Chem-Set RTV4500 100% Silicone Sealant – Bronze – 10.2 oz Cartridge

Bronze is a very dark warm brown-black RTV silicone in a 10.2 oz cartridge, part of the Chem-Set RTV4500 line. One-component 100% acetoxy silicone that cures with air moisture to a durable rubber. It is used on seams and sink perimeters in dark granite and brown-toned quartz, and on bronze, oil-rubbed, and dark anodized metal where a true black bead would read as a hard line. Made in the USA, NSF Standard 51 and FDA 21 CFR 177.2600 for incidental food contact.

Bronze is darker than most people expect from the name. It is not a mid-tone brown, it sits close to black with warmth in it, which is exactly what makes it work on dark stone. Plenty of granite that gets called black is really a deep brown or charcoal, and on that material a true black bead separates while Bronze settles in. Nine other colors are on the Chem-Set RTV4500 standard colors page, plus seven specialty translucent shades.

Key Product Details

Full physical properties including viscosity, tensile, elongation, hardness, extrusion rate, and QUV data are on the RTV4500 standard colors page.

Bronze or Black

These two are the only dark colors in the standard range, and they are close enough that the wrong pick shows on a finished seam.

Quick way to sort it: put the slab in good light and look for warmth in the dark areas. If you can see brown, Bronze. If it stays neutral or reads slightly blue, Black. Most stone sold as black granite is not actually neutral black, so Bronze gets picked more often than the name suggests it would.

Using the Cartridge

• Fits a standard 10 oz caulk gun. One component, no mixing, no additives, no static mixer.
• Clean both faces with 100% IPA or acetone. Never a petroleum based solvent, it leaves a film that kills adhesion.
• Tool inside 10 minutes at 70°F. Less in a hot humid shop, so work one joint at a time.
• Tape both sides and pull the tape while the bead is wet. A dark bead shows a ragged edge on a dark slab more than you would expect, since the highlight along the bead traces the edge.
• Keep a rag and IPA at hand. Uncured dark silicone marks porous light material on contact, and a smear onto an adjacent light surface is much easier to deal with before it skins.
• Check the match in the lighting the job will live under. Warm undertones in a dark bead read differently under warm LED than under shop fluorescent.
• On polished marble or quartzite use a neutral cure silicone instead. See Sil-Flex RTV-7500.

Common Applications

• Dark granite countertop seams, sink perimeters, and backsplash sealing
• Brown and charcoal toned quartz seams
• Dark solid surface seam and sink deck sealing
• Bronze, oil-rubbed, and dark anodized metal joints
• Bronze window and door frame perimeter sealing
• Dark architectural cladding and trim joints
• Appliance and equipment assembly on dark bronze finishes
• Exterior sealing where a dark bead should disappear into the assembly

Documents

• Chem-Set RTV4500A Technical Data Sheet (PDF)
• Chem-Set RTV4500A Safety Data Sheet (PDF)

Related Products

• Chem-Set RTV4500 Standard Colors, all ten colors with full specifications
• Chem-Set RTV4500 Specialty Translucent Colors, including Trans/Brown and Trans/Charcoal where a translucent bead blends better than a solid one
• Sil-Flex RTV-7500 Neutral Cure Silicone, for polished marble, quartzite, and finished metal fixtures

Frequently Asked Questions

What color is Bronze silicone?

Bronze is a very dark warm brown-black, much darker than the name suggests. It is not a mid-tone brown. It sits close to black with brown warmth in it, which is what lets it settle into dark granite and brown-toned quartz where a neutral black bead would read as a hard line.

Should I use Bronze or Black silicone on dark granite?

Put the slab in good light and look for warmth in the dark areas. If you can see brown in it, Bronze will blend better. If it stays neutral or reads slightly blue, Black is the match. Most stone sold as black granite is actually a deep brown or charcoal rather than a true neutral black, so Bronze gets used more often than its name would suggest. Bead both on an offcut if the seam is one the customer will look at closely.

What silicone matches bronze window frames and hardware?

Bronze is the standard color for perimeter sealing around bronze and dark anodized window and door frames, oil-rubbed hardware, and dark architectural metal. It carries a 10,000 hour QUV pass under ASTM G154 and a -70°F to 400°F service range, so it holds up on exterior joints. Note that dark anodized and oil-rubbed finishes vary widely by manufacturer, so test adhesion and appearance on an offcut before a production run.

Is Bronze RTV4500 food safe?

Yes, it meets NSF Standard 51 and FDA Regulation 21 CFR 177.2600 for incidental food contact, which covers sanitary seals in commercial kitchens, foodservice equipment, and countertop and sink joints in food prep areas. The approvals apply to the material, so every color in the RTV4500 line carries them.

Can Bronze silicone be painted?

No. Silicone is not paintable and paint will not bond to the cured bead. Pick the color that matches the joint instead, which is why the line runs seventeen shades across the standard and specialty ranges.

Will Bronze silicone stain a light surface?

Uncured dark silicone will mark porous light material on contact, so tape the joint and keep a rag and IPA at hand while you work. Wiping a smear before it skins is straightforward, and abrading cured silicone off light stone is not. Separately, on polished marble and quartzite use a neutral cure silicone rather than an acetoxy one in any color, since acetoxy can cause staining or bleeding on those stones.

How many ounces are in the cartridge, and how many come in a case?

10.2 oz per cartridge and 24 cartridges per case. It fits a standard 10 oz caulk gun. Printed net fill has varied slightly between production runs, so read the tube in front of you if you are speccing an exact volume. Fill across the silicone category commonly runs 9 to 9.8 oz, so compare price per ounce rather than price per tube.

Where is it made and how long does it keep?

Made in the USA. Shelf life is 24 months stored at 70°F and 50% RH, and a hot humid stockroom cuts that down. Chem-Set is the Chemical Concepts house label, and cartridges ship from our warehouse in Huntingdon Valley, Pennsylvania. In-stock items ordered by 2pm EST ship the same day.

Not sure whether Bronze or Black is the closer match on your slab? Call (800) 220-1966 or email [email protected].