Using Pigment Pastes  
by Warren D. Messer - Seattle, Washington - USA

One of the things that I've been trying to do as I build prototype boat after prototype boat, is to learn from my mistakes. For every two steps forward there is the occasional step backward, and once in a while an evolutionary step to the side. Speaking as a fish that grew legs, I have to admit that the changes I've made in my technical abilities of fit and finish can actually speed up the process of building a boat. What seemed like lazy short cuts at the time, have turned out to be paths of enlightenment.

When I built the FlyCaster prototype, I found that I was fighting myself when finishing up the hull's exterior. The flaws in the hull that should have been fixed and smoothed with QuickFair while I was still filling the weave in the fiberglass cloth, and coating the hull with a layer of epoxy couldn't be seen clearly; even when using a bright hand held light. Several of the flaws only showed up after I had applied the first of several coats of System Three's WR-155 epoxy primer. That's the purpose of the primer, but some of the dings and scratches were deeper than what the primer can fix. Things that should have been found and fixed before getting to the primer stage. I don't use the WR-155 primer on every hull, and most Duckworks readers won't go for the added expense. Especially if you told your better half that it was only going to cost $200 for a complete boat - A price that even a Texas boat registrar would find hard to believe. ;) So things need to be filled and faired long before the paint goes on; and better yet before the last couple of coatings of rolled on epoxy.

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While I was re-reading System Three's "Epoxy Book", I studied the section on using pigmented epoxy pastes. Basically, pure color pigments added to part A epoxy. Just cut back the straight part of the part A epoxy mix to equalize the added amount of pigmented part A. I told myself to get some pigmented paste when I had to resupply for building the PUD-g prototype hull. I got 2oz of white and 2oz of black to add to the epoxy I used to filled the weave of the cloth bottom. You will remember from the PUD-g story that I put too much black in the mix, and got a darker hull than I wanted. But I was able to lighten up the tint of the hull before I painted it white. Even with the wrong pigment paste mix, I found several spots in the hull that needed attention before getting around to the painting. Most of the fixes needed were from not doing the best job of fairing that I could do. Mainly from an accumulation of bad lighting, bad eye sight, and the low color tone contrast between the various shades of white from the different layers of cured QuickFair.

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As I was fairing out the daggerboard on the PUD-g with a second coat of QuickFair, I vented some brain gas. During that thought, the idea of using some of the black pigment paste in the QuickFair came to me. I think the fish can walk! So I added just a smidgen of the black paste to the mix and stirred. After a couple of seconds, I thought I was making licorice, or maybe even black plastic. It was some weird looking stuff. But as I was spreading it on the daggerboard, I knew this was going to work, and big time. This was something to try on the next hull, by adding it again to the SilverTip epoxy coatings, AND the QuickFair.

When I got the glass cloth for the bottom of the 10ft Nuthatch, I picked up 2oz of yellow and 2oz of blue pigmented pastes; and yes, if you mix them together (or overlaid) you get green, as you can see in several of the photos. The first layer of QuickFair I left uncolored, and just faired it in as normal. The only application change I made, was to use a new 3" putty knife, which worked out well. Not too wide, and not too narrow.

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After a night of curing, and a good sanding with 100 grit, it was time for the second coat to fill in the scratches and low spots from the first pass. To this I added maybe a 1/4 teaspoon of yellow pigmented paste, and mixed it in. I tried adding the pigment paste to the mix in a couple of different ways. Once mixing it in to the part A of the QuickFair, and then adding the part B with a final mix; and adding the paste after mixing parts A and B. Seems to work both ways, but I liked adding the paste after mixing the A and B so I knew that the main mix was complete. Again I thought I was making some kind of plastic, but this time it was yellow. Strange looking stuff, and it was a very bright yellow.

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It still went on like normal QuickFair, and boy did it stand out. You could see exactly where it was, and wasn't going down. All the low spots were yellow, and all the high and smooth spots were the off white color of cured fairing compound with maybe a staining tint of yellow left behind. It looked kind of blotchy with the mixing of colors, but it would all get covered again with a third, blue tinted coating, which on the yellow areas went green, and on the white parts stayed blue. The upturned hull started to look like an over sized parakeet.

