What kind of glass do I need?

[BlueNinja]

I have been wanting to get into fiberglassing. I want to know what kind of glass i need, as in the 3oz, 4oz, 5oz, etc. Most likely I will be doing light glassing, but what are the differences in strength?

 

[solrules]

It depends on what you're doing: For estes models, the lighter the better. I got 1.5oz glass from a hobby store to glass my Black Brant II, 2 layers of that stuff is super strong and easy to finish. For the bigger progects, I use the bondo fiberglass cloth (I have heard that is somewhere between 6-8oz), with a layer of 1.5oz over that, it turns out <u>much</u> stronger.

 

[BlueNinja]

SO the strength dpends on the weight? What is it measured by, ounces in a square yard?

I might get some of the cheap 3oz stuff from US composites.

 

[Ryan S.]

I use 6oz but this was for 4" 5,5" and 6" projects. It is a little tough to finish. it really depends on what you are doing

 

[SwingWing]

Originally posted by Blue_Ninja_150
SO the strength dpends on the weight? What is it measured by, ounces in a square yard?

I might get some of the cheap 3oz stuff from US composites.

The weight of the glass is measured is oz. per sq. yard. The weight of the final layup will be this weight plus the weight of the epoxy/resin.
The strength of the layup is proportional to the weight of the glass. You can also layer the glass. Two 3oz layers is roughly equal to a single 6oz.
There are also different types of "fabrics" The standard glass is known as E glass. There is S glass, Kevlar, Carbon fibre (or graphite) and ceramic glass.
there is a neat chart in the Aircraft Spruce and Specialties catalog that compares properties. It goes something like this:
.................Best<---------------------------------------------->Worst
COST-----------E Glass---S Glass--- Kevlar---Graphite---Ceramic

WEIGHT--------Kevlar---Graphite---S Glass---E Glass---Ceramic
(density)
STIFFNESS----Graphite---Kevlar----S Glass---Ceramic---E Glass

HEAT ----------Ceramic---S Glass---E Glass---Kevlar-----Graphite

TOUGHNESS----Kevlar---S Glass----E Glass---Ceramic---Graphite

IMPACT----------Kevlar----S Glass---E Glass---Ceramic---Graphite
RESISTACE

 

[Ray Dunakin]

Whatever you do, make sure you get the "half-full" glass, not the "half-empty" kind.