Timing is everything with this operation. With the oven preheated to 300-325F and the glass clecoed to the form, the whole thing is placed in the heat. I spent three minutes starring through the oven window, then chickened out.
As luck would have it 3 minutes was about right. Too much and contact forming occurs meaning that the surface picks up marks from whatever it touches. Too little and of course the glass fails to take the desired shape.
I used 732 clear silicone after experimenting with various options.
As it happens I found the metal frame, screwed to the bench, which worked very well for clamping the lower edge.
August 2016The interior panels are cleaned and primed, then the stiffeners and doublers are riveted in place.
Next up, I need to decide on how to do the sliding windows.
While waiting for material for the top cowlings I went back to the doors to make interior panels and window frames.
The left interior panel was salvageable.
In addition to a couple of repair doublers, I added a stiffener to make the panel a bit more knee-proof.
The right panel was toast, and made of 040" soft aluminium anyway so both over and under-kill as it were.
A new panel is fabricated from 025" material.
Again a 'Z' channel is fabricated and added to reduce drumming and provide some additional stiffness.
I used 2024 T3 032" at least in part because it's what I had on hand.
I have not yet decided what do do about the windows.... to slide or not to slide, that is the question.
Given bringing the doors back into acceptable shape continues to be a project in and of itself, I felt they deserved their own section.
At some point the passenger side door had been damaged and "straightened" and I suspect as much damage was done in the straightening as in the original mishap.
Dismantling without damaging the magnesium door handles was tricky
Reinforcing the structure by inserting a doubler. This type of repair was done in several places.
Both doors were repaired/reinforced in the latch area.
Start with a standard 1/8" bit but stop before penetrating the channel. Grind the end off a 1/8 bit and finish the stop hole. This bit will tend to stop cutting once its through the first layer but a little at a time caution gets the desired result.
I'm no expert but I have developed a technique that yields satisfying results in what I believe is a reasonable time-frame.
First I buy the cheap rubber gloves, in Canada available from Canadian Tire usually for less than $2. I wear cheap vinyl surgical gloves inside those and put barrier cream on my hands. At the first sign of failure, I change out the gloves. Tried all the so-called chemical resistant gloves and they don't do much better at four times the price.
Next, when I was restoring my 172, I made the pictured scraper from and old laminate counter-top. I guess its formica but the key is the stripper doesn't soften it and it won't damage aluminum. I keep a 45 edge on each end by occasional running a sanding disc over it.
I use Klean Strip I think it's called, available from US hardware stores. Applied with a natural fiber brush. The brush goes hard after but then the stripper softens it up again. My brush is just about completed its second aircraft! Actually so is the paper cup I put the stripper in.
Lay down some paper (some stripper will seep through so make sure you're on a resistant surface or use more paper layers).
Apply lots of stripper and don't be tempted to move it around or work it with the brush.
Use the scraper to remove the lifted paint and move still-wet stripper over areas where the paint is still stuck.
apply a second coat of stripper and repeat the scraping process.
Step three is dabbing more stripper on any still stuck areas.
Finally scrape off all remaining stripper and immediately clean with lacquer thinner. Use scotchbrite with thinner on tough areas of primer around rivet heads etc.
On larger surfaces work in sections about 2 sqft each, you can have two or three sections going at once, each at a different stage but don't try to do too much at once.
Roll up the paper and put it somewhere where it will dry out. After a couple of days all the pain/stripper will be dry and hard and it can be disposed of safely.
Right Door SkinAs mentioned I should have bit the bullet and gone for re-skinning sooner but I think I was spooked by the spot welds. Then I realized I could simply ignore the spot welds.
Door is traced and 2024 T3 is cut for the new skin
Skin is tacked then hung on the door frame to ensure the shape is still good
A few tense moments while the window opening is cut... please don't mess it up now! and rechecked on the door frame.
The left Door was in better shape except for the multitude of holes left by various window mods over the years. The original Tcraft windows slide and the plan is to recreate that so I needed to find a way to plug the holes.
After etching the doubler was bonded in place using proseal. and all my clamps. Door had to be supported to prevent any twist. Gallon of thinner is used for ballast :)
Doors get etched, alodined and epoxy primed.
We don't want floppy door handles so the old tubes are carefully cut out and new ones installed and reamed.
Still to do are the interior panels and window sliders. Wow, a lot more work than I thought. How many times have I said that! Oshkosh 2016 may be not enough time.