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Re: Strip: A cautionary tale of two epoxies
By:Farback
Date: 6/12/2011, 12:42 pm
In Response To: Strip: A cautionary tale of two epoxies (Al Edie)

: Finally, after a long time, I had the deck and hull all tightly
: masking taped together, with the glass strips nicely hanging
: inside from dots of hot glue. All ready for the internal seam
: epoxy.

: I had been using some West System epoxy for putting together
: various carbon bits and installing the Maroske fittings. I had
: been running lower than I expected on my Mas supply, so I used
: the West System stuff to conserve the Mas. Anyway, I reverted to
: the Mas for the hull/deck seam because I expected it to produce
: more transparent results, and I didn't want any color difference
: between the Mas and West System.

: So, I mixed up my Mas, and used my spiffy 1 1/2" wide roller
: to apply it in both ends of the boat- you know, the areas where
: you have to stuff the loaded roller, one arm, your head (with
: respirator) through a hatch opening, all while executing a 90
: degree rotation so as to vaguely see what the heck you are
: doing, and while attempting not to drool or smear epoxy anywhere
: other than where intended. I managed to get the seams nicely
: loaded with epoxy back to the hatch openings, and congratulated
: myself on getting the worst part done with relatively little
: pain, aggravation or mess. I then went back to the Mas supply
: and mixed up an new batch for remaining section of seam in the
: center of the boat. 30 mls part A, 6 mls part B, carefully
: measured.... Then it hit me. I had mixed the Mas at 5:1, the
: ratio I had been using for the West System stuff. The Mas, of
: course is a 2:1 mix. The shock of my stupid mistake spread over
: and through me like cold water. I could not believe what I had
: done. But there I was with faulty epoxy on the most difficult
: sections of the starboard seam. The hull and deck could not be
: separated without surgery because the bow and stern blocks, as
: well as the skeg box, were already epoxied and set. What to do.

: To shorten the story, I ripped out the fiberglass tape with the bad
: epoxy on it, scrubbed the epoxy off the seam with rags,
: maneuvered a new tape in place (try this with a sticky seam
: surface - it is great fun, especially at the end of a four foot
: stick while you are stuffed through a hatch opening), and
: applied new epoxy. In retrospect, I might have been better
: advised to also scrub the seams with solvent, but I figured the
: tiny bit of epoxy left on the surface of the older glass would
: bond ok, and it did.

: So, my advice to those who are tempted to have two types of epoxy
: involved in their project is this. On each and every container
: of epoxy to be used, put very large labels indicating the mix
: ratio to be used. Make it impossible to mix epoxy without an
: in-your-face reminder of the ratio to be mixed.

: Humbled, but not yet defeated,

: Allan Edie

I use an indelible marker and label all containers with the mix ratios. So far, a bad mix is one of the few mistakes I haven't made.

Kirk

Messages In This Thread

Strip: A cautionary tale of two epoxies
Al Edie -- 6/12/2011, 11:49 am
Re: Strip: A cautionary tale of two epoxies
Farback -- 6/12/2011, 12:42 pm
Re: Strip: A cautionary tale of two epoxies
jwuts -- 6/12/2011, 1:08 pm
Re: Strip: A cautionary tale of two epoxies
Bill Hamm -- 6/13/2011, 12:09 am
Re: Strip: A cautionary tale of two epoxies
Bill VerSteeg -- 6/20/2011, 2:03 pm
Re: Strip: A cautionary tale of two epoxies
Bill Hamm -- 6/20/2011, 2:38 pm