Hammerite underbody seal

[rix313]

Does any one have experience with the Hammerite underbody seal range? I've been looking at both the spray on and brush on versions. Should I be choosing one over the other or is it much of a muchness?

[Dlb26]

To be honest there is better stuff out there. Have a look at places like Frost, they sell products like Dinitrol etc. Bilt Hamber is another one to try.

[steve_k]

have a look at this place,

https://www.rust.co.uk/?gclid=CjwKCAjw9 ... GsQAvD_BwE

a mate of mine lives down the road from them & got some rust proofing paint from them a few years back & swears by it.

[flybynite]

Depends on what you are doing, bare metal or patching in, is it clean etc etc.

If you have a lot of bare metal then you cant beat the 3M 2-part bagged stuff, only tried it once but it is worth going back to bare metal just to use it. looks factory.

In the past we used stone chip over etch primed metal and then mixed shutz with waxoil heated over the fire, put on with a shutz gun.

Gave a good consistency. We found Shutz on its own dried and cracked eventually, waxoyl was too thin, together the waxoyl kept the shutz soft and shutz stopped the waxoyl being worn away too quickly. It could be jet washed and added to easily and if you needed to repair behind it, easier to remove than shutz.

I see it is now available ready-mixed

[rix313]

It'll be a mixture of clean bare metal from repairs and what is already under there from factory

[flybynite]

I'd put etch prime and stonechip over the metal repair then 75/25 Shutz/waxoil mix over that. Blend it in with a light coat of 50/50 Shutz/waxoil over everything. Warm up the shutz can before spraying and lower the pressure, doesn't go everywhere then.

If it is a resto/show car etch, 3m 2K bag and overpaintpaint under wheel arches

[Brianmoooore]

Stay well away from bitumen based underseal on any vehicle you want to last. It will crack and lift after a few years, trapping water behind it, and accelerate rust. It's intended for tarting up old bangers, hiding poor quality repairs from the MOT tester, and generally helping to stave off the one way trip to the weighbridge for a few more years.
The stuff to use is polyurethane underseal, as BMW did when the car was made. The 3M stuff mentioned above is one such underseal.

[rix313]

Stay well away from bitumen based underseal on any vehicle you want to last. It will crack and lift after a few years, trapping water behind it, and accelerate rust. It's intended for tarting up old bangers, hiding poor quality repairs from the MOT tester, and generally helping to stave off the one way trip to the weighbridge for a few more years.

It looks to me like that's what has been used in one of the areas. The surface looked like a dried up river bed and underneath was evidence of welding wire and spatter.

Thanks for the info guys.

[magpie]

this is good shit .

https://www.ebay.co.uk/itm/UPol-GRAVITE ... SwPXFcJi1J

comes in black,white or grey .

[215m3]

When doing the underside of my track M3 I used some underside paints from Frosts. POR15 (Paint Over Rust if required) does not dry rock hard any has a little give to absorb to prevent cracking etc.

[clarko74]

Another thumbs us for the 3M stuff from me, it sticks like sh*t to anything and will never come off.

[clarko74]

Here's a small repair done to mine recently, once it's been smeared on and painted you'd never know.

[flybynite]

Well I have been using uPol gravitex for many years (since the tins looked like this one still on the shelf )

Good stuff and done me well but things move on and the 3M 2-pack stuff is better (and a lot more expensive) but it is what will be going on mine if I am going to the agro of taking the old stuff off

[Brianmoooore]

The 3M stuff is the underseal. The Gravitex stuff above is intended for visible areas, such as sills, where the panel is likely to be bombarded by road dirt. The Gravitex can also go over the 3M underseal in places like wheel arches, to help protect the underseal from abrasion.

[flybynite]

The 3M stuff is the underseal. The Gravitex stuff above is intended for visible areas, such as sills, where the panel is likely to be bombarded by road dirt. The Gravitex can also go over the 3M underseal in places like wheel arches, to help protect the underseal from abrasion.

Not so sure,

From the manufacturers info:

uPol Gravitex: High build formula for covering seams, Substrates: Bare steel or Original Paint

3m 2-pack: Use for reproducing the original appearance of body joint seals and restoring stonechip coatings

From using them both they spray and handle very similarly as is the end result. Both can be used to cover bare steel in high wear (stonechip) areas. Both can be overpainted. I find the 2-pack stuff (as in paint) seems tougher when cured.

[DanThe]

Gravitex can be removed with your finger nail, I definitely wouldnt use it on bare steel, 2 pack products are much better in my experience

[rix313]

Is the 3M applicator required as well as it’s a bit scary to spend in the region of £75 on what looks like a very basic spray gun? Or am I missing something.

[DanThe]

Yes it is needed, but worse than that is a bag is emptied in about 20 seconds