Monday, February 17, 2014

A kitchen scale saves the day.

I took another boatbuilder’s suggestion, and bought a kitchen scale to use in measuring my epoxy mixtures. This simple device I bought for about $30 at K-Mart has made a huge difference. I can now precisely measure any given amount of epoxy, with no guesswork. It’s such an obviously superior method that I wish I’d done it this way all along.

Not surprisingly, the last 2 layers of epoxy went on easily, with no problems whatsoever in curing time. With the stem & related parts now encapsulated, I could move on to finishing the side planking.

On February 15, the 1-year anniversary of my heart surgery, I got the forward starboard planking attached.

Again, the kitchen scale was an indispensable part of the process, and really saved my tail at one point. With weight-based measuring, the Silvertip Gel Magic is mixed at a 1:0.41 ratio, (rather than the 2:1 ratio by volume.) I had mixed a little over 150 mL, because I had a considerable amount of area to cover: both surfaces of the butt joint, the forward 7 feet of chine and sheer, the side of frame #2, the upper part of the stem, and all the same mating surfaces on the planking itself.

I ran into trouble about 3/4 of the way through this batch of epoxy. Enough time had elapsed that the mixture had become so viscous that it was unworkable. At that point, I had coated everything on the boat framing, and had only just coated the mating surface for the butt block on the planking. I had all the rest of the planking left to go.

Luckily, I had 1 extra mixing cup and 1 extra chip brush on hand. Going quickly back to the kitchen scale, I mixed a small batch of approximately 75 mL, allowing me to finish the job. The epoxy cured solidly by the end of the afternoon.

The next day, I faired off the front of the starboard planking at the stem, and started fitting the port side.





Starboard side planking, finally attached!
Now to fit the port side.

3 comments:

  1. Ah, the old running out of epoxy problem!! I've run into that as well. Now I always have extra cups ready with resin already measured into them. All I have to do is add a measured amount of hardener and I can move forward. Ask me how I learned this lesson! :)

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  2. Hi Carl!

    Yes — no doubt about it — I will make certain to have extra cups & brushes on-hand every time from this point forward. For that matter, I think I'll order some more epoxy before I tackle the port side, just to make certain I have plenty on-hand just in case.

    Sounds like you've got a really good story there, about learning "the extra epoxy lesson!"

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  3. Well, it actually was learned over 25 years ago when I was working for United Airlines as an aircraft mechanic and ran out of epoxy on a critical lay up. Had to rip the whole thing apart and start completely over. Needless to say, the supervisor wasn't too happy about that!!

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