jtisch

Greetings,
I am getting close to glassing the fuselage for my Albatros DIII.I have been glassing small parts latley but really haven't glassed a large surface for almost 25 years.At that time using polyester resin was what everyone seemed to be doing and I have stuck with it since then.My question,is there a better way to go?I would like something less stinky and messy yet still provide the puncture resistance that I want in the first place.I know people are using epoxy but is that really any better?I also heard about people using urethane but I wonder if that would provide the same strength.TIA for sharing your experiences.

J

John Sohm

My Feedback: (9)

For hard surface, I don't think you'll find anything much better than polyester resin. Do yourself a favor and order some fresh stuff from SIG. K&B is no longer available and Sig is about the best replacement going, you might even like it better. Epoxy would be a close second. Zap Z-Poxy Finishing Resin is the stuff I use. You can sand it a bit but nothing like you can with polyester. Train of thought with epoxy is you don't really sand it, you sand the filler/primer you apply next. I do sand off the runs and any slight "goofs" that might appear as it cures. As for urethane, I'm going to try it but it definitely isn't as hard or secure a bond as either of the previous methods. For one thing, the fiberglass is sized with a chemical that reacts with either polyester or epoxy (or both) to form a chemical bond to the glass. The usual sizing agents are Silane or Volan but there are others. I don't know if the polyurethane has the same reaction to those agents and the fiberglass distributors don't mention anything about it either. So I'm not sure how well it will endure over time. The one benefit I do see to the polyurethane method is less smell and less cost. A pint or less of either epoxy or polyester will run in the neighborhood of $15 but a gallon of polyurethane will set you back about $22. That's about it.

Steve Collins

My Feedback: (8)

I am currently using the West System epoxy which is a very good epoxy. I used to use Polyester but I eventually gave it up over the strong odor.

Properly sanded, you don't really have a hard or puncture resistant surface. That isn't the purpose for glassing a model. It really only serves as a stable surface for the application of paint.

Deadeye

Glassing with Minwax water based polyurethane is an excellent route to go. It takes more applications, but it dries quick, cleans up with water, and is lighter in weight in the end. The pictured TF Cessna 182 was glassed this way, and from bare wood to glassed, primed, painted, and cleared only added 11 oz of weight.

Mike Emilio

http://www.rcuniverse.com/forum/m_72..._1/key_/tm.htm

If you can scrounge one of these spray guns, , , , go for it!

jtisch

In my first post I wrote "puncture resistant" but that my have been too bold of a statement.I just want to avoid somewhat denting the balsa sheeting.

Thanks to all who have replied.

J

mgnostic

I've been happy with Kwik Poly. It is very thin and wets out nicely. It's biggest limitation is that it sets up VERY quickly. It also means that you can put down a second layer very quickly. I buy disposable brushes by the bagful and mix it 1/2 to 1 oz at a time and have brush fast to avoid it setting up in the cup. Once spread where it can stay a little cooler it cures more slowly. It sands nicely.

Jeff Foley

My Feedback: (45)

I too use West Systems with good results. I used polyester for many years and got tired of the smell and poor curing qualities. I use one coat of the West Systems to attach the cloth and "steam roll" it with toilet paper to blot up as much as possible. After it cures, sand lightly without cutting through the cloth and apply another coat of resin. After that cures....then the real sanding starts. I use 80 or 100 grit to get it down to a smooth even finish with no glossy spots. Use a block where you can. You are then ready for primer. Also.....a little heat will help the epoxy cure quicker and harder, making it less likely to load up the sandpaper.

saramos

I also like and use West Systems epoxy with .5 to .75 oz glass. I brush the glass down onto the surface with a soft brush. This creates a static cling and the glass lays down smooth. I apply the epoxy with an acid brush, working from the center outward. I then squeegee off what I can with a small plastic squeegee. Phony credit cards in the mail work well for this. Then I roll the toilet paper roll over until the gloss is gone.
I don't use a second coat of epoxy, I fill the weave of the glass with several coats of high build automotive primer, wet sanding between primer coats with 320 to 400 grit until the weave is just exposed, repeating until I get a smooth, uniform surface. Then, it's on to painting.

Here's my TF Spitfire painted with latex, and my 4 * with sheeted and glassed wings painted with automotive metallic poly paints.

Scott