What brand of underseal for car these days.

[GRW]

I admit I'm confused by what to consider for underbody.
I have 3 vehicles - 08, and 2 of 11-plate. Some corrosion underneath inevitable, but none are bad AFAIK.
None of the vehicles have been done before (I have had one just 2-days, and one 18-months, only the OH's Kia Rio has been with us a long time).

I was thinking to clean off any loose, then perhaps coat anywhere there was rust with some Phosphoric and then some Bilt Hamber Electrox high zinc paint. Is that a reasonable approach?

Then, I wanted something to overcoat & protect. It sounds like you need 2 further products, one for cavities & one for external.... but which ones for older vehicles that I'm not intending to pull apart (& only have car ramps, Jack's & axle stands to get under)?

I have a compressor & Shutz gun, and also a cheap nasty Clarke spray gun with a gravity pot that I've never used (& brushes of course).

 

[barracuda816]

Can you spray bilt hamber ub with a schutz gun ?

You could but I wouldn’t, it doesn’t need to go on thick like waxol. A Parafin gun would be a better option in my opinion.

 

[barracuda816]

I admit I'm confused by what to consider for underbody.
I have 3 vehicles - 08, and 2 of 11-plate. Some corrosion underneath inevitable, but none are bad AFAIK.
None of the vehicles have been done before (I have had one just 2-days, and one 18-months, only the OH's Kia Rio has been with us a long time).

I was thinking to clean off any loose, then perhaps coat anywhere there was rust with some Phosphoric and then some Bilt Hamber Electrox high zinc paint. Is that a reasonable approach?

Then, I wanted something to overcoat & protect. It sounds like you need 2 further products, one for cavities & one for external.... but which ones for older vehicles that I'm not intending to pull apart (& only have car ramps, Jack's & axle stands to get under)?

I have a compressor & Shutz gun, and also a cheap nasty Clarke spray gun with a gravity pot that I've never used (& brushes of course).

I think that sounds like a good plan. I would use both Bilt Hamber UBC (clear underbody) and S50.

With what you have I would recommend buying the S50 aerosols with a few extension wands. It’s a bit more expensive then buying the bulk but for the cavities you need a decent coverage/spray pattern with reach.

Then I would get the UBC in the larger container and spray that with a cheap parafin gun.

Either way you don’t need to do a lot of disassembly, minimum would be the inner arch covers to expose the cill / arch area behind the front tires and infront of the back tires. These trap mud and stay wet meaning it’s one of the first places to rot.

Then remove the cill bungs and spray the S50 in the cills. Then focus on subframe cavities. Then just go at everything else with the UBC.

I like the products like lanoguard but I don’t like working on cars with it. It does a good job and stays wet but attacks dirt and gets everywhere when working on the car. But can also be uses under body or in cavities.

 

[Onoff]

I Waxoyled the underside of my first Capri. Did a cracking job of keeping the water IN, that found it's way into the sills and onto the floorpan from the badly fitted Webasto sun roof.

 

[charlysays]

I admit I'm confused by what to consider for underbody.
I have 3 vehicles - 08, and 2 of 11-plate. Some corrosion underneath inevitable, but none are bad AFAIK.
None of the vehicles have been done before (I have had one just 2-days, and one 18-months, only the OH's Kia Rio has been with us a long time).

I was thinking to clean off any loose, then perhaps coat anywhere there was rust with some Phosphoric and then some Bilt Hamber Electrox high zinc paint. Is that a reasonable approach?

Then, I wanted something to overcoat & protect. It sounds like you need 2 further products, one for cavities & one for external.... but which ones for older vehicles that I'm not intending to pull apart (& only have car ramps, Jack's & axle stands to get under)?

I have a compressor & Shutz gun, and also a cheap nasty Clarke spray gun with a gravity pot that I've never used (& brushes of course).

Sounds good. I would use a needle gun on any surface rust. you need the products in contact with conductive metal rather than rust. This also helps ensure the substrate is dry because iron oxide is very hygroscopic and will ensure rust continues under the coating if there's significant amounts of rust left. In my experience a needle gun is the most effective one stop solution for underbody prep short of needle blaster wheels or media blasting.

