Micro-blistering

[Phil Speight]

The boat being the cathode could it start evolving water at the cathodic interface? If so, where are the protons coming from? Is there an acidic element that could contribute protons to the arrangement; the oxygen's freely available after all.

 

It's fair to say that an increase in CO2 concentration leads to an increase in pH... FTS that an increase in Boron concentration is a natural result and hey presto, you've invented cold fusion but it's a thought. (Sorry but having come up with it I'm leaving it )

 

Seriously though an increasingly acidic element in the atmosphere and any hydroxyl groups lurking in the solvents would be a consideration for what's left of the chemistry component of my education.

 

Plus, colder temps mean more dissolved gases and a greater ionic reaction potential therein. (?)

Thank you - but still completely over my head I`m afraid !

I have been at the factory in Manchester all today with the white coated chaps and , once I have gathered my thoughts I have something to add on the whole blistering issue.

Phil

[Phil Speight]

I`m going to quote here from a document produced by the British Coatings Federation ( of which we are not members incidentally ) . It is clearly based on the automotive side of things but the message is common to all paint application industries. I am implying no direct criticism of the numerous painter/boatbuilders who do their utmost to control the conditions in which they work. It is , and always has been the case , that if you paint things for a living you are going to get bitten on

the bum occasionally. I have told many new painters this in the past when they have asked me for advice. The following takes some account of the "ice-barrier" theory affecting boats now the snow has gone - and paint chemists at at least two major factories take that very seriously.

 

" One of the complaints levelled at all paint manufacturers concerns moisture blistering, which is probably one of the hardest problems to explain to the repairer on the bodyshop floor. With inclement weather conditions , there are bound to be some cars developing micro-blistering which is , more often than not , blamed on the paint used. The bodyshop rarely realizes that the blistering is due either to application, conditions in which the vehicle is sprayed, preparation or, indeed , the weather itself.

 

The cause of micro-blistering is the saturation of the film by exceptional levels of atmospheric humidity , together with the presence of water soluble materials , either absorbed into the film or present on the surface before painting. The blisters are formed when the moisture eventually escapes from the film as humidity decreases and temperature increases. The pressures formed in the film are enormous and often sufficient to deform the film into blisters. Where very low temperatures are involved moisture freezes in the film and this leads to weakness in adhesion, which makes the subsequent blistering much more likely."

 

The paper goes on to the deal with solvent entrapment - but that is not what we are concerned with here.

 

Consider the conditions usually found in a car repair body shop - if they have problems how can canal painters be anything but worse off in that regard, however good their facilities and however diligent they may be.

Edited February 16, 2010 by Phil Speight

[system 4-50]

Could rapid fluctuations in barometric pressure during the paint curing process be a contributing factor to the formation of a paint surface that was then more disposed to water damage? (Ignorant but curious.)

[Ally]

Whilst that all makes sense Phil, what still doesn't quite make sense is why the sudden outbreak in recent months?, when, as far as i am aware, there has been very little example of this problem in the past, even during other cold winters.

[David Schweizer]

Whilst that all makes sense Phil, what still doesn't quite make sense is why the sudden outbreak in recent months?, when, as far as i am aware, there has been very little example of this problem in the past, even during other cold winters.

It has been going on for several years, I have repainted part of my roof twice in the past thre years and both coats developed microblisters. In an earlier thread it had been suggested (by Phil I believe) that higher levels of humidity in the atmosphere may be a conributory factor.

[andywatson]

Could rapid fluctuations in barometric pressure during the paint curing process be a contributing factor to the formation of a paint surface that was then more disposed to water damage? (Ignorant but curious.)

 

That is a sound question.

 

Air will carry less moisture at lower pressure. The formation of a cloud water droplets when the pressure is suddenly reduced can actually be seen to spectacular effect around fighter aircraft executing hard turns where a cloud forms above the wing and trails off at the tips.

 

However IMO normal barometric fluctuations, as likely to be seen in a paint shop, are much less likely to cause this problem than temperature and natural moisture variations.

