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ORIGIN PRO COMPARE
HP3 vs. DOWSIL™ 999-A Building and Glazing Sealant
A Practical Comparison for Window, Door & Siding Professionals
Compared with
DOWSIL™ 999-A Building and Glazing Sealant
The ORIGIN PRO Compare™ series provides contractors with an objective, side-by-side comparison of product technologies, performance characteristics, and application advantages using publicly available technical information.
HP3 utilizes premium neutral-cure (alkoxy) RTV silicone technology engineered for professional window, door, siding and trim applications. DOWSIL™ 999-A is a one-part acetoxy RTV silicone designed primarily for glazing, curtainwall sealing and general construction applications.
Core Performance & Application Attributes
Sealant Technology
Origin Pro: Premium Neutral-Cure (Alkoxy) RTV Silicone
Compared product: One-Part Acetoxy RTV Silicone
Product Class & Movement (ASTM C920)
Origin Pro: ASTM C920 – Class 50 (±50% Joint Movement)
Compared product: ASTM C920 – Class 25
HP3 carries a higher ASTM C920 movement classification for applications requiring greater joint movement capability.
Skin Formation / Cure Performance
Origin Pro: Skins in approximately 20–30 minutes. Tack-free in approximately 30 minutes. Full cure approximately 24 hours.
Compared product: Tooling time approximately 5–10 minutes. Tack-free in approximately 10–20 minutes.
Application Temperature Range
Origin Pro: 40°F to 100°F
Compared product: Not published in the provided TDS.
Service Temperature Range
Origin Pro: -60°F to 400°F
Compared product: -76°F to 350°F continuous, with intermittent temperatures up to 392°F.
Packaging
Origin Pro: 10.1 oz. cartridge and 2.7 oz. squeeze tube.
Compared product: 10.3 oz. cartridge and 4.5-gallon bulk pail.
Purchasing Options
Origin Pro: Direct online ordering, plus dealer and supply-house options by market.
Compared product: Available through traditional commercial and building material distribution.
Color Availability
Origin Pro: White and Clear.
Compared product: Color availability not specified in the provided TDS.
Comparative Overview
| Attribute | Origin Pro | Compared Product |
|---|---|---|
| Neutral-Cure Silicone | ✓ | — |
| Acetoxy-Cure Silicone | — | ✓ |
| ASTM C920 Compliant | ✓ | ✓ |
| ASTM C920 Class 50 | ✓ | — |
| ±50% Joint Movement | ✓ | — |
| Professional Window, Door & Siding Applications | ✓ | — |
| Building & Glazing Applications | ✓ | ✓ |
| Direct Online Ordering | ✓ | ✕ |
| Flexible Ordering Options | ✓ | ✕ |
| Pro-Dashboard Tools | ✓ | ✕ |
Differences You’ll Notice
Both HP3 and DOWSIL™ 999-A are professional 100% silicone sealants designed for demanding construction sealing applications.
- Contractors switching to HP3 will notice several differences that can improve application versatility and purchasing flexibility.
- HP3 utilizes neutral-cure (alkoxy) silicone technology, while DOWSIL™ 999-A utilizes acetoxy-cure silicone technology.
- HP3 meets ASTM C920 Class 50 requirements compared with Class 25 for DOWSIL™ 999-A.
- HP3 provides ±50% joint movement capability and is specifically positioned for professional window, door, siding and trim applications.
- HP3's neutral-cure formulation is non-corrosive, while Dow specifically limits DOWSIL™ 999-A on surfaces sensitive to corrosion from acetic-acid cure vapors.
- HP3 is available through flexible contractor and dealer purchasing programs with delivery where you need it.
Beyond the product, Origin Pro’s Pro-Dashboard makes buying simpler, faster and more organized. See pricing before you order, find and save color matches, track projects and past orders, and quickly reorder—all in one place.
Ready to Make the Switch?
- Premium neutral-cure silicone technology.
- ASTM C920 Class 50 performance.
- ±50% joint movement capability.
- Non-corrosive formulation.
- Direct online ordering.
- Delivered where you need it.
- HP3. Built for window, door, siding and trim professionals.
Product Comparison Disclaimer
Product comparison information is based on publicly available technical data published by the respective manufacturers and available at the time of review. Comparisons are provided for general informational purposes only and do not imply product equivalence, specification approval, certification, or suitability for any particular application.
Product names, trademarks, packaging, and images are the property of their respective owners and are used solely for identification and comparative purposes. Legacy Sealants Inc. and Origin Pro are not affiliated with, sponsored by, or endorsed by any referenced manufacturer.
Product formulations and specifications may change. Users should review current manufacturer technical literature and independently determine product suitability for their specific application.
Brand-Ownership Statement
All third-party trademarks are the property of their respective owners. Their use is solely for identification and comparative purposes and does not imply affiliation, sponsorship, or endorsement.