Cleaning and painting the engine bilge

[Froggy]

Well, this job is overdue. We bought the boat in November with standing water in the engine bay, and although for some of this time it's been dry, with one application of Fertan applied, we now want to get the job over and done with. So, would i be correct in assuming that these are the requisite steps:

1. hoover out any loose debris

2. apply degreaser

3. remove degreaser with warm soapy water

4. liberally apply Fertan and allow to dry

5. hoover out any loose debris

6. one coat of primer

7. two coats of bilge paint with rust inhibitor additive

I've been advised to 'remove loose rust' by one boatyard. I'm reluctant to start chipping away at rust. Would i be doing the right thing to interpret this literally and just remove rust that is literally loose, i.e. flakes that have come away from the steel and can be brushed/hoovered out?

[mrsmelly]

Mine needs doing. To do it properly the first thing to do is remove the engine.

[rusty69]

9 minutes ago, Froggy said:

'ive been advised to 'remove loose rust' by one boatyard. I'm reluctant to start chipping away at rust. Would i be doing the right thing to interpret this literally and just remove rust that is literally loose, i.e. flakes that have come away from the steel and can be brushed/hoovered out?

That's what I was doing a few weeks back. I'm now Sat under a crane waiting for a surveyor 

[Froggy]

5 minutes ago, rusty69 said:

That's what I was doing a few weeks back. I'm now Sat under a crane waiting for a surveyor 

That's worrying - and you know that i already have more than enough worries!  ;-)

So what did you find? I'm aware that 1mm of rust is equivalent to only about a tenth of a mm of actual metal loss, but still don't want to weaken the structure unnecessarily by chipping away at partially rusted stuff. If the Fertan does what it claims it should prevent further rust advance in this anyway. I'm guessing you found some serious plate loss? Was it in your engine bilge?

19 minutes ago, mrsmelly said:

Mine needs doing. To do it properly the first thing to do is remove the engine.

There's no way i'll be doing that! I will use rollers or spray cans to get to the drip tray under our engine, and also our now redundant mud box.

[rusty69]

2 minutes ago, Froggy said:

That's worrying - and you know that i already have more than enough worries!  ;-)

So what did you find? I'm aware that 1mm of rust is equivalent to only about a tenth of a mm of actual metal loss, but still don't want to weaken the structure unnecessarily by chipping away at partially rusted stuff. If the Fertan does what it claims it should prevent further rust advance in this anyway. I'm guessing you found some serious plate loss? Was it in your engine bilge?

There's no way i'll be doing that! I will use rollers or spray cans to get to the drip tray under our engine, and also our now redundant mud box.

Yes, engine room, counter floor. I will find out after the surveyor has been. 

[Froggy]

1 minute ago, rusty69 said:

Yes, engine room, counter floor. I will find out after the surveyor has been. 

Please keep me posted. How old is your boat and did you have standing water on an unpainted surface like we have had?

[rusty69]

Just now, Froggy said:

Please keep me posted. How old is your boat and did you have standing water on an unpainted surface like we have had?

Early 80's.Dry most of the year, paint could have been better (obviously) 

[Froggy]

9 minutes ago, rusty69 said:

Early 80's.Dry most of the year, paint could have been better (obviously) 

That's a fair bit older than hours, which is 1997 build. Good luck with the results, if the formula 1mm of rust = .1mm of loss then hopefully you will have no serious issues. I've wondered (during my worrying moments ) how worthwhile the survey's ultrasonic measurments are, and how effectively they can differentiate sound metal from rust on the other side of the plate, i.e. the inside of the boat.....

 

Edited August 5, 2017 by Froggy

[rusty69]

2 minutes ago, Froggy said:

That's a fair bit older than hours, which is 1997 build. Good luck with the results, if the formula 1mm of rust = .1mm of loss then hopefully you will have nothing to serious issues. I've wondered (during my worrying moments ) how worthwhile the survey's ultrasonic measurments are, and how effectively they can differentiate sound metal from rust on the other side of the plate, i.e. the inside of the boat.....

 

They reckon boats rust from the inside out. Guess the good old hammer test will give us the answer though. 

[rusty69]

15 minutes ago, rusty69 said:

That's a fair bit older than hours, which is 1997 build

The difference between a 20 year old steel boat and a 40 year one is:-

A) The level of maintenance 

B) The thickness and quality of the steel

C) A regular survey 

D) none of the above 

E) Something else

F) 20 years

Don't phone in, it's just for fun. 

