What’s I do wrong!?

[Ray Kepler]

(That’s supposed to say, “What’d I do wrong)

So I decided to put fiberglass on my three paddles because I had used western red cedar and one of the laminations cracked. Also, another rookie mistake, the western red cedar was on the outside edge of one of my paddles. Anyway I decided I should fiberglass the blades. I bought the West 207 and 105 as recommended, and did the 3:1 ratio. The West site says: “Clean contaminated surfaces with lacquer thinner, acetone or another appropriate solvent. Wipe the surface with paper towels before the solvent dries. Clean surfaces before sanding to avoid sanding the contaminant into the surface,” so that’s what I did. I think. I sanded and then used paint thinner to clean the dust. And then applied epoxy. And scraped off the excess. Two days later, the epoxy is still sticky. And the glass peels slowly off.
Did I screw up with using paint thinner? Or maybe with the ratio, or not mixing long enough?
AND how do I clean this mess up!? Paint thinner and sanding? It’s really gooey right now!
Any suggestions would be appreciated.

 

[Dan Miller]

While there are a number of folks very experienced with West System products here, and who will probably be along shortly to give advice, the best thing you can do is call the manufacturer directly and talk to their technical support folks.

 

[Rob Stevens]

I am not clear on why you are glassing. Is that to compensate for the crack?
Or were you forcing epoxy into the crack? Depending on the size of the crack, you might have to thicken the epoxy with silica/cabosil or fine sawdust to fill it ie. so the glue doesn't run out.

Using thinner or turpentine takes a lot longer for it to dry than acetone, lacquer thinner, or even methyl hydrate. The wood needs to be completely dry before the epoxy will soak into the surface.

In order to get the ratio correct use the proprietary graduated pumps. One pump of each gives a ratio of 3 resin to one hardener. Mix thoroughly, though about a minute of stirring is sufficient.

When gluing up paddle blanks, ideally, a thin strip of hardwood would be laminated on the outside edges, to give protection against impact damage.
If the blade still has a crack, you can run it along a table saw and re-laminate, carve/thin and sand. This procedure is easier if the paddle sides are parallel rather than curved.

 

[Ray Kepler]

Hi Rob and Dan,
A call to WS may be in order, depending on the advice given here.
The crack I had was about 3 inches by 1/64, and I was able to glue it up.
My decision to glass was based on how easily the wrc cracked and I’m worried BC I used it on the edges of a paddle.
I bought the WS pumps and believe I mixed things properly. UNLESS I did it wrong: I pumped three pumps of epoxy and one pump of hardener. Should I have just done ONE pump of each??!! could that be the issue!!?

 

[Dan Miller]

Yes, that is indeed the problem. The pumps are calibrated for one push each. Thus, you didn't have nearly enough hardener in your resin.

 

[Ray Kepler]

Wow, good to know; I kinda feel better. I guess the issue now is how to clean this mess up and start over.
Lots of paint thinner??!

 

[Todd Bradshaw]

Ditch the solvent. It is not needed and is more likely to contaminate the surface than help anything. There have been thousands of cedar strip canoes built using 105/207 with no solvent wash of any kind and the resin put directly on bare sanded cedar with beautiful results. Also, as solvent goes, anything labeled "paint thinner" (usually at least mostly mineral spirits) is usually the least pure solvent you can get. It has no place in epoxy work.

 

[pklonowski]

Peel the glass cloth off all surfaces.
Scrape the goo off as best you can, with whatever works. A wide putty knife might help, but try not to ding the wood too much.
I vaguely recall, about 20 years ago, reading about a solvent that would help remove that gummy mess, but I have no idea where that information is. Try acetone, mineral spirits, or turpentine? I could have this mixed up with something else, too...

 

[Gil Cramer]

Try vinegar to remove the uncured epoxy.

 

[Dan Lindberg]

Ya, no solvent when using epoxy.
My memory is poor but IIRC, alcohol may clean the mess.
Scrape it as best you can and then wash lightly.

 

[Jim Dodd]

Good suggestions. I've run into a lot of people working with Epoxy, that don't mix thoroughly.

Mix for a minimum of 3 minutes.

Did you ?

Acetone is what I've used on uncured epoxy.

Jim

 

[Ray Kepler]

I mixed for maybe 1 1/2 minutes. Turns out the problem was improper mixing.
Acetone and sandpaper and several hours got the stuff off of my three paddles. Will try again tonight.
Fingers crossed.