Mold pattern for a new glareshield

[BrianW]

Hi,

I have an M20J with a glareshield that's cracking apart.  I contacted Hector at Aerocomfort and he looked my photos.    He said it was beyond repair.  Luckily he had a new M20J glareshield available.  He previously covered it in leather for a project but now it was just sitting around.  He offered to sell it, so I bought it.

It looked great but didn't fit.  It appears that it's about 1/2" to 3/4" long (but l guess all new glareshields need to be trimmed to length).

But more importantly, the underside section is missing.

The underside section is molded to stiffen, match the profile of the panel, and hold the panel lights.  Without this underside section of the glareshield, there's a 3/4" gap between the glareshield and the panel.

I contacted Hector. He said it didn't come with the underside section.

I am thinking that I could make a mold of the underside section from my old glareshield. Then I can have a part vacuum molded to use in the new glareshield.

Making the mold pattern from my old broken glareshield will be difficult and take time.

Any tips, options, or advice would be appreciated.

Thanks,

Brian

P.S. The first photo is the underside of my broken glareshield. The second and third photos are the new glareshield.

 

Edited February 24, 2019 by BrianW

[LANCECASPER]

It might be easier just to do this:   https://www.aircraftspruce.com/catalog/appages/mooney201.php?clickkey=86629

[kortopates]

The after market unit is pretty crappy per LASAR and also doesn't have the underside molding for lighting. They won't install them.
Maybe salvage? Or check on new pricing.


Sent from my iPhone using Tapatalk

[milotron]

The under side part you want it the brow and lighting assembly I presume? The other ribs are stiffeners to prevent vibration and oil-canning.

If I recall, that is a separate piece glued on. Perhaps try cutting it off the old one and affixed to the new one?  I did some repairs on mine and the MEK/dissolved plastic mix works well.

 

 

Edited February 24, 2019 by milotron

[N201MKTurbo]

I have an Ashby glare shield in my plane. It took quite a bit of customizing to get it to fit. I built new light mounts and built up the underside from fireproof upholstery foam. I had the whole thing covered in leather by an aircraft upholstery shop. It came out pretty good looking and strong as can be. I don't think it will fit your year with the high spot for the annunciator lights. 

[ArtVandelay]

Has that glare shield spent a lot time in the sun?


Tom

[BrianW]

I think the glareshield was in the sun for many years before getting repaired and eventually covered in vinyl.

The plane is a 1979 M20J.

New glareshield from Mooney is over $3000, is a special order, and takes several weeks cuz Mooney has to fabricate them when odered (non-stocking item).

Ashby won't work cuz my glareshield has the bump for the annunciator, and Ashby doesn't have the bumped up section for the annunciator 

I called a salvage place in Tennessee and LASAR.  They didn't have used or new glareshields.  I don't know any other salvage place for M20Js.

Yes, the underside section is the light brow and the brow extends back to form the stiffener ribs. The brow and stiffeners are one formed piece of ABS plastic.

Edited February 24, 2019 by BrianW

[Steve2]

Looks like Dodson has a bunch parted out.

https://www.controller.com/listings/aircraft/salvage/list/category/13/aircraft/manufacturer/mooney/model/m20j

 

 

[BrianW]

I just called Dodson.  They haven't received a salvage M20J in years.  None of their older scrap Mooneys have glareshields. 

Edited February 28, 2019 by BrianW

[ArtVandelay]

I just called Dodson.  They haven't received a salvage M20J in years.  None of their older scrap Mooneys have glareshields. 

Did you see this:
https://mooneyspace.com/topic/29212-parting-out-1977-m20j/

Shows the glare shield in one of the pictures.


Tom

[BrianW]

Hi Art,

No, I didn't see that post before.  I took a look at it.  Lots of cool stuff there.  But, the glareshield is the old style where it goes straight across the panel.  Mine has the hump in the middle area where my center post goes thru (as shown in my photos).

I committed to using the glareshield from Aerocomfort.  I spent a couple hours today peeling back the leather from the edge and trimming the glareshield to fit in my 1979 M20J.  It is because the new glareshield with the leather covering looks so good that I am commiting to using it, even though I will need to mold the underside  section for stiffening and lights.

I'll post pictures soon.

Thanks.

[MB65E]

Make one. Or have one made.

-Matt

[BrianW]

I am planning on making the underside section.  It'll take me several hours to make the mold pattern.  The part can be then vacuum formed for $45 setup and $40 for the abs sheet.

