Underseal or the like

[Dearg1275]

Hi Ms. I use a u pol product -Gravitex. I like this as it gives a thick none runny stone chip coating very quickly and you can use it at fairly high line pressure which helps to get into all the nooks and crannies. You can vary the texture a bit too using different pressures and distances. I’ve used the Tetrosyl product in the past but this is rather too thin for my liking.

Others use an epoxy product called Raptor, also by U pol. Folk on here have given it the thumbs up.

D

[Andrew1967]

I've always used Gravitex and then painted body colour.

However, been persuaded by various people on here to use tintable Raptor on my Mk1 S project.

Haven't used it yet, but it's in the garage waiting to be applied when I get back to the bodywork.

[IAIN]

My view on this is I hate seeing a good restored car tarred with stone chip what ever make or type. But it is good at hiding poor preparation on the floor pans and involves less paint preparation work.

If your car is unrestored or newly restored you could clean the floor and spray it with waxoil . I use clear waxoil thinned down with paraffine 50/50. If you have a good paint coloured floor it will look the same when the wax oil sets, it will be sticky but you see the colour through it.

If you want it removed later it will come off with a hot pressure cleaner, or just clean it with a cold washer. You try and get stone chip off to repair some thing in the future !

I restored my woody in 1998 and waxed the painted floor, its still as good now as when it was done, even the nuts and bolts still look fresh. BUT it is only used in the summer.

[Polarsilver]

I can agree that Ian,s woodie is superb .. me i use a various mix over past years Waxoil or Dynatrol it runs everywhere but maybe that is a good thing or i now use & its good stuff "Dynax UC clear film anti- corrosive wax" ..this is a clear wax in a 750ml rattle can that will also spray upside down..product seems to go a long way & does not stain into topcoat paint & wipes off with white spirit any dried on wax overspray that is not needed .. i found it ideal to put under my Stainless Wheel Arch Trim & could float some more wax into the joins after trims were pop rivet fixed into position

[AndyPen]

Following this thread with interest as my mostly original floor is pretty good. I was wondering about the pipe tabs and keeping them rust free as possible?

I have already gone mad with seam sealer elsewhere

[Nathan1293]

I’m interested in what you choose to go with, I’ve read on another car forum where they have had really bad experiences with raptor coating. It got damaged and water crept in.

It could of been an application failure?

Either way it’s much harder to remove than other products, if you need to make repairs.

[Dearg1275]

I have cars from 62 through to 67 that had lashings of black bituminous underseal over factory primer with colour on top. Fairly well applied under the wheel arches (the colour that is) and less so underneath. As this was factory practice I don’t have any issue using stone chip as a modern replacement for the bitumastic stuff that tended to go brittle and chip off allowing the rust in.

There is of course nothing to stop you using wax oil type products over your finished paint work even if that’s on top of stone chip.

D

[IAIN]

Most cars I have seen that were coated with the bituminous 60's tar type coating had issues with it coming away on some areas and didn't in others. Saying that I have a customer with a 69 Elf which had this coating and apart from new sill / floor sections front to rear is still original inc. the rear subframe.

Rover minis which were stone chipped from new sparingly along the sills, it did protect them but as an every day car, they all rust in the same place. They start at the lap joint of the sill to floor in front of the jacking point, under the stone chip.
Its not because the chip is damaged from the outside it starts because water travels down between the sill and floor joint and is trapped under the stone chip until it cracks at the sill edge, then the rust has started and you don't see it till its too late. I had spi cars in and the stone chip looked good but the floor was holed behind it. But again that was every day hard used cars.

[Dearg1275]

I do agree with your analysis. At the end of the day, BMC got the design of the floor pan wrong at the start and amended it as best they could without incurring huge costs. Cars were not expected to last back then and BL and Rover ended up with this legacy.

Then there is the matter of the quality of steel used. While I have been restoring my current project (1962) and indeed the 1960 850 before it, I have been impressed at the lack of surface rust developing on stripped and bare original steel. Where as my 1967 Mk2 would develop a nice orange coat in a trice, my mk3 much the same.

The minis also suffer from having a short wheel base and being very close to the ground. This produces a dense atmosphere of road wetness and salt which has trouble escaping. The open sill flutes are an easy target for the exiting storm.

If you are going to use your mini in anything but arid conditions you have to expect to meet the rust man sometime. Anything that you feel might delay that day is, to my mind, worth a try. Whether anything actually works, who knows?

D

[nick@dunsdale]

If you are not a lover of stonechip or raptor look

Why not just epoxy prime the underside and paint it, epoxy will grip better than almost ever other product giving you very good long term prospects.
there are several reasons for using a quality epoxy it's lack of porosity and it's excellent adhesion properties.

You will have a higher adhesion yeild applying epoxy to bare metal than applying stonechip products to bare metal

Fill the cavity's with wax, and wipe of after it runs out through all the joints

[finchy533]

If we're talking about adding protection to something that's already painted, and you don't want to add a black coating like stone chip or Dinitrol, another option is ACF-50. It's an anti-corrosion spray that's like a thick WD40, or a thin cavity wax (so essentially a very similar approach to Iain's of using a thinned cavity wax).

I used it everywhere as I put my car back together, and everything I put it on is still looking good. It would probably need fairly frequent re-application on a car used a lot in all weathers, but as it's just a case of spraying a bit more it on that shouldn't be too hard. That's my plan for maintaining mine underneath anyway.

(plus normal cavity wax in the sills/box section of course).

[gr4h4m]

Dinitrol do a clear wax

[nick@dunsdale]

If we're talking about adding protection to something that's already painted

Doh........ I never read first post properly my advice would only apply to new fitted panels

[mk1]

There needn't be a "Raptor Look" depending on thinning & gun pressure you can apply it anywhere between babies arse to elephants scrotum.

Rich & I have used it on a few cars now as has at least one body expert we know & trust.

It can be coloured to any colour required & TBH, it doesn't seem to have a down side.

[Nick W]

We have let black Raptor down 30% and done transit bumpers etc. Much more durable than bumper paint.

[iain1967s]

Underside of my car seems to have been liberally caked by a previous owner using a greasy mix of some kind of soft bitumen mixed with old engine oil, a bit like a home made version of “tetroseal” if anyone remembers that nastiness from the 80s... much thicker than wax-oil.

It seems to do the job in terms of water/rust proofing. But it stinks the garage out in the summertime, and every time I do any maintenance on the underside I get covered in the sh*t - it’s like napalm... sticks to everything.