Product Review click here to read or make an observation about this  article
By Bob Throne - Willow Grove, Pennsylbania - USA

System Three Silvertip GelMagic

I had put up a 12’ x 20’ screen room to serve as a boat shop, constructed a strong back, bought a pile of plywood, and begun to measure and cut out bulkheads … so it was time to purchase some adhesive. About this time Chuck and Sandra added Gel Magic to their line and it seemed like the right thing to use. A day after I ordered I got a confirmation from Sandra, a couple of days after that and UPS dropped it off at my home, and the next day after that Chuck sent me note asking me for a short product review.

After all the help folks on Duckworks have given me designing my 15’ Pocket Cruiser “Wanderer”, how could I refuse. Except. The good news is that I’ve never built a boat before so I have no preconceived notions to bias my opinions. The bad news is that I’ve never built a boat before so I have no preconceived notions to bias my opinions .. or experience to compare with. I am, however, a life-long builder of radio-controlled model airplanes and I’ve been using epoxy since it first became available, albeit in much smaller proportions. And among other things that I knew was that most epoxies are “runny” .. not quite water-like, but pretty thin. The thicker viscosity purported with Gel Magic appealed to me. It was time to give it a try.

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This is what it looks like in the bottle.

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This is what comes out.

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The correct ratio is two parts resin to one part hardener .. And that raises the first point about using GelMagic. The resin is VERY thick and pours VERY slowly and settles very slowly into the mixing cup. The hardener is much thinner, about what I’ve experienced with other brands so it is easy to pour too much. A well marked cup will help, but it takes attention. Happily, I see no real difference in results in the batches where I used too much hardener.

The second point is so common that I might not have mentioned it. It is easy to mix too much at first, until you learn to judge how much you need for each joint. Here are a couple of shots that illustrate my first tries:

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The first shows GelMagic used to fill an errant saw cut.

It filled just fine - Thick enough to fill that 3/16” gap without running.

The next shot shows what it looks like a half hour after mixing too large a batch (on the right).

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The third shot shows the bulkheads ready to glue...

 
... and the fourth after they’re done.

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With latex gloves on and working with the epoxy, I didn’t take any close ups of the joining process itself, but it’s pretty straight forward to mix a batch, spread it on the parts and put them together. I’ve used a few brass wood screws every time to assure a tight joint. The cured GelMagic is so strong that they’re probably not necessary if you clamped parts securely as you joined them. Working time is about the 10 minutes the directions specify and it sets in about 20 to 30 minutes. I haven’t worked with any of the pieces until the next day but you probably could after a couple of hours if you didn’t stress any of the joints.

The other major joint to illustrate is where the transom is joined to the bottom. This is four foot long by 1” and not fully beveled, so there is a press fit across the back, but about ¼” gap across the front.

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As you can see, it’s a clean, strong joint.

After several days the GelMagic is hardened like steel … well, maybe more like aluminum. It will sand with effort and cuts with a jigsaw but is very tough and difficult to cut with a utility knife. It pays to work carefully, because spots that remain and need to be taken off take some work - The wood will give before the GelMagic.

Oh, every significant project requires a significant helper. Mine is my four year old granddaughter, Mattie (Maitlyn) who is learning to swim and can’t wait to sail with me next year!

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The bottom line is that I’ve just ordered a second batch. I tried Gorilla Glue in just a couple of non-critical places for comparison. There’s no contest. The Gorilla Glue is runny and seems to expand and sets up with air bubbles where it flows out of a joint. I can’t speak about other adhesives, of course, but I don’t see a need to use anything else than GelMagic. This is hardly a professional review but if you have questions I’ll try to respond below.

Oh yes .. If you’ve been reading Duckworks this year you realize that these parts are for my 15’ pocket cruiser Wanderer, but some of you may be new to this great site, or maybe just ‘Googled in “. You’ll find the articles under “Designs” from the main page. Since these shots the bottom is cut, transom, bulkheads and stem glued in place, and the stringers added. It’s beginning to look like a boat.

Good boatbuilding .. Good sailing.

Bob Throne