[Froggy]

20 minutes ago, rusty69 said:

The difference between a 20 year old steel boat and a 40 year one is:-

A) The level of maintenance 

The thickness and quality of the steel

C) A regular survey 

D) none of the above 

E) Something else

F) 20 years

Don't phone in, it's just for fun. 

Possibly F, dependent on A  

But i'd still be interested in somebody confirming whether the steps in my top post are the correct ones, because i want to get stuck into this job on Monday.

[David Mack]

 

[Dr Bob]

Froggy,

we have the same problem as you on our newly purchased 2002 nb. I was thinking of starting the same job this week but instead started on the rusty bits on the outside instead using Fertan. The instructions on the Fertan say wash off with water after 24 hrs and my experience is that that is needed to get rid of the black 'dust' that is formed from reaction of the fertan with the rust. Therefore I would insert this task in your list - but then you have to mop it out and dry it again before painting. I think I would also use a 'tolerant' primer - someone is bound to chip in with their recommendations. Given the amount of rust in ours, it must have been underwater for a lot of its life so a coating designed for water immersion would be best - so a 2 pack epoxy would be good - but again I am sure there will be some good recommendations given.

I have not had the experience with Fertan yet to say how much rust needs to be scraped off, but for best performance you should remove all loose stuff - ie any thing that comes off with a sharp scraper.

Ultrasonic thickness testing is usually quite accurate and your surveyor should have tested that area - but I seriously doubt a 20 year old boat with 10mm steel plate would have corroded through from the inside. Scrape it as best you can then treat it. That is what I will be doing.

[Froggy]

Many

5 minutes ago, Dr Bob said:

Froggy,

we have the same problem as you on our newly purchased 2002 nb. I was thinking of starting the same job this week but instead started on the rusty bits on the outside instead using Fertan. The instructions on the Fertan say wash off with water after 24 hrs and my experience is that that is needed to get rid of the black 'dust' that is formed from reaction of the fertan with the rust. Therefore I would insert this task in your list - but then you have to mop it out and dry it again before painting. I think I would also use a 'tolerant' primer - someone is bound to chip in with their recommendations. Given the amount of rust in ours, it must have been underwater for a lot of its life so a coating designed for water immersion would be best - so a 2 pack epoxy would be good - but again I am sure there will be some good recommendations given.

I have not had the experience with Fertan yet to say how much rust needs to be scraped off, but for best performance you should remove all loose stuff - ie any thing that comes off with a sharp scraper.

Ultrasonic thickness testing is usually quite accurate and your surveyor should have tested that area - but I seriously doubt a 20 year old boat with 10mm steel plate would have corroded through from the inside. Scrape it as best you can then treat it. That is what I will be doing.

Many thanks for your advice.

[WotEver]

Because of the requirement to wash off Fertan and the fact that 1) this introduces water into exactly the place you don't want it and 2) if you don't do a thorough job of washing it off the paint won't stick... I much prefer Vactan. 

Tony

[Neil2]

3 hours ago, mrsmelly said:

Mine needs doing. To do it properly the first thing to do is remove the engine.

Yep, can't see how you can do anything like a decent job without taking the engine out, this is how to do it https://canalworld.net/forums/index.php?/topic/92346-engine-ole-before-and-after/& I'd ask him how he went about it.  (Garage floor paint IIRC)

 

[Froggy]

1 hour ago, David Mack said:

 

Thanks, that was an interesting read.

43 minutes ago, WotEver said:

Because of the requirement to wash off Fertan and the fact that 1) this introduces water into exactly the place you don't want it and 2) if you don't do a thorough job of washing it off the paint won't stick... I much prefer Vactan. 

Tony

I wish i'd known this before i bought the Fertan!! How much is Vactan for a can?

EDIT: i've had a look at this product on what is presumably the official website, http://www.paco-systems.co.uk  Are you recommending this on the basis of personal experience, and are you saying that it doesn't create any dust and can therefore be painted straight over with primer? Is this product considered as effective at neutralising rust as Fertan, which is what i was recommended and sold by a reputable boatyard? The product doesn't seem to be available from either Amazon or eBay so i might have problems obtaining it, otherwise i'd seriously consider using it for this job.

 

Edited August 5, 2017 by Froggy

[Dylan]

2 hours ago, WotEver said:

Because of the requirement to wash off Fertan and the fact that 1) this introduces water into exactly the place you don't want it and 2) if you don't do a thorough job of washing it off the paint won't stick... I much prefer Vactan. 

Tony

Interesting. Is Vactan less messy?

[rusty69]

1 minute ago, Dylan said:

Interesting. Is Vactan less messy?

Its what the pope uses. He is always immaculate! 

