Help - Paint Blistering

[mvgeorgia]

Hi all,

I have been watching here for a while, but this is my first post.

We (hubby and I) are in the middle of a restoration of a 86 CHB trawler.

My question is about paint. We recently finished painting all the topsides using Brightside white paint - all instructions were followed to the letter and the paint looked amazing. Some items were painted on the boat, some were painted in our shop.

Fast forward to a week of rain in the PNW - now the white paint is COVERED in tiny blisters. ALL surfaces that were touched by rain have been affected. Areas not touched by rain are fine.

We have reached out to Interlux and they have been helpful, but my question is has this happened to anyone else?

Side note: We also used Brightside blue to paint he hull and it has not done this, in fact it looks great (prep was the same in both case)

Pic one is the blistering - pic 2 is the boat

 

[RT Firefly]

Greetings,
Bubbly welcome aboard.


Edit: Nice boat. Is the blistering primarily on horizontal surfaces?

 

[Portage_Bay]

(trying to figure out how to upload pics lol)

See this post How to post pictures

 

[mvgeorgia]

Thank you!

 

[psneeld]

That paint usually does that when covered by somethng that keeps it wet like a rug, but continuous rain for a week may do the same. Especially true if anything went wrong with the prep or painting phase.

 

[PierreR]

Some questions. I will take your prep at face value.
Did you thin the paint? If so with what and how much?
How long after application was the humidity high or exposed to wet conditions?
What was the temperature at application and how long after application did the temperatures drop?
Did you apply in direct sunlight?

 

[mvgeorgia]

None of the areas were covered - many of the surfaces are vertical surfaces so the water would run off.

 

[mvgeorgia]

Fair.
Paint was thinned as per instructions and all of the parameters were within the limits indicated by Interlux. Hubby is pretty particular, so we followed instructions to the letter. The boat was in a covered structure for painting.
There are three items (hatches and a propane locker that were painted inside a closed shop. ALL areas where rain water has touched the paint are doing this. Areas that are covered ie ceiling, inside boxes etc are fine - no blistering
I will be clear - Interlux is helping us with this, I am just curious if this has happened to others.

 

[mvgeorgia]

Greetings,
Bubbly welcome aboard.


Edit: Nice boat. Is the blistering primarily on horizontal surfaces?

Thanks, we do love her lol - most of the time
The blistering is on both vertical and horizontal surfaces - only where the rain has touched the paint

 

[sean9c]

Moisture in the substrate.

 

[PierreR]

I will take a crack at it.
Others probably have experienced what you are having. I believe it is just inherent in the type of paint that you selected for the job. I doubt the paint was formulated well outside the parameter and I will take it at face value that you believe that you did everything right.
I believe that Brightsides is a one part Alkyd Poly-Urethane aliphatic solvent based paint. Not cheap but not expensive either. As such it will have leveling and coalescing agents added. Namely either based solvents in small amounts. Eithers are much slower evaporating solvents than water and are hdyroscopic.
Your conditions might have been within parameters for temperature, humidity and non wet conditions but in the PNW these conditions can all be present at the limits of painting conditions and is the perfect storms so to speak for problems. With temperatures on the lower end of the scale (below 70 deg F) and humidity high (above 70%) and rain within three to five days of painting this can happen.
My suggestion is not something that Interlux will tell you because it violates warranty and information standards but I will tell you. You can crosslink Alkyd Poly-Urethanes with Poly Isocyanate to get a hybrid two part paint with better drying and hardness characteristics. Especially in marginal conditions.
Cheapest easiest buy is to go to Tractor Supply and but the Magic Enamel Hardener and follow the directions for their paints.
In the long run you may not be satisfied with this type of paint. Brightsides is a good product be limited. Blue is the most expensive colorant and the hardest colorant to stabilize against sunlight. It will likely start to chalk a bit within a year. Clear coating will prevent it but the best clear coats are aromatic based and will blister the Brightsides without some crosslinking. Wax after a couple of months drying might help a lot with chalking

 

[mvgeorgia]

Pierre, thanks for your comments and the time to write this. I will go over this info.

 

[psneeld]

Moisture in the substrate.

My next best guess....

 

[Choices]

I think this is gas popping.

Did you use a primer then sealer?

One of those was not dry when final coat was sprayed.

It was still off gasing when final coat was added, causing gas pockets. Temperature can also cause it. Boat getting hot as spraying also off gases.

You could sand it and spray another coat with no problem.

