More blasting and a door dis-assembly

I've been working steadily on the airplane.  I got the co-pilot seat all bead blasted and cleaned and found a couple of the straps are broken on that.  I sourced some 4130 steel strapping here, but it's too thick and more expensive than the aircraft supply house Aircraft Spruce so I'll order that plus some Aluma-prep and Alodine to pre-treat all the cleaned aluminum parts I have stripped before painting.  Kevin and I went to the Golden West Fly-in a couple of weeks ago in Marysville, CA because we've never been and wanted to attend some workshops there and see some planes.  The wind was blowing stronger than 20 knots so the turnout was low.  We didn't see any stinsons, but a nice 1956 Piper than had a similar paint scheme we plan on using.  The owner did the restoration in one year!  I am amazed at the great job he did.  I think we'll do just as well but it won't be that fast.

Here's a cabin ceiling light and speaker grill, exactly as we will have in N97917.  This even has the exact same color headliner we have too.

Here's the Piper we saw (closest thing to a Stinson there).

I'm still in parts-cleaning mode.  I was always intrigued by what was behind the old black vinyl-covered door panels so I continued to strip and dis-assemble the co-pilot's door I started removing the paint in the previous blog entry. I found out that there are 2 door window designs on Stinson 108s--square corner window frames and round corner window frames.  Ours has square corner window frames which I believe are from the earlier versions (N97917 was assembled in late 1946).  I found the window frame channels to be screwed and glued in which I dis-assembled and scraped the gunk off.

Here's the clean door exterior side.

Door interior stripped down after soda blasting (except the section which will be behind the interior paneling.

I can re-use all the channels and window trim except for the bottom guide.  Here they are laid out as they were taken off the window (bottom of photo is bottom of window frame, left side is forward edge of the window.  Stinson 108-1 had cool sliding windows on the doors so you can easily open the window to take a photo or let in the breeze, or just park your elbow on the sill on a nice sunny day of flying.   I bead blasted these parts and sanded and cleaned them up.

After cleaning, I discovered it had rust holes on the bottom channel only so I will have to source a new channel somewhere.

I bead blasted other parts of the door latch hardware as laid out here and explored polishing the aluminum door handles with some buffing disks and rouge (sp?).  The partially buffed interior handle really cleaned up great and looks like chrome.  I will have to finish the buffing process and then work on the cool stream-lined exterior door handle.  I found a mysterious thin wood piece that was broken in 2 as seen in the photo below on the right.  It has a hole drilled in the middle and has a step/ledge halfway through the hole.  It is unclear where this piece came from, but it fell out when I removed the old fiberglass insulation that was in the door.  I'll be curious to see if there is a similar piece in the pilot's door when I get to it.

I purchased 2 new polycarbonate windows for the co-pilot's side door window.  I thought about purchasing from a known aircraft window supplier, but found a local plastic's shop (Tap Plastics) had the same thing at the same price so I just saved the shipping costs.  The forward window slides back, but when it is forward, there is a small spring-loaded pin in the door frame that locks into a notch on cut on the bottom of the sliding window so someone can't easily get into the locked airplane.  I'll leave the protective plastic on until it's time to re-assemble the window (after painting).

New window laying on top of old window (still in one piece, but cracked from age)

Matching notches for window lock pin.

The window lock pin and handle.

To date, I've been using glass bead to clean all my parts (steel and aluminum). However, I was trying to clean the interior door post aluminum trim pieces that cover the fuel lines and electrical leading to the panel and firewall, but discovered that the glass bead did not easily remove the blue paint AND seamed to warp the aluminum (from heat).  I researched other blasting media and read that soda blasting is gentler on aluminum so I purchased a 50 lb bag from Harbor Freight for $35 to try it on the co-pilot door (too big to fit in my blasting box anyway).  Setting it up outside my shop on some sawhorses I found it did a pretty good job on the door (all the photos in this post are taken AFTER the soda blasting).  I still need to clean up some areas for a perfectly clean surface as you can see in the photos.

 I  had plenty of soda so I proceeded to clean the rudder too.  The dark designs on the rudder proved to be very thick paint which I had to rough up more by hand together with more soda blasting effort.  The soda blasting removes the old paint very well around the rivets and in the grooves in the rudder which would be a bear to sand by hand.

