Post-prime and pre-slime. 
 
 
I had just finished priming the white trim before applying Bondo(tm) polyester resin. I'm happy with how painting a tiny bit of the copper roof turned out; it restored the proportions of the entrance gable.
 
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Bondo! 
 
 
100% waterproof! No shrinking! 15 minutes working time! Ready to paint in 2 hours! Thin with lacquer thinner!
 
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Bondo thinned 
 
 
It looked a bit thick to roll, so I thinned it with lacquer thinner. Big mistake.
 
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Roll-on 
 
 
The thinned resin was easy to roll on, and eventually I got the hang of distributing the walnut shells evenly.
 
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Steps 
 
 
The steps were a lot more porous than the deck so they soaked up a lot more resin. I figured this would just waterproof them better but it didn't work out that way because the resin didn't harden.
 
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Finished steps 
 
 
So far so good. What I didn't realize is that the resin was thinned so much that it wouldn't cure correctly.
 
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Crushed walnut shells 
 
 
I bought the walnut shells (20-30 grit) at an industrial abrasives retailer. Apparently they are an acceptable material for cleaning delicate parts such as jet engines, where embedded bits of SiC would cause real problems.
 
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Shells closeup. 
 
 
These are english walnut shells, not the black walnut shells I was looking for. But they are fine.
 
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Final texture. 
 
 
Final texture of walnut shell on steps.
 
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