fiber glass guestion

[dmc602]

Ok it is getting warmer now so I plan to start doing some glass work. I will be using 1.5 matt on the stringers and ribs on the boat I am building. My question do I need more than one layer of matt?

[Bond-o]

Ayuh,... Just 1 layer of matt, per layer of cloth...

[drewpster]

A typical layup goes as follows;

roll on resin
2 layers of matt
1 layer of Woven Roving
1 matt
1 roving
2 matt

This schedule, using 1.5oz matt and 18oz roving will yield a total thickness of about 1/4".

On my stringers I did 2 layers of matt. 1 layer of roving in all the inside corners and finished it with a cap layer of matt over everything.

[ondarvr]

Mat adds little strength, so using it alone, or extras layers don't help much

You need 1 layer of mat to start with and then one layer between each woven or stiched fabric, extra layers of mat on top don't really do much, but will hide the pattern of the stronger stuff.

Read some of the other threads and you'll get an idea of how to do it.

[Good Ol Boy]

Fiberglass Mat is a non-woven felt consisting of chopped glass fibers 1" to 2" in length, crisscrossed and randomly interlocked, held loosely together with a binder. Since it is not woven, it can be stretched to fit into difficult areas. It is highly absorbent, soaks up a great deal of resin, and the resultant structure is stiffer than a layer of cloth, although not as strong.

Fiberglass Cloth is a woven pattern and is alot easier to cosmetically deal with and is ideal on flat surfaces, I.E getting air bubbles out of Mat ends up being like a string cheese tornado.

Mat vs. Cloth… Both have their advantages. Mat is short strands of fiberglass pressed into a sheet randomly. Cloth is woven. For compound curves, mat is the only way to go, whereas large flat surfaces, cloth is very nice! Cloth comes out smoother, but is less pliable.

Suggestions For Working with fiberglass

Wear latex or rubber gloves, spray them with a lil wd40 after you have them on, will help keep the fiberglass from sticking to you.

Wear a respirator when you are sanding or while dealing with resin in a closed area.

Careful of how much harderner you use, Too lil it will takes hours to dry, too much and you will be racing against the clock and risk a bad finish. Also be aware of how hot it is, quicker dry time.

Brush on the resin with a throw away brush unless you clean the crap out of it with lacquer thinner. Lay the dry fiberglass down over the wet resin and use a putty knife to press into any corners. Pour your mixed resin on the dry fiberglass that is in place. Grab a roller, like for painting walls, put a skin on it, once again like rolling walls and then wrap 2-3 layers of masking tape around it and saturate the fiberglass then make sure to roll all the air bubbles out by going multiple directions, center to edges. Let dry and sand, if any hard edges either sand like a villian or use a lil fiberglass bondo to feather out the edges or fill in any undesired pits.