Installing fiberglass

[Bootlegger]

   Fellows, what is the best method you have found for getting fiber glass to lay down smoothly?  I am wanting to cover the center section of a foam wing for extra strength, and also over the nose of a model for strength and smoothness.

   Thanks for your ideas, and  Merry CHRISTmas  to all.
  One other thing, I plan to use 3/4 ounce glass cloth, and where have you found the best cloth?  Again thanks...

 

[bob whitney]

use a light coat of 3M contact spray  to hold cloth down then brush on the resin and wipe off excess

[George Truett]

Gil,  I have been buying glass cloth from Steve Thayer more than 20 years now.  I have never found a better deal on quality glass cloth.  https://www.thayercraft.com/fiberglass-for-models.html
I have heard of using the 3M-77 method but I never bother.  Cut the cloth to size and lay on your part, smoothing it with your hands after you lay it down.  Start brushing your resin on at the center, working to the edges.  I use 1" chip brushes from Harbor Freight and throw them away after 1use.  After brushing the resin on, use a business or playing card to squeegee off all the excess.  You can also soak it up with soft paper towels like Viva.  If you lift the cloth any removing resin, just use a fresh card or your same brush to smooth it back down.  I use the same epoxy laminating resin I use for making fuselages simply because I have it and it works.  Zap or Bob Smith Finishing Epoxy works just fine.

[Ken Bird]

The trick I use for any weight fiberglass cloth is to thoroughly soak the cloth with resin and then steamroller it down with a roll of toilet paper. Cheap stuff works great. You will want use the direction of the roll that does not unfurl. The excess resin soaks into the TP and you peel it off and continue. Works with polyester finishing resins as well as epoxies. A second coat of resin after the first one dries will be necessary to fill the weave but you will end up with a flat surface without any wrinkles or excess resin.

 Ken 

[Avaiojet]

The trick I use for any weight fiberglass cloth is to thoroughly soak the cloth with resin and then steamroller it down with a roll of toilet paper. Cheap stuff works great. You will want use the direction of the roll that does not unfurl. The excess resin soaks into the TP and you peel it off and continue. Works with polyester finishing resins as well as epoxies. A second coat of resin after the first one dries will be necessary to fill the weave but you will end up with a flat surface without any wrinkles or excess resin.

 Ken

Ken,

I'm glad you mentioned "Polyester Finishing Resin" because I get trolled and marginalized every time I bring up PFR. 

I posted Sig's offering on Polyester Finishing Resin over at CFC Graphic's vendor's corner.

PFR is all the R/C pattern guys used for years, including myself. They taught me. 

I'd apply one coat of PFR thinned 50% with acetone on the balsa, let dry to the touch then scuff up lightly. Clean extremely well.

I would then lay the dry cloth in place and apply another coat reduced where it's brushable without pulling the cloth.

After the panel was given this coat, toilet paper, unused preferred  , was spread onto the surface, pressed only to remove the excess as 'blotting.' Lift the toilet paper gently then look for areas that may be 'floating,' rub them down, but generally doesn't happen.

Here's an interesting thing. Guys would do another coat the same way for extra buildup. I would just load it up with a good grade auto primer applied wet.

Most know the rest.

No photos this time. 

[Fred Cronenwett]

I have been fiber glassing my models for over 20 years now, below is a video I did recently for a Fox 35 speed model. I have several models that were fiber glassed and then never painted, the stuff is fuel proof.

3/4 ounce glass cloth and Zpoxy all the way

Fred

[Avaiojet]

Nice work Fred.

I found this in my archives. My last purchase was with this vendor.

https://www.fiberglasswarehouse.com/product/style-106-75-oz-x-38-fiberglass-cloth/

[TDM]

That will work great for a speed model where weight is not a concern. If it is for a stunt model that technique adds a lot of unnecessary weight in particular the way the epoxy is applied. Also in that application where torsion stiffness is important I would lay the cloth bias at 45 degrees.
To do this light and practical you must vacuum all the dust off the wood then use a roller with little epoxy in it (if you run it on a towel there should be no visible wet spots on the towel) and use that to apply the epoxy. I agree 3M77 lightly applied is of a benefit to hold the glass in place.
And merry Christmas to you too.

[Steve Helmick]

Fred Cronenwett was maybe being shy, but he published an article on the topic in the Controline Scale column he writes in (believe it or don't) Model Aviation, June 2018 issue. I hat to see a good article going ignored.

I last did this trick on 3 sets of F1A Nordic glider wings. That was .60 oz imported German FG cloth, applied on a 45 degree bias. I used some sort of slow-ish drying epoxy glue thinned with alcohol (shellac thinner from the hardware store). I applied a couple coats of thinned Nitrate to the 1/32" sheeted "C-Tube) and let it dry overnight. Cut the glass to a strip with excess, smoothed it out and brushed it down with the thinned epoxy, then rolled over it with a roll of TP to soak up the excess, giving a dry appearance. Trimmed and sanded lightly, then covered with Nitrate and Japanese tissue. This give the stiffness, but still a smooth surface pretty much ready to paint. On a stunter, I'd think about using silkspan or CF over the FG to give me something that is thicker and can be sanded better than tissue. My experience was that spray glue, hair spray, etc., wasn't needed, but you try what you want and decide for yourself!      Steve

[Target]

Use Twill vs plain weave on compound curves.