Edited February 16, 2010 by andywatson

[Phil Speight]

Whilst that all makes sense Phil, what still doesn't quite make sense is why the sudden outbreak in recent months?, when, as far as i am aware, there has been very little example of this problem in the past, even during other cold winters.

I`m only presenting evidence as I come upon it Ally. However , general opinion is that this winter has been different from any other in the recent past in that the snow, once it arrived , was followed

by temperatures consistently below freezing ( well below a lot of the time ) intersperced with more and more snow. In some areas we were not without snow sitting on ice for upwards of five weeks. That is, in my memory at least , very unusual. It is certainly enough for both temperature and lack of air movement beneath the snow to cause micro-blistering.As the BCF say - very low temperatures increase the danger. It also , in some cases , makes the painter absolutely blameless.

Making customers accept that point is the really difficult part.

[Grace and Favour]

I`m only presenting evidence as I come upon it Ally. However , general opinion is that this winter has been different from any other in the recent past in that the snow, once it arrived , was followed

by temperatures consistently below freezing ( well below a lot of the time ) intersperced with more and more snow. In some areas we were not without snow sitting on ice for upwards of five weeks. That is, in my memory at least , very unusual. It is certainly enough for both temperature and lack of air movement beneath the snow to cause micro-blistering.As the BCF say - very low temperatures increase the danger. It also , in some cases , makes the painter absolutely blameless.

Making customers accept that point is the really difficult part.

 

Which suggests that it may be a reasonable precaution to remove snow lying on the boats, whilst it will do nothing to improve the ambient temperature, it may go some way to reduce the risk of microblisters?

[system 4-50]

That is a sensible question.

 

Air will carry less moisture at lower pressure. The formation of a cloud water droplets when the pressure is suddenly reduced can actually be seen to spectacular effect around fighter aircraft executing hard turns where

a cloud forms above the wing and trails off at the tips.

 

 

However IMO normal barometric fluctuations of pressure, as likely to be seen in a paint shop, are much less likely to cause this problem than temperature and natural moisture variations.

 

I was thinking more in terms of a fall in external air pressure leading to a microscopic "boiling off" of still-liquid volatile organic components of the paint, after the skinning process (if there is one) had begun, leading to microscopic "perforations". This then allowing later water damage.

 

But then I always did have a good imagination...

[Phil Speight]

Which suggests that it may be a reasonable precaution to remove snow lying on the boats, whilst it will do nothing to improve the ambient temperature, it may go some way to reduce the risk of microblisters?

It would certainly help with paintwork in general if so many boat owners didn`t just leave their boats untended for extensive periods and then expect them to be perfect on their return. They`ll clean snow off a car they aren`t necessarily using but ignore the boat.

 

I was thinking more in terms of a fall in external air pressure leading to a microscopic "boiling off" of still-liquid volatile organic components of the paint, after the skinning process (if there is one) had begun, leading to microscopic "perforations". This then allowing later water damage.

 

But then I always did have a good imagination...

Synthetic alkyd enamels are touch dry in about 1.5 hours , hard dry in around 16 and fully cured after 4 or 5 weeks. We are seeing blistering suddenly appearing on boats that have been painted for up to 18 months. Remember as well that there are countless more boats without blisters than with them! Clever idea though -you obviously know more about physics than I ever did !

[andywatson]

I was thinking more in terms of a fall in external air pressure leading to a microscopic "boiling off" of still-liquid volatile organic components of the paint, after the skinning process (if there is one) had begun, leading to microscopic "perforations". This then allowing later water damage.

 

But then I always did have a good imagination...

 

One for a paint chemist/expert there.

-Although it look like they are also flumoxed.

 

Surely though, any trapped solvent would escape through or "micro dissolve" an area of young and uncured skin...?

[Phil Speight]

One for a paint chemist/expert there.

-Although it look like they are also flumoxed.

 

Surely though, any trapped solvent would escape through or "micro dissolve" an area of young and uncured skin...?

