Since no one offered use of their paint booth last October, I was forced to wait until spring. So, here we are, April 2015 and already plenty of days warm enough to paint, however.....I ran into trouble last fall. I shot the rudders with Polybrush right over the old dope finish and then Insignia white color base coat and proceeded to mask the accent stripes. After making a masking error requiring tape removal, I found the base coat peeled off with the tape right down to the old dope finish. No point in going further. Ripped off all the covering on both rudders and set about prep'ing the frames for recovering. This pretty much shot the idea of completing the painting last fall. I found that the left rudder had actually sustained some damage once I had the covering removed so I fixed that and beefed up the aluminum ribs which are definitely the weak link in the frame structure. Here's a shot of the rudder frame leading edge rib before.
I cut out a piece of ½ inch foam from the damaged wing rib to fit inside the aluminum rudder rib. I glued it in place using Gorilla glue which is supposed to work well on this type of foam. The stiffening effect on the rib was amazing. If I build another ER, I'd use this on all the aluminum ribs in the rudders which would also allow one to rib stitch rather than rely on the dicey fabric to aluminum bond using fabric cement (without the foam insert, the rib would just collapse as you tightened the stitch knot).
I recalled covering these rudders back when I first built this kit that they were very difficult to do without many wrinkles so both these rudders were ugly anyway. I decided to try a different method this time around and built a quick frame out of 1X2 fir and attached a piece of fabric to it using an office stapler.
I cleaned up the aluminum frame, coated it with Polytak fabric cement and then place the wooden frame over the rudder structure.
A small slit for the rivnut to poke through allowed the fabric to lay down nicely onto the rudder structure. I then ran a very thin line of 50/50 cement/MEK around the entire perimeter of the rudder, rubbed it in and let it dry (std process).
I then simply cut around the perimeter leaving enough fabric to do the wrap onto the aluminum structure and got an almost wrinkle-free main area. The hard part was doing the snips and cuts to get the fabric fitted around the ends, brackets and horn. Repeated the frame process for the other side and ended up with no wrinkles after doing the final shrinking at about 300 F. Wetted out the glue on the ribs to attach fabric then applied Poly-Brush (coat #1 brushed on, coat #2 & #3 sprayed on). Same pin hole bubble issue. Just have to re-brush back over what you've just applied as you go to knock down the bubbles before the P-Brush tacks up. What you don't get will be ironed out at 225F prior to spraying.
OK, on to painting. I've poly-brushed the rudders and shot the base coat of white. Two coats was sufficient. One thing I've found in getting an even coat aside from being very smooth and even on your gun passes (you need to always be aware of how far the nozzle is from the surface, what angle the spray fan is relative to your gun pass direction and how fast you move the gun along the surface). It's a tough job and was hard for me to do. I would finish a panel and then go back and look for uneveness. I would then spot spray the light areas until the whole thing looked relatively even. I tried to put on just enough color on the first coat so that the second coat was the final one. In the photo below, notice the different color masking paper on the leading edge at mid span. That stuff is the paper you use when you paint a room in your house. It's crap for this application. The pigment goes right through it and onto the surface under it.
In this next photo, I've removed a piece from the other wing panel where I had used it right in the area I was painting. You can see what happened.....bleed through! So go find your local supplier for automotive painting and get your paper from them but I'd still test it first before you commit to use it to mask an entire wing....it took me a couple hours to finish one panel and that was after I got the hang of it.
I used Reducer on a Q-tip in an attempt to mellow it out a bit with limited success. I went over the area with red but could not make it go away.
Here are some shots of the masking involved in creating a simple design scheme similar to the lines on the glider Brian Porter flew in the 1976 National meet.
The blue tape in that shot is vinyl tape used in automotive trim masking. You can form it somewhat around curves. I could not do a real tight curve successfully and ended up cutting the curves for the rudders which were much smaller radii compared to the wing panel curves.
Back in the converted RV shed with the drop-down lights for painting.
Masking the rudders.
The finished rudders ready for painting.
This next photo shows my attempt at getting an even first coat of red on the rudders. I always shoot the edges first since this is where the risk of generating drips is greatest. Making a couple light passes worked best followed with filling in the rest of the surface.
As a side note, it was 58F and raining when I shot these. I saw no problem with the paint nor did I note any difference in spraying under these cool conditions.