PETG for windshield?

12 posts in this topic

Posted

The lexan that came with my kit is very old and I'm afraid that it is going to crack just trying to unroll it (been packed since 1986) so im looking at what to get I was wondering if this PETG stuff may be a good option. http://www.ebay.com/itm/PETG-Plastic-Sheet-060-x-48-x-96-Clear-Lexan-Acrylic-/360431555926?pt=LH_DefaultDomain_0&hash=item53eb651556 has anyone actually used it how is it different from regular lexan?

-Robert-

Share this post


Link to post
Share on other sites

Posted

Robert,

I checked into this stuff this summer when i was looking at replacing my doors-the local plastics dealer talked me out of it- I can't remember the reason, i think it was strength. Plus the lexan was maybe $30 more. That piece of ebay will cost a small fortune to ship. My windshield, which is original 1993, had some scratches that where easy to polish out, looks almost new. Good Luck, Bryce

Share this post


Link to post
Share on other sites

Posted

The lexan that came with my kit is very old and I'm afraid that it is going to crack just trying to unroll it (been packed since 1986) so im looking at what to get I was wondering if this PETG stuff may be a good option. http://www.ebay.com/itm/PETG-Plastic-Sheet-060-x-48-x-96-Clear-Lexan-Acrylic-/360431555926?pt=LH_DefaultDomain_0&hash=item53eb651556 has anyone actually used it how is it different from regular lexan?

-Robert-

Mine was setting around almost as long and was fine. Save the money.

Share this post


Link to post
Share on other sites

Posted

PETG has very similar characteristics to lexan and is much less expensive. It is used a lot for race car windows due to low cost and shatterproof nature like polycarbonate. I used it on my MKIV upper and lower door windows with great results. I intended to use PETG for the main windscreen, but sold the plane before it needed to be replaced.

PETG cuts and works just like polycarbonate. You won't be able to tell the difference working with one material or the other.

I did hear somewhere that PETG is not UV resistant, but I do not know that lexan is either. Plus in the big scheme of things my plane spends a lot more time in the shade than in the sun even tho I fly a lot.

PETG worked great for me.

Chris Bolkan

Share this post


Link to post
Share on other sites

Posted

Oh, just thought of something else....

I think your lexan will be fine even if it's real old and been rolled up for years. I don't really think it goes bad unless it's been exposed to chemicals or direct sunlight for long periods of time. The only problem you may have is getting the paper backing off if it is too old to have plastic backing. I had to throw some away because I could not get the backing off. Now days polycarbonate and PETG come with easily removable plastic backing.

Chris Bolkan

Share this post


Link to post
Share on other sites

Posted (edited)

so 6 one way and half a dozen the other??? Does anyone know if Lexan has any UV resistance that would make it better. I do have the old paper backed stuff (.054)and when i tried pealing a piece off it doesn't want to come apart and it leaves a mess on the lexan so im just going to replace it anyways. I was thinking of ending the windshield piece on the front spar carry through tube and having the skylight back be a second piece that is the darker smoke color to keep the sun out. I'm also thinking about making my own "bubble" doors. My thought is to leave the center tube across the door and add a second one that attaches at the same points and make it bend out about 3" then bend the lexan around it then you would still have the original bar for an arm rest. Has anyone tried this? can the lexan bend in all these different ways without breaking and look good. I've never worked with lexan before.

-Robert-

Edited by High Country

Share this post


Link to post
Share on other sites

Posted

so 6 one way and half a dozen the other??? Does anyone know if Lexan has any UV resistance that would make it better. I do have the old paper backed stuff (.054)and when i tried pealing a piece off it doesn't want to come apart and it leaves a mess on the lexan so im just going to replace it anyways. I was thinking of ending the windshield piece on the front spar carry through tube and having the skylight back be a second piece that is the darker smoke color to keep the sun out. I'm also thinking about making my own "bubble" doors. My thought is to leave the center tube across the door and add a second one that attaches at the same points and make it bend out about 3" then bend the lexan around it then you would still have the original bar for an arm rest. Has anyone tried this? can the lexan bend in all these different ways without breaking and look good. I've never worked with lexan before.

-Robert-

One other thought Robert. If you are considering splitting the windscreen in two and making the skylight a different piece of material, I would strongly recommend going to 0.090 thick material for the windscreen. It would be easy to do and not as prone to the crazing that happens at the compound bend at the spar carrythtough as doing a one piece installation. I did my MkIV windscreen in 0.090 lexan (before discovering PETG) and I feel it was worth every bit of the effort even though it was a bit tougher to work with because of the additional stiffness. I did mine in one piece instead of converting to a different piece for the skylight which probably made it more difficult. Switching to 0.090 thick material just made the plane feel more substantial overall. Before the 0.090 when I would dive the windscreen would buckle and push in and I swear I could hear the windscreen flexing as part of the wind noise. With the 0.090 material it didn't flex at all and like I said, just felt better, stronger, quieter and more substantial. it was such an improvement I would never use 0.060 material again on an Avid windscree that goes over 100 MPH (even in a dive).

Chris Bolkan

Share this post


Link to post
Share on other sites

Posted

Thanks for the heads up. I should still be good using .060 for the sky light, and doors though right since they are not in the direct airflow.

-Robert-

Share this post


Link to post
Share on other sites

Posted

Thanks for the heads up. I should still be good using .060 for the sky light, and doors though right since they are not in the direct airflow.

-Robert-

Hi Robert,

That's what I would do. Use 0.06 for doors and skylight and 0.090 for the windscreen. Best of all worlds. If you are building it will be more challenging than if you have an original windscreen to use as a template. Even if you do have an original to use as a template, your final product will turn out just a bit different because not having the compound bend at the carrythrough will change the overall shape of things a bit, so cut a bit oversize.

Another option is to use your "bad" material to make a template. Make all of your mistakes on it first.

Polycarbonate and PETG work easily. it's actually fun. The thin stuff can be easily cut with tin snips or cut with a fine blade. Probably the best too to use is one of those triangular vibrating cutters you see on TV and at Home Depot. I borrowed a friend's and it cut the stuff like butter!

Be sure and sand all edges smooth to prevent stress cracking over time, especially where the material bends because stress accumulates at all bends! Have fun!

Chirs

Share this post


Link to post
Share on other sites

Posted

The old roll of lexan that i currently have does have the drawings on it to cut it out so i think that i will make it into a complete windshield and when i like it i will trace it onto the new lexan. also i do have a band saw and scroll saw these should cut the lexan nicely right?

-Robert-

Share this post


Link to post
Share on other sites

Posted

The old roll of lexan that i currently have does have the drawings on it to cut it out so i think that i will make it into a complete windshield and when i like it i will trace it onto the new lexan. also i do have a band saw and scroll saw these should cut the lexan nicely right?

-Robert-

I cut out my windshield with good heavy tin snips. Some of the tight corners I used the jig saw on. Just make sure you clean up the edges with a pretty smooth file so there are no sharp edges for it to start cracking at.

:BC:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now