Posted September 28 2011 - 07:27 PM
Some hints for making the experience of working with fiberglass a little better.
Get latex gloves by the hundred count if you can find them. Avoid the cheap stuff at the home improvement centers. Half of them will tear when you try to put them on, doubling the cost. You should be able to get them for less than a dime apiece if you can buy them in the 100 count box.
Get a gallon of acetone for cleanup. It's expensive, but worth every penny. Might be about twenty bucks per gallon now.
Get a couple of four inch paint roller handles. Don't buy the four inch rollers. Buy the six pack of rollers they sell at Home Depot, for about seven bucks. Cut them in half and you end up with two 4.5 inch rollers which will work just fine.
Get a narrow roller tray and liners for the tray. You can toss the liners when you are done.
Mix the resin. Use a little less catalyst than recommended. It will give you more time to work with the resin before it starts to cure. do not mix large batches of resin. It will cure faster in the container since it will build up heat, which acts as a catalyst to speed up curing.
I use plastic gallon milk and water jugs to mix the resin. For starters, mix up a quart at a time, pour it into the paint tray, and wet out the roller. If the roller drips, work some of the resin off on the slope of the tray. Apply like paint to the stringer or whatever part, then place the mat over it and use the roller to work it flat. You can add resin as needed by getting it from the roller tray. If you have an area that is too wet, roll out a dry area of the material, then you can go back with the roller and pick up the excess by rolling over it. If it's still too wet, repeat the process.
If the material doesn't lie flat, keep rolling it. As the mat gets wet, the two inch strands will be able to slide around. The strands are held by a binder which dissolves in resin. Once wet, they can slide around.
You don't need to use a lot of pressure. Always lay the material on a wet surface. It's easier to wet it out when it comes up from behind the material rather than trying to work resin down into it.
Don't try to do too much at a time. Take it slow until you get the hang of it.
The other tool you might need is a "bubble buster". It's a grooved roller made of metal or plastic. The ridges will work the trapped air to the surface.
Use "tear edges" on the mat. Cut edges make a small step at the edge. Tear edges feather into each other and give a better finished product.
It's also much easier to work with smaller pieces with torn edges, than big pieces of material.
Once the stuff is wet, it's nearly impossible to handle, or move. It stretches out because the fibers are no longer held in place by the binder.
Work in the areas that are easiest to get at for starters. Don't struggle with the difficult areas while getting comfortable with the process.
Start small. Keep it as simple as possible.
When you are finished with the glass, if you want a smooth finish, you can spread bondo over the new glass, after it has cured of course. Then sand smooth and apply a couple of coats of a good marine paint. Fiberglass resin is not waterproof. It will absorb water. While water won't pass through it like a piece of cloth, it will absorb moisture.
In colder climates, if exposed to freezing temps while it contains water, the water will freeze and expand, damaging the composite.
If you need any advice or have any questions, you can ask them here, but it's better to send me a p.m. since I don't always go back to a thread for a few days. I check a couple of times a day for messages. If you want, you can also email me through the forum.
Regards, Tom
