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Discussion Starter #1
Surface rust

what i started with (i had already put rust treatment on it as i was not going to deal with this part yet but as i thought i would make a guide it seemed like a good idea to start here)


the first thing to do is to remove as much of the lose rust as you can be it with a flap wheel on a drill or grinder or by hand with some 40 grit or 80 grit paper. once that is done you should end up with something along the lines of this

the bit inside the red mark is the section i had been working on and the bit out side is the bit that still needed more work

once you have removed as much of rust as you can its now time to put on your rust treatment. here i used kurust but another good rust treatment is wurth's rust killer but i have only seen this online on places like ebay or in car bodyshop supplies

with the rust treatment on (kurust turns from a milk colour to a purple/black when it comes into contact with rust so you can see its working. wurth's version of rust killer is just purple/black to start with.


with the rust treatment dry and done its job the next stage is to apply a some fibreglass in the shape of p45 if there is any small holes that have gone throw the metal. its better to use P45 or a like because once its gone off it wont suck up any water where as the bodyfiller will if its not sealed on both sides with paint or stone chip etc. if you dont have little holes or deep marks in the metal surface then just go straight on with a skim filler. no matter if you need to use a skin of filler or a little fibreglass you need to make sure that the rust treatment is 100% dry before you apply any fibreglass or filler because if the rust treatment is still wet it could stop the fibreglass or filler from sticking to surface and leading it to be pulled out when flatting back or worse still falling out at a later date.

the next stage is to flat the filler back to remove any filler thats unwanted for this i would use 80grit paper to get it almost there and then the next stage is to use some 320 grit paper to take the filler the rest of the way down which will also remove the marks left by the 80 grit sandpaper and also with the 320 grit paper you want to feather the edge of the paintwork out so that its smooth where it meets the metal around the area you have had been working on.

the next stage is to mask up around the area you have just repaired in orde to stop the over spray from going on the rest of the paint work. along the edge where the new and old paint work will meet its well worth masking it with soft egde masking tape but this can be expensive so if you dont want to shell out the money for it ill let you into a secret at the end which will save you some money.

once you masked up its time to clean the surface with some alcohol or pannel wipes to remove any dirt from the surface to be painted. with the surface clean you now want to apply 2 or 3 layers of acid etch primer to the repair area before leaving it to dry and applying a few coats of normal primer although you dont have to use normal primer over the acid etch i like to use it on areas that have rust treated or dents taken out as this gives another few layers to help hide and wobbles or anything that maybe left.

with the primers on and dry you want to apply some guide coat to the surface to help with flatting back the primer. for the guide coat you can use normal black spray paint and mist it on or you can buy guide coats in powder or spray but i find the black spray paint works just as well and is cheaper to buy. you want to flat back with 800 grit paper if your going to be using a pearl colour or anything from 500 grit to 800grit if your using a solid colour.

the next stage is to remask the area a little high up than last time and then clean the surface with your wipes and apply your colour and once that is dry apply your lacquer.

soft edge masking tape secret

soft edge masking tape is a tube shape foam tape that helps stop the build up of paint. because the shape of the edge on standard masking tape you tend to get a build up of paint there which gives you a lip where the new paint meets the old paint but because the soft edge masking tape has a rounded edge on it it helps to feather that edge out so your left with less of a lip if any at all. but to save buying this tape as its not always that cheap depending on where you go you can take some stand masking tape and fold it/roll it up down the length of the tape and this gives you a softer edge than the standard masking tape has. photo below so you get the idea (it was brown tape instead of masking tape as i was to lazy to go and get the masking tape)

 

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cheers for that ive got a few tiny spots i need to nip in the bud so this should prove useful. It should prove even more useful when I get round too my MK2 golf!!
 

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that roll up the tape is genius. i'm not that good with paint and those bloody lip lines you get with tape really winds me up.

Thanks
 

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Discussion Starter #5
lol it dose help alot and when you think a roll of soft edge masking tape is around £25 a box of 50 meters its not realy that cheap but dose save time if you have a lot of soft edge masking to do other than that its just as good to use the rolled up tape.

your welcome
 

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Excellent advice, thanks!! A:
We're beginners when it comes to rust but this has ensured me in what we're doing!
I'll post some pictures of the before and after if ok?
When it comes to body filler, what product would you recommend?

Thanks! T:
 

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Discussion Starter #7
your welcome Amber
you have to start some where with everything you try
yer would be good to see the outcome and to see that the thread has help a few people
most of the u-pol stuff is very good and also david's P38 is ok. as there is not going to be a dent as such i would use u-pol smooth 7 if you can get it (i know halfords did have it but not sure if they still do) if not P38 is the next best thing as the filler is fine and will give a better finish with less pin holes and marks but if you have places where it has gone all the way throw the metal you will need to use glass first. you can also thin the bodyfiller down with standard cellulose thinners to stop it from dragging and this also helps it to self level and it becomes a bit more like a sprayable filler
 

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This is a very useful guide that you have provided for us. Are there any other brands of rust treatment that you have used with good results?
 

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Discussion Starter #9
i used some acid from the local bodyshop which to start with i was a little worried about as it was a apply and leave for 10 mins and wash off with water, towel dry and repeat till the acid runs clear. i must say it was very good stuff but it did take 2 whole weeks to get a old beetle done. dont remember what it was called tho but ill try and find out.

i would say that most rust killers work pretty well if the prep is done good. at the moment they are all i have used as thats all the bodyshops supplies people have
 

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we just use brick cleaner (hydrochloric acid)
problem we have is behind the arches, the thick underseal has peeled at the edges & so actually holds moisture, reckon that & the sharp exposed edge is why so many have problems on the arches. hellish difficult access to cut back to where it's still bonded as it's tough stuff.
 

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Discussion Starter #12
thats why i always tell people not to use underseal and to use stone chip instead. because stone chips easier to get off and when it starts to let go it just flaks off most of the time so it dose not hold the water so much and you can sandblast stone chip off a lot easier than underseal.
 

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this stuff is like a hard thickish putty (on the sills too), assumed it was put on by VW - maybe not?
was looking at a T5 y'day, note the i/s of the arches don't level off & are turned over to avoid the sharp edge - looks like they learned (late)
 

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Excellent guide! A:

I will be following this to the letter! I'm and electrician, I have to when it comes to this sort of stuff!!;)
 

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Great guide. thanks!
I am planning on tackling all 4 arches and sills, it's been touched up by someone before me but not a great job so good to know what prep etc to get good result.
cheers T:
 

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Big Thanks for this how too T:

learnt lots am nearly ready to embark on sills and arches, have left it a bit longer than i should of I:

Thanks again
 

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Frost sell some awesome rust stuff. Anything in the POR15 range is fantastic.

The acid stuff is great for killing off rust.

Not so sure about the skimming over rust killer with fibreglass....I use the rust converter/killer until the metal is clean. Just keep re applying it until its conpletely gone. Fillers only stick to bare metal.
 

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I have started attacking the rust on my passenger side sill and front arch today. I have found two holes :( one is under the sill and was around 1"x 1/2" so I chopped the rot out and patched it up. The other hole is on top of the sill on the middle of the doorway. It has a small hole but I dont really want to weld a patch here as I think it will show up and possibly look a pig. In this thread someone mentions P45, is this a fibreglass filler or fibreglass matting and resin? Im thinking if it is a fibreglass filler then I can use rust remedy, then the non porus? fibreglass filler, then bodyfiller then acid etch primer, high build primer, colour, then laquer?
 
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