Fuel sight gauges

First of all, a little disclaimer about my fuel sight gauges:

The original per plans fuel sight gauges are "built-in" to the side fuselage walls. This traces all the way back to Chapter 5 when the plans has us build the fuselage walls and make a depression into the wall. While doing my recon before starting my build, I noticed most Long-EZ builders skip this step and install an actual fuel sight gauge bubble.

Fast forward now back to Chapter 21 and it was time to install this gauge. So I started to ask around "What material should I make the gauge out of? How do I heat form it?" The canard community was quick to direct me to Vance Atkinson - he's been making/selling these gauges for years and has a very positive reputation. Don't try finding a website - he keeps things simple - you send him an email, he sends you a pricelist.. and you order. (nostromo56@tx.rr.com)

I purchased the DIY "kit" gauge without lights. This includes the clear bubble, white backplate, and two eyelets (standard pop rivet heads used as a channel to let fuel in and out of the backplate). I went with the DIY kit to save some money. As for deciding on the not lighted version... I didn't like the idea of permanently installing an LED inside the gauge - so if the LED goes bad, I would have to replace the entire gauge. I'd rather install an external light later on.

With that said - let me show you how I installed it:

First, I had to cut the clear bubble perimeter to match that of the white backplate. It was obvious that the "DIY kit" came rough cut and needed to be fine tuned. I placed the back plate onto the clear bubble and outlined the edges. Took it to my bandsaw and trimmed away...

The inlet and vent holes come pre-drilled through the back plate...

To protect the bubble from getting micro or epoxy on it throughout the install, I covered it with duct tape...

I then scuffed up the bubble's backside border with sandpaper to make sure the micro will get a nice bond...

On the backplate borders too...

I then made dash lines to help me know where to apply the bead of micro. Too far in would cause the micro to ooze into the bubble.. so I biased the line closer to the outside edges...

Another item to note, before the bubble gets micro'd onto the backplate, the eyelets need to be installed. So I took a scrap piece of foam and punched out two holes with a screwdriver to allow the eyelets to go through when I install them..

With everything prepped, I mixed up epoxy... I used a toothpick to hold the eyelet, and used another toothpick to spread epoxy onto the underside of the flange (being careful not to get any epoxy inside the eyelet).

I then installed the eyelets into position...

I used the remaining epoxy and turned it into micro... put it inside a ziplock bag and gently applied a bead of micro where I had marked the dashed lines...

I then grabbed the bubble and lowered it onto the backplate... being very careful to have everything aligned and not get any micro inside the bubble...

With everything centered, I then pressed on the bubble until the micro spread, creating a fuel tight seal. I pressed until the micro reached just shy of the bubble's inside perimeter...

I let the assembly cure for a day...

After everything cured, I sanded the edges to remove any slurry run-off...

With the fuel sight gauge assemblies complete, it was time to install them.

I decided to mount the fuel gauges 3" outboard of the fuselage wall (the plate is 2.5" wide.. so to be clear, I placed the center of the gauge 4.25" outboard of the outside fuselage wall). I drew vertical lines indicating the left, center, and right of the gauge.

It's important for the eyelets to pass through the bulkhead via flox (not foam). So I measured where the eyelets will go (located on the centerline)...

And then used a dremel to remove a 0.5" dia hole...

I did not go all the way through... I kept the back fiberglass so that when I fill the hole with flox it will have a backing to bond to.

I then filled the holes in with flox and let cure. The next day, I needed to drill the exact size and location of the eyelet. I measured the distance of the eyelet to the top of the gauge.. 1"..

So I measured 1" below the top of the BAB bulkhead along the centerline mark..

And drilled the same diameter of the eyelet through the flox filling...

I then measured (very precisely) the distance between the two eyelets...

 And marked the bottom eyelet location along the centerline..

Both eyelet holes have been drilled through the flox filling...

I then test fitted the gauge.. perfect fit! Eyelets went right through the flox filled holes...

It was now time to prep the BID plies (notice the eyelets sticking through the backplate).. I placed toothpicks to prevent dust or dirt from getting inside the bubble...

I started by drawing a template of the bubble onto wax paper (the red and green lines)...

I prepregged 2 plies of BID and used a knife blade to precisely cut the bubble outline...

Sanded the surfaces and painted plain epoxy on all mating surfaces...

I then applied a liberal amount of micro on the back of the gauge assembly... the eyelets prevent any micro from getting inside the bubble...

I then installed the gauge in place...

View from the backside of the BAB bulkhead...

I then made a nice micro fillet for a nice transition...

 And painted plain epoxy all around the bubble where the glass will bond..

Installed the prepreg on and peel plied all edges...

Next day, I trimmed the overhang at the top, removed the peel ply and cleaned everything up...

I removed the toothpicks and put tape on the holes to protect dust from getting inside the bubble... this tape gets removed prior to sealing the tanks with the top skin!

And there you have it! Fuel sight gauges are installed!