These instructions were found on a website that is no longer available.  I have found this to be a great method.


The Brushing Lacquer method. This gives me one of the hardest and lightest finishes I have ever gotten.
1: Super hard Finish
2: Super Fast Drying time (tack free usually in 15 minutes can add second coat within 1 to 2 hrs.
3: Idiot proof no mixing, just dip a brush and go for it as it is already as thin as water or thinner and spreads evenly.
4: Very Light Weight
1: Toxic Fumes needs plenty of ventilation ( I do mine on back porch or in garage)
2: Leaves a slight gumminess on top ( This gumminess is a styrene that is added to it which helps it cure rock hard. It comes off quickly and easily when wet sanding with 220 or 320 grit paper but you initially go through a lot of paper at the very start after you get that layer off a sheet will go a long way)

Also here is the reason it comes in as the lightest. Like the older automotive lacquers, you have a color (pigment) and a carrier (the lacquer liquid). The liquid "Carries" the pigment and glues it to the part, in the case of polyurethane finish it is a clear type pigment. (I know this isn’t scientific or 100% accurate, but for most people they will get the idea) Now with the Lacquer based product the liquid evaporates in the air. 80% of the product is normally the carrier which evaporates, and 20% of the product is actual material which will stay on your plane. That is why even though it may be tack free in 15 minutes you need to let it breath for an hour to allow it time to keep evaporating. So if you have 10 lbs of a material and 80% of it evaporates off your left with only 2 lbs. Epoxy, and Polyester resin doesn’t have anything to evaporate it just hardens chemically thus the weight you put on is the added weight it will add to your plane.

Finally you have all the technical background and my reasons why I use certain products we can now get down to business. Sorry to bore you but if I let you go blindly along and just do it, then if something goes wrong or someone tells you their way is best and this is wrong, then at least you will have some idea of why you are doing what you are so you can have an intelligent discussion with someone or know what something is doing if you are having problems. Secondly because this technique will work with any of the above products so you are informed of all their properties.

Okay the way I don’t do it but can be done just as easily is to open your can of lacquer based polyurethane and to wet out the top of the wing. You have plenty of working time so if you want you can do 1 side at a time or the entire wing. For now let’s just do one side. You then want to lay your glass in place and dry brush it down letting the resins underneath hold it in place. You then do the same to the other side and let it sit for about a half an hour until it is cured fairly well. Then flip and do the bottom the same way.
The problem I have with this is that there is no weight to the polyurethane as it is thin as water and goes on just as thin. Now we all know they fold the glass cloth and those folds don’t like to lay flat very well as thin as this stuff is.

This is the way I solve that problem and works out very good.

Instead of using the polyurethane to hold the glass down I stand back a couple feet and using some Elmer’s Duro or 3-M spray adhesive mist a very light coat over the top of the wing. I then lay down my glass and use my hands to smooth out any wrinkles. This super light coat of adhesive helps out tremendously in holding the cloth down to the surface and around the leading and trailing edges. I then use a nice soft paint brush and brush on a coat of polyurethane doing the entire top half of the wing and the LE and TE.

NOTE: It is best to do this with the wing raised up on some sandbags or something so that after you put a coat of polyurethane down you can go around it with your brush underneath to make sure you don’t have any drips or runs. This is very important since this stuff is so thin it will sometimes run.

Let this sit for about one hour to set good. Later on you won’t have to wait so long but this is the most important coat as it is what adheres your glass to your plane. After an hour flip your wing over and trim any loose glass and lightly sand any rough areas. You want to be careful here you do not go pulling on the glass and loosen it. (It only has 1 thin coat of resin on it and it is just sticking it to the wood it will need more coats to seal it down good.) Now you want to repeat what you have done to the top layer on the bottom and that is spray a light layer of 3-M (or your favorite spray glue) and lay the bottom wing glass down and smooth it out. Add a coat of polyurethane to it, check for drips and let it set for an hour.

After the bottom dries flip the wing over again and trim the glass and lightly sand and rough spots. (If you have to do any sanding be very careful. You only want to sand if you have a run or something because the sandpaper will mess up your glass if you aren't careful.

Now the glassing process gets easier. You want to put a coat of Polyurethane on the top of the wing, let set about 1/2 hr or until the surface feels good and dry, then flip the wing and put a coat on the bottom.

NOTE: Do not sand between coats. Lacquer based polyurethane creates a chemical bond. What this means is that when you add another coat over a previous coat it will "melt" into the previous layer, which means there isn’t no way you will have layers peeling off over time. Also because the can says right on it do not sand between coats.

While you are waiting for the coats to dry, Go ahead and cut your cloth for your fuselage. When doing the fuselage I like to make the fin glass one piece, but you can do it in two if you like. I usually cut my glass for the fuse so that it overlaps the stab and fin glass which seems to make a nicer seam.

About this time your wing should be ready for another coat. You now have another option if you like (or can do it) and that is if you have a way of hanging your wing on edge you can do both top and bottom at the same time. I have done this with a twin by using wires through the motor mount brackets and tying it up to a clothesline. On a wing without nacelles I just drill a small hole into the dowel used to pin the wing to the fuse and wire it up this way. There is a downside to this and that is because the polyurethane is so thin you get more of a chance of having runs or drips. The good side is you can do both sides at once cutting down on time. The thing you will notice as a big difference between Polyurethane and epoxy is that you can brush it on and don’t have to worry about using a credit card or like material to "Skreet" your resin on like you have to with epoxy. In-between coats on your wing you can use the same technique on the fuse. I spray glue the top half of the fuse including the fin and the top of the stab and start glassing here.

Because this lacquer based polyurethane is so thin it may take 4 to 6 coats to fill the weave of .5 oz glass. Then after the weave is filled I usually put three extra coats on so that I can wet sand the part smooth. Because it dries fast you can have all your glass cut Friday night and spend about 8 hrs on a Saturday and have your entire plane glassed fully. I then like to let my plane sit for 2 or 3 days before I start wet sanding the entire plane with 320 to give me a perfectly smooth finish. Then I can finish it in my favorite finish techniques.

One last thing to remember and that is even though I only lightly touched on the fuse the technique is the same, do the top glass flip over trim, sand if needed, do the bottom. If it is a single engine plane you can hang it by the motor mount and if not you can use the wing mounting area to hang it by.