underseal

[ice man]

underseal is it a good idea? my van is used every day work shopping ect 300+ miles a week
i just want to make the already solid underside stay solid. just wonderd what you all think :?:

 

[slammedresto]

i planning on doing my undercarriage in the new year

planning on stone chipping it, then waxoil in the chassis rails etc, should keep the rust at bay i hope

 

[ProfessorWheeto]

If its that "underseal with added waxoyl" brush on stuff in a tin then NO!

Stone chip on the arches is a good idea. Waxoyling when the vehicle is dry is advisable as well. If its heated slightly it sprays better, you can also mix it with a little used engine oil.

 

[noddy]

This question has come up before, and I will give my opinion for what its worth, as I know last time some people did not agree with what I had to say.

Let me start by saying I am an automotive engineer and have been for the last 15 years working for various prestige car makers in the UK and Germany, I currently work for Bentley motor.

Rubberized underseal is fine when applied to a brand new body shell with no rust or road dirt. When it is applied to a new body shell it is applied before the car is fully painted and in a clean environment. Then painting over the sealer seals the edges against water ingress under the stone chip layer.

It is also worth noting that modern body shells are E coated, this is an anti corrosion coating applied in a dip tank, the steel used is also zinc coated when it is a sheet prior to pressing.

The problem with using a rubberized stone chip on classic vehicles in my opinion is:

1. the condition of the surface its being applied to is usually dirty and some time rusty which does not promote a good bond and dirt can act as a sponge and keep water trapped.

2. Because most classic cars have no real corrosion protection in the box sections when any moisture gets in it will bleed through the seams and get behind the rubberized layer and set up rot which will not be apparent unless the stone chip layer is removed or blisters.

3. how do you seal the edges around the wheel arches, to stop water getting between the stone chip layer and the body, modern vehicles have a wheel arch splash guard which takes care of this.

In my opinion the waxoyl/tar based sealant that can be brushed on is the best option at least it contains a corrosion, inhibitor which the rubber based options do not.

Which ever route you chose I would make sure you get a good coat of waxoyl in all the box sections and give it time to melt into the seams, (which will mean waiting till we get some warm weather), before you apply any underseal at least this way you will know your not sealing moisture in the seams only waxoyl.

At then end of the day its your van you should do what you think best suits the way you use it.

Ian

 

[ice man]

thanks that sounds like good advice to me. waxoyl it is. with abit of stone chip (good work men) :mrgreen:

 

[james_stan]

If its that "underseal with added waxoyl" brush on stuff in a tin then NO!

Can you say why ?

Noddy implies yes in his message. I'm interested because i have been using just this stuff.
Normally on clean (new) metal or bit's I've prior treated with Hammerite No1 RustBeater (contains the phospheric acid stuff I think)

Cheers

James

 

[ProfessorWheeto]

It's too thick and it dries. Stones hit it, make a chip in it or expose some of the metal and water gets in behind it because its thick it holds the rust back and you'll never know it there until you bring it for an MOT or someone like myself and I stick my trusty big screwdriver through what looks like a nice solid undersealed vehicle! (Before I got into the trade I learnt the hard way on my old beetle :roll: )

Personally I stone chipped my inner arches (with UPOL Gravi Guard rather than that awful rubbery stuff), and sprayed the entire underside with the topcoat I used on the van. It was a primer based industrial paint and is a direct product so can be sprayed directly onto bare metal and contains rust inhibitors.

I didn't have chance to waxoyl it before the weather turned. When the weather improves I am going to pressure wash the underside and once completely dry spray with a mixture of waxoyl and old engine oil.

It sprays into all the nooks you can't get with a brush and although provides a protective layer its thin enough to see whats going on underneath.

It's worth doing once a year, I have friends that do it at both the start and end of the summer.

 

[ProfessorWheeto]

Which ever route you chose I would make sure you get a good coat of waxoyl in all the box sections and give it time to melt into the seams, (which will mean waiting till we get some warm weather), before you apply any underseal at least this way you will know your not sealing moisture in the seams only waxoyl.

Or just warm it up before spraying it? :wink: