Fiberglassing Made Easy

“Glassing Rules…Monokote Drools”

It’s stronger, looks better, easier to repair, resistant to the elements and just plain looks better. You should be able to fiberglass an entire .60 size model, half hour at a time, over a few evenings…easy!

Materials

• Fiberglass cloth sold by the yard. Commercially available from a handful of places.
• 1/2 oz or 3/4oz
• Finishing Resin. (Not Epoxy Resin) ZAP (Pacer) Finishing Resin, 8 oz sets
• Alternate: Liquid Polyurethane
• Rubber gloves
• Measured mixing cups
• Paper clips
• Paint brush
• Old credit card or 1/64 plywood

Preparation

• Prepare your plane just like you do when you Monokote a plane. No high spots, no low spots, no seams and no bumps.
• Take special care of high spots! They should be fixed before you glass. Low spots are easier to manage after glassing but high spots are real trouble. Seams of sheeting are especially troublesome and common!
• Clean good. Then use a Tack rag to get everything off.

Wings

• Do bottom first
• Then do top

Fuselage

• Do top first
• Then do bottom

Control surfaces

• Do bottom first
• Then do top

STEP ONE: Tack cloth one more time!

STEP TWO: For Wing and Control Surfaces cut cloth 1- 1-1/2 inches larger than needed. I cut my glass with a fresh blade on my glass table top. For Fuse you want to cover as much of the airframe as you can in one piece as big as you can control. If you take your time and make a paper template you should be able to glass the entire fuse in two pieces. If you do the top first you should, depending on the plane, be able to glass 90 percent of the visible part of the top and sides of the fuse with one piece.

STEP THREE: Lay glass on surface. Do not drag across. Do not snag.

STEP FOUR: Run paint brush over glass very carefully to create static electricity to hold cloth in place. It’s amazing how this will hold the glass in place for you! The more you tug at and drag the cloth it will snag and make runners which are a real pain to work around.

STEP FIVE: Mix no more than 1 oz of Finishing Resin at a time. This stuff takes 2-3 hours before it starts to set up so you can go back and make more if you need without worrying about the surface that you have started.

STEP SIX: Dribble a little resin over center section of surface. A little goes along way.

STEP SEVEN: Work resin over glass from the center out in ALL directions with your old credit card or a smooth piece of 1/64 plywood. You do not need to work this very hard. Just slowly smooth it out until you feel you’ve got the entire surface covered. All you want to do is saturate the cloth enough to see the color of the cloth go from white to the color of the balsa.

STEP EIGHT: Check for “white” spots. Areas where you did not saturate with resin will look white to the naked eye and easy to spot

Check for “pools”. Areas where you have too much resin will look like pools across the surface.

STEP NINE: “White” spots can be filled with a little dab of resin on your finger then smeared into the cloth.

“Pools” can be drained by taking your card and simply scraping off the additional resin. The glass in the pools will “float” in the pool rather than lay on the balsa. Resin pools add weight not strength. These low spots will be treated later in the process and made stronger and lighter

STEP TEN: Run clips along edge, if needed, to add weight to the glass to conform to surface such as wing tips and leading edges etc.

STEP ELEVEN: Cure overnight. Have a beverage, watch a movie, enjoy life.

STEP TWELVE: Trim off excessive glass with a 120 sanding block flip over and do the other side. Overlap the two sides with glass at the leading edge etc.

A .60 size wing should take about 30 minutes from tack rag to paper clips. THAT’S IT!

Prepare for Painting

STEP ONE: Wet sand entire glassed surface with 120. Just to get a clean, smooth surface. You do not want to bite through the glass you just layed down. You just want to prepare it for the next step.

STEP TWO: Add a “Flow coat” of Finishing Resin. Go back over the entire surface with another coat of Finishing Resin to fill in the weave. If it took 1 oz to do a wing it will take about ¼ of an ounce or less to do the “Flow Coat”. Coat all surfaces. This will take about ¼ of the time it took to do the first coat.

STEP THREE: Cure overnight. Have a beverage, watch a movie, enjoy life.

STEP FOUR: Wet sand with 180-220. Just to get a nice smooth feel. Let dry.

STEP FOUR: Spray entire surface with a decent coat of sandable primer. I use lacquer based automotive primer. Let dry (15 minutes). After the primer dries your ego will take a huge hit because every flaw and bump you thought you got when you were sanding before you glassed will now show up like a big wart! Don’t worry!

STEP FIVE: Look for high and low spots. The high spots are hard to fix at this point. There isn’t much you can do expect try to hide them with panel lines when you paint. Low spots, where the “pools” used to be are easier to manage now. Fill low spots, scratches, dings and any offensive depressions in surface sparingly with Bondo. That’s right Bondo. Light weight and strong! Much stronger than a pool of resin. If you see and area of weave that is not filled in (believe me you will spot it in second) just prepare some resin and fill it back in with a dab or two and a little piece of glass.

STEP SIX: Let dry. This shouldn’t take more than n hour depending on how humid it is and how thick the Bondo is. If you had to use resin that will of course take a while to cure.

STEP SEVEN: Wet sand surface, primer and Bondo with 180-220. You basically will remove 95 percent of all the primer and Bondo. When you are done you will have filled all the remaining weave, low spots and have a very smooth glass like finish to paint on. If done well it will look like it has the mange!

STEP EIGHT: Prime and paint. Depending on the color of paint you should be able to just put a dusting of primer on the surface. Some colors you will have to lay a full coat of primer to get your true color to show through (Red, Yellow). Paint the solid colors, wet sand and then paint them again. You’ll be amazed at how smooth and shinny it looks with a wet sanding in between coats.. Or dull and mean if you are going for that look.

REPAIRS: If your plane should happen to run into something offensive such as the ground, a tree, a corn stalk, kitchen table, car door, lawn mover or any other offensive object, repairs can be made very easy. If the balsa is damaged replace balsa as needed. If the area is moderately gouged just clean out the area with Windex, rubbing alcohol, let dry. A 5 inch hole in the wing won’t take long at all. Fix damaged area with Balsa or filler. The beauty of glass is that you can lay glass right over the painted edge of the good and damaged area then proceed to “feather” the new glass into the original glass and proceed with the before techniques. You will never notice the repair if the colors match up. Because the glass and resin is so light, smooth and thin you can get away with it. It’s like fixing a dent in a car. First you fix the biggest part of the dent then you fill in the rough edges and then you sand and paint.

ALTERNATE METHOD: Polyurethane. I have tried this twice so far and it works just like the resin but it is much thinner and will require many more coats (4-8) to fill in the weave. Also because it is thinner it is not as “sticky” as the resin and harder to get around compound curves. But it does work and is cheaper than resin and shows a very, very nice finish. It adds steps but it does dry a lot faster than the resin and sands just as easy. But because it dries so fast you have to work fast! If you were doing some very flat surfaces and didn’t have to go around a ton of compound curves this works very well. I prefer the resin because I really don’t want to be rushing at this stage of the game.

Fiberglassing Links:

Fiberglassing with Polyurethane

Come to the May 3^rd meeting to get a lesson on Scale building and painting

by Chuck Hamilton, future Scale Masters competitor!