Why Not To Underseal

[Packedup]

The underseal all looked like the stuff still on the panel in the picture, and that's what lurked beneath. I imagine the whole car it like that, though hopefully I won't find the hidden horrors I did on the Midget (gaping holes in the structure!).

I'm sure underseal does a good job of making everything look pretty and persuades Mr or Mrs MOT tester it's all solid, but it's really just a time bomb slowly ticking IMO.

[chickenjohn]

Yes! Good idea, I agree, underseal is rubbish- take it all off, remove the rust go back to bare metal, zinc prime, top coat of your choice and use underbody wax.

[Packedup]

I've not had chance to do any more removing, cleaning up or painting, but have liberally sprayed milkstone remover over the exposed area which will slow things down till I find time. It'll be sanded back, zinc'd (wih Teamac equiv of Galvafroid), and chassis blacked. Same goes for the whole car eventually. Aside from time, energy etc another delay is trying to find chassis black at a sensible price - It's gone from £25 to £40 for 5l around here I'm waiting to see if the local agri place that stocks various Teamac paints can get hold of their version for sensible money.

This post was to show proof of what some people and myself have been saying for years - Underseal really is nothing more than hidey paint! OK, it might do a good job when fresh, but unless you're willing to strip it all off and redo regularly it's just a water trap and tinworm haven.

[youngun]

It'll be sanded back, zinc'd (wih Teamac equiv of Galvafroid),.

Damn good stuff that, ive used it on most of the panels on my mog, the tin weighs an absolute ton!

[Peetee]

and that's what lurked beneath

Oh yes. RIP Joemog

[Packedup]

Damn good stuff that, ive used it on most of the panels on my mog, the tin weighs an absolute ton!

It's when you tell someone how much it cost, and they look at you as though you're insane - Till you hand them the tin and they suddenly have to grab it with both hands!

I find it settles terribly, so you get a big lump of zinc atthe bottom and thin paint on top - Luckily the "man that can" who kindly lets me abuse his tools and drive cobbled up a stirrer that took care of that last time

I don't have any pics of what I found (or is that what I've found so far..) under the hidey stuff on the Midget, but basically the front closing panels on both sills were pop riveted patches, which had rusted out anyway. There was 1/4 - 1/2" of underseal slapped over the top, so they looked perfect. I only found the holes because I was stripping the hidey stuff off to put real paint on there!

[Packedup]

though hopefully I won't find the hidden horrors I did on the Midget (gaping holes in the structure!).

Spoke too soon

There's a couple of holes along the lop to the ledge near where the wings bolts go, and when I got the wing off (which a previous previous owner seemed to have welded onto the sill!) there's a lack of anything around the bottom corner of the front of the hinge post.

The holes don't look too nasty in terms of welding (bet they'll be huge now I've said that), but it's yet more to do and I HATE welding!

And again, it would have been almost impossible to know about any of this by looking alone - The underseal looked perfect and it was only my hatred of the stuff and an hour with a hot air gun that revealed the true story.

And yet I still read posts (mainly on other forums) where people advise slapping underseal on to protect the metalwork!

[chickenjohn]

" And yet I still read posts (mainly on other forums) where people advise slapping underseal on to protect the metalwork!"

Yes, even practical classics in its terminal decline advises to protect your car with underseal.

BTW, after removing all the rust, zinc priming and chassis blacking- thick underbody wax, topped up every couple of years is the best thing you can do to protect your car. I washed the traveller yesterday and hosed down the wheel arches- almost no mud or dirt at all underneath where the waxoyl was applied and the water just runs off, like the proverbial ducks back, hence underbody wax repells moisture, also repells dirt too and the underside of the car is kept dry, clean and rust free!

[chickenjohn]

Wheras underseal seems to attract mud and moisture and hold onto it!

[alex_holden]

I hose underneath every time I wash the car - usually about once a week. Especially important in winter when you're driving on salted roads. It's nice and clean under there apart from the oily bits near the engine and transmission.

[Packedup]

Just to ram the point home a bit further!

The bottom of the post was a major, and unpleasant surprise, but though underseal is the likely culprit it was hidden behind the wing. The holes going around the inner arch panels don't surprise me at all, but once again, the underseal covering them looked perfect.

I don't have any "after" pics, I forgot (after finding how hellish the rear repair turned out to be) and to be honest I'm not exactly proud of my workmanship either But there is metal where there wasn't, and it's zintec covered in zinc rich primer and soon chassis black too (time, weather etc was against getting it all done today). I'd love to trowel on some underseal to tidy up the welds of course, but hiding a solid repair is a less genius idea if it's only going to mean it needs to be done again in a couple of years!

