Draggy

Hello,
I know this has been covered many times, but I needed some experienced opinions on what is best for coating or "glassing" epo foam on edf type airplanes? I have read of various techniques, but I feel I need more info. before I decide on which one to use. I mainly want more durability, as we all do. I am a longtime hobbyist, but new to foam edf's. Thanks for any help offered!


Draggy.

Ductedfann

My Feedback: (2)

Hello Draggy,

With EPO foam any of the methods you have most likly seen will work fine for durability. If it's about hard landings, dings, and hanger rash type durability, you can use carbon fiber or balsa in the corners or in areas where you know you will have the greatest chance of impacts like the wing tips, leading edges, the tips of tail, (elevator, rudder), and the belly if you don't have landing gear.
Just keep in mind that all these things add weight to your foamy, which works against the beauty of foam planes, which was most likly designed to be inexpensive, quick, and easy to get into the air, and not to be a kit that you have to put a lot of work and time into. Another thing to consider is that you did purchase an EPO foam plane and EPO foam is considered pretty resiliant.

Morris, Ductedfans.com

MaxThrottle

If its just reducing foam rash and dings Polycrylic like Minwax is very easy to brush on. I light especially if sprayed or brushed on in thin coats.
Its not structural though. For that fine fibre glass and epoxy thinned with isopropanol. The isopropanol evapourates as it sets. Then lots of sanding. Then repaint.
My experience had been start looking into composite/fibre bodies.

Draggy

Thanks!
For those who replied, thanks! I feel that it is not a good trade off to add too much weight when trying to strengthen foam also. I am trying to achieve as much power to weight as possible, and with most minor crashes, repair is fairly simple anyway. Clear tape is so tough, I think this works very well on most pressure points, and leading edges of the wings, ect. I also think I will try some type of polyurethane spray as well, though not go overboard to avoid the dreaded weight gains.


Draggy.

FrankWilliams

My Feedback: (13)

I would avoid Isopropyl and use Denatured. Isopropyl has water in it and tends to leave a film after it dries and I would bet that would affect the way the epoxy cures. I've always used Denatured when glassing with epoxy (and waterproofing boat hulls). Lately I've been using water-based polyurethane for glassing and applying silkspan (yup, I do that sometimes) and have been extremely happy with it. It's not as durable as epoxy, but it's lightweight, easy to sand and cleans up with water... and the smell isn't nearly as bad.

-Frank

ny_hawk

Zpoxy does not smell at all, adds little weight when used correctly and sands very well..

raido56

My Feedback: (10)

Hi, I like 1/2 oz F/G cloth and WBPU as it adds very little extra weight. Plus you can paint over it with any kind of paint. I have done a few jets this way because of the extra power I put in them and to keep them looking good. Here are a few pic's of my Jas-39, F-5e and F-16 these were all covered from nose to tail this way. The T-45 just has a coat of WBPU over the foam no glass on this one.

Keep em flying
raido56/ Herb

jesses151

My Feedback: (1)

Hey, I  don't know if anyone else has mentioned this stuff, but I've been using the liquid sheeting offered by wowplanes.com. Here's the link: http://www.wowplanes.com/product_inf...f4abd5e19d11b3
This stuff works great.
-Jesse

BD5wingnut

My Feedback: (1)

I like to use 3/4 or 1oz glass on the fuse and 1/2 oz on everything else with West Systems epoxy. The trick, well my trick, to keeping things light is to use those little throw-away foam rollers. Get the higher density white foam ones that slip onto the metal and plastic handle, the cheaper yellow (low density) foam rollers with cheap throw away handle do not do so well.

I sand the foam (on the aircraft) and vacuum carefully to remove all the dust. Do not forget to vacuum the work area as well, the foam dust has a nasty static charge and will contaminate your work when you least want it.

With the area cleaned and prepped for glass work, roll out your glass and cut two pieces (one Top/one Bottom) on a bias (fibers running at 45 degree angles to the center-line) cut them well over-sized for extra material to grasp. Be aware the glass will tend to stretch and distort when cut on a bias, but you will not get wrinkles or puckers when applied properly.

Next I dust (just a light spritzing) 3M 77 spray adhesive onto the bottom half of the fuse or wing, do this outside or where you do not mind the spray adhesive getting all over EVERYTHING. Now carefully lay the glass down on the fuse/wing and smooth it flat working from the middle out, ensuring good contact. On the fuse I pick a line about half way around and carefully cut the glass with a very sharp blade. I do not cut much into the foam, only deep enough to cut the glass. On wings use the leading and trailing edges to cut along.

Now go back outside and dust the other side with the 77 spray and repeat the glass step as well, except overlap the first layer by about a 1/4 inch or so. Now you mix up a couple of ounces of resin which I do not like to thin, proper laminating resin will be thin enough. Stir it thoroughly and let it stand for a minute or two, this is called dwell time and allows the resin to "Homogenize" kinda. You will be using slow resin of course, no need to rush yourself needlessly.

Pour the resin in a plastic or foam plate and break-out your foam roller, saturate it well and go to town, you want to move the resin around quickly and evenly trying not to spend too much time in one area as the glass will start to lift. I do this in two stages which allows me to rest the fuse on one side while the resin cures then do the other side and let it cure. Sometimes, I have the ability to hang the part from the ceiling and do the whole unit at once.

Of course then begins the fun of sanding, filling and painting. Your finish applies here...

Good luck, Wolf

vicman

My Feedback: (10)

A trick for cutting out the glass cloth is to lay it out on cardboard and your knife will zip right thru it with a nice clean edge.

I second West Systems epoxy, after you use it one time with the pumpers, you will never think of using anything else again.

BD5wingnut

My Feedback: (1)

Yes the pumps are a great boon to measuring the epoxy.

I use one of the circular cutters, kinda like a pizza cutter. Use on a piece of vinyl flooring.

vicman

My Feedback: (10)

Yeah, I tried the pizza cutter too but slicing over just plain ol cardboard seems to give me a much cleaner cut. By getting that stretch free cut I also seem to hold my glass in the same shape as I want it to go onto the plane better. Just my experience.