I poured my first countertop with an integrated sink and the finish of the sink came out a lot rougher than expected. I had built the mold from foam and wrapped in tape. Upon first removing the foam the lines were barely visible, but after putting on and sanding a first coat of slurry the sink looks much rougher. By no means do I need a perfect sink, but wondering if anyone has any thoughts or tricks to help get it a bit more finished looking? Would a thin coat of slurry over the entire thing sanded smooth hold up? Picture of sink below.


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I'm by means no expert but the guy who did my sinks wet sanded with pads starting at 50 grit down to 2000 grit. They r very nice and smooth to the touch.
I would use a lower grit until the lines diassapere then work your way up until you get the finish you are looking for.

I agree with what Jeff said.  Grind then polish.  You can use diamond hand pads or use an extension shaft on a polisher.

here is a link to a nice set of hand pads...


Show us a picture Nick. I can tell you if you want to make nice stuff foam and tape are probably not going to do it for you. there are cheap alternatives that will provide you with the look you are going for and less work to process your piece. This forum has a wealth of knowledge within it and many people will help wit questions you have.


We also use foam but coat in an epoxy. This makes it smooth and is always a one off.

I think even if you grind and polish you're gonna get some ghost lines in there. But like Tony and Liz said....coat the foam with a bondo and fiberglass resin mixture.... sand that smooth and then coat it again. If you have time on your hands....you can use old latex paint to coat the foam first and let it dry before you put the bondo layer on there....otherwise the bondo/epoxy will eat the foam. use half bondo and half fiberglass resin and mix together. Drip it over the paint coated foam and let it cure....takes about 20 minutes to cure.....sand and put one more bondo/resin mixture over it.....done. put wax on it and its ready to go 

I use gyproc filler to fill all my imperfections as it doesn't eat the foam and it is easy to sand smooth and epoxy goes over without issue. Sorry you guys call it dry wall not gyproc.

There are many ways to skin a cat Nick. You should show us a picture so we can give you some ideas  if we know what you are trying to accomplish.

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