Fiberglass help

[GySgtUSMC]

Chris,

Do have any good ideas on glassing a balsa fuse with .56 oz cloth?


WB poly / boat resin / epoxy

[Grug - American Neanderthal]

Hey Marty, Tom Shinneman had at one time made a post about it on RCO way back when and I stole it.

www.fubarhill.com/fiber.htm


I have used water based on a fuse and I liked it, though it is some softer than epoxy is. But clean up adn application was a heck of a lot easier.

[RetNavySuppo]

Dan Parsons used to market a 0.6 oz fiberglass cloth that was the lightest fiberglass you could get. I bought up a bunch before he went out of business. With the fiberglass, he included very detailed instructions about its application (about 5 pages).

If you want, I can photocopy the instructions and send them to you. By the way, he favored epoxy.

[ctdahle]

I'd read, or been shown Dan Parson's method years ago, and I think what I do is pretty much what he was recommending. I didn't realize he was not in business any more. He used to sell Gougeon (WEST) epoxy in modelling quantities, and I'm sure there is someone else doing it too. Quart cans with little pump dispensers for proper ratios of resin and hardener. Nice to have on hand, and cheaper then the 6 ounce bottles you get from the hobby shop, although that will do the job too.

Be careful glassing a whole model though, it is easy to get it way too heavy, but you can get a heck of a nice finish if you take your time.

Anymore I just apply fiberglass cloth in high stress areas, leaving some "open" balsa around it if I can to stick the Monokote.

Anyway epoxy is what I use. I thin it out with denatured alcohol to easy brushing consistency (think hot pancake syrup) and then brush it through the cloth with a 3/4" artist's brush. Go easy or the weight builds up fast. Squeegee off the excess with a scrap of balsa, old AMA card or a rubber squeegee pad. If I'm not doing a painted finish, that is as far as I go before I sand and cover.

For a painted finish, you need to fill the grain, so do a second coat, this time thinned out more with denatured alcohol (about like water) then thickened up a bit with microballoons. This is to fill the grain of the cloth. Add a drop or two of food color to the epoxy mix so you can tell where you have been with your brush.

I wet sand with those nifty little sanding sponges, to 600.

When it comes to painting and final finish, I can't help. I figured out a long time ago that I suck with an airbrush.

Eric, what water based product do you use? Epoxies are starting to really bother me. I get rashes and stuff.

[Grug - American Neanderthal]

I used the Minwax poly the 1st time, it was softer when it dried than I expected but worked ok tried another one, but the brand slips my mind now and I don't see the can on the bench anymore, it seeemd to be a little harder. Still the water based stuff doesn't get that super hardened coat that epoxy does, though it still seals off nicely and sands a lot easier it doesnt fill as fast. It sticks better if you are using film. I have both covered over and painted over it and it seems to work fine. I didn't get too carried away on finish, it was 40 sized warbird and I painted with flat paint which hid a lot.

[RetNavySuppo]

I use Pacer Z-Poxy finishing resin for fiberglass work because I want a hard finish. It has a nice long pot life. I minimize the weight of the epoxy by first giving the balsa 2 or 3 coats of thinned nitrate dope (sanding in between coats). This seals the wood and keeps it from absorbing too much epoxy. Any epoxy that is absorbed into the wood is useless weight. I want the epoxy ON the wood, not IN the wood. The epoxy sticks to the nitrate dope quite securely.

For sanding, I either wet sand or dry sand. Whichever way I sand, SHARP sandpaper is a must. I like the Norton 3X sandpapers (the dry is gray and the wet is black) that I find at Home Depot. I find that Monokote sticks very well to either sanded or unsanded fiberglass (at least this brand) as long as the surface is smooth.

For removing excess epoxy, I use a roll of toilet paper that I just roll along the surface. As the toilet paper picks up the epoxy, you just discard those sheets. This also presses down the fiberglass cloth and epoxy onto the balsa with a nice, even pressure.

I purchased some West System epoxy at Aircraft Spruce & Speciality Co. (www.aircraftspruce.com) but I haven't had the opportunity to test it out yet. The neat thing about this stuff is that you can purchase different hardeners that allow you to vary the cure time.

You can also use nitrate dope (instead of epoxy or water-based polyurethane paint) with the fiberglass cloth and then fill the weave with a compatible primer.

[Richard]

Here is the Polycrylic method I used, and to harden it left it out in the summer sun for a few days and the finish was hard as a rock. Using the finger nail you could not leave a mark in the finish.http://www.rcscalebuilder.com/forum/forum_posts.asp?TID=801&PN=2

[GySgtUSMC]

Thanks for all the great ideas and links.

I'm goint to give Eric and Richard's polycrylic method a shot. --- the no smell method ;D

Thanks again

[RonaldFodge]

RetNavySuppo:
Hello would you be willing to send that information to me?

[ctdahle]

Here's another good one.

[tejician1]

Richard has the best technique for HARDENING the Polycrylic water base varnish...Set it in the sun for a couple of hours and the surface get quite hard....

I also used this technique when finishing several large warbirds ( 1/5 scale T'bolt, 1/5 scale Heinkel HE 219, et al ) The 1/2 oz glass went down without a wimper and dried well, it also sands quite nice. Tho', it takes several more coats of the Poly Crylic to fill the weave, that's OK..lt is.better to apply many thin coats instead of one or two heavy epoxy coatings. The Poly Cryl is also more affordable than Z Poxy.

Trying to convert other modelers into trying the Poly Crylic method is almost like pulling teeth...Repairability of the Poly Crylic is excellent and is now SOP for laying down 1/2 & 3/4 oz glass cloth.

[Grug - American Neanderthal]

As long as there is sun and above 50 degrees. I will have to try that next time I do one.