My S1 Restoration

[czr7s1]

Following…keep us posted on the oven!

 

[Steve Stephenson]

You have alot going on. I did a big kitchen renovation that got bigger when "surprises" happened - so I feel for you.

Building a garage/game room this summer. We're hoping the price of lumber comes down a little.

Please don't feel any pressure from me to dig into those logs. I was previously looking for some answers from Gaston but that probably won't happen. In any event my S1 has pretty much been restored from the seat back to the tip of the spinner - including the wheels, pants, tires and brakes.

I think we jacked Roger's thread.

My canopy is from Airplane plastics.

 

[ROGER WINGER]

 

[ROGER WINGER]

Some pics of my oven.

 

[ROGER WINGER]

A baffle so the heat wasnt directly on the plastic but had to swirl around. I managed to get the oven up to 315 degrees F.

 

[ROGER WINGER]

 

[ROGER WINGER]

Another baffle so the air wasnt blowing directly on the soft plastic

 

[ROGER WINGER]

 

[ROGER WINGER]

Viewing window. Eventually i cut out the circles in the wood to let more heat in from the propane heater

 

[ROGER WINGER]

 

[ROGER WINGER]

Unlike the article I posted earlier, I blew the canopy upside down so gravity was helping not hindering in any way.

 

[Steve Stephenson]

Slick.

 

[Aviacs]

Roger -
That is really cool, and very reminiscent of the original S1 canopy oven John Monnett used, or at least had at the early seminars!
His was a little cruder - length of black pipe with holes drilled in it for the propane burner. But they had the box wrapped with fiberglass batts.

Did you/how will you anneal it? For me that has been the sticking point or most difficult part of the puzzle.
Also, plastic manufacturers literature indicates that apex thickness will be about 35 - 40% of original sheet thickness for a full 1/2 circle free blown form.
About .050" thick for 1/8" original material. Are you comfortable with that thickness, or has success given you any thoughts of trying a thicker starter sheet?

Thanks for posting, there are a lot of us out here "thinking about" doing it.

smt

 

[ROGER WINGER]

Interesting, I didn't know about the annealing step. Not sure how to do it other than borrowing the wifes oven I can tell you the canopy is very strong and I don't think its brittle, but on a molecular level, who knows. It drills beautifully. Also, as I remember I measured the thickness at the peak of the bubble at .070 or .080 thou but I can confirm next week when I'm back in my shop.

 

[Aviacs]

Nice that thicker than predicted thickness can happen. That is encouraging.
I wonder if it was due to blowing at the lower end of forming temps? There seems to be a lot of trade off options within a narrow range of temperatures & heat distribution within the sheet. It also seems likely that fewer stresses might occur in very thin sheets, so perhaps crazing with time will be less of a factor as well (compared to thicker sheets)?

Acrylite dwells on temperatures and annealing processes extensively, with specifics. Plexiglas is a little more obscure, though mentions it.
Proper heat during forming & cool down over time intervals, followed by annealing ("long" periods and specific conditions spec'd by Acrylite) is supposed to resist the propensity for thermoformed sheets to craze after a couple years. Some reading indicates it might add a little bit to solvent resistance. (I'm not "clear" on that)

Acrylite manual:
https://www.acrylite.co/thermoforming-acrylic.html
Plexiglass per Curbell plastics:
https://www.curbellplastics.com/Res.../Technical-Resources/Plexiglas-Forming-Manual
There are more papers/manuals online from other sources and older research programs.
No need to get bogged down in general industrial methods, but the graphs, tables, and specifications on forming temps and process seem to be a good starting point to inform any method.

smt

 

[ROGER WINGER]

It's not much progress but it is some progress. The aircraft came with these bent bolts and a couple screws for the canopy release. I found them hard on the fingers and tough to use. These knurled knobs should be better.

 

[Steve Stephenson]

Great idea.

 

[ROGER WINGER]

Nothing exciting to see today. Prepping fuselage frame for paint. Blue now but it will be black when im done. Listening to spotify and enjoying the moment. Back to work

 

[ROGER WINGER]

Oh and my new prop is done and waiting for me. 52x48 by GSC in Vernon. Took 2 weeks and $535 cdn. Pretty sweet deal imho

 

[Steve Stephenson]

This is my 52-48 just after I restored it in December. You got a good deal on yours and it looks great.