Fiberglass Question

[cwbullet]

I found a web site that has cheap fiberglass: http://thayercraft.com/

I have a question after reviewing the website. I have question on silane or volan fiberglass. Are they useful for rockets and do they work with standard laminating epoxy?

It appears the site sells mostly to RC and surf board makers.

Chuck

[G_T]

The fiberglass itself is glass. Epoxy doesn't stick very well to glass, and neither does polyester. So, the fabric manufacturers apply a surface treatment to improve the bonding properties. From what I've seen, silane and volan, or modified or hybrid versions of these, are the most common. I'm not sure I've ever encountered anything else, actually.

Silane works well with epoxy. Volan works well with both epoxy and polyester resin. Volan makes a slightly more flexible fabric.

A finish is pretty much required for the glass. It does weaken the glass from what I've read, rather considerably, but without the finish you won't get the fabric to wet out or to bond well. In any event, properties stated for the glass already take into account the finish applied.

Useful for rockets - that is a function of the application and the fabric. There is no simple single answer.

Gerald

[cwbullet]

So,

you are saying that the silane and volan finish weaken the glass fibers?

[G_T]

Yes. But you have no choice. Without the finish, the bond to the resin will be very weak and the resulting layup will be weaker.

I don't think you are going to find fiberglass cloth without a surface treatment anyway. It would be contrary to the intended usage.

Gerald

[cwbullet]

Thank you. I need to buy some and the deals from Thayer are too good pass up.

[Sandy H.]

I've purchased from Thayer in the past. Good people.

Sandy.

[cwbullet]

Thanks. I appreciate the response.

[cavecentral]

I bought 20yd rolls of 7781 (9 oz) twice from them. First batch was good. Second batch just shipped.

I recommend them.