upper right part in the picture. The joint will be glassed over from the back, filled with putty on the visible face and sanded smooth. Then the whole thing will be glassed on the face visible from inside the cockpit. The backside will be "painted" with epoxy then painted in order to preserve the plywood.

This is how the build looked before I mounted the last two pieces (1 and 2)

After the epoxy and putty has cured on the last two pieces (and all seams are filleted and taped), I will use a round over bit on my plunge router and make nice, beveled corners around the table area. The "rib cover" will be mounted (I actually plan to use foam for this, just as a test), then the whole thing will get one layer of woven glass fiber cloth and epoxy resin. I will then spacle the whole construction, sand smooth and paint. I plan to use semi-gloss paint - high gloss is not used in a cockpit because of glare.

The diagonal structure beneath the windows will be constructed using some plywood for the parts that needs to be strong, the rest will be made from foam (dense, small-celled type. Underground insulation pieces is ideal). When covering foam with 2 layers of fiber glass (preferably laid so one layer is laid at 45 degree) and epoxy resin, it will be both light and very strong. The foam is very easy to shape into smooth curves and shapes, giving a very nice look.

All in all, this construction method has proven to be super easy! The structure in the image above doesn't have a single nail or screw in it! Just plywood, epoxy resin, glass fiber and micro glass balloons (in the putty).

Update 14. may 2012

The last two pieces are now epoxied in place, the joints filled with putty and glassed in. I used my plunge router to create a rounded edge - done in a minute! Beats sanding and filing...

I "painted" the backside with epoxy in order to seal the wood from moisture. It just need a light sanding and some paint. I'm going to paint it white just in case I ever need to work inside the side walls. The oxygen mask panel is removable, and the space beneath would be ideal for running wires.

I then applied glass fiber putty on different areas where there was gaps or bumps. After a light sanding, the surface is ready for the glass fiber layer.

In the image above, you might notice the putty on the aft wall (part no. 1). As i mentioned earlier, I had to insert a small piece because part 1 is too narrow. By glassing the piece in place, the structure is extremely rigid. If all errors could be fixed that easy...

The next job will be to glass the entire surface. I'm doing it to get an even surface with minor sanding needed before painting, and the layer of fiber glass will make a sandwich construction in all the joints. There should be no problems standing on the parts when finished.

Now I just need to source the oxy panels...

 



Last Updated on Thursday, 24 May 2012 16:07
 
Copyright © 2017 Fagerjord.org. All Rights Reserved.
Joomla! is Free Software released under the GNU/GPL License.
 

Random image

felt_strips_glue.jpg