

🔥 Mold your fire safety future with 3M’s red-hot putty power!
3M Fire Barrier Moldable Putty Stix MP+ is a professional-grade, intumescent firestop putty stick offering up to 4 hours of certified fire resistance. Its ready-to-use, moldable formula creates durable seals against fire, smoke, drafts, and noise, while remaining re-enterable and noncorrosive—ideal for fire-rated assemblies in demanding industrial environments.



| ASIN | B002FYAMPM |
| Best Sellers Rank | #46,088 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #131 in Hardware Sealers |
| Date First Available | February 28, 2010 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 1.6 ounces |
| Item model number | 98040054540 |
| Manufacturer | 3M |
| Product Dimensions | 7.9 x 6 x 8.4 inches |
M**S
Critical to fire safety sealing.
This is the Ul/CSA certified stuff that works! I was rebuilding a Suburban RV furnace and needed a fire/heat certified putty to replace the 30 year old stuff used to seal the fuel gas supply line between the heat exchanger and blower enclosure. This is a fire safety item and I did not want to trust the foreign-sourced material. I was delighted to find this 3M product here on AMZ. Genuine 3M quality sticky stuff that seals perfectly and likely to endure another 30 years. I had to look up the word 'intumescent' lol. Oh, yeah, just what is needed.
L**R
Very easy to apply, and very effective
I needed something to block openings around the electrical boxes for lights and smoke detectors in my ceiling, and this is a much better option than only using caulk (at least in areas where the red color doesn't show). I'm impressed with how easy it is to mold into the right shape with its putty consistency - as well as its ability to be stuffed into odd shaped openings. The fire retardant capability is a great plus
B**G
This fire barrier will keep fire from spreading to an adjacent location.
I've been using 3M fire barrier for 30 plus years. As a requirement under the National Fire Protection Association, it is a requirement when running telecommunications cables through firewalls. Every now and then, I pick up a project that requires me to use this. It is most always readily available, and the price is competitive with other manufacturers. It is also moldable to any form. In my opinion, this is the best fire barrier on the market.
T**R
Easy to use for a first-timer.
I bought this to fireblock a short 2-foot conduit I ran from the electrical panels in my garage through the rim joist into the basement to carry a bunch of yellow 12 gauge Romex wire. The inspector didn't care if I fireblocked it or not but I did, as I also want to keep bugs from using the conduit as a superhighway and I try to keep my house as tightly air-sealed as possible. This stuff was easily moldable and mashable and did the job with no problem. I sealed the conduit from both ends for good measure. I have a bit leftover from the job that should keep for a long time in the original tube.
K**H
Product is smaller than other brands. Pictures are deceptive.
The pictures are deceptive. I was comparing with others and they weren't consistent. One was in fluid ounces another in pounds. I should have known. Not a horrible price but now I have to order another tube.
S**S
Works great for my needs!
Wanted this product to put in my incense sticks and it works great! I am sure there are lots of other uses but this one works for me!
N**Y
Easy to work with!
You can't beat the standard 3M CP-25WB+/10.1 10.1 Oz. Fire Barrier Sealant (Pack of 1) for fast application, but I really like this moldable putty for small jobs, and jobs you may have to pull the plug out, install another cable, and stuff it back in. I don't have to try and keep a tube of caulk from drying out, I don't get red caulk all over everything, and the putty is stiff enough to plug the sloppiest hole. I always keep one in the tool box. Just pinch off as much as you need and stuff it in the hole, great for remodel jobs.
W**O
Awesome stuff, I'm using it to fill gaps in ...
Awesome stuff, I'm using it to fill gaps in soundproofing applications, and in running conduit for air-lines for a compressor. Easy to work, removes and can be reused if not contaminated by plaster or wood dust. Also not crazy expensive, given that it comes from the 3M company, one manufacturer who seems to have maintained quality in this age of atrociously bad quality for cheap consumer goods. Thumbs up!
S**E
I use this for blocking holes in engine firewalls. It molds easily around cables and wires and sticks well to block the holes. I have not checked its fire resistance. After a year it is still flexible and stuck in place. Does the job of blocking fumes from making their way out of the engine compartment.
S**R
Very workable and hopefully flame proof putty. Easy to work with and good to put a temporary seal around air drafts.
Trustpilot
5 days ago
1 month ago