Theres not much love for Electrox on here but I've found it to work really well and be very quick and easy to apply. Woco unidox seems to be the same stuff fyi as Bilt Hamber seem to be out of stock of the 1l tins of Electrox. I've used it as a standalone coating on sill repairs on one car which was always outside and in daily use. It's been on there for years and it's still there with minimal progression of rust. Prep was just cutting out and welding up rust, needle gun for surface rust and no meaningful degreasing or other cleaning beyond a scrub with a dry brush for dirt etc. I think i did key it up with 80 grit.

 

[bricol]

While shifting cars around yesterday, I look a close look at my 91 Pug 106 - bought battered from a breakers to use in (off-road) car trials, but also pressed into service as a road car for long periods. I think it got accidentally washed around a decade ago. Left outside all year round. Used to be treated to a regular (annual or bi-annual) top up of waxoyl, but it's been parked since covid.

Still looking very sound, rust free on sills, floor, cross members etc.

My experience of it is that it does do what it claims - but it's not a use once and forget - all aftermarket stuff needs top ups and recoating. Needs applying properly - not the crap hand sprayer of from a shultz can down a tube with a nail in the end - a proper pressure pot that gives a good fine spray all round. If you've spent money on repairs, on decent coatings and waxes, it makes no sense to do not even a half-ar sed job on applying them. If you've got a compressor, even a small one, a pressurised pot will help do a decent job. I have one of these, can't remember if it's branded "Sealey" or not, but it cost around the same more than 20 years ago - it's been well used and worth every penny.

https://www.amazon.co.uk/Sealey-SG18-Air-Operated-Injector/dp/B000R9ZUGS

If you apply so much it blocks drain holes . . then re-read the instructions! Checking for clear drain holes in the sills and doors used to be car owners manuals anyway, when people had common sense and a hint of self-help-ability.

As for underneath, I like paint followed by underseal of some description, and reasonably regular checks for damage - again, aftermarket stuff is not going to be as good as OE galvanising, dips and electrostatically applied coatings. It's worked for 21 yrs of pretty daily use Lancia Delta.

I applied the same idea to my Dodge, sold from new with little to no underbosdy protection - an extra-cost item at the dealer. However, two years in Texas didn't do it any harm, so when I got it over here, it got 3M shultz where I could get, Bilt Hamber underbody wax down a lance where I couldn't, and Noxudol in all cavities. Now 8 yrs old, another 40,000 miles of UK year round occasional use, it still looks excellent.

 

[RWD3M]

I see more issues caused by Waxol than helped by it ,,,, I loath and detest the stuff , there are far better alternatives these days , Im an acf 50 fan for internal stuff , after that lots of choices , but Waxol is not even on my list.

Really? like what

 

[tom2207]

Really? like what

trapping moisture and rotting , cracking like it never used to do before they changed the recipe , people spray it in cavities where it catches fire if you have to go in and weld , its awful stuff. by its nature it will float over any damp / moisture and trap that to aid rusting thats why I dont use any wax based product on things I repair.

 

[RWD3M]

trapping moisture and rotting , cracking like it never used to do before they changed the recipe , people spray it in cavities where it catches fire if you have to go in and weld , its awful stuff. by its nature it will float over any damp / moisture and trap that to aid rusting thats why I dont use any wax based product on things I repair.

Ah, ok. I think you're referring to the cavity wax whereas the OP and I are talking about the underseal. Granted there been more than a little drift!

 

[bricol]

I think any internal waxes, if it's got enough crap in to do any good, will catch fire when you weld. I just use compressed air and blow it out.

I've only seen waxoyl crack when it's applied too thick, or simply due to age. Which is why all the cavity waxes I've used suggested reapplication after a year or two.

Nothing much works applied over moisture - best time to shove the stuff in is after a good few hot summer days - metal is dry and warm, and it seeps nicely in where you want it - and make sure all the drains are kept clear. And apply a mist - not a flood.