 

The chemists aren`t flumoxed in the least. They know the causes of micro-blistering and have found no evidence that we are seeking a new explanation now - despite major effort. The difficulty is demonstrating to the world at large is that it happens, is caused, or provokedby,solvent or moisture entrapment, and in a number of well documented ways. We`re dealing with moisture entrapment exclusively in all the cases we are studying. I`ve been very political so far and haven`t tried to point the finger anywhere - I am determined however to show , one way or another, that it isn`t a paint manufacturing fault while at the same time trying to be helpful to those who are the victims of it , whether they are boat owners, painters or a considerable number of paint makers.

The mystery has been why there has been an increased incidence of the problem recently. We are satisfied at our end that the pattern of snow ,ice and temperature accounts for some of them. If I could get a comprehensive list of all the boats affected ( irrespective of the paint used ) and when the blisters first appeared, I could then subtract the ones that suffered during this particular winter from the overall total. This would then tell me whether what remains is an average number or a marked increase. This would need a degree of honest co-operation from all sides - and since not everyone wants to accept the possibility of fault ( including the boat owners themselves ) I`m not having much luck. The paint doesn`t go out with water in it , the topcoats are not remotely porous in anything but extreme conditions - and then only slightly so, like when they are kept virtualy UNDER water - and any painter worth his salt knows that primers should not be exposed to damp in any form. See again the quote I posted this morning from BCF.

I was told by a well respected sales manager from a major competitor recently that he would normally expect to see perhaps one case a month. It`s a pity I can`t publish every conversation I`ve had - but ethics and confidentiality preclude this.

 

I must point out again that we ourselves have three cases to deal with. We haven`t complained to HMG ( although we did ask that the formulations be checked against the original specs.) because we know, as boat painters , that some day this problem will cause you griefand cost you money. It goes with the territory I`m afraid. Why so many now ? That`s the question. I want to help everybody concerned where I can - but it would easier if people would accept that it ain`t the paint - ours or anyone elses. Then we could have sensible conversations about the actual potential causes

and do something to alleviate the difficulties. Ally - you`re a gem. So`s Andy Russell. They know why.

Edited February 16, 2010 by Phil Speight

[Grace and Favour]

 

Phil - you're clearly lost for words . . . . .

[WotEver]

Phil - you're clearly lost for words . . . . .

After reading phrases like " microscopic "boiling off" of still-liquid volatile organic components " so am I

 

I'm enjoying watching this thread. Even though I know next to nothing about the subject, I'm finding it fascinating.

 

Tony

[andywatson]

The chemists aren`t flumoxed in the least. They know the causes of micro-blistering and have found no evidence that we are seeking a new explanation now - despite major effort. The difficulty is demonstrating to the world at large is that it happens, is caused, or provokedby,solvent or moisture entrapment, and in a number of well documented ways. We`re dealing with moisture entrapment exclusively in all the cases we are studying. I`ve been very political so far and haven`t tried to point the finger anywhere - I am determined however to show , one way or another, that it isn`t a paint manufacturing fault while at the same time trying to be helpful to those who are the victims of it , whether they are boat owners, painters or a considerable number of paint makers.

The mystery has been why there has been an increased incidence of the problem recently. We are satisfied at our end that the pattern of snow ,ice and temperature accounts for some of them. If I could get a comprehensive list of all the boats affected ( irrespective of the paint used ) and when the blisters first appeared, I could then subtract the ones that suffered during this particular winter from the overall total. This would then tell me whether what remains is an average number or a marked increase. This would need a degree of honest co-operation from all sides - and since not everyone wants to accept the possibility of fault ( including the boat owners themselves ) I`m not having much luck. The paint doesn`t go out with water in it , the topcoats are not remotely porous in anything but extreme conditions - and then only slightly so, like when they are kept virtualy UNDER water - and any painter worth his salt knows that primers should not be exposed to damp in any form. See again the quote I posted this morning from BCF.

