Canopy Crack

[skippydiesel]

Hi,

Sonex Legacy 175 hrs, a few months short of 2 year since first flight

Did my pre flight. Taxied down to the Club House. Came back to my Sonex & saw a 50 mm (2 in) crack in the Canopy had just appeared.

Crack is almost exactly mid point, on the opening side, radiating perfectly straight up. Its so perfect, it looks deliberate.

What to do??

Should I drill a stop hole?

Perspex glue?

My last air craft had no cracks after 20 years, now this!!!

Any good instructions on how to deal with this problem? 😈

[Blueadventures]

Usually a very easy repair, take at least 2 hours but likely 4 hours and pretty much invisible, someone at your airfield or within 100kms would have done these repairs. 

[440032]

Consult FAA AC 43.13-1B

Chapter 3 fiberglass and plastics.

Section 3. Transparent Plastics.

3-24 Repair of plastics.

[skippydiesel]

Thanks 440032 - looking into your suggestion now.😈

[onetrack]

Skippy, did you know about this following Sonex canopy service/availability?

 

https://www.sonexaus.org.au/but-and-sell/for-sale/australian-made-sonex-canopies/

 

[onetrack]

And there's this following modification for Sonex canopies -

 

https://docs.google.com/document/d/1z01IFU3TZG-q1dtxzjAUgkD_JUyMqMiwJATMaQ1hnB0/edit?tab=t.0

 

[skippydiesel]

 

Has anyone  used any of the following adhesives, to make good a crack in a canopy;

• E600 Industrial Strength
• Scigrip Weld ON 16 Acrylic/Polycarbonate
• Goroilla Glue Epoxy
• Gorilla Clear Grip - Fast Setting
• Permatex Permapoxy 5 Minute Weld
• Permatex Clear RTV Silicone
• ZAP Thin CA Glue
• JB Weld Plastic Weld
• JB Weld Superweld Instant Adhesive
• Acri-bond 110 Acrylic Cement
• Bostic Hard Plastic
• Loctite 406 Instant Adhesive
• Acrifix 192
• Selleys All Plastic Glue
• Weld-on 3 Acrylic Cement
• TENSOL 12 Acrylic
• EVO-PLAS TC 731

Please make your  Perspex crack repair recommendation, based on actual experince.

My thanks . 😈

 

[skippydiesel]

18 minutes ago, onetrack said:

And there's this following modification for Sonex canopies -

 

https://docs.google.com/document/d/1z01IFU3TZG-q1dtxzjAUgkD_JUyMqMiwJATMaQ1hnB0/edit?tab=t.0

 

Thanks for both of your suggestions.

 

My canopy is almost new. Has no other cracks (at this time). I would like to try and extend its safe service life, if this is feasible.

Canopy replacement, after just under two years & 175 hrs, just doesn't bear thinking about.

I will contact Ian Linke about his Australian made canopy - bound to be a more durable product.

 

Q. Is SonexAus still operating - I tried to join about 3 years ago😈

[Moneybox]

Most plastics cannot stand compression at the fasteners. If the rivets or screws are excessively tight it’s likely to develop a star crack originating at the hole. 

[BrendAn]

8 hours ago, skippydiesel said:

Thanks for both of your suggestions.

 

My canopy is almost new. Has no other cracks (at this time). I would like to try and extend its safe service life, if this is feasible.

Canopy replacement, after just under two years & 175 hrs, just doesn't bear thinking about.

I will contact Ian Linke about his Australian made canopy - bound to be a more durable product.

 

Q. Is SonexAus still operating - I tried to join about 3 years ago😈

that link said he was out of stock in 2020.  you would think there would be an update in the last 5 years if he was still selling them.

[facthunter]

Cracks are caused by stress Points. Nev

[skippydiesel]

Found this;

ULRICH NEUMANN

25 Dec 2000, 07:23:42

 

