Carplan Tetroseal Underbody Sealant Aerosol

Carplan Tetroseal £6 – £8 (per can).

What do you get?

Depending on the version you get it’s an aerosol or a brush on tin. Obviously I went for the rattle can version or aerosol with 500ml capacity, mainly because I needed to treat a couple of hard to reach places that I couldn’t get to with the POR15 paint. Purchased from an online auction sight with free delivery, I got 2 cans as a package.

Carplan Tetroseal twin pack
Carplan Tetroseal twin pack

First Impressions

The can promises lots of good things, the blurb on back promises rust protection, stone chip protection, salt & water corrosion proofing, and to top that it offers excelent sound proofing. I ve been looking forward to this for nearly a week now.  before I started this morning I pulled the cap of and knocked the nozzle, it feel off. Not the greatest of starts I must say.


Shake for 2 minutes and spray from side to side in a thin layer and wait 30-40mins to dry and apply a second coat for extra protection, or so the tin says. I was shaking for 3-4 mins, after I had masked of the holes (for the badges on the wings), and the screw areas. I started to spray at 24 – 30cm as it says on the directions and a nice even spray sprouted forth. So far so good, I sprayed into the difficult areas so far so good. After about a few seconds the blow back from the confined area the fine particles started to coat my hand and the can, in a sticky goo. This is what looks to me like a pressurised can of tar and other chemicals I dare say, but I’m no expert! As a result the tin was now uncomfortable to use, I stopped to clean the can with white spirit to make it nicer to hold. Starting the spray up again and things had started to change; after a minute or so the spray was now harsh and small droplets were dropping onto the surface. I checked the nozzle and it was clogged again. I had to wipe it clean. I Started spraying and it was better. After another minute or so the spray pressure was fluctuating. The propellant seems to come out more than the formula. More shaking and cleaning helped a little. But, as more of the formula was used the worse it got. I managed to use 3/4 (or so) of the can on the inside of a fender.

I swapped the fenders over and tried to use the remainder. Impossible,  it was coming out in dribbles and splattering everything. I swapped the cans over and started again. To cut a long story short, exactly the same things happened. I thought it was a dodgy tin to start with but both were the same.

Carplan Tetroseal clogged
Carplan Tetroseal clogged


It coated ok, and looked just like a black gloss spray. It did look a little pitted and rippled as I sort of expected. The 30 – 40 minutes drying time was still wet after 3 hours. Perhaps the cold weather was part of it, but even so, not good.  It wasn’t feezing by any means and the sun was beating down on the shed at around noon time. I didn’t have enough for a second coat. Maybe I sprayed too much or sprayed it on to thick? I don’t think so. Looking at the spraying unless it went on fairly heavy I refuse to see how it would stop anything.


Not impressed to be honest. I was hoping for more, the thickness applied I can’t see how it will stop noise. Cynical of me? Maybe.

Time will tell, how it holds up to the road & weather with what they can throw at it. The fine spray particles looked like specs of tar. It smelled a bit like tar and was sticky like tar, lets hope the chemical concoction does the job it says it will.  I am hoping that overnight that the compound will dry.

Tip: Where gloves and wipe the nozzle repeatedly, and shake it a lot between sprays.

How am I going to rate this? Difficult, I expect it will protect, but if it was going onto bare metal it’s nowhere near enough for my liking. My now undercoat of POR15 will protect what I wanted it to, and this now just becomes an extra coat.

Rating – 3 / 10

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