How should i treat and prevent further rust

[Oz Striker]

How to paint & prevent further rust, once treated?

Hi, guys i'm new to the forums I was actually meaning to join in order to find out what type of welder i should get, but joined today as i need some advice regarding rust prevention, as I recently found some rust on the underside of my car

Heres a link to rust that I've found on the underside of my car, near the right rear jacking point:

http://lifewithabmw.blogspot.com/2010/09/uh-oh-rust-in-chassis.html

Reading the above will explain what i've done so far, but to summarise:

1) Cleaned up rust with drill and wire brush, then dremel with smaller wire bursh
2) Applied Kurust, then Jenolite
3) Used Dremel some more with sanding tips this time
4) Painted over with Davids Zinc 182 primer

I stopped at step 4 cause its a temporary fix. This coming weekend I intend on removing this primer layer and going at it as best i can with my shot blaster, but after that I'm not sure in which order to apply different products??

A few pics from my blog, more and larger versions there.

So after shot blasting should i Re-apply the Zinc Primer, then apply "Clear Waxoyl" over this?
Is it ok to apply waxoyl over the primer, or would be best to apply Waxoyl direct to the metal, and not bother with the primer?
If the latter i think I would apply Hammerite Underbody Seal first, then Clear Waxoyl over that.

I like the idea of clear waxoyl so you can see what things are like underneath, but it would be harder to spot if it was starting to come away.

I'd rather go overboard and get as good a job done as possible, and i read this on some random forum:

1) Firstly POR 15
2) Then something like Davids Zinc 182 Primer
3) Then Dinitrol 3125
4) Then Clear Waxoyl

Ive read that Dinitrol 3125 is a 'lighter' wax and is probably more prone to abrasion or weathering over time which is why some people would cover it with something tougher like Waxoyl.

Any help and opinions would be much appreciated

 

[ger]

Do yourself a favour and get a 4 1/2" grinder and a big jaggy wire brush for it....

Will make for much quicker progress....(PS Also get some goggles or safety goggles as well. )

 

[Chipper]

Kurust/Jenolite isn't right? - Jenolite goes on bare metal to convert any rust left after wire-brushing with ^^ and doing porcupine impressions. Kurust also goes on bare metal.
Put Kurust on shelf, ignore it. The stuff seems pointless and caused reactions when I did use it so haven't touched it. Unless it's changed, that was like 15 yrs ago.

Definitely get the grinder out, Dremel must be so slow... Or a drill with those fine brassy wire brushes is also good.
Heat gun + scrapers first, if there's waxy glop on the undersides.

Prime, paint, cover with substances of choice. Not sure of the 182 stuff, keep reading of adhesion problems but not tried it.

 

[Oz Striker]

Do yourself a favour and get a 4 1/2" grinder and a big jaggy wire brush for it....

Will make for much quicker progress....(PS Also get some goggles or safety goggles as well. )

Haha i actually bought one of those wheels 2 weeks ago and was trying to figure out how to get it on to my drill, i thought there must be an adaptor!!

This is what i was using on the 240V drill, worked reasoanbly well, but hte wheel was just too big to get into the seams and crevices.

Definitely get the grinder out, Dremel must be so slow... Or a drill with those fine brassy wire brushes is also good.
Heat gun + scrapers first, if there's waxy glop on the undersides.

Prime, paint, cover with substances of choice. Not sure of the 182 stuff, keep reading of adhesion problems but not tried it.

Cool i'll stick witht he jenoilite, bought some of it in jelly/paste form as well.

The 240V mains dremel was actually incredibly good, first with minuture wire brush attachments and then with the sanding heads, could use it very precisely, without stripping off good underbody sealant.

Already ordered POR 15 and have emailed a retailer of Dinitrol (Rejel) and i queried about 3125's resistance to abrasion & weathering. He replied that if i wanted to go for a "belts & braces approach" i could apply a light coating of 3125 (to get into little seams) and then 4941, a tougher black under body seal on top of that.

So heres the layers I think I'm going to go with:

1) POR 15
2) A primer (perhaps Zinc 182)
3) Dinitrol 3125
4) Dinitrol 4941 or Waxoyl clear

My only concern is layer/step 2. Having seen pics and vids of POR 15, it seems to form a very hard and smooth ceramic type finish, and i wonder how well the primer adhere to it??

 

[MG David]

There is little value in trying to put a zinc primer on top of POR15.

POR15 is a good product if applied correctly. It needs a surface with alot of tooth or else it is in danger of peeling. Such a surface would be one that is freshly sandblasted although heavily pitted from where the rust was is a close substitute. In that case any unpitted areas would need to be heavily abraided, as you will always have some unpitted margin.

I have used POR 15 in the past but have moved away from it for the time being because of the peeling issues. Currently, I use Epoxy Mastic from www.rust.co.uk on the underside of my car. It seems to tolerate a variety of surface finishes. In 5 years time I will be able to tell you if it is better.

My method would be:-

1) Mechanically remove any rust and old paint.
2) Chemically treat the metal to remove any more, such as jenolite or other.
3) Epoxy Mastic
4) Waxoyl or Dinatrol etc

 

[steveo3002]

1) Mechanically remove any rust and old paint.
2) Chemically treat the metal to remove any more, such as jenolite or other.
3) Epoxy Mastic
4) Waxoyl or Dinatrol etc

agreed , if you hit it with a wire wheel in a grinder that will get it almost there , for step 2 consider bilt hamber deox gel ...it works at advertised given enough time

 

[Oz Striker]

Thanks for the advice regarding how to prep and best products. I've already ordered the POR 15, so i'll see how that goes. A question about POR 15...... Seeing as it drys to form such a hard impermeable layer, will i have to run neat white spirit through my gravity spray gun pronto after finishing spraying, or else risk clogging the gun up?

 

[steveo3002]

white spirit wont touch it , you want thinners /gun wash

id use the whole por system with the marine clean and metal prep as per the instructions , it peels off in sheets if the prep isnt 110% to the book

 

[Oz Striker]

white spirit wont touch it , you want thinners /gun wash

id use the whole por system with the marine clean and metal prep as per the instructions , it peels off in sheets if the prep isnt 110% to the book

Thanks for that i'll run paint thinner through. Yeh ordered the marine clean and metal ready as well. Just need to get myself 5 straight days when I dont need the car to get it done now.

 

[steveo3002]

wear a good mask too..it sticks to stuff like crazy , you wont want it in your lungs

 

[Cris B]

Another vote for POR15 it is great stuff, but you have to use it as a system and follow the instructions. Also if you are not sure about how to use it (some of the instructions are not that clear when you are combining things - phone up Frost and ask them, as they are very knowledgable about the product and its application to different situations.

 

[Weldinator]

Granville rust converter is very good, check this site out, http://browse.uk-plc.net/Companies/2012_Marine__-_Specialist_Tools__Products/products/Rust_Treatment.htm

I my self will only be using this stuff in areas such as inside the sills and other cavities that cant be reached. I will be using this stuff http://www.bilthamber.com/electrox.html its 90% zinc and is recommended for use on off-shore structures, harbour installations, jetty and pier pilings and extreme duty vehicle chassis work. Ill then put some of this in the cavities as well http://www.bilthamber.com/dynaxs50.html. All my other areas will be having the above primer, sealant, body colour stone chip.