Misc parts, priming & painting

 Previously, I had mentioned that we had some difficulty with some sort of contamination that was causing fish-eye (small crater) blemishes in the primer.  This happened while priming the aluminum front kick-panels, the baggage door, and the lower rear cover plate.  We took several additional steps to ensure everything was super clean, and that the paint and air were well filtered before spraying.  However, the problem did not go away.  We now suspect that the problem is with the metal primer itself, especially since we didn't have any of these issues when shooting the fabric primer, or the topcoats.

Small crater blemishes in the primer (streaks are just water marks after wiping the part)

After a few coats of primer and too much additional sanding, we now have parts that are ready for paint, but this was a frustrating experience.  I think we'll change to a different metal primer for remaining metal parts that are not yet primed (such as the turtledeck).

We then decided to paint the front gear leg, front fork, and rear aluminum cover plate, as these parts will be all orange.  The parts were prepped, cleaned, and hung.  We sprayed a coat of orange... and as expected, we did not have contamination issues like we experienced with the metal primer.  We then sanded/scuffed the parts to prepare them for a second coat.  Hours: 12

First coat of orange on some additional parts

Paint room and priming updates

 We finished downsizing the paintbooth, which also required modifying the front door panels to fit the new shape, adding some gasketing, and making sure everything was sealing correctly.   With a smaller room, we can now keep the fuselage outside of the paint booth.

Paint booth for smaller parts

We also have a temporary air outlet that we can setup before painting to exhaust the paint fumes out of the garage, and then disassemble after painting so that we can fit the fuselage back in the garage.  This was constructed with two U-shaped pieces constructed with 2x4's on each end, along with two 10 ft 2x4's clamped to these pieces, and a single sheet of plastic clamped to the 2x4s.  We can set this up in about 5 minutes and raise the garage door about 2 feet to allow the fumes to exhaust out the garage.  Seems to work great.

Paint room with lower exhaust outlet

We then prepped some smaller aluminum parts for paint.  The baggage door has some pulled rivets, and we filled the holes with 3M filler and sanded them so that we would have a smoother surface.  This door door, along with a few other parts (rear cover plate and side kick panels) were scuffed, cleaned, and hung in preparation for priming with an epoxy primer

Michael sanding rivet heads on baggage door

We applied a coat of primer, but ran into an issue with some sort of contamination that caused fish-eye type craters in the primer coat.  We allowed it to dry, sanded the coat of prime down to eliminate the fish-eyes, then adjusted some of our procedures to ensure we cleaned everything better and put new filters inline with our paint gun.  We remixed some primer and tried respraying two days later day.  Unfortunately, the contamination problem still exists so we haven't solved the problem.  This is frustrating because we are using the same products and procedures that we have used in the past, yet we are getting these fish-eye blemishes.  We will now go back to painting some practice parts until we get the issue corrected.   Hours: 16

Painted the Main Lift Struts and More

The last large (i.e. long) part that needed to be painted were the two main lift struts.  They came from Just Aircraft with gray powder coat applied but we decided that they would look much better painted the same Vestal White as was applied to the fuselage.  We had to scuff the powder coat and clean the parts before painting.  We also painted the small Jury Struts at the same time.

Lift Strut Painted Vestal White

To paint the Struts we moved the fuselage outside for it's debut in the sun!  We had to take a photo with the two builders (i.e. US!) for our family and friends!

First time Painted Fuselage has been outside

With the last long part painted and allowed to cure we no longer needed the large paint boot taking up a large portion of the garage.  Over the Thanksgiving week, the front part of the paint booth was removed.  The side entry door was re-framed and installed. The two front doors still need to be extended in height in order to allow them to seal up the room.

Re-Sizing Paint Booth

We started working on the firewall next.  Just Aircraft had provided us with stainless steel material for the firewall.  To save some weight (about 2.5lbs) we chose to use titanium as our firewall material.  That material was sourced from McMaster Carr.  First the width was trimmed using hand shears.  We then had to cut notches around the nosewheel mounting points on the fuselage.  The nibbler tool worked perfectly for this task. Once we had the bottom edge of the firewall where we wanted it to be we marked the side areas that needed some clearance notches.  The process was identical to the original notches and quite a bit quicker since they didn't need to be as deep.

Ed using Nibbler tool on Firewall

Finally, once the firewall had a good fit we drilled the 8 attach point holes and cleco'd the firewall in place.  We also drilled the four corner engine mount holes.  We still have some work to do on those holes before we can put the engine mount on the fuselage.  The top of the firewall still needs to be trimmed to match the boot cowl, but that too is for another time.

Firewall Drilled and Cleco'd in place

Hours: 15