Re: resin mixing tips and techniques
You can normally use from 1% to 2% catalyst safetly with most resins, going with more or less can create problems even if the resin gets hard.
You can use a bucket, coffee can, or whatever you can find that may be the right size. Mark the container at a known spot for 1qrt. 1/2g. or what ever amount you want, a baby bottle or measuring spoon will work for the catalyst. All you need to do then is fill it to the line with resin and dump in the catalyst, then mix well.
Smaller plastic buckets can be purchased at a paint store, they're already marked and when the resin cures it will just pop right out of it so they can be reused. If you can't find a container small enough for catalyst at the paint store, then go to a Pharmacy, they carry small measuring devices calibrated in CC's
If the containers are marked in grams, CC's or ML's then its much easier to do the math for the correct amount of catalyst. 100 CC's of resin needs 1 CC of catalyst for 1%, 2CC's for 2%, just scale it up for larger amounts from there.
If you think you need to use less than 1% because its hot out, then mix less resin at a time , don't use less catalyst. Do the work in the shade, never in the sun.
Get the cheapest brushes you can find and get a box of them, same thing with paint rollers, just get the cheapest six pack (not refering to beer, you should already have plenty of that on hand from the planning stage of this project). Use gloves, the thin cheap ones work, but tend to get holes in them easily and then you get resin on your hands anyway, so I try to use the slightly thicker ones, dishwashing gloves will work.
I use very little acetone and sometimes none, I just throw all the stuff away after it gets used, it can be cheaper than using acetone and unless you clean everything thoroughly, it will have hard spots in it any way.
When doing areas where you don't want get drips below it, wet the glass out on a board or something and then lift the glass up and put it in place. This needs to be done fairly quickly, as the glass will begin to fall apart as the resin soaks in. If cloth or roving is use in this type of repair then you don't have to worry about it falling apart as much. Don't over work the mat though, if you do, it will turn to a sloppy mess before you can pick it up. Don't get too much resin on the brush or it will drip, and always tape off and cover anything of value. For small odd shaped repairs or when filling a small low spot, just pull the mat apart in your fingers and wet it out with brush as you put it in place. This way you can shape it to fit the area with the brush and there will be less to sand off later.
If you plan on doing an entire floor or other large area and roving or cloth is being used, then use a squeegee to move the resin around and get the air out. To do this roving or cloth needs to be the top layer, a plastic bondo type spreader will work (use a large one), but don't push too hard or you'll remove too much resin. You can do a whole floor very fast this way. Also if needed you can do several layers of glass very easily, just wet out the wood (it's best to have precoated it and let it get hard) and lay down each layer, a paint roller may make it easier to wet out the mat, but not always. Don't worry about the air as you're wetting out each layer, just get enough resin on it, the squeegee will remove the air and excess resin from the layers rapidly.
Never use cloth or roving as the first layer as it will result in a poor bond, always use mat first, then whatever you want on top of it. Cloth is rarely use used by boat builders, the cost is too high for the strength it adds and because its so thin, you need many layers to build much strength. Boat builders use roving or stitched products, they're much better for most jobs and cost less.
Round the edges of all wood so the glass will form around it, use putty to fill a sharp inside radius, or you can use a wood strip cut to the right size.
To prep a surface, grind it thoroughly with course sand paper and not by hand. Get a small grinder at everyones favorite cheap tool store (H/F) with a stack of 36 grit discs and get a couple of cutoff wheels while you're there. Clean the surface before you start grinding or you may just move around wax and oils while grinding. Part of the "polyester doesn't bond well" line of thought, comes from poor prep work and using cloth as the first or only layer. It actually sticks very well to a sanded and clean surface when mat is used.
I used a 4-oz jelly jar to measure the resin, then counted drops of hardner into a separate small glass jar. Combined the two in an aluminum bread baking pan and mixed. That amount was just right to work with in fifteen minutes before it started to gel. Acetone worked well for cleaning the bread pan, brush and roller, although it's kind of pricey. I usually had latex gloves on, but a couple times not. I've been through a little over a gallon of resin using the 4-ozs at a time method, and two gallons of acetone for clean-up and prep. All of the spreading of the resin was done with either a 2" or 3" brush, probably could have made better time with a roller or wider brush, especially on the deck and stringer coating work.