Thread: Rust removal from roofing - wire brush and pressure wash, or skip the brushing?

Cheers Bob. Given that it is galvanised roofing it's just as well I didn't get the Phos.

I put another thread up to see if anyone has ever used Penetrol, but no bites, so I guess I'm the forum guinea pig on Penetrol.

I'll get back to yez in a few years and let yez know how it goes.

Originally Posted by Pete F

If it's that good, I guess nobody in areas dealing with rust would ever bother cutting out rust, and would instead slap on a coat of this stuff and call the job good to go

Originally Posted by chambezio

Brett,
My experience with mechanical wire brushing is that it takes off the loose stuff and puts a glaze over the rust. Good you say.....well that glaze is still active rust and will start up again under what paint you put on top.

Originally Posted by Toggy

I am very sceptical about the claims of the 'snake oil' salesman.

Originally Posted by Simplicity

Do you also believe in alchemy?
So Brett there's no easy way out.

Bah! All you nay-sayers. At last we have a user of Penetrol for stopping rust:
https://www.woodworkforums.com/showth...81#post1816981

Applied some 4-5 years ago, and still no-rusty. YEEHA! (mainly because I have completed the Penetrol prep).

For all you doubting Thomases see my reply here :

https://www.woodworkforums.com/f65/penetrol-stopping-existing-rust-189101

Frankly, I can't speak highly enough of it. I use it all the time (no, make that only when I'm painting ).

My only question was why did't they put it in oil based paint first up? I think the answer to that is that the paint goes off quicker. If you are using it as an additive to oil based paint, just make up a mix sufficient for that job. Also only buy enough to be used in a reasonable period of time. It does go off if exposed to air for a long period of time. How long? More than six months perhaps with say the tin half empty, but that is an approximation.

I would never bother with the "kill rust" "phosphoric acids" etc ever again. (Qualification to that is that, regrettably, it is not compatible with automotive paints.

Regards
Paul

PS: All the usual disclaimers, but if anybody wants to send me large sums of money in recognition of my endorsement I am very happy to supply bank details. Please PM me without delay .

I've had success with Penetrol as a rust preventer. About 5 years ago I purchased a Landcruiser that was previously used for beach recovery work ... hence it had a lot of rust in it.

I cut out all of the "bad" rust and replaced it with new steel, however there was a lot of minor surface rust in areas such as the inside of the bottom of the doors, etc. I thoroughly cleaned out these areas and applied a liberal coating of Penetrol. I also sprayed Penetrol (with an engine cleaning gun) into areas such as the inside of the sills and the chassis rails.

After all this time, no rust has developed in the areas that I treated and when I last had one of the door skins off, it looked the same as when I treated it all those years ago i.e. no progression of the rust.

A couple of points:
1. Only surface rust was treated i.e. not bad flaky rust.
2. The areas I treated are not exposed to UV.

Immmmmmmm lol

EEeeverybody is looking for a cheapand easy solution to rust.

There are heaps of products on the market that offer a low effort solution...because that is what people want to hear.

Fact is there is not one that is long term AND cheap AND easy in a 100% weather exposed situation.

start withe the pressure washer.....there are high pressure industral pressure washers that will take rust and anything else back to bright bare metal.

They are very commonly used in heavy industry and minning.....A mate's son is cerified to use one.......they will also cut the end off you boot toes and all.....they won't let you near one without the certification.
He is an indiustrial painter, he has used these monsters on a few oil rig and mine trips...they just take everything off heavy steel work..rust, paint, oil, marine growth anything not realy firmly attached.

In the roof restoration business they use "slightly less vigorous" pressure cleaners that remove the vast majority of rust leaving only the lightest residue....a residue light enough that the chemical agents in the paints that follow can deal with.

In general the paint supplier will specifiy the required output of the pressure cleaner.......that is if you want the 10 year paint manufacturer warranty.

There is a new generation of roof paints out there specifically designed to deal with this exact issue.......they may not be cheap...but the good ones are spactacularly effective.
Some of the latest ones are water borne, self primming, single pack epoxies.

They react with the surface....converting or stabilising any corrosion, etch to any bare metal and key very agressivly with just about anything.....then the set up very hard and bright..and seal out moisture.....being water borne, slight moisture in or on the surface is not an issue because it is reacted........singularly spactular products.

Some of them even have thermal barrier technology included......the latst thing is dichroic pigments......pigments that show their colour by reflecting light and heat out of the surface.....one supplier claims their black thermal barrier paint is as cool as conventional white.

I have not used any myself...but I have been on a few roofs that have been treated...very impressive.

Got a roof to do myself.....that is the way I will be going.

Receene have a new generation roof paint that is suposed to be $#!Thot.

One thing these products don't like is oil.

There are some other priducts that claim to stabilise all but flakey rust....some of the better ones suceed.....but they are not cheap or pleasant to use.

POR15 has been arround for a very long time, and they have products for sorting out corrosion in a number of situations..including inside fuel tanks.

as for the rest.
Well...some of them work modestly, but to be at all effective long term they depend on some sort of long term durable finish over them.

SO..do you want to fiddle with a stop gap solution or do a propper job.

Buy one of the current technology roof paints, hire a beefy pressure cleaner and it will probably be cheaper and easier..AND a better job.

cheers

Originally Posted by soundman

EEeeverybody is looking for a cheapand easy solution to rust.

There are heaps of products on the market that offer a low effort solution...because that is what people want to hear.

Fact is there is not one that is long term AND cheap AND easy in a 100% weather exposed situation.

start withe the pressure washer.....there are high pressure industral pressure washers that will take rust and anything else back to bright bare metal.

"SNIP"

SO..do you want to fiddle with a stop gap solution or do a propper job.

Buy one of the current technology roof paints, hire a beefy pressure cleaner and it will probably be cheaper and easier..AND a better job.

cheers

I like the sound of these roof coatings, but it is my experience that the worst rust is often underneath the joints. This is the case with my 60 year old roof. What happens here?

Dean

Well ya can't polish a ......

cheers

Originally Posted by soundman

Well ya can't polish a ......

cheers

Yes, well I find good advice hard to find these days.

Dean

well seriously...the practicalities or treating rust under the laps of a roof sheet simply are not there.

There are all sorts of pacth ups that people would have done in the past.....and that is what they where..patch ups.......but nobody bothers these days.

Most roof work these days is done in continuous sheets ridge to eave..either ordered to size or rolled on site.

Thus the problem with rust and leaks between the laps are solved.

cheers