[bradp]

Make sure you keep the mold so others can benefit too.  This type of DIY is going to become more common as the fleet ages. 

[steingar]

Mine is badly cracked too.  Not looking forward to dealing with it.

[bradp]

If anyone wants to donate a glareshield that is cracked or damaged beyond repair I’m happy to make a mold. 

[steingar]

3 hours ago, bradp said:

If anyone wants to donate a glareshield that is cracked or damaged beyond repair I’m happy to make a mold. 

Won't we run into FAA type opprobrium if we start making these kinds of parts?  Glare shield seems like a glaring example, if you'll forgive the pun.

[bradp]

Having read over and over the owner produced parts rules I can’t see any impediment to these type of parts being considered ok under the letter and spirit of those regulations.  

The big opening is that the parts can still be available at the factory, or PMA’d but if they are prohibitively expensive you can do an owner produced part.

$3500 for a piece of plastic in a $35000 C model would meet most anyone’s reasonable definition of prohibitively expensive  

 

[BrianW]

An update on the project so far:

I'm almost complete on the mold for the lower section of the glareshield (a.k.a. the light tray p.n. 130342-007).  Just need to drill holes through it for the vacuum form table.

I called Mooney Technical Support in Texas to ask about the material used in the M20J glareshields.  Mooney called me back and read the information off the drawing. 

He told me the material was ABS plastic.  He said the ABS material name on the drawing calls it Royalite 26 Series, HC grain, black.  He said the ABS plastic makes it very easy for customers to repair their own glareshields by gluing or melting together the ABS.  (He mentioned that in later Mooney production they moved to making the glareshields out of fiberglass).

I previously bought what I thought was a new and complete glareshield.  But when it arrived, it was incomplete and useless without the missing mating parts.  Turned out it was just the upper glareshield section, pn 130342-003 (again not useable without the missing mating parts).  The lower section that I am going to vacuum form is the crucial missing part.

If time weren't a consideration I'd love to make a mold of the upper section as well before I bond the 2 parts together (just in case the upper warps or cracks in the future).  But that would take even more time, and I really want to get my glareshield put together so I can get my plane out of the shop.

Edited March 26, 2019 by BrianW

[mike_elliott]

15 minutes ago, BrianW said:

An update on the project so far:

I'm almost complete on the mold for the lower section of the glareshield (a.k.a. the light tray p.n. 130342-007).  Just need to drill holes through it for the vacuum form table.

I called Mooney Technical Support in Texas to ask about the material used in the M20J glareshields.  Mooney called me back and read the information off the drawing. 

He told me the material was ABS plastic.  He said the ABS material name on the drawing calls it Royalite 26 Series, HC grain, black.  He said the ABS plastic makes it very easy for customers to repair their own glareshields by gluing or melting together the ABS.  (He mentioned that in later Mooney production they moved to making the glareshields out of fiberglass).

I previously bought what I thought was a new and complete glareshield.  But when it arrived, it was incomplete and useless without the missing mating parts.  Turned out it was just the upper glareshield section, pn 130342-003 (again not useable without the missing mating parts).  The lower section that I am going to vacuum form is the crucial missing part.

If time weren't a consideration I'd love to make a mold of the upper section as well before I bond the 2 parts together (just in case the upper warps or cracks in the future).  But that would take even more time, and I really want to get my glareshield put together so I can get my plane out of the shop.

Understand your need to get this finished, but as you suggest, without both pieces, you really don't have a replacement glareshield. If you plan on selling/giving etc. to others your "mold" for their glareshield replacement uses, do consider making still yet another mold off of your upper section. If you envision this work you have done being just for you and you only, then you are on track.

[BrianW]

UPDATE - I took the mold into the vacuum mold shop.  They said it looked very good for a first timer. 

They pulled the form with .090" thick Royalite.  It wasn't perfect, a few small spots that look like air got trapped underneath and one area where it had a deep draw and the material was stretched thin.

They then offered to pull a second part with .125" Royalite to have more material for the deeply drawn section.  The second one wasn't better.  It appeared that my form had some air bubbles in my plastic form itself.  The trapped air within my mold forced up air bubbles that then permanently set when it cooled. 

They said that if I body-shop my mold (sanding and filling) to restore the smooth contours, I could use fiberglass to make a negative and more durable mold.  They said negative molds produce better surface finish results.  I may do that.