Several years ago, I had to repair a crack in my Libelle's canopy. Acrifix

works well - I let it cure by the window.
But just smearing Acrifix over the crack looks horrible. I think the main
thing about crack repair is the preparation of the seam. Here is how I did
it:
1: Place a 2" wide clear plastic tape over the crack. This will protect the
canopy's area to the left and the right of the crack during the following
operations.
2: Drill a 1mm hole at each end of the crack to keep it from propagating.
Caution: examine the orientation of the crack. It may not be perpendicular
to the surface, so the hole may have to be drilled in an angle and be sure
to really catch the end. Otherwise, it may spread beyond the repair.
3: Using a Dremel tool and a small ball grinder (dia. 2-3mm), carve out the
crack to halve of the material thickness through the clear plastic tape.
4: Do not remove tape and clean 'weld-prep' area with rubbing alcohol.
5: Fill seam with Acrifix and let cure. Over-fill seam slightly since
Acrifix will shrink slightly as it cures.
6: Repeat procedure from other side of canopy. Be sure to carve into the
repair material of the first operation.
7: To remove eccess material, use file, fine wet sanding paper and buffing
compound.
8: Remove plastic tape and buff area with plactic buffing compound.

My canopy is holding up since more than 10 years now with minial optical
distorsion. Feel free to contact me, if you have any questions.

[skippydiesel]

FYI;

PlastiFix

• Aircraft Spruce $76.00
• JB Tools $50.00

😈

Edited October 6 by skippydiesel

[Blueadventures]

1 hour ago, skippydiesel said:

Found this;

ULRICH NEUMANN

25 Dec 2000, 07:23:42

 

Several years ago, I had to repair a crack in my Libelle's canopy. Acrifix

works well - I let it cure by the window.
But just smearing Acrifix over the crack looks horrible. I think the main
thing about crack repair is the preparation of the seam. Here is how I did
it:
1: Place a 2" wide clear plastic tape over the crack. This will protect the
canopy's area to the left and the right of the crack during the following
operations.
2: Drill a 1mm hole at each end of the crack to keep it from propagating.
Caution: examine the orientation of the crack. It may not be perpendicular
to the surface, so the hole may have to be drilled in an angle and be sure
to really catch the end. Otherwise, it may spread beyond the repair.
3: Using a Dremel tool and a small ball grinder (dia. 2-3mm), carve out the
crack to halve of the material thickness through the clear plastic tape.
4: Do not remove tape and clean 'weld-prep' area with rubbing alcohol.
5: Fill seam with Acrifix and let cure. Over-fill seam slightly since
Acrifix will shrink slightly as it cures.
6: Repeat procedure from other side of canopy. Be sure to carve into the
repair material of the first operation.
7: To remove eccess material, use file, fine wet sanding paper and buffing
compound.
8: Remove plastic tape and buff area with plactic buffing compound.

My canopy is holding up since more than 10 years now with minial optical
distorsion. Feel free to contact me, if you have any questions.

That's how I've done single and multiple joined cracks.

[facthunter]

Most earlier stuff was FLAT Perspex supported by a fairly strong frame  on 3 sides.. Nev

[skippydiesel]

Just got off the phone with Nick (working on a Public Holiday??) from Acrylic Technologies Australia Pty Ltd, who sell ACRIFIX.

 

Nick  recommends ACRIFIX 105 https://acrylictech.com.au/product/acri-bond-105/

 

ACRI-BOND 105 Acrylic Adhesive is the industry standard in bonding Acrylic (PMMA) to itself as well as other listed plastics. Fabricators use ACRI-BOND 105 when they want unmatched strength and bubble free joints. ACRI-BOND 105 is a solvent cement meaning it works by chemically softening and fusing the surfaces of compatible plastics. This creates a true molecular bond where the two parts effectively become one solid piece after curing. This provides a strong bond that other Acrylic Glues cannot achieve.

 

As this is a hairline crack, invisible at some angles, I think I will give this product a go

😈

Edited October 6 by skippydiesel

[facthunter]

Are you sure of what your Material IS?  Nev

[skippydiesel]

Well some of us live & learn, others don't. Such is life! ;

 

I got my ACRI-BOND 105 - be warned its heavier than water and pours very readily.

I have polished my canopy with Vuplex on numerous occasions.

Thinking it may be a good idea to remove any surface polish/dust residue, I wiped the crack area with isopropanol.

I think I may have been overgenerous with the isopropanol - some ran down the canopy, into the "sandwich" section of the frame.

Left the job to completely dry.

Came back 30 min later  - Yea Gads!!! about 4 arcing cracks had appeared and the original had extended by another 20mm.

Canopy now not airworthy at all.

 

Have contacted Ian Linke  (sailplanecanopies@ gmail.com) to discuss a new canopy.

