A journal following the history, design, construction and operation of Bernard Kempinski's O Scale model railroad depicting the U. S. Military Railroad (USMRR) Aquia-Falmouth line in 1863, and other model railroad projects.
©Bernard Kempinski All text and images, except as noted, on this blog are copyrighted by the author and may not be used without permission.
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March 12, 2017

A Two-Part Resin Tsunami

Polyurethane water surface has too many brush strokes

The calm before the pour
After using a quart of gloss water-based polyurethane to simulate the water surface at Aquia Landing, I was dissatisfied with the look. I could see some brush strokes in the water surface that were just not convincing. It was also tricky to paint in between the pilings without getting polyurethane on the pilings.

So I decided to pour two-part resin. I had already ordered a large bottle of Unreal Details resin and hardener. I used several layers of masking tape around the perimeter of the peninsula  to create a sealing dam. Near the shore I used some gloss acrylic gel to paint the crack between the tape and fascia to try to seal it better.

Plastic cups made measuring easy
 I then mixed up  about  three quarters of the large bottle of the Unreal Details water in 5 batches.

At first all was well. After about 2 hours, I went to dinner. After dinner, I checked the resin.

Yikes, the resin had nearly breached the tape on the side near Burnside's Wharf. Apparently the benchwork is not level, nor is it truly planar. So the resin formed a "tsunami" at the low point and was nearly over the tape dam. The weight of the resin, now about a half inch thick, was also causing the tape to release from the fascia. I was a few minutes from a disastrous mess.

Before the tsunami
I grabbed a bunch of clamps and pieces of plywood to shore up the masking tape dams.  I also used my floor jack to elevate the benchwork at the low spot and placed shims under the legs.  These actions seemed to have solved the issue. It is now seven hours after the pour and there are no signs of leaks.

I will set my alarm tonight to do some late night and early morning checks.

14 Hour update - Good news - no leaks. The resin is still tacky. I have been running my spray booth fan all night and the basement is cooler than the rest of the house. So the resin will take longer to cure. There are a few ripples in the resin. Hopefully they will settle out and not be a problem.

Final Update: Tape is off and the resin is nearly cured. No serious leaks, though some seepage occurred along the tape.  Some touch up on the fascia will fix those problems. The surface is not glass smooth, but it will work out.  Overall looks good.

Reinforced tape with plywood and clamps helps hold the tape while the resin seeps in the opposite direction.

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