The past couple of weeks in the RV-8 factory have been devoted to fiberglass...the dust is everywhere, and I am looking forward to doing almost anything else! I've come to both love and hate it...I hate it because of the mess, and because I always seem on the edge of disaster; love it because it is pretty easy to fix disasters....or at least cover them up! Fortunately, most of the fiberglass work on the RV's won't make us fall out of the sky if it comes undone.
Since my canopy bow glass is curing for the night, I figured I'd jot down a few things I've learned so far - keep in mind I'm a novice and turn out serviceable (not show-quality) work! Thanks again to all the folks who have pictures on their web sites - I'd never get this ight if I had to rely on the drawings and instructions alone!
1) For sanding the large "acreage" areas on the cowl and skirt, I used an orbital sander with 60, 160, and 220 grit disks. The disks tend to load up quickly when sanding epoxy-only layers for pinhole filling, but you can scrape them clean with a razor blade a couple times, then throw them away and use a fresh one. I bought a "job box" of each grit, about $10 a box at Home Depot, and won't use them all. Luxury is a fresh sanding disk!
2) I used four coats of epoxy, each thinned 50/50 with acetone for pinhole filling. After the fourth coat, I shot a coat of sandable rpimer, and the parts look really nice or at least good enough for a paint shop to turn them into something nice!
3) I started out using foam brushes, becasue you can get a bunch of them at the dollar store, but had lots of brush strokes to sand out of each coat. I switched to $1 bristle brushes from the dollar store, and got much better results. By getting a couple things ready for a coat of epoxy at the same time, I didn't even use ten brushes.
4) The top cowl and canopy skirt were easy to do on the airplane - a good working height and orientation. I took the bottom cowl off, so I didnt have to work upside down. Epoxy will find it's way into the cowl hinges, and it is not a bad idea to pull the pins after each coat dries, just to make sure you haven't glued them shut permanently!
5) I filled the centers of all the skirt pop rivets with very dry micro - basically a putty - applied with a razor blade. Then I painted over each rivet as part of each coat of epoxy. The rivets have pretty much disappeared. I suppose they will move a little and re-appear, but I don't know how else you'd do it.
6) The forward windshield fairing was not as bad as I feared. I followed the directions in the builders manual more or less. One tip is to use two different colors of vinyl tape to mark off the edge. I used black underneath, and gray on top. You overlap the fiberglass on top of the tape, and when it dires, you sand down until you'd gone through the first layer - this gives you a clean edge to peel the second layer. The nice thing about two different colors is...you can see when you've sanded through the first!
7) I was able to use my Orbital sander to finish most of the forward windshield fairing as well - I just used the edge of the disk. If you have covered the windshield well with tape, there is little danger of damaging it. I sanded the edge of the fairing in to the aluminum using a 220 grit disk, and when I hit it with primer you can't see where they meet.
8) I had to build up the forward edges of the canopy skirt to match the lines of the forward top skin where they meet. Just used Microballoons and it worked well. Also had to build up the area where the windshield and skin meet to meet the canopy skirt. I made this parting line match before starting the overlap fairing.
9)I remembr that many people have complained becausewhen they sit in the cockpit and look through their windshield, they see light-colored, raw epoxy on the inside of the forward fairing. To prevent this, before I fastened down the windshield, I put the tape on the outside marking where the fairing would cover, then masked off inside on the workbench, and painted that lower 3/4" black (on the inside). Then when I had it mounted, I filled the little gap under the edge of the windshield with epoxy and flox, but I added a little black dye from a gel-coat repair kit to make it black as well. Since I had already painted the glareshield black, I now have everything that can be seen from the cockpit done black!
Well,I'll leave it there for the night. That way, I can tell of the disasters I find in the morning when I check the overlap fairing. Will I have glued the canopy shut? Will it be a horrible lumpy mess (hey, you can fix that with micro!)? Will it all have to come off and I'll have to start over? Angst takes over as I head off to bed.....
