Making the filter/gascolator doubler - 9 hours

 Big day on the build, but unfortunately not a whole lot of progress. I want to place a doubler under the Aerolab Filter/Gascolator. The floor is thicker aluminum (0.040") however there still is some flex in the floor and that may add stress to the attached rigid fuel lines. My thinking is that a doubler will reduce flex and stress on the fuel system when I'm climbing in and out of the plane and also when servicing the gascolator.

I need to finish setting the correct location of the gascolator based on my new j-tube. It's just a tad further aft than my original position.

 I have the stainless steel template for the gascolator and I am able to drill the exact center of the unit.

Now comes the fun part...I've previously settled on a 0.032" doubler. It allows the bottom of the Aerolab cap to sit perfectly flush with the bottom of the floor skin. I cut out a square doubler shape and started "making" the doubler. 

After placing the template on the doubler, there is no doubt in my mind that this does not look good. First, I don't care for the doubler to be off center, and the round unit on a square rivet pattern just doesnt work. 

After talking with my buddy Mike (A local builder) and diving into the Standard Aircraft Handbook it inspired my to attempt a different doubler and rivet patten. While I won't have the recommended 6D spacing of rivets in all locations. I think the more radial pattern of rivets will work really well.

So I drew the pattern/template on CAD and printed it out. Its looking good. So I then cut a new doubler plate and using the CAD template I drilled all of the holes 3/32". Since the pattern and fit just work...There was no hesitation to start drilling the gascolator mounting holes through the floor skin.

Satisfied with where I am at, its time to drill the 2 1/2" diameter hole for the Aerolab unit. Drilling these holes with a holesaw is always a stressful event. My holesaw is not a precise tool and it likes to wobble...So my method to prevent this is to make a cutting template out of wood. This helps keep the holesaw in the correct location and makes a clean hole. Using 1/4" MDF...I went to work.

The hole in the floor is correct, just need to repeat the same hole in the doubler.

Once done, I am now ready to drill all rivet holes in the doubler/floor skin.