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Another product option:
TECHNICAL DATA PR-1425 Class B Windshield And Canopy Sealant Description PR-1425 Class B is an aircraft windshield and canopy sealant. It has a service temperature range from -65°F (-54°C) to 250°F (121°C), with intermittent excursions up to 275°F (135°C). This material is designed for fillet sealing of properly prepared glass, polycarbonate, acrylic and other aircraft sealing appli- cations. This product is specifically formulated not to craze substrates. The cured sealant exhibits excellent resistance to UV and weather exposure. PR-1425 Class B is a two-part, dichromate cured poly- sulfide compound. The uncured material is a low sag, thixotropic paste, suitable for application by extrusion gun or spatula. This sealant has excellent adhesion to common aircraft substrates. The following tests are in accordance with PRC- DeSoto International and other OEM specification test methods. Application Properties (Typical) Performance Properties (Typical) Cured 7 days @ 77°F (25°C), 50% RH Cured specific gravity 1.49 Nonvolatile content, % 93 Ultimate cure hardness, Durometer A 55 Peel strength, pli (N/25 mm), 100% cohesion Dry, 14 days at 77°F (25°C) Color Part A Part B Mixed Mixing ratio By weight Base viscosity (Brookfield #7 @ 2 rpm), Poise (Pa-s) Black Black Black Part A:Part B 10:100 16,000 (1600) *Primed with PR-142 Adhesion Promoter Thermal rupture resistance - Retains pressure of 10 psi with only negligible deformation, both before and after immersion in JRF. Low temperature flexibility @ -65°F (-54°C) - No cracking, checking or loss of adhesion. Corrosion resistance - No corrosion, adhesion loss, softening, or blistering after 20-day immersion in 2- layer salt water/JRF @ 140°F (60°C). Resistance to fluids - Excellent resistance to water, alcohols, petroleum-base and synthetic lubricating oils, and petroleum-base hydraulic fluids. Flexibility - No cracks after bending 180 degrees over 0.125 inch (3.18 mm) mandrel. Repairability to itself - Excellent to both freshly cured as well as fuel aged and abraded fillets. Fungus resistance Non-nutrient Note: The application and performance property val- ues above are typical for the material, but not intend- ed for use in specifications or for acceptance inspec- tion criteria because of variations in testing methods, conditions and configurations. Slump, inches (mm) Initial B-1/2 0.20 (5.08) B-1 0.15 (3.81) B-2 0.20 (5.08) 50 Minutes 90 Minutes —— —— —— —— 0.25 (6.35) 0.25 (6.35) MIL-G-25667 (Glass) MIL-P-8184 (Acrylic)* MIL-P-83310 (Polycarbonate)* MIL-S-5059 (Stainless steel)* AMS-T-9046 (Titanium comp. C)* AMS-QQ-A-250/12 (Aluminum) 50 (222) 48 (214) 46 (205) 46 (205) 46 (205) 46 (205) Application life and cure time @ 77°F (25°C), 50% RH Cure time Application Tack free life time Durometer (hours) (hours) (hours) B-1/2 1/2 <8 B-1 1 <24 B-2 2 <24 24 48 48 to 30 A Where Smart Solutions Take Flight® |
Many people fiberglass their windows into the top. If you're gonna do that, why not glue the windows in with something user friendly like Lexcel (a hardware store product for plexi and lexan) or Proseal?
With the fiberglass capturing the plexi, what's the benefit of a specialty adhesive? |
Other method
As I embark on the fuselage kit I know the windows are not far off. The little research I have done has lead me to consider the silpruf method done by glastar for their windows. The 5 part series on YouTube details the installation process. Why has no one thought of molding a fairing for the windshield that can be riveted/glassed into place and do all the transperiencies with this method...including the windshield? I think it would be interesting to create a fairing that attaches to the upper forward fuselage that already has a curve in it. Light glass work to blend it in. It would also have a relief for the windshield to be cut to fit into place.
1.) It would crest a uniform look. 2.) pretty much avoids the cracking worry 3.) allows for window installation at anytime even after exterior paint 4.) if there is a window crack it's easily removed and replaced |
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There already has been once incident in which a rear window has departed the aircraft in flight. I don't recall what adhesive was used, but I'm sure that the thread is still in the archives if somebody wants to search for it. I used Lord adhesive. I've been very happy with it and there has been no cracks after five years. I don't recall the product number of the adhesive, but Geoff @ Aerosport Products sells it. |
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Already decided
I'll be doing this for the transparencies -
https://www.youtube.com/watch?v=A336SG-fsiI But this discussion does have me wondering about the use of Gflex instead of West 105 for the windscreen fairing. :confused: |
Another vote for Lord. Super easy to work with, great bond, and easy to get a nice looking finished fillet.
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FWIW, I've installed RV-10 windows using both Weld-on (Van's recommended) and Lord adhesive (from Aerosport Products). Adhesion with both is great however the Lord adhesive is MUCH easier to work with. Issues with the Weld-on are that it skins over very quickly so working time is short. Not really an issue for the rear windows but can be an issue on the door windows and windscreen. It also tends to get "stringy" at about the time it skins over so you better have everything well masked. Final issue is that it cures very, very hard. This makes it difficult to sand out and remove masking material that the Weld-on dried on top of. This is also likely a major contributing factor to the cracking issue many have experienced, especially if the gap between the actual window and joggle is filled with Weld-on. The Lord adhesive cures more slowly, doesn't quickly skin over, doesn't get stringy, and the fully cured product is more like epoxy than concrete (like weld-on).
My recommendation would be to use Lord adhesive. |
Sikaflex is your friend
I am busy with RV build number 7, this my third RV 10 and have always used Sikaflex 295. Easy to work with and never had any problems.
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