What Underseal should I use??

Thanks for your replies I want to use a product that drys and that can be easy applied I do have a compressor but it would be hard to spray with the car only on ramps?

Hi,
It's not impossible to spray on one set of ramps, but it's better if you can lift both ends, two sets of ramps or ramps with axle stands. See DAGZOOK thread, it will give you a good idea.
Plenty high enough, but it's not a clean job, you and the ground it's parked over will be the same colour as the Jimny underside when you have finished. I used a cheap tarpaulin to protect the ground, alas nothing you can do to protect yourself other than glasses and a hat!
So yes it's possible, but always going to be easier the higher you get the Jimny.
Mike

Agreed, you'll be able to do a fine job with all four corners of the car up on axle stands/ ramps. If that isn't an option just do the front and rear of the vehicle in stages.

You will get covered in crap, that's a given. You can buy tyvek protective hoods and wear goggles to protect your face.

In my opinion, if you've got a compressor and a decent spray gun with a fine mist, I would use that. It's more economical to buy a small drum of the underbody wax. Chances are you'll need to top the high abrasion areas up every 12-24 months.

I've been a long term user of WaxOyl. You can spray it on with the right gun and a compressor. But it is a messy job and the WaxOyl needs to be warmed to flow well. The aerosols don't go very far, can clog easily and be messy. Brushing it on (have done that too), works but is even messier.

That said, I've generally been pleased with the results. The Waxoil does semi-dry, but it will take a few weeks to a couple of months to go 'off'. But will always remain tacky and can be messy if you work on the car.

We used to use a pit and have done lots of vehicles with it.

I no longer have access to the pit sadly. On my 4th Gen I have just finished Dinitrol'ing the underside. I used a pair of ramps and lifted one end, then the other. Plenty of room to crawl under.

I used the aerosol 4941. Goes on very well, less messy than Waxoyl and doesn't need warming. There is a compressor canister too, but haven't used those. Dinitrol has a good name, but this is the first time I've used them. The 4941 stays semi tacky, but not much as the WaxOyl. The aerosols also apply a thinner coating than how I used to apply WaxOyl.

I also used Dinitrol ML to inject the chassis rails and any cavities.

Nice job, I think aerosols or a more professional spray set up are the way to go. All of the above waxes need to be applied in light even coats that are built up and allowed to dry.

I think the brush application method has given these wax products a bad name. When applied like thick gloopy jam, people wonder why the stuff never dries and why it blisters and traps moisture.

Can't go wrong with any of the above aerosol products.

I'm a big advocate of Waxoyl...
Years ago, in another life far far away, I bought a six month old '79 MG Midget - took parts off it that were in known rust-prone areas such as the rear spring-hangers and reassembled them with the honey-coloured Waxoyl that is still available today. I sold the car in 1999.

I was lucky enough to find, and buy the same car back three years ago, and shortly after had reason to disassemble some of the very same components I had reassembled with Waxoyl almost 40 years previously . It all came apart easily - no corroded-in nuts and bolts, and the rust-prone metalwork underneath was literally like new!

I've since started using the black Waxoyl stuff (coated a replacement fuel tank with it) - it doesn't fully harden so shouldn't crack and let moisture form undeneath as with the old bitumen type underseals - therefore as has already been stated, any subsequent work can be messy - but for me, that would be a small price to pay for peace-of mind