Landing light plastic cover

[Minnesota Mooney Guy]

Anyone have a better plastic landing light cover that Lazar provides.  I bought one from them which came without the screw holes drilled and the lens plastics cracked with drilling.  Now I have a crack in the lens and it never really covered the light space completely.  

[kortopates]

Its not the source of the material you're having but learning how to work with the material. These, like the majority of airframe parts, require final trimming to install because of the nature of our hand made airframes. The main source of windows and lenses is, but it's also where LASAR and Mooney get them:

https://www.glapinc.com/Mooney/m20K.htm

But recognize you can't use a regular drills for wood and metal to drill acrylics without continuing to crack them. You'll need to follow the drilling and trimming instructions located on their website here: http://www.glapinc.com/instructions/index.htm#general

 

Specifically, though many of prefer to use a single unibit drill for drilling different sized holes in acrylics - they make it simple and easy and don't require multiple drilles - see this more detailed except of 43.13.1b they provide:

http://www.glapinc.com/instructions/pdf/AC43.131BChapter3.pdf

[N201MKTurbo]

I got mine from the aviation isle at the Home Depot. I used 1/8 inch Lexan (polycarbonate). I cut it out with my scroll saw using a 10 tooth blade. I heated it with a heat gun and bent it around a Home Depot bucket. 
 

I can’t imagine a cutout from Laser would have saved that much time.

[carusoam]

28 minutes ago, N201MKTurbo said:

 

I can’t imagine a cutout from Laser would have saved that much time.

There are many shades of DIYers on MS...

I achieved the level of successfully drilling holes in acrylic sheet for installing windows...I bought the drill bit and the windows at the same time...

Which is probably a 2 on a scale from 1-10...

Rich, on the other hand...  a 10+ with the ability to fashion a plane from it’s basic materials... including boxite... aka aluminum ore.  

The tough news for the OP... check your skill level... it may make sense to hire a mechanic.  Many of the skills that look easy, take training and an attempt at doing it the first time...

You have probably learned enough to get it right the second time...

It is possible to pre-drill the acrylic, but none of the suppliers will take the risk of putting the holes in the wrong place...

Mooney would be able to do this...but, that adds more hands on the project...

As for the size mis-match... IIRC, that allows for airflow.... so the acrylic doesn’t melt in front of the hot bulb... if you are using an LED bulb... the temps will be much cooler...

Now... about that Lexan... it is tougher, more impact resistant, and less thermally sensitive than the traditional acrylic sheet...  

PP  thoughts only, not a polymer processing or manufacturing guru...

Best regards,

-a-

[carusoam]

1 hour ago, Minnesota Mooney Guy said:

Anyone have a better plastic landing light cover that Lazar provides.  I bought one from them which came without the screw holes drilled and the lens plastics cracked with drilling.  Now I have a crack in the lens and it never really covered the light space completely.  

Let’s see what it looks like...  got a pic?

In case you got the wrong part or something got lost in translation...

Best regards,

-a-

[N201MKTurbo]

1 hour ago, carusoam said:

Rich, on the other hand...  a 10+ with the ability to fashion a plane from it’s basic materials... including boxite... aka aluminum ore.  

If I thought it would save a buck, I’d figure it out.

[N201MKTurbo]

5 hours ago, N201MKTurbo said:

If I thought it would save a buck, I’d figure it out.

I checked my hangar, I only have a 15amp outlet. I can’t do it!

[jaylw314]

If you don't have a unibit, you can sand or file down the cutting edges of a standard drill bit (handy use for one at the end of its life anyway).  This makes the bit less aggressive while drilling acrylic and less likely to crack it.

[N201MKTurbo]

If you use a standard drill bit, and feed it very slow, you will be OK. If you push, it will bite into the plastic and pull the bit into the plastic, cracking it. A dull bit will melt its way through the plastic. A tapered bit will work well without issue.

Either way, drill a bunch of holes in a scrap area until you get the desired results.

If you buy the performed piece from LASAR, you won’t have any scrap to practice on.