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Time for a bit of lateral arabesque on using pigmented pastes to the plot of this story. Another thing I picked up in the System Three Epoxy Book, was using a "toothed" spreader (like you would use to apply thick adhesives for linoleum and flooring tile) to fair in deeper voids and low spots on a larger hull cursed with boat pox. The 4 sided plastic spreader I used to even out the GelMagic when I scarfed the panels for the 10ft Nuthatch, had three sizes of teeth. I used the middle length side of the spreader to apply un-tinted QuickFair to the rudder and daggerboard. This let me control the amount of fairing compound I would be adding, and to leave behind a much smaller surface area to have to sand and shape after it had cured. Instead of having a large semi-flat area to have to sand back to the NACA outlines I wanted; I only had to shape the tops of the "grooves" that the toothed spreader left behind. The sanding and shaping went much quicker than ever before, and all I had to do now was to fill in the low spots and do the final touch ups and finish sand.

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For the second fairing coating on the rudder and daggerboard, I used the yellow paste. It didn't take that much, since most of the major filling was done on the first coat. I used a straight edged applicator for this layer. The next time I do this, I think I might do the second layer with the smaller teeth on the spreader just to see what happens. That would fill the big grooves, but give me a second chance at shaping the outline of the foils. One thing to be cautious of is applying the fairing compound too thin; as it may not want to stick in the very thin spots if the area hasn't been sanded that well. It would be better to apply a couple coats of straight epoxy and sand that to the final shape if you are just trying to get rid of small scratches. The paint you use may get rid of them too; if not this time around, then maybe the next. Remember it's a boat in your yard, and not a priceless artifact at the Smithsonian.

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After giving everything a good sanding with 100 grit, I looked and felt around the hull for imperfections, and marked any I found with either a green or orange pencil. For the final layer of fairing compound, I mixed in the blue pigment paste. QuickFair is smooth and creamy to begin with, but adding the pigment pasted to it is an other worldly experience. I can't explain it; you just have to try it yourself and see what I mean when you add the colors.

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Now it was time to fill in the weave of the glass cloth on the bottom of the hull and give everything else a coating of epoxy. On these coats, I added some blue paste to the straight epoxy to give it some color and to give the paint I was going to use a good deep base. This hull was going to be "Shaw Island Blue", and was a pretty close match to the color of the blue pigmented paste. Each coating of epoxy added more base color to the hull; and I think that if I had added more paste into the mix, I wouldn't have needed to paint the hull. I will have to try this some time with a daggerboard to see if it works out better that way, than with just a coating of epoxy, and paint. The epoxy will be more flexible, and less likely to chip when dinged than when top coated with paint.

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A good look and feel after everything cured, showed me a couple of spots that needed some touching up. If it was going to be my own boat, I wouldn't have given it a second thought; but I need to sell some hulls to make room for all the others (10) than need to be made. Because I have to make them as flawless as possible for a potential customer; out came the sander again, with more fairing compound, and sealing coats of epoxy.

My hull surfaces are not yet as smooth as gel coated fiberglass, but getting damn close. I'm finding that good lighting is the key to flaw detection, and some changes need to be made at the Red Barn. I need to change the tubes in my florescent fixtures from the "warm" 3200k's (degrees kelvin) I'm using now, to the higher "day lite" 6400k's. Also adding a couple of windows would help too. An even better option would be to move to a place I found in Port Townsend that has a 40x48 foot heated shop. I would also benefit from the more than halving in my property taxes by the move. More money to build boats with, and closer to some excellent sailing waters. :)

I hope that all my thrashing about at the waters edge helps you in your own boat building endeavors. Try using pigmented pastes on your next or current projects; it really adds to the value of your finished work. Thanks again for reading my stories.

Warren Messer
Still evolving at
Red Barn Boats

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EPOXY

GEAR