I was told by a well respected sales manager from a major competitor recently that he would normally expect to see perhaps one case a month. It`s a pity I can`t publish every conversation I`ve had - but ethics and confidentiality preclude this.

 

I must point out again that we ourselves have three cases to deal with. We haven`t complained to HMG ( although we did ask that the formulations be checked against the original specs.) because we know, as boat painters , that some day this problem will cause you griefand cost you money. It goes with the territory I`m afraid. Why so many now ? That`s the question. I want to help everybody concerned where I can - but it would easier if people would accept that it ain`t the paint - ours or anyone elses. Then we could have sensible conversations about the actual potential causes

and do something to alleviate the difficulties. Ally - you`re a gem. So`s Andy Russell. They know why.

 

Well there's one good thing to come out of this.

No one can accuse you of doing a "Toyota"....... (cover up)

 

EDIT

I have just spoken to Phil and accept his assurances that the paint is sound and that the cold weather and temperature fluctuations are at the root of this problem.

Edited February 16, 2010 by andywatson

[Smelly]

Is there a lab that could knock up a test? Maybe a Paint Manufacturer's Association that could fund someone's PHd to find out?

[Phil Speight]

I`m dropping out of this for a while now - there is currently no more I can say. However - let us all bare in mind that in all my recent research I personally have discovered only around 25 boats , using a variety and even a mixture of paints,out of the hundreds that will have been painted in the past 18 months that have any sort of problem at all. Our own average , of 4 in 30 years , suggests that 25 is a lot - but I have never before had to consider cases that have nothing to do with us at all.

[Ally]

I believe the BMF are now involved with this issue, and are getting a chemist to look at the various theories....again, he feels it may well go down to the porous primer and moisture retention....or 'hydroscopic osmosis' as he put it....I am no chemist!!!!!

He does suggest doing something to aid future problems being analized, which may be helpful to painters.....

Using a 12" square piece of glass, which is inert, to paint the whole scheme of the boat on to this, as the boat is being painted, and in the same timing and conditions. Apparently super yaucht painters do this as a 'guarantee panel', and may be a helpful suggestion, that way, the application and paint can be ruled out of the issue in future.

They are hopefully going to be arranging a seminar day aswell for painters/builders to attend and air the problems and concerns with other professionals.

I would just like to add that this problem is affecting many major paint companies, NOT just Phil's....it has been noted before, but some don't seem to want to take that on board.

Also, if it is down to the weather conditions, there is the pointer that the boat owners do need to be ensuring wherever possible, that they are taking all precautions to keep their boats as free as possible of snow and ice.....not always easy I know!

That sets me to wondering about the best way to clear it......with modern insulations, the internal heat won't necessarily melt it even for liveaboards, and clearly we don't want to be scraping.....especially with 'young' paint, or using any chemicals......suggestions?

Obviously with fresh powdery snow, it can be gently brushed off, but ice?

[David Schweizer]

I believe the BMF are now involved with this issue, and are getting a chemist to look at the various theories....again, he feels it may well go down to the porous primer and moisture retention....or 'hydroscopic osmosis' as he put it....I am no chemist!!!!!

He does suggest doing something to aid future problems being analized, which may be helpful to painters.....

Using a 12" square piece of glass, which is inert, to paint the whole scheme of the boat on to this, as the boat is being painted, and in the same timing and conditions. Apparently super yaucht painters do this as a 'guarantee panel', and may be a helpful suggestion, that way, the application and paint can be ruled out of the issue in future.

They are hopefully going to be arranging a seminar day aswell for painters/builders to attend and air the problems and concerns with other professionals.

I would just like to add that this problem is affecting many major paint companies, NOT just Phil's....it has been noted before, but some don't seem to want to take that on board.

Also, if it is down to the weather conditions, there is the pointer that the boat owners do need to be ensuring wherever possible, that they are taking all precautions to keep their boats as free as possible of snow and ice.....not always easy I know!

That sets me to wondering about the best way to clear it......with modern insulations, the internal heat won't necessarily melt it even for liveaboards, and clearly we don't want to be scraping.....especially with 'young' paint, or using any chemicals......suggestions?

