[NoalK]

Hi, I've been reading lots of posts and have a good idea of what I want to do to fix my Transit Custom sill rust but I am stuck on one part.
The rust is penetrating up behind the stone chip and paint on the outward facing surfaces and surely up between the steel sheet sections forming the bottom of the sill seam.
How can I deal with the rust between the steel layers? Some sort of acid to strip the inner paint/rust layers so I can feed Hydrate 80 from inside the sill cavity? I can't fit much (if anything), tool-wise, between the layers to remove the paint/rust.

I can't imagine Dynax-S50 would penetrate down through the cavity and through the paint "curtain" to halt the rust sandwiched between the bottom sill seam.

It's a real head scratcher to me...

Thanks for reading.

 

[grunty-motor]

Depends if it has come from the outside (e.g. because its been used as jacking point) or come down from the inside. Looks like the former, but until you get in there you wont know how far in it goes.

1. Start of with a wire brush on a drill / grinder and see if you end up with bright metal.
2. Go in with a small pick/screw driver and see how solid it is.
3. Grind it back if you were really keen.
4. Last resort, cut it out

But, doesnt look that bad to me. I'd go as far as 1 & 2 and then gel/hydrate/zinc/underseal or wax. And see how long it lasts before it comes back.

 

[NoalK]

Depends if it has come from the outside (e.g. because its been used as jacking point) or come down from the inside. Looks like the former, but until you get in there you wont know how far in it goes.

1. Start of with a wire brush on a drill / grinder and see if you end up with bright metal.
2. Go in with a small pick/screw driver and see how solid it is.
3. Grind it back if you were really keen.
4. Last resort, cut it out

But, doesnt look that bad to me. I'd go as far as 1 & 2 and then gel/hydrate/zinc/underseal or wax. And see how long it lasts before it comes back.

The issue I have is how to treat the inner surfaces that are spot welded together. They still have paint, which is broken at the bottom and allowing trapped rust to travel up inside.
I can't get a tool up between these surfaces.

 

[grunty-motor]

yep, i understand. so, other than cutting it out (excessive in your case) you can only remove the worst, and seal it to stop more moisture getting in. And see how long it lasts.

I dont believe there is any way of killing the rust within those two mated surfaces.

Or am I misreading the photos and the plates have swollen all the way up to the inner sill? Clean it up, spray WD40 / penetrating oil on the inside and see if it seeps through?

 

[steveo3002]

id clean up and treat the outside best i can with whatever product you believe in , then drown the inside with a runny cavity wax hoping it will creep into the void

any older used car will have some hidden rust in a seam somewhere

 

[NoalK]

That's exactly the issue, yes. Thanks for your input Inside the mated surfaces.

Because the rust has penetrated upwards into the seam, only the bottom of the sandwiched paintwork is broken. Any treatment applied via the sill cavity could likely not reach the sandwiched metal.

Do you reckon WD40 is as good as anything without resorting to new metal?

I wonder, would WD40 be an obstacle to further treatment attempts with something else...

I thought there might be a common/best method for dealing with such areas other than welding.
Perhaps WD40 is it.

 

[NoalK]

id clean up and treat the outside best i can with whatever product you believe in , then drown the inside with a runny cavity wax hoping it will creep into the void

any older used car will have some hidden rust in a seam somewhere

Thank you. Feeling better about things thanks to you two guys.
It was scary when I couldn't find anything specific to dealing with this area.

I love my van

 

[steveo3002]

no on the wd40...it would be around long

 

[grunty-motor]

Do you reckon WD40 is as good as anything without resorting to new metal?

I wonder, would WD40 be an obstacle to further treatment attempts with something else...

I mentioned spraying WD40/penetrating oil on the inside of the sill because it might show if the rust is coming from the top down....i.e. if it seeps through and wets the rust on the outside, then you are going to struggle. S50 really is the best you can throw inside the sill.

If you are really worried, get yourself one of these and then you will know whats on the inside!

