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Epoxy Tricks


Howard

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Don, now I use Q-cell, but I have microballoons still. Microballoons are phenolic and brown in color, while Q-cell is another material. Most sources say it is inorganic hollow spheres, another said E-glass bubbles, another called it "ground up surfboard foam. I dunno. Whatever it is, it seems to work just like microballons to me. If you want an easy to sand mixture for fairing, then this (these?) are what to use. If you want strength, use Cabosil, Aerosil, or the equivalent. You can mix them together for different characteristics. Microballoon fairing compound tends to run or slide off of vertical surfaces. Adding some Cabosil will stop that.

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Don, it's really quite easy,but more time comsuming,  trace your deck outline (i used 36'' wide painters paper) Place on wood working surface and allow at least 1" extra all round, and cover with a clear plastic  sheet. Select your wood. I used western fed cedar, ripped into 3/4'' x 1/4'' strips. Then edge glue (titebond III ) using small brads at regular intervals ( I go with 12'' alternating every strip so every 6'' effectivly ) to clamp up.

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Next day remove nails/clamps turn over to let bottom fully dry.Then no matter how carefully I cut my strips and how careful I was gluing up, you will have a slight uneven surface, so now comes our favourite thing to do SANDING.

 

OR if you have a planer, as I now do, (huge time saver) I made my deck up in panels the width my planer can take,then jioned the planed panels with thickened epoxy. which means a little sanding,but not much.

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I do sheath both sides with 6 oz cloth, the topside after gluing deck to hull, trimming to size and rounding edges to take overlap to hull.

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All epoxy wet out done with squeegee and chip brush for edges

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still requires another fill coat before sandind and varvishing.

 

MM

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Q-cells are quartz spheres. Cabo-sil and the others are silica and typically used as a thixotropic agent (viscosity control). Silica alone tends to make epoxy brittle, though very stiff and strong. Most filler mixtures will have some silica in it to stiffen it up as required, especially vertical or overhead work. It keeps the goo from sagging or running out of a joint for example. Balloons and spheres are bulking agents and simply put air into the mix, making the cured result lighter and easier to sand.

 

If making your own fairing compound, you'll use a fairly high percentage bulking agent, plus some silica to control viscosity and maybe some talc, to help the smoothness and spread-ability of the mix. If you don't have a need for a lot of fairing compound, much could be said about the pre-mixed stuff from the epoxy companies. System Three's "Quick Fair" is a well known and good product. If you count up the materials and cost up everything ounce for ounce, you'll get pissed, but it's handy to have a tub to spoon it out of, instead of mixing this and that, plus it's consistent results.

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OK, confession time, after priming the stbd side I found a number of small inperfections that I needed to fair.Mixed up a small amount of Quickfair and applied with putty knife. Next day went to sand fair but clogged up my abranet disc right off !! after a couple of days it still didn't seem to set up, I wondered if it was a reaction with my primer. Endad up scraping it all off down to bare wood.

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Turns out it was my fault, mixed up (2 to 1) by eye and got it wrong. I later did the port side the same way but used my electronic scale to measure correctly, applied the same and worked as advertised. Lesson learned !!

 

MM

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Yeah, this is a lesson we all learn. You can be "off" by a good bit, but once you've crossed the line, you're screwed. How much can you be off ratio? Hell, I don't know, as each formulation is different, but a few percent is a safe bet, but not much more. With QuickFair, I know a guy that uses plastic table spoons he gets with his fast food chilli at lunch time. He's stock piled a few and and uses them to literally spoon out a little dollop at a time, 2:1 of course. He makes sure each spoonful is leveled, before he scrapes it's contents out onto a mixing board. I found this a pretty clever use of cheap dispensing equipment.

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