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3.5 oz Fill Quart
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6 oz cartridge (Fill: 3.5 oz. sealant) or Quart size available

CS3204 is a fuel resistant sealant for use on integral fuel tanks and pressurized cabins as well as other areas subject to contact with aircraft fuels, lubricants, oils, water and/or weathering.

At room temperature, this two-part polysulfide cures to a flexible, resilient rubber.

Meets requirements of specifications AMS-S-8802 formerly MIL-S-8802, CMNP021, Lockheed, Gulfstream, Hughes Aircraft, Fairchild SPS 6-1 & 6-2

Technical Data: Class B*
Cure Profile B-¼ B-½  B-1 B-2 B-4
Application Life (hrs) ¼  ½  2 4
Tack Free Time (hrs)  6 8 15 24 36
Cure Time (hrs) 16 30 40 72 90
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Resealed a seep in my RV9A fuel tank--let it sit a week after applying the sealant before adding fuel--so far so good!

October 5, 2020

Ive used this to seal up EVAP leaks on a couple of cars. Bonds well to plastic fuel system parts. Saves the expense of having to pay for costly parts

Jackson C
July 27, 2020

Used it to successfully seal a fuel tank leak on my RV-8A. Seems to perform just like Proseal.

Lee E
June 24, 2020

Item was delivered on time and worked as expected. I would definitely use this vendor and product again.

June 24, 2020

This stuff is the best thing since sliced bread !! I used it to repair a fuel tank in a Bobcat skidsteer. the only way to get that tank out is to pull the engine out of the machine, so to avoid having todo that i used it to repair it which was still not easy but saved me countless hours of work, Ive been runniong the machine for days now after the repair and not a sign of a leak anywhere. now that Ive tryed this stuff I can think of many other things it would work great on. Its not cheap, But it is worth every penny I paid for it for the work it saved me.

Dale P
April 20, 2020

The sealant worked great for my application, however, the cure time I believe was more like 48 hours rather than 30 hours as in the spec. Im very happy with it though.

Steven S
March 12, 2020

I thought that I would try using this product since the price of Proseal is outrageous. I only needed to seal a few screws that’ were seeping slightly on one of my RV-8’s fuel tanks, so it was a small project. I’m happy to say that the Chemseal, at half the price of Proseal, did every bit as well. I’ll be purchasing Chemseal over Proseal in the future.

Roy M
March 5, 2020

In all fairness, I cannot rate this product since I have not used it as of this time. However, I am certain that it will meet or exceed my expectations. Presently, I am attempting to find a brass end cap fitting 3/8 inch with tapered NPT. Once I have found the fitting and sealed my fuel tank I will be able to use the sealant.

Lowell C
November 12, 2019

I used this to seal a crank case bolt on the top of the engine which was leaking oil. Works great. Smells like Proseal and is just as messy but a great product.

Thane O
April 29, 2019

We used this to seal the crankshaft plug on my Piper Cherokee. A little goes a long way. Just make sure you mix it properly and you will not have any issues. Cheaper than Proseal and works just as well! Great Product.

Nicholas S
March 2, 2018


Q: Does the quart size of this Chemseal sealant come in a can?

Yes, the quart size is in a can.

Q: What is the shelf life of Chemseal CS3204B1/2?

The storage life of CS 3204 is nine months when stored in the original unopened containers at temperatures below 80f.

Q: Where can I find the Safety Data Sheet (SDS) for this Chemseal B 1/2 sealant product?

We have added the MSDS PDF to the Documents section of this web page. Please review it there.

Q: What is the color?

These are an off white and when mixed they become a gray in color.

Q: does the B1/2 come in black?

We only offer it in off white.

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