Rusty seam advice

[Helga]

I'm going to begin on certain seam areas soon - where they are starting to bubble. Now, I have a couple of questions if possible:

1. Do you need to do both sides of the seam, ie in the van and obviously out? If you do need to do the inside, how do you get to the buggers?

2. What 'IS' the seam? Are the two panels actually attatched in some way? Is there actually a physical gap between the panels?

3. What do YOU do, I was thinking of grinding out all rust and 'matter' using a dremel, sanding down to metal, rustproofing and then painting on the inside of the seam with anti rust paint... how does that sound?

4. I have read posts about putting SEALER back into the gap then - but what IS the sealer? A particular product of some sort? OR could you just fill the gap with anti rust paint?

Thanks!!!

[AngeloEvs]

The seams are the point at which separate body panels meet and are spot welded. Some parts of the seam are thus within the structure and other sections of the same seam can be exposed to the elements. No hard and fast rules about seam corrosion but expect plenty of replies about treating......

[jaylo264]

The big problem with seams is that , being two flat, closely - applied surfaces , usually of two separate panels , CAPILLARY action can take place as well as residual wetting , allowing damp to creep deep into the seam, and often from the inside as well due to condensation i. e. poor ventilation/ insulation ( in order of priority ).
This is the main reason why I have used a 0.8 mm cutting disc , very carefully , on a 41/2 grinder to cut deep into the webs of the seam, separating them and stopping capillary action. Treat with your preferred antirust ( currently kurust for me ), then red oxide, then paint , then seal with white tiger or in my case with unibond universal ( domestic ! ) sealer , white ( same as the van ) but this is also perfectly overpaintable unlike tigerseal and comes in a neat wee tube with a tiny nozzle.
Capillary action -- which is amazingly powerful -- is why welded seams often rust up, i reckon.
jaylo

[rainman]

Yes do inside, otherwise the repair will only be cosmetic and the rot will continue. I went at them with a very thin cutting disc and then applied Vactan followed by seam sealer http://www.halfords.com/webapp/wcs/stor ... _langId_-1" onclick="window.open(this.href);return false;

As for getting to the inside, depends on where they are but be prepared for some unpleasant sights, if it's bubbling on the outside there's going to be some nasty looking brown stuff eating away at the inside.

[Helga]

Thanks guys, that is really helpful - but one question remains - why use sealer, why not simply fill up with a good quality rust sealing paint luike kbs rustseal or something? Surely the 'sealant' is an unnecesary addition?

[Helga]

Oh, and rainman, that sealant looks interesting - if one used it, how much, either side of the actual seam, would you paint with it, or would you just carefully brush it INTO the seal itself?

[xpress]

i am of the feeling that if the water can seep in from the outside in then vactan will seep in there too, and you can never get totally into the seam unless you undo the welds, therefore i clean up the surface free of rust inside and out then i let vactan soak into the seam from the inside and the out, i don't dremel or cut, sandblast or anything like that.

vactan has actually sealed my seams from a leak before without putting any sealant in there, however if you have cut out any sealant on the outside or there is some missing i would definitely top it up with fresh sealant, in answer to OP question, sealant is firmer than paint and likely to have different waterproof characteristics over time and will bend with the movement of the van not crack like globs of paint would in a cavity. i would definitely seam seal where it's needed. just seems like common sense to me. then i would either primer and or paint/spray over the top of the seam sealer as preferred.

[Helga]

For me, I have simple little cracks in the seam - so you would say, xpress, simply put rust curer onto what is there withough touching it or scraping or messing? Just let the gloop soak in and in then seal the crack? Basically what you mean xpress yes?

