Fiberglass Question--slider rear canopy skirt

[rv9builder]

I have a question for the fiberglass experts, or somebody who has made the rear canopy skirt out of fiberglass on a side-by-side RV . . .

I plan to use the fuselage as a mold to make the rear canopy skirt for my 9A slider. Is it better to cut the fiberglass cloth to the exact finished size before you do the layups on the fuselage, or is it better to make the layups slightly oversized and then cut the skirt to the correct size after the resin hardens?

If you make the layups oversized, how do you determine the exact size to trim the skirts after the resin hardens?

Thanks in advance for your help.

[sf3543]

There are several ways to do this, but here's how I did it and it worked out well for me. (RV6)
I created a form on the fuselage and canopy, from styrofoam, while it was in place and covered everything with clear packing tape, except for the area on the plexiglass and aluminum skirt where I wanted it to adhere. For those places, scuff up the areas with heavy grit sand paper.
Then, drew the outline of what I wanted on the fuselage with a sharpie.
Get some clear plastic and lay it over the whole thing and trace out the size and shape of the piece youwant to make. Cut the plastic and tape it together in order to get a nice smooth template if you have to. You can fold it in half to compare both sides and to make it symmetrical.
Take a larger piece of plastic and lay it over your template on a bench, so you can see the template through it and trace it on to the bigger piece.
Use your first template to cut out the fiberglass cloth, adding about 1/2 inch all around. You can make the skirt in one piece or two pieces, which ever is easier for you to handle. One piece means less sanding later.
Mix up the epoxy (use slow hardener) and spread it on the larger sheet, lay on the cloth and begin saturating it with the epoxy. Do all the layers together at this time, using a brush or credit card to work out all of the bubbles from between the layers.
Once the layers are all saturated, cover the whole thing with another piece of plastic and make sure there aren't any bubbles. Now, you have a plastic sandwich with your glass layer in the middle. Trim away the extra around the edges and carry the whole thing to the plane. Peel off the bottom layer of plastic as you place the lay up on the plane and mold everything to fit the shape. Then you can peel off the top layer of plastic. Then, cover the wet layer with peel ply fabric, which gets pulled off after everything cures, leaving a fairly smooth finish.
Make sure you tape up the plexi and skirts where you don't want the resin to get on it. I used black electrical tape (plastic) at least 2 layers thick for this edge, since you can sand on it with out going through, if you are careful.
how many layers you use is up to you and how heavy the glass fabric is, but for the skirt, I would say at least 6 layers. Others may chime in here. But, you can always add layers on the inside of the skirt, later to make it stronger.
There are a bunch of posts that describe this and similar methods much better, but it is a quick and dirty description. I have used this method to create skirts and intersection fairings and it works well, at least for me.
I'm sure you will get quite a few responses as to how to proceed on this, so I would say pick the one that seems easiest to you.
Good luck.

[TrueAirSpeed]

I took a very thin piece of aluminum, cut it to the size I wanted and used it for my template. Used two-sided tape and taped it nice and tight to the fuselage and canopy (with the canopy blocked open about an inch). Then used foil tape and taped around the template. Applied mold release wax (Carnuba wax) to the template. Used a Sharpie to trace out the cloth and cut each piece about one half inch larger than the template. Applied the cloth/resin mix. Once dried, sanded down smooth, removed and trimmed to size on the bandsaw. Using the .20 aluminum gives the glass a nice smooth finish on the inside.

Good Luck

Terry
RV-7 ready to install I0-390

[RFazio]

I'm doing my slider skirt the second time. First was aluminum and came out very good. This time redoing it I have fiberglass, and I don't have aluminum. So I'm doing it in fiberglass. I used a method my buddy gave me. I closed up the slider. I laid out vinyl shelfing paper on the plexi and on the fuse. I drew where I wanted the fiberglass to cover and started laying the glass. I'm making mine so the fiberglass can come off the plexi all around. It's on with screws counter sunk into the fiberglass. I did the same on the windshield. This is my second windshield so I figured I'd make it removable.

[MarkDews]

Since I did not like the fit of the original skirt, I decided to go the fiberglass route. I admit to being a little on the lazy side at times (not too lazy, I am flying!!). I simply cut back the existing skirt creating an approx 1/2" gap between the skirt and the rear deck. I used paste wax on the rear deck and then laid up three layers of 4" fiberglass tape (8.7 oz from aircraft spruce). The fiberglass tape was able to easily make the curved transition. The edges don't ravel and fray so it is easy to work with.
The result was an almost perfect fit.
There was little effort to separate the layup from the rear deck due to the paste wax. The tape kept the width of the layup even without having to make complex patterns, etc.

Mark Dews
RV6A N885SM
Texas

[Rick_A]

I molded mine on the plane larger than the final size. Once I figured out the exact shape that I wanted, I drew it on the "mold" before coating the mold with mold release ( I used the liquid stuff that I picked up at West Marine).

Since the cloth is clear when it's wetted out, it is easy to see the line on the mold. I was not able to get good results wetting the cloth before putting it on the plane - I only did that on the first layer. So after the first layer of glass, I added additional plys by putting the cloth in place and then working the resin into the cloth.

After I was done with all the laminations, cutting it to size was the easy part.

BTW, I screwed the plexi to the rear frame skipping every other hole. I then screwed the glass skirt to the plexi and frame using the open holes. I also used some plexi adhesive to seal the edges.