Fuel Tanks/New Toy!

Got the EZ-Burrs in the mail today! WOW these things are awesome. After one day using them, I'm hooked. Out of the box, the blade height has to be adjusted slightly to achieve the desired spring pressure (it's a simple allen screw adjustment). What seemed to work best was setting it so that there is a slight amount of resistance felt by the drill when the blade makes contact with the hole, in both directions. There is definitely a short but necessary learning curve in proper technique, too. You can't just blaze through the hole in both directions-- the blade won't have time to do its job. It takes just the right amount of control and finesse with the drill to have the blade make contact for a few turns of the drill, and then poke through to the other side. Then the same sort of controlled pull on the way back through. After a few dozen holes it became quite simple, averaging maybe 2 seconds (at most) per hole. Speedy!

The 2.5mm EZ-Burr for #40 holes

Using this new device, we made *very* quick work out of deburring the tank skins, ribs, and stiffeners. I dare say, the holes came out better and smoother than our old deburring method, in less than half the time! Did I say I was hooked?

After deburring, I went ahead and masked off all the rivet lines on the inside of the tank for some "targeted scuffing" to help the proseal stick better. This took waaay more time than I thought it would, especially after cruising through the whole deburring process. But, we ended up with some pretty neat patterns in the skins:

Tank skin masked off for scuffing

After a visit with some Scotchbrite

With that, we got right on to dimpling the skins. Most of the holes are #40, although there are six #30 holes that we made for the fuel caps (non-standard) and then a series of #8 screw holes around the perimeter of the skins. All needed to be dimpled (except for a few called out in the plans), so we went three rounds with the three different size dies. It actually went quite well... woo!

Now that the dimpling is complete, it's proseal time!!! Had to clean up the shop a bit in preparation for the process, including lining two of our tables with paper and getting out the gloves, popsicle sticks, MEK, and acetone.

The proseal station!

Tomorrow.... proseal!!!!