Would this be good to use around a dry stack fireplace where cold air pours in through the cracks?

That's certainly not it's intended purpose. I'm sure there are products that would work better for what you want that would also be less expensive.

What happens if this is used in an exterior application?

I used mine in an unusual circumstance, to bond soft decorative brick faces to a high heat painted stainless steel surface (backing to a bio-ethanol fireplace). Even after following instructions for a controlled curing/heating process, the sealant was bonded to the steel nicely and also the soft brick face, but the brick face shrunk slightly, causing the sealant to separate and the brick fell off. Maybe I did something wrong or not long enough. I'd say it is more for an indoor/dry weather free application. Outside it may not dry completely to rain and high humidity. Once bonded and dried completely though it is pretty strong, great adhesion.

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3M Fire Block Sealant FB 136, Gray Color, Single Component, High Temperature and Smoke Passage Resistant, 10.1 fl oz Cartridge

3M Fire Block Sealant FB 136, Gray Color, Single Component, High Temperature and Smoke Passage Resistant, 10.1 fl oz Cartridge

Product ID: 100223598

Details

Brand
3M
Color
Gray
Full Cure Time
24 Hours
Item Weight
16 ounces
Liquid Volume
10.1 Fluid

💧Water-based for easy cleanup

🔥Heat resistant up to 2000°F

🛠️Bonds to concrete, metal, wood & plastic

₩28086

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Description

🔥 Seal the deal with 3M Fire Block — where safety meets smart innovation!

ECO FRIENDLY CLEANUP - Water-based formula means effortless installation and cleanup without harsh chemicals.
UNMATCHED HEAT DEFENSE - Withstands scorching temperatures up to 2000°F, keeping your projects safe and secure.
VERSATILE SURFACE BONDING - Adheres flawlessly to concrete, metals, wood, plastic, and cable jacketing for all-around protection.
SAG FREE VERTICAL APPLICATION - Formulated to stay put—no sagging or running in overhead or vertical installations.
QUICK TACK LONG TERM DURABILITY - Tack-free in 15 minutes with minimal shrinkage, ensuring lasting fireblock integrity.

3M Fire Block Sealant FB 136 is a high-performance, single-component, gray cementitious sealant designed for industrial and commercial fireblocking. It resists extreme heat up to 2000°F, bonds to multiple surfaces including concrete and metal, and acts as an effective draftstop to reduce air infiltration. Its water-based, halogen-free formula ensures easy cleanup and reliable, sag-resistant application, meeting key fire safety codes for non-rated construction.

Specifications

ASIN	B005PYXUEY
Best Sellers Rank	#15,824 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #61 in Adhesive Caulk #122 in Industrial Sealants
Brand	3M
Brand Name	3M
Color	Gray
Customer Reviews	4.4 out of 5 stars 496 Reviews
Full Cure Time	24 Hours
Global Trade Identification Number	00051115165917
Included Components	3M Fire Block Sealant FB 136, 1 Each
Initial Hardening Time	15 Minutes
Item Form	Paste
Item Weight	1 Pounds
Liquid Volume	10.1 Fluid Ounces
Manufacturer	3M
Material Type	Halogen-free, Non-Combustible
Model	FB 136
Number of Items	12
Part Number	051115165917
Surface Recommendation	Pipe
Temperature Range	1.38E+3 Degrees Fahrenheit
UPC	051115165917
Unit Count	1.0 Count
Water Resistance Level	Waterproof

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₩28086

Duties & taxes included

In stock

Sold byAmazon South KoreaDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to South Korea.

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TrustScore 4.5 | 7,300+ reviews

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