


🛡️ Seal smarter, not harder — the tradesman’s secret weapon!
RectorSeal 81881 is a 5-pound gray duct seal compound designed for professional-grade sealing. This soft, non-toxic putty adheres to most clean, dry surfaces and works effectively between 25°F and 120°F. It forms a waterproof, airtight seal resistant to water, alcohol, and mild acids, while being safe on plastics and metals. Reusable and paintable immediately after application, it’s a versatile solution trusted across HVAC, plumbing, electrical, and construction trades.

| Brand | Rectorseal |
| Style | Putty |
| Item Weight | 1 Pounds |
| Item dimensions L x W x H | 4.5 x 10 x 1.5 inches |
| Water Resistance Level | Waterproof |
| Item Form | Paste |
| UPC | 021449818810 |
| Unit Count | 1.0 Count |
| Global Trade Identification Number | 00021449818810 |
| Number of Items | 1 |
| Color | Gray |
| Manufacturer | The Rectorseal Corporation |
| Part Number | 81881 |
| Item Weight | 1 pounds |
| Product Dimensions | 4.5 x 10 x 1.5 inches |
| Item model number | 81881 |
| Item Package Quantity | 1 |
| Included Components | Duct Seal |
| Batteries Included? | No |
| Batteries Required? | No |
M**E
Weight Checks Out!
I was skeptical as these five-pound blocks of duct seal were lower-priced than anywhere else. However, thanks to the thousands of reviews from folks like me and you, I purchased 4 of the five-pound blocks, and they do weigh 20lbs total. Duct seal is a bit on the expensive side compared to some other materials I could use for a pellet trap, but I shoot high powered units, and duct seal stops with no ricochets. I shoot in my basement, so no ricochets is obviously extra important. As a bonus, the pellet hits are nearly silent down range, and the lead captured by the duct seal can be cleaned out, melted down, and reformed into additional backstop plating. Always remember to use gloves and a respirator if working with lead. I always wash my hands after target practice as well! Thank you for the product reviews and to the old time airgunners that figured out that duct seal is a great and practically permanent product for use as a pellet trap.
P**S
Works as it is intended.
Used to seal up traffic lights around race track. The lights had 2 holes in the bottom to run electric feed them. Mice would climb up through the holes around the wiring and make nests inside the lights and chew the insulation off the wires causing them short out.This stuff is used to weather proof electrical service cables houses , seals cables , it doesn’t dry out and stays pliable.Working good so far.
P**H
Great for making a homemade pellet trap
I purchased and used this for making a pellet trap. It works extremely well, and was very easy to work with. I like that it is malleable, and can be spread about, while not drying or overly sticking to hands (it does have some tack to it, but only comes off a little bit on hands when working it around), It also seemed to have consistent density- my volume measurements for filling an 8.5"x8.5"x3/4" frame worked well. The tackiness is actually useful for sticking targets to, without having to pin or nail them. It proved to be extremely effective in the wood frame I constructed; Pellets shot by a pistol drop in front of the target with bouncing or ricochet; pellet rifle shots pierced the paper target and penetrated very little @~800fps (only smaller high velocity pellets with a plastic jacket penetrated about 1/4-<1/2"). The shots produce little to almost no sound.I would recommend this to anyone pursuing the same use I purchased it for: The volume of compound and excellent performance are well worth it!
H**R
good stuff
I bought it for my A/C furnace to fill a gap of the suction line going into the evap. It was an old unit and the gap was patched by some duct tape. But one day I found that the condensation was dripping down the gap to the outside of the box. The duct tape couldn't stop the water. The duct seal compound did the job.Another use was sealing the dryer duct vent to the floor outlet. The floor outlet hole is too close to the base board of the wall and very hard to put in any adapter. I just nailed a bracket to the wall and put in a straight adapter and put the seal compound around the hole. Solved a long time headache!
E**Z
Cheap but good
This product is cheaper than big stores. Same quality. Used to fill my quiet pellets trap. It stops pellets from.177 to .25 caliber.
A**N
Duct seal
Duct seal works great for stealing all kind of holes for medium to small holes you can use this for about anything I used to get putty tape for mobile home windows and it was just about the same thing except in a flat for for about 2 in wide
M**E
Tight, Permanent Seal
I pulled strips of product from the ‘brick’, rolled it into strips and wrapped it around my sprinkler system’s supply line, then smoothed it out. Before wrapping the pipe, and sealing the exterior perforation, I filled the hole with this product. After sealing the exterior, I did the same on the interior side. This tenaciously stuck to my vinyl siding and the interior wood. Unlike caulk, which I previously used, there’s no mess, and I was easily able to seal a wider area. I preemptively wore latex gloves when rolling and molding the product, but don’t believe they were necessary. I stored the leftover product in a freezer Ziplock bag.
L**E
Holy cow does this stuff work!
3 months ago I had rain coming thru my windows and doors sideways from a hurricane. The insurance inspector told me it’s not uncommon and I told him I thought I needed new windows. He explained even the best windows aren’t effective against sideways rain blowing 80 mph. Then we had another storm coming in, I saw this product on a YouTube video bought two HEAVY packs, and lined every window sill with it and I had ZERO rain come in! This saved me $5-$10,000 !! Warming it up is key to rolling strips of it out. Then you just press it into the sill. I didn’t care what it looked like as long as it worked . And it did. Then afterward, you just slowly start pulling it away - I used a plastic knife to lift in tight spots and every bit came up AND left no residue. This is a plumbers secret but I’m telling everyone I know because I don’t have thousands for new windows or floors because of rainwater or leaks and maybe you don’t either. But if you do, spend it on something fun and use this putty for the temporary emergency situations.