i am trying to learn how to fiberglass??i know how to use the cloth,but i'm wondering what do you do with the glass?? do you put the glass on top fo the cloth.or do you dip the cloth in the glass (like papermache~).what is the deal with this??please relay some of your methods that work (or don't work).any thing will be greatly appreciated thank john

This will help:

http://www.rcuniverse.com/showthrea...d=&goto=newpost

Bish
K7QCP

I give up.. Trying to post stuff here is not worth the trouble.

When fiberglassing, if you bear in mind exactly why it's so strong, you can improve your results.

Fiberglassing basically works by stopping any tiny cracks that develop under stress from traveling through the whole structure and making the whole thing fail.

The joint between the glass fibers and the matrix (the glue) is weaker than the glass fiber itself, so any crack that tries to pass through it gets diverted along the length of the fiber as the material starts to delaminate, which is a different direction from the original stress, so tends to it stops the crack from developing right across the structure resulting in the whole thing breaking..

It's a bit like trying to tear a plastic film without starting it by creating a crack with your teeth!

That's why it tends to buzz before it finally breaks, and finally explodes when it fails.

Sooo, try to make sure the fibers are at 90 degrees to most likely stress direction, and concentrate more glass fiber at the high stress points.

Hope that helped a bit!

David C.

If you are talking about glassing the wing or any other part of the plane for the sole purpose of finishing, then lay the glass on the surface and resin on top of the glass.
Here's what works for me: http://www.gailvin.com/glassing.htm

david thanks for the input,but i'm looking for ways to put on the fiberglass so, how do you do it?? tell me your method.

goggles thanks for the link.is thats the way you glass an airplane?it sounds like a great way to do it.i give it a try.


my method is to dip the cloth in the glass then apply.i know it's a mess way to do it,but it's the only way to keep the cloth from fraying.now you have to understand that i've never put fiberglass on an airplane.i've used it on a boat with a hole in it.that was my first attempt at fiberglass.so you know i'm not an expert.

now, what kind of glass resin do you use?why is it thined?will the bondo resin work?thats whats i used on my boat.

thanks for all the posts so far keep them coming.
john

Like I have on the web site, you can use Z-Pozy Finishing Resin http://www.zapglue.com/. I have heard of others using West Systems resin also but I have only used Z-Poxy. The reason I thin it is to cut back on the amount of resin used so it will add very little weight. Remember you are not looking to add strength but a perfect surface to paint.

If you lay the cloth down and use the brush to make static you won't get hardly any fraying. I'm not sure I would dip the cloth in the resin first....seems like a lot of waste when it's expensive stuff.

I've never heard of bondo resin, is it some sort of polyester resin....does it stink??

Let us know if you have more questions.

Remember, keep it light!

that bondo stuff came from the auto parts store.i can't remember if it had an odor or not.it cane in a gallon size can.it also came with the cloth and a cup to mix it in.it was my first time working with fiberglass,so i did waste a lot of it.it was about $8.00 a gallon.it might would make a good sub for z-poxy,if it would take to denatured alcohol.i bought mine at wal-mart.
john

What you got from the auto parts store is probably polyester resin and the cloth is real thick. I've tried polyester resin but didn't like it because it wouldn't cure right sometimes.

For airplane use get glass cloth that is 3/4 or 1 oz. weight from the hobby shop or someplace like Sig or Tower. That stuff is very light, like silk. You cut it out a little bigger than the area you're doing, lay it on the surface and smooth it out.

Then you brush on either epoxy finishing resin(which is thin), regular epoxy thinned with acetone or even water-based polyurethane. You start from the middle and work towards the edges. After it hardens you trim or sand off the excess cloth, then put on another thin coat. After that hardens you can start priming and sanding.

thanks for the reply tmoth4.sounds likeeveryone does it the same way.