Template Forming for Farmhouse Sinks

Farmhouse sinks require cabinet frames to be scribed and fit to the sink. Here, cabinetmakers discuss ways to make a template for better accuracy and fit. November 26, 2007

I have an idea about how to fit face frames around farmhouse sinks, but I've never tried it. I thought I would throw it out to see if anybody has done anything like this. We usually do our scribe fitting in a three step process. We make a pattern for the left side, one for the right side, then join the patterns at the middle. It sounds more complicated than it is, but the whole process only takes about a half an hour.

The idea I have is to make a mold of the shape. We've done this in the past when replicating existing moldings for reproduction work. On those projects we would wax the existing molding, then produce a reverse pattern out of bondo.

The machinist industry uses a shapeable wax for testing prototypes. This wax is stiff enough to hold a shape or take a screw and very inexpensive to machine. What I was wondering about is if there was anything similar we could use for patterning sink curves?

The thought here would be to put a three inch piece of blue painter's tape on the sink, then push some warm wax into the curve. When the wax dried it would be a perfect reciprocal of the sink shape and very easy to trace from there. Will this dog hunt?

Forum Responses
From contributor K:
Sounds interesting... What about using a flexible curve?

From the original questioner:
I think you are right about that flexible curve. What made me start to think about the bondo idea was that one of the farmhouse sink cabinets we have in the shop has a really lousy scribe job. The guy that did it got in a hurry and can sometimes be resistant about redoing work. When I looked at it, my first thought was to try to fix it with bondo... which led to the pliable pattern idea.

To tell you the truth, I don't know how this gets done in my shop. I have theories about how it should be done, but sometimes by the time I come out from the office, it has already been done a different way. Which leads us to another thread about picking your battles.

From contributor M:
Here's how we do it:
1. Put the sink upside down on a perfectly flat bench.
2. Cover the area where the frame will wind up going with a couple of layers of masking tape.
3. Cut out a U- shaped piece of scrap plywood about the size of the sink and clamp it over the sink in the same position that the frame will later be in.
4. Bondo in any voids or gaps. It helps if the piece mentioned in the above step has small triangular blocks hot glued in to cut down on the bondo needed in the radius corners.
5. You now have an exact template of the necessary cutout. Just use a router to trim the finished frame to final size.
6. You'll probably still have to back bevel the finished frame with a belt sander to get a perfect fit.

Have you ever noticed whenever these sinks are advertised they are never shown being scribed into the sink frame? It's always a square "insert gunk here" cutout.

From the original questioner:
That sounds like a pretty good method. I hadn't thought of the upside down part. I wonder if there would be any material out there that is less noxious than the bondo?

From contributor M:
One thing I forgot to mention... Since these sinks are hand made, they're rarely dead flat on top. When the sink is upside down, now is the time to decide which corner should be shimmed to keep it from rocking. Whichever corner is shimmed, that's the part of the sink where the stone top will not be making contact with the sink. Obviously, a perfectly flat bench is critical here.