[xpress]

best to take some pics and post it up if you want details on a certain situation but i would say to clean it up with steel wool so no rust is there any more. then pick out the cracked sealant because that's the area that's caused the leak, right? clean that up with steel wool then hot hair dryer and dry the area out, and then treat with vactan once or twice maybe with a hot hair dryer lightly over the area, then seal up from the outside with fresh sealant. it's a patch up but that should sort it and this is what i am comfortable with doing, but as i say take some pics and post them if you can, some of the guys and myself here could tell you just by looking at it how far gone it is and what you need to prepare yourself for. in short, i wouldn't just blob the sealant on top of the cracked old sealant,

i would clean it up a bit, dry it out, rough it up, then put it on, it should take a lot better and only after you've dried it out thoroughly and vactanned, but i would pick that part of the seal out and apply fresh instead of on top, this is the best way, but going on the top of it is better than leaving it the way it is. again it's hard to say without seeing it.

[Helga]

Thanks for that - I'll get some pics up tomorrow

[HarryMann]

Wire wool in seams

best to take some pics and post it up if you want details on a certain situation but i would say to clean it up with steel wool so no rust is there any more. then pick out the cracked sealant because that's the area that's caused the leak, right? clean that up with steel wool then hot hair dryer and dry the area out, and then treat with vactan once or twice maybe with a hot hair dryer lightly over the area, then seal up from the outside with fresh sealant. it's a patch up but that should sort it and this is what i am comfortable with doing, but as i say take some pics and post them if you can, some of the guys and myself here could tell you just by looking at it how far gone it is and what you need to prepare yourself for. in short, i wouldn't just blob the sealant on top of the cracked old sealant,

i would clean it up a bit, dry it out, rough it up, then put it on, it should take a lot better and only after you've dried it out thoroughly and vactanned, but i would pick that part of the seal out and apply fresh instead of on top, this is the best way, but going on the top of it is better than leaving it the way it is. again it's hard to say without seeing it.

Agree but would caution about use of wire wool. very good on the ebnch of extenrla surfaces, but in cavities and closed areas, really must be careful not to leave a masss of hidden broekn wire clippings form wool, they won't always vacuum out and nothing creates a better surface for rust initiation than a large irregular raw steel surface.. if its fully ecapsulated after rust paint/sealer/treatment then OK, but it's still better not to leave wire-wool fragemnts embedded in a tight seam joint, apart from anything else will hold the seam open.

A stainless steel wire brush, knife blade to pick out joint, or sand-blasting with inert medium would be best... wire wiool also doesn't always have quite enough 'bite' in hard-rust removal. A twist-knot brush on a 4.5" grinder on inside of seams will pretty soion show up any weknesses... if yiou are prepared to tog up for a good spattering and risk going through the seam if it's really rusted badly... >> but needs brazing welding back uip with fresh steel.

A couple of coats of Dinitrol RC900 really seems to blind off any incipient rust deep into crevices before painitng a day or two later...

[ghost123uk]

"watching" this topic (and you can guess why )

Waiting for some hot and dry weather before having a go at some signs of this on our bus.

[melmelody]

hi just about to start the seams on my caravelle and my westy joker, caravelle has slight bubbling and westy has hardly any problems other than its 30 years old and the previous owners have almost polished the paint off it.a long time ago i used to be a panel beater and sprayer and did lots of resto work and for me i' d go with 3m stripping pads. they are plastic coated wire pads that will rip paint and sealer out but don't remove large quantities of the metal panel like a grinder or dremmel does .you can get them to fit a drill or a 4 12 in. grinder so even if you only have basic tools like a household electric drill it should'nt be a problem.definitley reseal the joints(seams) as the sealer is flexible and will allow for vibration otherwise the paint will just crack and the h2o will flood back in there.hope this helps.oh and definitley use some sort of rust treatment too and if you can get to do the inside too then do it .it'll be worth the work one or two years down the line.

[ghost123uk]

i' d go with 3m stripping pads. they are plastic coated wire pads that will rip paint and sealer out but don't remove large quantities of the metal panel like a grinder or dremel does .you can get them to fit a drill or a 4 12 in. grinder

This sounds good but could you give a bit more info as to what they are and where you can get them ( a quick Google and search on Ebay didn't show me anything like what I imagine you are referring to - I just got info about pads for stripping floors )

[Nicola&Tony]

I think melmelody is referring to a stripping disc similar to these:
http://www.mig-welding.co.uk/shop/clean ... -115mm.htm" onclick="window.open(this.href);return false;

Tony