Underbody rust, including beams

Thin bits of metal and bright blue light. Including glass & trim.

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Wilso
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Underbody rust, including beams

Post by Wilso »

Hi all,

I’ve just got back from 5 months away and intend to preserve my van against future rust problems. I’ve got some surface rust on the box sections of the frame and want to know what is the best method to get rid before it becomes deep?

Angle grind with a metal brush back, prime, paint (spray cans ok?) and then seal (with?)
Or
Hammertoe rust eater, wait, prime and seal?

I intend to under seal the floor again so suggestions on the best seal would be grand.

Cheers,

Deano

PS I have some pictures but struggling to find the post that details how to post them in after uploading them somewhere else?
Own; T25(3) RHD Carravelle conversion into camper. 2.1 petrol Wasserboxer.

Michael4
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Re: Underbody rust, including beams

Post by Michael4 »

For those who have an interest in sheep I use Fluid Film, it is lanolin based...

Poured into box sections, squirted wherever I can squirt and sprayed on the underneath. I bought 10 litres about ten years ago and still have half left, use it on the boat too.

I'm new to t25s but it worked on old Austins and Citroens which are quite famous for their crumbling.

It is has an ability to creep into seams and never seems to dry.

A bit messy (like sheep) but makes the whole thing a much easier job.
1985 1.9 DG Devon Moonraker with solid sided pop top

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Dubworth
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Re: Underbody rust, including beams

Post by Dubworth »

I'd wire brush everything down thats showing surface rust, paint Vactan on affected, then once dry use stone chip paint, or use something for underbody protection from the likes of Bilt-Hamber or Dinitrol. For box sections I'm a big fan of Dinitrol ML, can get it in aerosol form and use the extra long hose attachment to spray it in, it's quite searching so will run into areas then set like a waxy layer.
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ZsZ
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Re: Underbody rust, including beams

Post by ZsZ »

+1 on the Fluidfilm, altough now I use Carplan Waxoyl with good results on surface rust
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adie89
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Re: Underbody rust, including beams

Post by adie89 »

Gold plated solution
Strip back with wire brush - if needed cut out and weld in fresh metal
1. Etch primer to adhere to the metal
2. Epoxy primer - it’s sealed unlike regular primer which absorbs water
3. Seam seal with PU sealer
4. Chipguard to reduce chipping through to metal
5. Colour coat to seal the surface
6. Underbody spray like unterbotenschutz over the top. This will stay softer and flexible and increase resistance to knocks, moisture and salt.
Inside frame rails clean out and product of choice

Before resorting to rattle cans if you have no spray facility you can buy the better, two part, products from your paint factor and brush it on.

Platinum
Before 1 get the underside hot zinc sprayed. V expensive I bet though
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mhowood
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Re: Underbody rust, including beams

Post by mhowood »

Great to find this thread - was just about to ask the same questions. Thanks!

When I got my T25 a few years ago, I was complemented by the garage, after it's yearly services, on what good condition the undercarriage was in. I could blush!
Then at last year's MOT it's suddenly falling to bits! :shock: Cue: 2 grands worth of welding work and another grands worth of parts. :cry:

I'll be investing in some ramps and some Frost Extreme Chassis Black and Waxoyl < hope I got those right. :wink:
No idea what I'm doing but presuming coat everything that isn't a nut, bolt, or moving.

Also found this thread >
Under body paint/protection https://forum.club8090.co.uk/viewtopic. ... lit=Waxoyl

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mhowood
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Re: Underbody rust, including beams

Post by mhowood »

I've got a noob question: box sections? 'spraying it in'? 

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AngeloEvs
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Re: Underbody rust, including beams

Post by AngeloEvs »

You can buy Dynax S50 in a large spray can, it comes with an extension nozzle that you can insert into cavity sections and costs around £12 a can. The T25 chassis rails have a lot of access points along their length that you can insert into.

If you have a compressor you can buy various underbody wax products in special high pressure cans which are used with a spray adaptor that fits onto the can.
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mhowood
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Re: Underbody rust, including beams

Post by mhowood »

Many thanks. Then finish the job by pairing with Hammerite waxoyl?

How are people cleaning the undercarriage, before getting the wire brushes out? Steam clean, jet wash?

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AngeloEvs
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Re: Underbody rust, including beams

Post by AngeloEvs »

Waxoil is not as good as Dynax S50, there are comparison tests that show their relative effectiveness against water and salt, etc. Also, waxoil usually has to be heated and thinned with white spirits to be able to spray it - Dynax S50 does not require heating or thinning, is far easier to use and sprays straight from the can.

I use Dynax S50 for box sections, cavities and low impact areas and Dinitro 4921 for arches and areas that get a lot of wheel wash, this is slightly thicker and self healing - both products last longer than waxoil and give better protection.
1987 DG Karisma LPG with remodelled interior

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