Is "aesthetic" painting going to create a problem? 2

[DefenderJ]

The management of the refinery I work in want a lot of painting done by operators and fitters to improve the look of the place. This painting will not be done with proper surface preparation (cleaning/blasting) nor special paint systems. They will be brush painting a general purpose paint out of a tin over old paint with surface residues and rust. This is on structural steel, motors, guards, pipes etc.

My opinion is that this could cause accelerated corrosion particularly where active rust will get some level of coating over it and then may stay wetter for longer and may tend to generate aggressive corrosion cells. (We have plenty of rain here)

I would value your input on this. If my fears are correct I could do with some reference material to back me up (I have not been able to find anything, I suspect because doing something like this is a bad idea)

 

[dik]

It likely won't last. You should be talking to a good painting rep and find out what kind of coating is appropriate. It may require the use of a specialised primer to help with the adhesion.

 

[DefenderJ]

Dik, thanks for your reply.

I perhaps haven't explained myself that well.
It is a conscious decision not to follow our normal procedures on painting and understood that it won't last that long. It is intended to smarten the place up using the workforce that are not that busy due to production cuts.

I am concerned over longer term effects that may require costly rectification.

 

[KENAT]

If it's busy work, why not also busy them with at least doing some basic surface prep first?

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[btrueblood]

Probably the management knows that a potential buyer/investor is coming in for a visit, and wants to get some quick "bang for the buck". Which implies the OP is fighting a losing battle.

 

[rustbuster]

DefendeJ,

Monti Tools markets hand held (pnumatic & electric) surface prep tools. Web site is

http://www.monti-tools.com,

considering this myself for repair jobs.

Painting over oxidized, oily surfaces is a waste of time and money, I agree with your concerns.

Good luck

 

[brimmer]

I would say if you do this it will only cost you more in the long term... You would soon be blasting all this new paint off as well as it would not adhere for long. You are somewhat correct in assuming a new coat of paint can lead to problems, as it will trap the H20, O2, salts that are already in the corrosion cell in there and not let them diffuse out, or slow the rate of diffusion. On the other hand, you are better protecting the areas that do not have problems, or by not not allowing H20, O2 or salts to diffuse in the first place. Material will be a consideration as well. Try a search on under-paint corrosion and see what you come up with.

 

[KENAT]

btrue, I figured similar, but still, giving the surface a good rub with a wire brush or similar and maybe a quick sanding plus spot treatment of minor corrosion with some kind of inhibiter wouldn't take that much longer, would it? If it does then prioritize the visible areas to treat first.

But this is a bit off track, sorry.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[SJones]

Atmospheric corrosion rates tend not to be in the 'fearsome' category and the items being painted do not appear to be safety critical - I wouldn't lose sleep over it. The only downside of this scenario is if future management fail to recognise that this was an occupational exercise and want all painting to be performed this way.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[dik]

And if the operation was up for sale and this was considered as a cosmetic to hide latent flaws/corrosion, it could even end up in court!

 

[DefenderJ]

Thanks everyone for your input, it is helping me get things in perspective. Such is the benefit of using this forum I suppose

Rustbuster, thanks for the link to Monti MBX - looks very good - I want one!

SJones, good point about cororosion rates not being that high, but in our 25 years service we have had some nasty corrosion under failed coatings (e.g. ø67m tank roof has to be replaced due to poor painting). I suppose I should be concerned about stuff that will be painted badly and forgotten about. I think most of the painting intended will be highly visible.

Brimmer, thanks for your scientific input.

We are not expecting visits from purchasers. A refinery in our group has already done this and the feedback has encouraged the management to pursue it.

Overall I agree with all of you that say that some surface prep should be done. I think I will write a short note indicating the potential pitfalls and recommend that a work method involving surface preparation is drawn up and followed

 

[racookpe1978]

If I had extra hours available from a refinery operations crew, I'd use them inventorying valves and fittings for leaks and stopping the leaks that they can, isolating and doing PMS where they can, and getting set up for the next outage.