Forming Plexiglas

[WLIU]

It might help if you posted how large the part that you have to form is.

It is not that hard really. Plan on throwing away your first try, but you will likely get an acceptable part on the second try.

I would not resort to hot oil. Hot air us good enough. I did the skylights for a Globe Swift in the kitchen oven. You might consider building an insulated box on the front of your kitchen oven to extend its size. Use the oven temp control to creep up on the right temp. Patience is important.

Best of luck,

Wes

[Mike Switzer]

I would not resort to hot oil. Hot air us good enough.

I tend to agree - I'm having visions of a gigantic turkey fryer fire.

[flyingriki]

A fellow in Kitplanes, a few months ago, made bowed side windows for his plane in his wifes' oven. He built an extension to the oven box with simple materials and was pleased with the results. Probably had the temp info you require. Sounds similar to the suggestion above for Swift Skylights. Good luck!
Link attached.

[Pearson]

Thank you for the article "Kitchen Window". It gave me a couple of ideas. I have a small forced air propane heater I use to heat my garage during the winter. I think if I made some sort of box to hold the hot air I could use it as an oven. Also I like the idea of using air to "blow" the plexiglass. That would save a lot of labor associated with making a male mold out of wood. I will have to fabricate female curves to match the curve of the top of the wing and the front and rear cross pieces, but I think that will be less work than a male mold. Blowing it also eliminate my concern for protecting the plexiglass from scratches when using the male mold. Thanks for the ideas.

[Neil]

I made windshields for my Biplane using an oven that is designed for baking silk screened immages in "T" shirt shops. The process was outlined in the Acro Sport Newsletter #62. These newsletters can be accessed from the homepage of <BiplaneForum.com>
Attachment 0

[Pearson]

I am going to try to use what I have on hand to heat the plexiglass. If my little propane heater doesn't work, I will investigate the link to the ovens.

[Yen]

Get hold of Light Airplane Construction by Leo Pazmany. He gives a good run down on making a canopy for the PL1 and PL2.
He recommends air heating in an oven with the sheet hanging from pressure clamps. Felt or flanel moulds should be covered in grease.
If you can't get a copy easily. email me 355yen@tpg.com.au and I will see if I can photopy and email the relevant info to you.
I must stress that I have never tried this process myself, at least on anything over the size of a light lens.

[Sirota]

What temp do you need? Companies that do powder coating have large ovens that heat to 400 degrees. Possibly you could strike a deal with someone that would let you put your skylight in their oven?

[Pearson]

Hey, that is an excellent idea. I need a temp of around 300F. I will ask a couple of friends that do powder coating.

[Yen]

According to Pazmany temps vary dependant upon ambient temp. He gives a working time for 1/8" plexiglass of 1.5 min at 75degF and heated to 320 Deg F Going to 2.8 mins at ambient of 120 deg F. He suggests 280 to 360 deg for heating, and thinner materials need greater heat due to their quick cooling, so your project should be OK I would think at 300 deg.