 

[tom2207]

I think any internal waxes, if it's got enough crap in to do any good, will catch fire when you weld. I just use compressed air and blow it out.

I've only seen waxoyl crack when it's applied too thick, or simply due to age. Which is why all the cavity waxes I've used suggested reapplication after a year or two.

Nothing much works applied over moisture - best time to shove the stuff in is after a good few hot summer days - metal is dry and warm, and it seeps nicely in where you want it - and make sure all the drains are kept clear. And apply a mist - not a flood.

acf 50 actually does ,, and wont catch fire if your ever back in there again ....

 

[RWD3M]

acf 50 actually does ,, and wont catch fire if your ever back in there again ....

Maybe I'll give that a try.

 

[Smallfry]

Can you spray bilt hamber ub with a schutz gun ?

Yes. Thats what I do.

 

[Smallfry]

I have cut up a few cars that were treated with Waxoyl. In sills with existing rust flakes and dirt in the bottom, it just sits on top and does nothing, but I am sure this would be the same with any viscous product. Unless it is thin fluid (think white spirit or thinners) it will not penetrate this detritus, so is a waste of time, unless you can clean out this cavity.

Waxoyl also seems to emulsify faster than Bilt Hamber S50. These products need to be applied in a thinnish, even coat as much as possible. Less is definitely more in cavities, and retreat every few years.

Underneath I use Bilt Hamber UB applied not too thickly with a shutz gun, and rejuvenate it every other year with S50.

I tried Waxoyl black underseal in aerosol cans, to cover up some naughtiness on a car I sold a couple of years ago, but found that it flaked fairly quickly, but maybe this was because of surface contamination to be fair. However, I didn't like it and would not use it on anything I was going to keep.

TBH though, IMO chainsaw chain oil or gear oil would be better than anything. Just can't bring myself to do it. YET

 

[Matchless]

Restoring classic BMW's for a living back in the day we used to use a lot of waxoil, we heated the cans up before application and tried wo warm the car panels up with an electric fan heater in cold weather or a good warm up in the spray booth first, as for underseal, on slightly crusty cars I sometimes sprayed a mist of waxoil on the surface crusty bits followed by a shutz gun with black stone chip, followed up a few days later with a mist of waxoil, it seemed to work for me..... I hate doing things twice!

 

[fizzy]

I once used the roof sealant Acrypol under my mates old ~Range Rover. Still looked good 10 years later when he sold it.
We also injected all the cavities using black waxoyl. He removed the bungs around the doors etc and pumped loads in. A few days later he was driving down a hill with his wife. Nice warm sunny day. Her wearing a brand new jacket. Suddenly she gets a lovely shower of back waxoyl

 

[Cobbler]

Restoring classic BMW's for a living back in the day we used to use a lot of waxoil, we heated the cans up

Some mates & I used to share a barn attached to a friends house as a workshop years ago, one of the group was rebuilding an AH 110/4 & as he made bits for the chassis he used to nip into the house & put the can of underseal in the oven & cook it up. One day, can in oven & forgotten about, only trouble was, he forgot to take off the lid. You can imagine the result, loud bang, lady of the house going mad, the cooker was such a mess, funny really looking back.

 

[bricol]

acf 50 actually does ,, and wont catch fire if your ever back in there again ....

But if it's that fantastic, how do you know?

 

[bricol]

No cavity wax is going to stop existing rust - do any of them claim to?

A mate sprayed every which way in a Vauxhall Omega he bought last century - he ran it a good few years, then it passed to his wifes parents who ran it for years, then it came free with the caravan I bought from them when it would have been at least 20 yrs old . . parked across my sloping driveway on a hot day, it smelt of waxoyl . . . it was still running out of the drain holes in doors and boot lid!

No rust in sills, doors or boot lid.

Applied on decent metal, I reckon it works as well as any other.

 

[tom2207]

lol ,,,, epic
are you by chance a farmer ?