The previous owner said underseal could be considered dangerous (none of this is of his doing, and he doesn't have quite the allergy to the stuff as I do so never removed it), and I agree. It can hide severe structural damage and give an utter sense of complacency regarding the condition of the metalwork. I shudder to think of the cars I've undersealed in the past before I saw the light

[coogee]

What’s the recommended way of taking off underseal, techniques, Etc.

Phil

[chickenjohn]

Heat gun to soften the underseal, then use a paint scraper. Can have an inner rear wheel arch clean in 20 minutes.

Then use thinners to remove the remaining traces and sand/wire brush the rust off.

[MarkyB]

I think you are all being a bit unreasonable about the original underseal.
I'm no fan of later stuff put on to hide bad welding or other bodgery.

But I don't think you can complain too much if you strip off the original stuff and only find only surface rust.
If that's all there is after 30 or 40 years hasn't it done a pretty good job?

I've lost count of how many newer cars of many different makes that I've given up on because they were far too rotten.

Even Mercedes only give a 30 year warranty on their galvanised cars IF you only have them main dealer serviced and the rust is goes through a panel from the inside.

It is the nature of mild steel sheet metal to rust in our climate especially with the added salt
In America they look for cars from "dry" states to find rust free cars.
Unfortunately we don't have that option.

Anyone remember the Renault Dauphine? They seemed to come off the assembly line rotten and went downhill fast.The streets were littered with them for a while about 25 or 30 years ago R.I.P.
Rust in peace indeed.

[Packedup]

I think you are all being a bit unreasonable about the original underseal.
I'm no fan of later stuff put on to hide bad welding or other bodgery.

Like bits of alloy glued into box sections you mean? Yes, I found some of that on the rear inner arch area!

But I don't think you can complain too much if you strip off the original stuff and only find only surface rust.
If that's all there is after 30 or 40 years hasn't it done a pretty good job?

Take a look at my last pic - There was no bodgery there to hide (there is now - 2 inches of perfect weld, followed by two foot of dire ) but there was a lovely collection of hitherto unseen holes.

At least with just paint you can see the signs of rust early on. With any form of thicker coating you can see nothing until you strip it all off - And who (other than me) is going to do all that for no apparent reason?

I've lost count of how many newer cars of many different makes that I've given up on because they were far too rotten.

And of all the Minors made, how many still exist? Cars rot, but there's things can be done to at least slow that down. Underseal just seems to keep it at bay for a couple of years, and then make up for lost time plus a bit!

[aupickup]

well i have the original underseal on my car and i have taken off patches of it to see what the metal work is like, and it is perfect, even the front chasis legs have the original paint under neath the underseal, and inner wings etc
obviously where the ssmall amount of bad bits are , are where the road dirst, mud etc are on teh backs of the inner arches and wings are not so good

so i am going to leave mine on now, well it has kept the car good for 40 years even 90 5 of the crossmeber is like new

[MarkyB]

And of all the Minors made, how many still exist?

Lots really. It would be interesting to see what percentage of Beetles or 2CVs there are left for a comparison.

Underseal just seems to keep it at bay for a couple of years

I'm saying its done a lot better than that. Have you got the worlds newest Minor? or is it a bit older than that?

I've had another look at the pictures and I still don't think you can blame the underseal for much, if any of the rot.
The holes in pic 1 look like they have been caused by dirt,salt water etc. settling in the seam from the engine bay side.
Something similar probably caused the other rot holes on the inner wing. Were they undersealed with the wings off? Probably not.
I bet that bit didn't get any.

I agree that a painted waxoyled surface lets you see what is going on now but these are just cars like any other in that they were built to a price not to last forever.
How many previous owners would have taken off the wing to check the inner wing? Not many.

How long would they have lasted without underseal?
If they had been put together with seam sealer they would have lasted even longer.

I think the old boys who used to paint the old engine oil onto the underneath of their cars were onto something

With the hindsight we have now things might have been done differently, look at the design of the van gutter. A rust sandwich in the making in retrospect.

I think they did a really good job with the Minor. If they didn't this would be a much smaller club than it is

[bigginger]

Bear in mind that this underseal could have been applied at any time in the car's history, and from personal experience it is applied over pretty shoddy work for appearances sake. And I've just spent an afternoon stripping it from an engine bay - with much the same results as Packedup. OK, not holed, but it did cover a fair bit of surface rust

[aupickup]

took some of mine off and its shiny paint underneath

[Packedup]

I would like to point out I am applying no underseal at all to hide my shoddy work! Better to have it looking ugly but functional rather than pretty and a time bomb

Found some truly hideous surprises in the last few days of fettling, all hidden by underseal. But unlike the front inner wings/ arch, these have been genuine hidey paint jobs. Which, thinking about it (which I'm trying so hard not to do right now), I'm not sure if that's good or bad!

Which shows that underseal in a genuine attempt to protect the bodywork is counterproductive over time and hides rot, and underseal to hide rot hides rot.

It's not looking good for underseal at this point in proceedings..