DEPSTECH 5.0MP Endoscope, 8.5mm Type-C USB Borescope,Waterproof Inspection Camera with 16.5ft Cable and 6 Adjustable LED Snake Camera for Android, Windows/MacBook OS : Amazon.co.uk: Business, Industry & Science

Buy DEPSTECH 5.0MP Endoscope, 8.5mm Type-C USB Borescope,Waterproof Inspection Camera with 16.5ft Cable and 6 Adjustable LED Snake Camera for Android, Windows/MacBook OS at Amazon UK. Free delivery on eligible orders.

www.amazon.co.uk

 

[NoalK]

I mentioned spraying WD40/penetrating oil on the inside of the sill because it might show if the rust is coming from the top down....i.e. if it seeps through and wets the rust on the outside, then you are going to struggle. S50 really is the best you can throw inside the sill.

If you are really worried, get yourself one of these and then you will know whats on the inside!

Yes, cheers for clarifying I suspected that's what you could have meant.
I find those cameras so frustrating to use! I don't know how the feds cope...
I think I will be using S50 inside.

 

[MaDMaXX]

Yup to the S50 on the inside, it'll creep and kill rust whilst it's in there.

You'll have to manually clean the outside and treat/seal etc.

 

[steveo3002]

do it on the hottest day , after standing the product in hot water , then warm the panel with a heat gun , will give it the very best chance of flowing into gaps

 

[NoalK]

do it on the hottest day , after standing the product in hot water , then warm the panel with a heat gun , will give it the very best chance of flowing into gaps

Steveo, I searched Hydrate 80 and the first result was you, many moons ago.
I have to ask, what's your long term view on Hydrate 80? Do you have any wisdom you could give me here to save me trawling please?
Thanks.

 

[steveo3002]

hmm
something like your lip it may help , on flat /accessible areas theres no substitute for removal, all you can hope to do is remove as much rust as possible then seal it away both sides from air and moisture , it wont stop it coming back but can slow it down vastly

no better /worse than vactan

 

[NoalK]

hmm
something like your lip it may help , on flat /accessible areas theres no substitute for removal, all you can hope to do is remove as much rust as possible then seal it away both sides from air and moisture , it wont stop it coming back but can slow it down vastly

no better /worse than vactan

How long did your results last using Hydrate? Before something needed doing again?

 

[steveo3002]

honestly i cant recall mate , just do your very best at removal and thats all you can do

 

[Ennoch]

The sills on my Impreza are similar. I'd start with emptying a can of Bilt Hamber Ferrosol into the sills and then follow it up with S50 wax, or similar. I suggest the Ferrosol first as it'll creep into the join far more effectively than the S50 and will then hopefully keep the S50 liquid for a bit longer (do one straight after the other) to help that creep in too. I'd then grind the rust off the outer sides as best you can, convert what remains with a convertor such as BH Hydrate 80, sand back the excess, re-apply, seal the seam (apart from the drains) in tigerseal and then overcoat in EM121 epoxy in white. I suggest this over the BH epoxy mastic as it's white rather than grey/black, and is available from rust.co.uk

 

[NoalK]

The sills on my Impreza are similar. I'd start with emptying a can of Bilt Hamber Ferrosol into the sills and then follow it up with S50 wax, or similar. I suggest the Ferrosol first as it'll creep into the join far more effectively than the S50 and will then hopefully keep the S50 liquid for a bit longer (do one straight after the other) to help that creep in too. I'd then grind the rust off the outer sides as best you can, convert what remains with a convertor such as BH Hydrate 80, sand back the excess, re-apply, seal the seam (apart from the drains) in tigerseal and then overcoat in EM121 epoxy in white. I suggest this over the BH epoxy mastic as it's white rather than grey/black, and is available from rust.co.uk

I can't help thinking that if I oily-waxed the inside first, it could affect the outer treatments adhering.
As though the Ferrosol and S50 would continue to creep, into H80, Tigerseal and epoxy while they are trying to bond to the metal.

This is only how I imagine it could play out. I have no experience of this.

 

[steveo3002]

yeah that would be foolish...get all the paint type products on a cured before spraying wax

 

[Ennoch]

It's a valid point and you can certainly do the paint first, but the reality is that you're only going to get so much creep into the join, and the joggled drains in the sill panel shouldn't be plugged with paint anyway as they are intended to allow moisture out that has got in. And as you'll be prepping the paint before hand with panel wipe, again, hardly an issue. The main reason I'd sort the sill first is that it gives you your best chance of driving moisture out the join, however little that may be.