Overall, soda blasting worked well for large parts, but I had to wait for my 20 gallon compressor tank to refill sometimes to keep up the pressure I needed.  I got about 1/4 the way on the back side of the rudder so I will complete that another time.  Looking forward, I either need to soda blast the aluminum flaps, cowl, lower cowling, nose bowl, and wing struts and covers, and landing gear fairings, or sand and clean by hand or use a chemical remover.

Cleaning and Sanding Parts

Each night I’ve been able to spend an hour or so on doing something on the plane.  I've been spending most of my time cleaning parts to prepare for painting.  I got the rear window frames all cleaned up for painting.  Funny, the exterior paint came off really easily, but the primer was harder to remove.  I sanded these all by hand.  I had to scrape of a putty/window glazing that had the consistency and look of plumber's putty.  I have all the window frames all cleaned ready for painting.  Here's the rear window frame, one is clean and the other in as-received condition.

I also cleaned and painted the fuel valve selector switch and the starter switch.  I painted them with rattle-can paint and I think they look great finished.  I will prime the fuel vale selector extension after I prep some more parts.

On Memorial weekend I got two interior cabin pieces cleaned up.  These had a lot of glue from carpeting on them (and old blue carpet) that I had to remove.  One is the control column cover that is on the floor between the pilot and co-pilot's feet, and the other is the oleo strut landing gear cover located under the seats.  I hand sanded and scraped these using aluminum oxide sanding sponges and scotch-brite pads.  Now I need to get some Alumiprep and Alodine to prep these and all the aluminum parts for painting.  The inside of the control column has some phenolic stiffeners riveted at the top that need replacing.  I'll do that at some time before installation and painting.

I also took a stab at sanding the co-pilot side door too to see how difficult it was.  At first I tried sanding it with roloc-type scotchbrite discs on my air angle grinder but I used 3 up just doing the very bottom closest to the lower hinge.  Then I tried a spatchula knife and that worked better (working hard not to scratch the aluminum).  This door has a patch near the bottom too so it's my least favorite door so if I really screw it up, I'm not going to be that upset about it.  The knife worked OK, so I that a flat razor would work even better!  I hardly pushed on it and it just flaked off the paint like crazy.  I sanded out some of the scratches some with sanding pads and scotchbrite but stopped there wondering if there is a better way to strip aircraft paint since I have more large pieces to strip like the other door, control surfaces, cowling, etc.  Enjoy the photos of the door below I worked on:

Not bad for just scraping and sanding, but there's got to be a better way to strip the paint.  Maybe try chemical stripper next.

I finished installing the ACK ELT antenna bracket I made in an earlier post after I got a plastic snap ring from Aircraft Spruce that I thought would work.  Here's the finished bracket I installed with pop rivets in the former along the spine of the fuselage.

 Last thing I did is to take one of the seats apart.  I chose the pilot side seat. I took the black seat cover off and think I found the original seat broadcloth fabric.  It is a blue lined fabric which explains the other blue-painted parts inside the cabin.  Somebody had used safety wire to wire on a split piece of hose on the seat back frame so that there was some rubber cushioning when you put the seat back.  If I want to have a rubber cushion again, I want a more elegant solution which will take some searching.  The seat frames looked OK, but after I cleaned them in the blasting cabinet I found one of the straps were broken and several more were cracked.  The seats had the original horse hair padding used for cushions when it was new.  I saved the old original seat fabric if I want to attempt to make my own seats or outsource it.

 Seat frame back uncleaned

Bead blasted frame nice and shiny clean metal

This strap is broken completely at the frame

This strap is cracked at the frame

Close up of the crack

With this new discovery of broken straps, I posted a question on the Stinson Yahoo forum and several said the straps can be easily fixed by welding new straps on top of the break or replacing the straps altogether.  I have sourced some 4130 steel straps 1" wide at Aircraft Spruce I am considering to use to make the repair.  However, before I purchase it, I will take apart and clean the other seat to see what repairs (if any) need to be made to that seat frame.