[WotEver]

3 hours ago, Froggy said:

i've had a look at this product on what is presumably the official website, http://www.paco-systems.co.uk 

Vactan is made by Performance Chemicals:

http://performance-chemicals.net/vactan/

3 hours ago, Froggy said:

Are you recommending this on the basis of personal experience, and are you saying that it doesn't create any dust and can therefore be painted straight over with primer? 

Yes, yes, and yes. Although it is in itself a primer so only requires an undercoat and topcoat. 

3 hours ago, Froggy said:

Is this product considered as effective at neutralising rust as Fertan

In my (and many others) opinion, yes absolutely. 

3 hours ago, Froggy said:

The product doesn't seem to be available from either Amazon or eBay

I found it on eBay on my first Google:

http://m.ebay.co.uk/itm/VACTAN-RUST-CONVERTER-AND-PRIMER-250ml-RUST-TREATMENT-/110979877654

1 hour ago, Dylan said:

Interesting. Is Vactan less messy?

Absolutely. Prep the surface as you would for any rust converter, slap it on, wait for it to dry, overpaint. 

[Lily Rose]

I've bought Vactan from Paco and a year later from Ebay, the latter being considerably cheaper.

Brush it on, wait for it to cure (it goes black on rusty steel) then paint it. No need for primer as it forms it's own primed surface.

I want to do under my engine in white. I've got some white Danboline (which I've already used in the stern gland bilge) and also some white Hammerite ("apply directly to rusty steel"). I can't make up my mind which to use under the engine but given how difficult it is to access I'm swaying towards the Hammerite.

 

 

[rusty69]

6 minutes ago, MrBeethoven said:

I want to do under my engine in white. I've got some white Danboline (which I've already used in the stern gland bilge) and also some white Hammerite ("apply directly to rusty steel"). I can't make up my mind which to use under the engine but given how difficult it is to access I'm swaying towards the Hammerite.

 

I would think the Danboline is more oil resistant. 

[dmr]

20 minutes ago, MrBeethoven said:

I've bought Vactan from Paco and a year later from Ebay, the latter being considerably cheaper.

Brush it on, wait for it to cure (it goes black on rusty steel) then paint it. No need for primer as it forms it's own primed surface.

I want to do under my engine in white. I've got some white Danboline (which I've already used in the stern gland bilge) and also some white Hammerite ("apply directly to rusty steel"). I can't make up my mind which to use under the engine but given how difficult it is to access I'm swaying towards the Hammerite.

 

 

Hammerite is made for painting garden gates (badly). Danboline is made for painting bilges, its called bilge paint. Does that help the decision?

I have no experience of Vactan but used Red Owatrol as a primer when I did the stern gland bilge. I then overcoated with Rylards bilge paint which I suspect is similar to, but perhaps not quite as good as, Danboline. That was about 8 years ago and its just starting to fail now. Bilge is dry all summer and wet with condensation all winter.

................Dave

[Dr Bob]

8 minutes ago, dmr said:

Hammerite is made for painting garden gates (badly). Danboline is made for painting bilges, its called bilge paint. Does that help the decision?

I have no experience of Vactan but used Red Owatrol as a primer when I did the stern gland bilge. I then overcoated with Rylards bilge paint which I suspect is similar to, but perhaps not quite as good as, Danboline. That was about 8 years ago and its just starting to fail now. Bilge is dry all summer and wet with condensation all winter.

................Dave

The tech data sheet on Danboline says that it should be applied over a primed steel surface.

STEEL

Prime with Yacht Primer or Interprotect.

Not sure if it has any tolerance to rusty surfaces. You certainly need a surface tolerant paint as the steel surface will be be a lower temp than the ambient air temp so condensation could  put moisture on the surface as well as the rust.

Red Owatrol is a tolerant coating (red oxide) so will be similar to red lead paint which is perhaps the best coating ever made. Shame it is now banned.

 

[dmr]

15 minutes ago, Dr Bob said:

The tech data sheet on Danboline says that it should be applied over a primed steel surface.

STEEL

Prime with Yacht Primer or Interprotect.

Not sure if it has any tolerance to rusty surfaces. You certainly need a surface tolerant paint as the steel surface will be be a lower temp than the ambient air temp so condensation could  put moisture on the surface as well as the rust.

Red Owatrol is a tolerant coating (red oxide) so will be similar to red lead paint which is perhaps the best coating ever made. Shame it is now banned.

 

I believe that most, possibly all, red oxide primers are Zinc based so naturally grey in colour but are died red only to please us older users who can remember just how good real lead oxide primers were.

............Dave