Dowsil silicone sealants

Description

[Dow] Dow produces numerous types of one-part, neutral-cure Silicone materials that can be used as adhesives/sealants. These room temperature vulcanizing (RTV) silicones were introduced in the 1960s and cure upon exposure to atmospheric moisture. There are two type of neutral cure RTS silicones. The first if an alkoxy neutral-cure that releases methanol upon cure. The alkoxy neutral cure silicones are considered suitable for use on all types of metal without risk of corrosion. The second type is an oxime neutral-cure silicones that releases methyl ethyl ketoxime. These withstand temperature better than alkoxy-cure but can cause stress-cracking in some plastic boards, such as polycarbonate and acrylics.

General properties for Dowsil silicones include:

• Stability over a wide temperature range – When fully cured, most can be used at temperatures ranging from -85° to 599°F (-65° to 315°C).
• Weather resistance – High resistance to UV rays, radiation and weather prevents our products from hardening, cracking, crumbling, drying and becoming brittle.
• Chemical stability – Do not readily degrade, even under long-term exposure to many chemicals and atmospheric pollutants.
• Good bond strength – Provide good adhesion to a wide variety of industrial materials, including glass, ceramics and wood masonry; painted surfaces; and many metals and plastics.
• Low flammability – In fire conditions, silicone adhesives/sealants are reluctant to burn. Many products comply with UL flammability standards.

Commercial name	Cure type	Properties	Features (comments)	Applications	Risks	Oddy tests	Product website
Dowsil 580 Neutral cure	Silicone; oxime neutral cure; one component			General Glazing; Weather-sealing applications for windows, doors, glass, metal, masonry	Not recommended for water immersion; do not use on structural glazing; may discolor copper and brass; cannot be painted; not for use on polycarbonates	AWMM 2007 (T); AWMM 2008 (T)	Dowsil 580
Dowsil 737 Neutral Cure	Silicone; oxime neutral cure; one component		Adhesion to most materials	Substitute for mechanical fasteners on large and small appliances; Adhering plastic moldings to plastic substrates for trim applications; Waterproofing electrical components	Not recommended for water immersion, or use on painted surface; may discolor brass, or copper; may stress craze polycarbonates	MMA 2016 (U); BKM 2017 (U); BKM 2018 Px4) BKM 2018 (U)	Dowsil 737
Dowsil 739 RTV	Silicone; moisture cure; one component			Adheres well to unprimed metals, ceramics and glass and some plastics;	Does not adhere to Teflon, polyethylene, polypropylene, or highly plasticized plastics or rubbers.	MMA 2016 (P)	Dowsil 739
Dowsil 791 Weatherproof Sealant	Silicone; moisture cure; one component; medium modulus		good for inside display envelope: glass and metal joins; glass and glass joins; Goppion uses black, grey, white due to aesthetic reasons (transparent caulks yellow within 5 years)	General weather-sealing joints; glazing and curtain wall seals; building façade seals		MMA 2016 (T); AMNH 2019 (Tx2); MMA 2021 (T); white is unsuitable	https://www.dow.com/en-us/pdp.dowsil-791-weatherproofing-sealant.04082594h.html#overview
Dowsil 795 Building Sealant	Silicone; moisture cure; one component; medium modulus		extra thick; skins over too quickly	Structural and nonstructural glazing; for most new construction and remedial sealing applications; weather sealing of most common construction materials including glass, aluminum, steel, painted metal, EIFS, granite and other stone, concrete, brick and plastics	Not recommended for water immersion, or wet or cold surfaces; not paintable	AWMM 2008 (U); MMA 2016 (Px2); MMA 2020 (Ux2); MMA 2021 (T)	https://www.dow.com/en-us/pdp.dowsil-795-silicone-building-sealant.01595717z.html#tech-content
Dowsil 9-1374 Silicone sealant	Silicone; alkoxy neutral cure; one component			Used for formed in place gaskets; provides strong flexible bond for movable or expanding joints, such as when bonding materials with different thermal expansion rates such as glass to metal, or glass to plastic or metal to plastic		MMA 2016 (Tx2)	https://www.dow.com//en-us/pdp.dowsil-9-1374-silicone-sealant.03119556h.html#overview
Dowsil 3145 RTV Mil-A-46146 Adhesive / Sealant	Silicone; moisture cure; one component	Skin-over time = 15 min;	may be hard to work with (one anecdote of it being very hard to work with); requires experienced person to apply and clean up; viscous, does not flow	Sealing openings in modules and housings; Adding mechanical stability to individual components; adheres to glass and nylon	Good adhesion to many reactive metals, ceramics and glass, as well as to selected laminates, resins and plastics. However, good adhesion cannot be expected on non-reactive metal substrates or non-reactive plastic surfaces such as Teflon, polyethylene or polypropylene.	AWMM 1988 (P); BKM 2016 (Px2); BKM 2017 (Px2); AWNH 2019 (T)	https://www.dow.com//en-us/pdp.dowsil-3145-rtv-mil-a-46146-adhesive-sealant.01059548z.html#tech-content
Dowsil 7091 Adhesive Sealant	Silicone; moisture cure; one component	Skin-over time = 15 min;	Click Netherfield mentioned this one as one they use	for applications which demand a strong but flexible bond, such as when bonding materials with differing thermal expansion rates, e.g. glass to metal or glass to plastic	Single component alkoxy cure with moisture; for applications which demand a strong but flexible bond, such as when bonding materials with differing thermal expansion rates, e.g. glass to metal or glass to plastic; For maximum adhesion, the use of DOWSIL™ 1200 OS Primer is recommended.	BKM 2016 (P); BKM 2017 (P); MMA 2017 (P); AMNH 2019 (T)	https://www.dow.com//en-us/pdp.dowsil-7091-adhesive-sealant.02436621h.html#tech-content
Dowsil 993	Two-component, fast cure neutral-cure	Click Netherfield mentioned this one as one they use
Silastic 1080 RTV	Silicone; one component			Provides reliable, long-lasting bonds with a wide range of substrates, including ceramics, metals, glass and filled plastics,	long service life, wide operating temperatures, resistance to oils and solvents; water and steam resistant	AWMM 1988 (P)	[1]

Personal Risks

• Wear eye, hands, and respiratory protection.
• SDS: sheets

Collection Risks

Literature indicates the sealant has no significant volatile components. Some silicones have curing byproducts of ethanol, peroxides or ketones. Risk to museum collections could occur if an object comes in contact with the sealant causing possible staining or adhesion (if not fully cured).

Resources and Citations

• Antala: Dow Silicone Selection guide (contains information on 3145 and 7190)

• Americas: Cow Silicon Technical Manual (contains information on 791, 795 and 993)