Edited March 7, 2021 by N201MKTurbo

[ragedracer1977]

Run a standard bit backwards and melt through.

 

 

 

[N201MKTurbo]

6 minutes ago, ragedracer1977 said:

Run a standard bit backwards and melt through.

That will work. If you have the time....

 

 

 

Edited March 7, 2021 by N201MKTurbo

[DonMuncy]

In drilling plastics, they crack as the drill bit exits the other side. If you support the work piece well on a piece of wood, it is much less likely to break. I have used standard bit on plexiglass and lexan many times. Truth is, I have probably cracked two out of a hundred.

[Jeph357]

https://www.aircraft-tool.com/shop/search.aspx?keyword=Plexiglass+drill+bit

Or

https://www.tapplastics.com/product/supplies_tools/plastic_tools_supplies/tap_plasdrill_bits/161/479?utm_source=google&utm_medium=cpc&adpos=&scid=scplp43303&sc_intid=43303&gclid=CjwKCAiAkJKCBhAyEiwAKQBCkn7qR0j0eLRCowRIgdcYDxbBZ_kOgUH91ZQdA_mUoPHvPJUitQIa1RoCKooQAvD_BwE

Or any of the other suggestions will work the same with proper technique

[A64Pilot]

At the factory I worked at we broke side windows and door windows pretty regularly, so I went on a crusade to cut down on wastage, There are special bits made specifically to drill plastic, helped a little, maybe, we tried dulling bits and grinding our own cutting edge on bits etc.

Nothing worked as well as a uni-bit, you know AKA Christmas tree bit.

‘I have a theory as to why, drill a hole in thin sheet metal with a normal bit, see how it distorts the hole, puts a twist in it? That’s what’s busting the plastic.

‘Drill a hole in thin metal with a uni bit, the hole isn’t distorted, there is no “twist” in a uni-bit to distort the hole.

So buy a unit bit and be done with it.

[PT20J]

Unibit is what I use. Besides, you only have to buy one bit and you can drill whatever size hole you need. Haven’t cracked anything yet . Also, flame polish or sand smooth all the cut edges. Acrylic loves to crack from a stress riser - same idea as prop nicks.

Skip

[carusoam]

Acrylic is extra sensitive to stress, and stress risers...

Try not to bend it while cutting, like on an uneven surface...

once installing it, there is a bit of bend to it as it gets bolted in place... any un smoothed cut May propagate a crack...

+1 for the cracked hole occurring as the bit cuts through the back side, not when you first start to cut...

The bit bites into the material and tries to accelerate through the unfinished hole...

Just when you are about to celebrate a job well done... 

Best regards,

-a-

[Stetson20]

I'd like to replace this yellowed cover with a new one when I replace the landing lights with LEDs. 

I like the 1/8" Lexan idea. Dumb question. Are the holes to dissipate heat? And would they be required with LEDs?

Thanks!

[N201MKTurbo]

On 3/11/2021 at 7:13 PM, A64Pilot said:

At the factory I worked at we broke side windows and door windows pretty regularly, so I went on a crusade to cut down on wastage, There are special bits made specifically to drill plastic, helped a little, maybe, we tried dulling bits and grinding our own cutting edge on bits etc.

Nothing worked as well as a uni-bit, you know AKA Christmas tree bit.

‘I have a theory as to why, drill a hole in thin sheet metal with a normal bit, see how it distorts the hole, puts a twist in it? That’s what’s busting the plastic.

‘Drill a hole in thin metal with a uni bit, the hole isn’t distorted, there is no “twist” in a uni-bit to distort the hole.

So buy a unit bit and be done with it.

https://www.mscdirect.com/browse/tn/Holemaking/Drilling-Drill-Bits/Metalworking-Multipurpose-Drill-Bits/Straight-Flute-Die-Drill-Bits?navid=12106212

 

[KB4]

3 hours ago, Stetson20 said:

Are the holes to dissipate heat? And would they be required with LEDs

Since at top cant be drainage, and since heat rises, gotta be heat and condensation dissipation.  Can’t see why 4-6 smaller 1/8l holes at top center wouldn’t be suffice.