I am trying to have the bottom of the boat painted by the middle of April but I don’t think I will make it. Boat building is a journey not a destination and I have been learning how to use System Three Quik Fair, a two-part epoxy fairing putty. Quik Fair comes in two tubs, A which is tan and B which is white. They are mixed at 100 parts of A to 44 part of B by weight. The A and B are somewhere between mayonnaise and peanut butter but stickier.
Rule Number 1. Don’t get any A or B in the wrong tub.
I took some old spoons and marked then A and B and I only have one tub open at a time. I measure out 100 grams of A on to the plywood palette and then put the A spoon in a tin of vinegar. I then measure out 44 grams on B, making sure that I don’t get any A on the B spoon. The B spoon goes in to the vinegar which should neutralize the epoxy until I get a chance to clean the spoons. I then mix the A and B well using tongue depressors with one end cut off. My 6 x 6 inch palettes are too small; I should have made them 8 x 8 inches.
I put two batches of 144 gram of Quik Fair on about 1/4 of the hull and I ended up sanding most of it off. I also found that I had high spots that took a lot of sanding and low spots that didn’t have any Quik Fair.
Rule Number 2. Put a thin skim coat hull to help find the high and low spots when sanding.
I made a longboard which is not that long; 4 x 10 1/2 inches which is a little smaller than a 1/2 sheet of sand paper. I spray a thin coat of adhesive on to the sand paper and wait a minute so it gets tacky and that allows me to peel of the sand paper when it is used up. I sand in an X pattern; down the hull at 45 degrees to the left and then back the other direction at 45 degrees to the right. I found that if I was not creating dust or I could not feel the sand paper cutting I was wasting my time.
Rule Number 3. Use good sand paper and replace often.
Some of my sand paper would clog up in a minute and I spent more time changing the paper than sanding. I found that 80 grit 3M SandBlasterPro “Only at Lowe’s” sand paper worked the best with a good balance of being aggressive without making deep scratches. I could sand an entire panel with 2 half sheets if I brushed the sanding dust off the sand paper regularly. On the high spot I went through the Quik Fair into the epoxy and on the low spots there was either no Quik Fair or the Quik Fair was rough. Any place that I sanded the Quik Fair was almost glass smooth and any place I missed for rough or shiny.
Rule Number 4. Make sure the Quik Fair has cured before sanding.
System Three says that Quik Fair will cure in 3 hours at 70°F; my garage is at 55°F and the Quik fair was not cured at 3 hours, 6 hours and still soft at 12 hours. I could tell the Quik Fair was not cured because the sand paper would get clogged in a few strokes. Once cured Quik Fair was easy to sand as long as I did not put too much on.
Rule Number 5. The last step to applying Quik Fair is to smooth out the ridges.
I found that as I apply the Quik Fair with the squeegee I would always have some ridges on the hull. I would try to smooth them out but sometimes I would make a mess and have to re-apply the Quik Fair. Sam Devlin talked about using a cloth wetted with denatured alcohol to smooth out the epoxy fillets which got me thinking that might work for the ridges. When I have put the entire batch of quick fair on the hull I would thoroughly clean my squeegee with a paper towel dipped in denatured alcohol. I would then go over the ridges with the clean and slightly wet squeegee. I would clean the squeegee often. I found that I could knock down most the the ridges without messing up the fairing.