Meanwhile, my first vacuum formed part is 100% structurally sound and looks pretty darned nice.  I will attempt to gently heat and smooth out the wavy area to see if it can look perfect.  I think it will still turn out nice.

[M20F-1968]

Use your ABS parts to make a fiberglass mold.  Lay some saran wrap or coat the parts with a mold release.  Buy some hardware store fiberglass, and hand lay-up fiberglass over the existing new glareshield.  Make it sturdy enough to act as a mold.  Then you can hand sand/finish it and you will have a mold to make all the fiberglass glareshields you want.  

John Breda

[PT20J]

If you do ever make a mold for the top section, maybe you can figure out how to get the raised section over the annunciator panel to sit flat. Mooney never could.

[carusoam]

13 hours ago, BrianW said:

UPDATE - I took the mold into the vacuum mold shop.  They said it looked very good for a first timer. 

They pulled the form with .090" thick Royalite.  It wasn't perfect, a few small spots that look like air got trapped underneath and one area where it had a deep draw and the material was stretched thin.

They then offered to pull a second part with .125" Royalite to have more material for the deeply drawn section.  The second one wasn't better.  It appeared that my form had some air bubbles in my plastic form itself.  The trapped air within my mold forced up air bubbles that then permanently set when it cooled. 

They said that if I body-shop my mold (sanding and filling) to restore the smooth contours, I could use fiberglass to make a negative and more durable mold.  They said negative molds produce better surface finish results.  I may do that.

Meanwhile, my first vacuum formed part is 100% structurally sound and looks pretty darned nice.  I will attempt to gently heat and smooth out the wavy area to see if it can look perfect.  I think it will still turn out nice.

Got a pic of your mold?

and how you were drawing vacuum/air out of the mold... based on your experience... you can tell where the air was last to exit...

A few more vent holes in the middle of the last to exit locations can work wonders...

lots of small holes all over are better than one big hole that gets blocked early in the draw...

Mold Corners are a natural spot to put vent holes...

Proper sheet temperature will help draw it into the mold better...  too cold, the sheet sets up before it’s is drawn completely into the mold...  too hot, the sheet droops uncontrollably and then the sheet gets drawn into the vacuum holes... leaving little bumps in your part...

How the sheet gets heated can also cause ‘air’ bubbles in the plastic sheet... you have two variables to adjust... time and temperature in the oven...  slow the time down, and lower the heat... this will get a more uniform heating... for the same desired sheet temperature...

Read up on finishing plastic parts around here... There has been plenty of threads on how to glue, finish, sand, and paint royalties parts...

As far as negative vs. positive molds go... it really depends on what side you want the best details on... if you have any details, they get molded in by the mold surface....

If the mold is really deep 10:1 L/D ratio... See if a pre-stretching pin can be used with the mold... the pin must have good insulation properties...like a foam plastic with good heat resistance...

PP thoughts only... I may have read a few books regarding extrusion of polymer sheet and thermoforming of parts along the way to the airport... 

Best regards,

-a-

[Hank]

1 minute ago, carusoam said:

Got a pic of your mold?

and how you were drawing vacuum/air out of the mold... based on your experience... you can tell where the air was last to exit...

A few more vent holes in the middle of the last to exit locations can work wonders...

lots of small holes all over are better than one big hole that gets blocked early in the draw...

 

Proper sheet temperature will help draw it into the mold better...  too cold, the sheet sets up before it’s is drawn completely into the mold...  too hot, the sheet droops uncontrollably and then the sheet gets drawn into the vacuum holes... leaving little bumps in your part...

PP thoughts only... I may have read a few books regarding extrusion of sheet and thermoforming of parts along the way...

Best regards,

-a-

As a plastics equipment sales professional, I hope you have read more than "a few"!! Us processors, on the other hand, typically have a much narrower experience band. For instance, mine is all thermoplastic injection--no thermosets, no silicones, no gum stocks, no extrusion, virtually no blow molding, no metal injection molding, no die casting, etc., etc. But I do know both tooling and processing. And no, you don't want to build a plastic injection mold for that glareshield unless you need several thiusand parts from a quick prototype mold, or manyntens of thousands from a production tool.

Congrats on building a functional vacuum form on your first try! You can probably find a few others here interested in having additional parts made from that mold, especially if you follow Anthony's advice above.