 

In the mean time Ian has advised a temporary fix to get me back into the air. Fine fiberglass cloth, glued to canopy surface with superglue - he swears by this technique having used it to stabilise many glider canopies.😈

 

[Thruster88]

Skippy, you have asked many questions on here, that would have been a good one to ask.

 

AI Overview

 

Isopropyl alcohol can damage many types of plastic, causing hazing, crazing, or cracking, especially on styrenic plastics (like ABS and polystyrene), polycarbonates, and PET. Damage risk depends on the specific plastic, concentration of the alcohol, and exposure time. It's safer to use soap and water, and always test a small, hidden area with a diluted IPA solution on a soft cloth before general use to avoid permanent damage.  

 

What You Should Know

• Concentration and Time: 

  High concentrations of IPA and prolonged exposure increase the risk of damage, including a white haze or surface degradation. 

   

• Surface Damage: 

  Isopropyl alcohol can cause a temporary white haze or permanent damage, especially on glossy or matte finishes. 

   

• Chemical Absorption: 

  Alcohols can absorb into the plastic, leaching out stabilizing chemicals and leading to cracks or other structural issues. 

   

• Plastic Type Matters: 

  Different plastics have varying resistance to isopropyl alcohol. For example, HDPE and PP are generally resistant, while PS and polycarbonate are more susceptible. 

   

What to Do

• Test First: 

  Always test isopropyl alcohol on a small, inconspicuous area of the plastic to check for any adverse reactions before applying it more widely. 

 

 

[facthunter]

Can I direct you to My Post just prior to your disaster, which you  didn't reply to. Nev

[Blueadventures]

2 minutes ago, Thruster88 said:

Skippy, you have asked many questions on here, that would have been a good one to ask.

 

AI Overview

 

Isopropyl alcohol can damage many types of plastic, causing hazing, crazing, or cracking, especially on styrenic plastics (like ABS and polystyrene), polycarbonates, and PET. Damage risk depends on the specific plastic, concentration of the alcohol, and exposure time. It's safer to use soap and water, and always test a small, hidden area with a diluted IPA solution on a soft cloth before general use to avoid permanent damage.  

 

What You Should Know

• Concentration and Time: 

  High concentrations of IPA and prolonged exposure increase the risk of damage, including a white haze or surface degradation. 

   

• Surface Damage: 

  Isopropyl alcohol can cause a temporary white haze or permanent damage, especially on glossy or matte finishes. 

   

• Chemical Absorption: 

  Alcohols can absorb into the plastic, leaching out stabilizing chemicals and leading to cracks or other structural issues. 

   

• Plastic Type Matters: 

  Different plastics have varying resistance to isopropyl alcohol. For example, HDPE and PP are generally resistant, while PS and polycarbonate are more susceptible. 

   

What to Do

• Test First: 

  Always test isopropyl alcohol on a small, inconspicuous area of the plastic to check for any adverse reactions before applying it more widely. 

 

 

He was told the correct time proven method to repair; but for some unknown and maybe not surprising reason he deviated from that method with some of his own ideas.  It's a real buggar to wreck a canopy.

[skippydiesel]

You guys - What does it take to confess to making a mistake??? 

 

Your a pack of "know it all's", who have never gone out on a limb - pull your heads in.

 

IF my little experiment had worked you would all be claiming you told me so anyhow. Sad Sad people😈

[BrendAn]

4 minutes ago, skippydiesel said:

You guys - What does it take to confess to making a mistake??? 

 

Your a pack of "know it all's", who have never gone out on a limb - pull your heads in.

 

IF my little experiment had worked you would all be claiming you told me so anyhow. Sad Sad people😈

You made a mistake.  Sh#t happens.

No good carrying on at people that gave you advice. 

Edited Friday at 02:02 AM by BrendAn

[BrendAn]

i learnt about drilling holes in lexan the hard way. ruined a $300 jab window.

[onetrack]

Skippy, look on the positive side. A crack developed for seemingly no reason. Then more cracks developed as you went to fix it.

It seems to me, that that canopy was getting suss anyway, and perhaps you avoided a bullet from having the canopy fall apart in flight.

It appears your model of aircraft has some canopy problems anyway, so now you can ensure you have a very good canopy, by installing the best you can buy and fit.

No-one ever said owning an aircraft was a cheap and trouble-free proposal - like all complex machinery, regular applications of money is the only thing that keeps them going.