Here is a How-To For those of you who have never glassed a plane before. This is how I do it and I know there are other ways but this is the way I do it and have very good luck with it.



OK Guys I need to Clear something up via a letter from one of my readers and thought this would help. The Deft I use is not laquer based Poly U but is Deft Brushing Laquer. I posted the E-Mail that I recieved Explaining it. other than screwing up on the name the can and everything is the same along with another product I have used before and never thought of and that is Defthane. I have not used it on planes but in dads furnature shop for finishing desktops etc and it will work here. Also I have had questions on the brushing laquer being glow proof. All Laquer finishes are Glow RESISTANT not glow proof. this means if you fly and clean up the fuel afterwords it will be fine but remember we paint over it anyways so this point is pretty much moot.

I have really enjoyed reading your articles. I especially enjoy your techniques on glassing with Deft products. One small technical error in your terminology has caused several people to ask unnecessary questions and be confused about some of the products you use. Deft Clear Wood Finish is a lacquer not a Polyurethane. Calling it a lacquer based Poly U is incorrect. It is a nitrocellulose lacquer and has nothing to do with Polyurethane.(They both are types of varnishes) Deft does have a Polyurethane product called Defthane. I have use both these products and have enjoyed both of them, but they are totally a different product. I am not trying to dis you or anything, I just want you to realize that Polyurethane is not lacquer based. Thanks again for your articles and knowledge with warbirds, I can't wait to try some of your techniques. Sincerely, Steve

To begin with, after my plane is all sheeted and ready to glass I first use 320 grit sandpaper and give it a nice sanding to get all the glue lumps etc out of the sheeting. Most of this should have already been done but you would have done it with a heavier grit paper leaving a rough surface and we are basically smoothing it out some.

NOTE: I get all the products used in this article at Lowes but you can use any brand laquer based product and most paint stores, Lowes, Home Depot, Meynards, Ace Hardware carry the products or another brand name of the product I will be mentioning here. This way I dont have to keep giving out where I get all this stuff as I get all mine at Lowes and I know some Lowes dont sell it so you have alternatives.

Now onward we go.

I use "Deft" Brand laquer based sanding sealer and give the entire plane 3 to 4 coats using 320 grit sandpaper and sanding the "Fuzz" off the part between each coat. This serves 2 functions 1: It seals the woodgrains so your balsa doesnt just keep sucking up your resins thus making the plane unnecessarily heavy. 2: It hardens your sheeting and also hardens and raises any hairs sitting on top so you can sand them off. This is very important if you want your glass to lay down good and flat against the surface.

After I have completed sealing my surfaces, I break out my glass and start with the wing panels because they are easiest. I lay out my glass and with a good SHARP pair of scissors cut it to a rough shape leaving 1/4 to 1/2 " overlap all around depending on how confident you are in getting it set right the first time.

Now I do a lot more than one part at a time, but in order to teach proper techniques I will do it the appropriate way for most people and when you get better and more confident you can adjust the amount you do at one time.

Now we have 4 sheets of glass, top left, top right, bottom left, and bottom right. Now when I am glassing my wing I usually remove my retracts and use some masking tape to wrap up my hoses and wires to keep them nice and for other reasons we shall see later. Also you want to remove all moveable surfaces ie. flaps and ailerons. Now standing (or sitting) behind the wing lay your pieces of glass off to the side next to the wing half they will be going on so that you have the proper sections where they go. (I know both sides of the wing should be the same but hey lets play it safe)

Now we get to have fun and start doing something. First thing is there are two ways of doing this. I will explain the way I dont do it first.

First I DO use "Deft" brand Brushing Laquer Just not normally at this starting point. And I must also explain why I use it. There is 4 different types of finishing resins a person could use for glassing.
1: Polyester Resin
2: Epoxy
3: Water Based Polyurethane
4: Brushing Laquer

Lets examine these one at a time.

First Polyester Resin, probably one of the best products you can glass with. Actually it is what IS used to glass with for such things as boats, shower stalls, bath tubs, insecticide spraying drums etc.
There are 2 problems with this that makes it unpreferred for glassing a plane, although you could use it for making a mold of a plane and would be great.
First problem is that it generates a lot of heat. You can adjust this with the amount of catalyst you use, but most people are not expert enough to properly judge this as air temp and humidity has a lot to do with how much catalyst you would want to use.
Second Problem is it is fairly heavy if not put on correctly, and also the heat it can gernerate could very easily warp a surface as it cures. On the Plus side is it is hard as a rock and almost impervious to anything it will be in contact with in the hobby business.

Next, Epoxy. Most of us have had exposure to epoxy and it can be used for glassing planes in fact most people use it.
Cons:
1: It leaves a soft finish. By meaning soft it will sometimnes if not exactly mixed or thinned too much with alcohol can be soft and gummy or rubbery feeling making it hard to sand. Now before any die hard epoxy guys chime in, I am not saying it always comes out that way but if a person is not used to using it they can mess up a perfectly good plane all too easy.
2: It is ungodly expensive.
3: It is not as fuelproof as some people think. I have seen glow fuel over time cause firewalls to come off due to deterioration of the epoxy. The only conclusion we could come up with was because of the gueyness of the epoxy it was attacked, thus I use polyurethane or brushing laquer on my firewalls as they are fuel resistant.
Next, Water Based Polyurethane. Now this I would prefer over epoxy as ease of using since there is no mixing and is idiot proof basically.
The drawbacks with this product:
The time it takes to dry as being water based the water carrier needs to evaporate
The product does put off a light odor, but isnt too bad unless a family member is very sensative to smells
And the problem I had with it, but not everyone does, is that I got some slight warpage to my sheeting (remember wood and water dont mix well) But you would just have to try it on a sample piece of wood to see how it reacts. I believe some of how it reacts is based on humidity and temperature, But I have heard from a heck of a lot of people that they use it without problems and so I stated this is just my experience.

Now the Last one, The one I use all the time Brushing Laquer. This gives me one of the hardest and lightest finishes I have ever gotten.
Pros
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: Idiotproof no mixing, just dip a brush and go for it as it is already as thin as water or thinner hehe and spreads evenly.
4: Very Light Weight
Cons:
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 wetsanding 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 laquers, you have a color (pigment) and a carrier (the laquer 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 isnt scientific or 100% accurate, but for most people they will get the idea) Now with the Laquer 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 doesnt 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 dont do it but can be done just as easily is to open your can of laquer based polyurethane and to wet out the top fo 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 lets 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 abt 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 dont 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 Elmers 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 dont 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 wont 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 drys 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 abt 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. Laquer 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 ain't no way you will have layers peeling off over time. Also because the can says right on it do not sand between coats hehehe.

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 dont have to worry abt 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 laquer 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 wetsand the part smooth. because it drys fast you can have all your glass cut friday night and spend abt 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 wetsanding 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.

Good Luck
Joe