Obviously with fresh powdery snow, it can be gently brushed off, but ice?

It has always concerned me that some boats sit in the shade all winter with ice on the roof for weeks on end. I have always made sure that any permanent mooring we have used gets the sun for most of the day. That usually ensures that the frost is quickly melted and the roof often dry by the afternoon. Of course this only happens when the cloud clears, but as heavy frost usually occurs when there are clear skies, it works for most of the time.

 

Having said that, I have had two repaints on the roof of our boat develop micro blisters, but I think that has probably been caused by inapropriate preparation and moisture retention in the primer, rather than snow or ice as it was first noticed in the summer.

[Ally]

It has always concerned me that some boats sit in the shade all winter with ice on the roof for weeks on end. I have always made sure that any permanent mooring we have used gets the sun for most of the day. That usually ensures that the frost is quickly melted and the roof often dry by the afternoon. Of course this only happens when the cloud clears, but as heavy frost usually occurs when there are clear skies, it works for most of the time.

 

Having said that, I have had two repaints on the roof of our boat develop micro blisters, but I think that has probably been caused by inapropriate preparation and moisture retention in the primer, rather than snow or ice as it was first noticed in the summer.

That is probably correct in your case, but if snow/ice is effectively holding the boat 'underwater', thus helping the problem along......normally natural melting does the job, but this winter saw extremes where sun did no melting for days on end, wherever the boats were positioned.

 

Hmmmmmmmmm........

 

As a side line, i painted my tug deck last autumn, with no zinc primer, just primer/undercoats, then deck paint....it had snow on it over the christmas week as we were away....and that was when we were experiencing -10 and the like, yet I have no blisters on it.......yet!

[jenlyn]

i have sray painted cars for many years, i have dealt with micro blisters many times, i have had them mainly where filler is used, and moisture has set into the filler. if i have let moisture get to the primer, i have also had micro blisters. you can even have moisture come from the gun due to condensation if you are spraying below a certain temperature. no remedy for them, other than perfect oven like surrounding which can give you perfect conditions for spraying.

[magnetman]

As this is something which effects new boats is it perhaps to do with the type of insulation used and the quality, thickness and surface finish of the bare steel?

 

(Thinking its not the paint but that which the paint is asked to adhere to)

[Ally]

As this is something which effects new boats is it perhaps to do with the type of insulation used and the quality, thickness and surface finish of the bare steel?

 

(Thinking its not the paint but that which the paint is asked to adhere to)

It is also effecting older boats with new paint jobs though!

[magnetman]

snip>>>>>>>>>>

I should have made clear that the problem we are chasing seems only to afflict new-builds, boats that have stood in primer and repaints done from bare metal and the boats that do have a problem are an insignificant number compared with those that don`t -

<<<<<<<<<<<<<<

 

:

 

Sorry, I've just jumped in this topic without reading it that thoroughly and I realise I probably misunderstood this comment from early in the thread...

Edited February 17, 2010 by magnetman

[WotEver]

I just stumbled across this article which I found interesting. It's not about paint micro-blistering as such, and not even about steel boats, but there were a couple of interesting points made.

 

Apart from debunking the myth that fibreglass boats suffer from "osmosis" the author also makes the point that a fibreglass boat, once having been in the water, can probably never be completely dried out. He surmises that the moisture is so deep within the material "at a molecular level" that it can't be removed.

 

So.... with the colder yet more humid climate we've experienced recently I was pondering over the possibility of water entering the primer coat 'at a molecular level' (whatever that means) and remaining there even when heat lamps have been used, only to want to escape eventually at some future time, thereby creating the micro-blisters. Or could it (moisture) possibly be 'in the steel'?

 

I'm not a chemist, I don't truly understand what the writer means by 'at a molecular level' and I might be talking complete b*ll*x, but the similarities between fibreglass blistering and paint blisters got me wondering.

 

I'll go away and shut up now.

 

Tony