Remember, this stuff is art, not engineering, and art is in the eye of the beholder. Panic not...just pull on those latex gloves and charge in!
Paul Dye
Since my canopy bow glass is curing for the night, I figured I'd jot down a few things I've learned so far - keep in mind I'm a novice and turn out serviceable (not show-quality) work! Thanks again to all the folks who have pictures on their web sites - I'd never get this ight if I had to rely on the drawings and instructions alone!
1) For sanding the large "acreage" areas on the cowl and skirt, I used an orbital sander with 60, 160, and 220 grit disks. The disks tend to load up quickly when sanding epoxy-only layers for pinhole filling, but you can scrape them clean with a razor blade a couple times, then throw them away and use a fresh one. I bought a "job box" of each grit, about $10 a box at Home Depot, and won't use them all. Luxury is a fresh sanding disk!
2) I used four coats of epoxy, each thinned 50/50 with acetone for pinhole filling. After the fourth coat, I shot a coat of sandable rpimer, and the parts look really nice or at least good enough for a paint shop to turn them into something nice!
3) I started out using foam brushes, becasue you can get a bunch of them at the dollar store, but had lots of brush strokes to sand out of each coat. I switched to $1 bristle brushes from the dollar store, and got much better results. By getting a couple things ready for a coat of epoxy at the same time, I didn't even use ten brushes.
4) The top cowl and canopy skirt were easy to do on the airplane - a good working height and orientation. I took the bottom cowl off, so I didnt have to work upside down. Epoxy will find it's way into the cowl hinges, and it is not a bad idea to pull the pins after each coat dries, just to make sure you haven't glued them shut permanently!
5) I filled the centers of all the skirt pop rivets with very dry micro - basically a putty - applied with a razor blade. Then I painted over each rivet as part of each coat of epoxy. The rivets have pretty much disappeared. I suppose they will move a little and re-appear, but I don't know how else you'd do it.
6) The forward windshield fairing was not as bad as I feared. I followed the directions in the builders manual more or less. One tip is to use two different colors of vinyl tape to mark off the edge. I used black underneath, and gray on top. You overlap the fiberglass on top of the tape, and when it dires, you sand down until you'd gone through the first layer - this gives you a clean edge to peel the second layer. The nice thing about two different colors is...you can see when you've sanded through the first!
7) I was able to use my Orbital sander to finish most of the forward windshield fairing as well - I just used the edge of the disk. If you have covered the windshield well with tape, there is little danger of damaging it. I sanded the edge of the fairing in to the aluminum using a 220 grit disk, and when I hit it with primer you can't see where they meet.
8) I had to build up the forward edges of the canopy skirt to match the lines of the forward top skin where they meet. Just used Microballoons and it worked well. Also had to build up the area where the windshield and skin meet to meet the canopy skirt. I made this parting line match before starting the overlap fairing.
9)I remembr that many people have complained becausewhen they sit in the cockpit and look through their windshield, they see light-colored, raw epoxy on the inside of the forward fairing. To prevent this, before I fastened down the windshield, I put the tape on the outside marking where the fairing would cover, then masked off inside on the workbench, and painted that lower 3/4" black (on the inside). Then when I had it mounted, I filled the little gap under the edge of the windshield with epoxy and flox, but I added a little black dye from a gel-coat repair kit to make it black as well. Since I had already painted the glareshield black, I now have everything that can be seen from the cockpit done black!
Well,I'll leave it there for the night. That way, I can tell of the disasters I find in the morning when I check the overlap fairing. Will I have glued the canopy shut? Will it be a horrible lumpy mess (hey, you can fix that with micro!)? Will it all have to come off and I'll have to start over? Angst takes over as I head off to bed.....
Remember, this stuff is art, not engineering, and art is in the eye of the beholder. Panic not...just pull on those latex gloves and charge in!
Paul Dye