 

[psneeld]

Check this out. Brightside on a van, a few years back in the PNW "atmospheric river". Just don't pat too much attention to a lot of the replies. Stick with what a few say and what you research and get from Interlux.

https://www.thesamba.com/vw/forum/viewtopic.php?p=9740318&sid=b423f50c6679c45c70e8fedefa9a1092

 

[Bmarler]

Looks like solvent pop to me as well. Rain on uncured paint may look like that too. The water drops can displace the paint and then evaporate, leaving the crater.
Solvent pop is trapped gasses making bubbles under the surface that eventually pop and leave a crater.
To the OP, when someone asks for particular information, it’s not really helpful to just say that it was all within interluxes parameters. Obviously something went wrong and most likely it was an application error as this paint system is pretty simple. Not trying to slam the interlux reps, but they seldom know more than the customer does when there’s an issue.
Many times it’s a combination of things that conspire against you. Like the temperature. Was it rising or falling? What was the substrate temperature? How about humidity? What was the cure time before it got wet?
Was this applied with a spray gun? Was there a good quality paint booth desiccant filter? Wet air coming from a paint gun can do this too.
There are a ton of variables that an experienced painter would need to know to really diagnose the issue.
Also mentioned was to use universal hardener. I do this regularly when using these types of paints. I also use higher quality reducers. If properly reduced and catalyzed, bright side can become a much tougher and longer lasting finish.

 

[psneeld]

Not sure of everyone else....but having used Brightside for the last 40 years on many boats and had the same bubbles in every place from shower pans (before my knowledge of constant wetness and bubbles) to decks to cabin tops and sides..... I can tell you those bubbles look very common to me.

Even when I was sure I did everything right, anytime something that attracted/cause moisture, even something like a boathook laying on a cabin top for days with dew, caused bubbles sometimes. Can't say for sure, but moisture seems to be a common cause.

If the paint was fine for weeks, then bubbles after a week of rain...sounds possible to be moisture.... though we all know it shouldn't be. The million dollar question is...."is it possible moisture could be getting behind the paint?".

 

[PierreR]

Whow, psneeld's posting sets off bells and whistles because the geographic locations and the colors appear to be the same. Although the vehicle and the carrier are likely the same, color to color, the pigments can vary drastically and can introduce weird surface chemistries. Grey pigments and tan pigments are the cheapest and most varied in color. light Grey is a real money maker of a color.
Just some scenarios running through my head. There are some really cheap fumed silicas out there that could serve as both a pigment and a thixotropic modifier that bean counters would love. They are grey and fairly consistent in color but not as consistent in properties and depend mostly on source. They are biproducts (waste) of silicon alloy manufacturing.
To a chemist formulating for a promotion these pigments are fun to play with but to a bean counter/purchaser, being taken to lunch by a salesman, one source is as good as another and well into production, no one may be watching the store or aware of an issue surrounding multiple sourcing.
You never know. Hardeners will help in any case.

 

[Bmarler]

Not sure of everyone else....but having used Brightside for the last 40 years on many boats and had the same bubbles in every place from shower pans (before my knowledge of constant wetness and bubbles) to decks to cabin tops and sides..... I can tell you those bubbles look very common to me.

Even when I was sure I did everything right, anytime something that attracted/cause moisture, even something like a boathook laying on a cabin top for days with dew, caused bubbles sometimes. Can't say for sure, but moisture seems to be a common cause.

If the paint was fine for weeks, then bubbles after a week of rain...sounds possible to be moisture.... though we all know it shouldn't be. The million dollar question is...."is it possible moisture could be getting behind the paint?".

It’s always possible for moisture to get behind the paint. It’s the second most common paint failure mode.
The picture the OP posted is showing a problem in uncured paint. Cured, or dry paint won’t get craters in it like that.

 

[PierreR]

It’s always possible for moisture to get behind the paint. It’s the second most common paint failure mode.
The picture the OP posted is showing a problem in uncured paint. Cured, or dry paint won’t get craters in it like that.

OP says blisters and the same for the steel panel on the van. I can't see moisture migration through steel.

 

[psneeld]

I believe they are blisters and yes, I have read from many sources that Brightside is the kind of paint that does not do well when kept wet from some covering and in this case constant "wetness" (even if a vertical, uncovered surface.)

 

[rslifkin]

If some amount of water can slowly migrate through Brightside, then the issue may depend on what's under the paint. My boot stripe is painted on with Brightside and is frequently wet (although rarely submerged for more than a few seconds at a time). I've never had blistering issues like that, although it's painted directly over gelcoat, no primer or anything in between.

 

[psneeld]

If some amount of water can slowly migrate through Brightside, then the issue may depend on what's under the paint. My boot stripe is painted on with Brightside and is frequently wet (although rarely submerged for more than a few seconds at a time). I've never had blistering issues like that, although it's painted directly over gelcoat, no primer or anything in between.

Thats what drives me nuts. It neither just the paint or just the water. While not uncommon in my experence to see patches like this, the vast majority of Brightside painted surfaces never seem to blister like this.

 

[Bmarler]

It’s interesting, looking at paint defect pictures. To me they looked like craters. Exactly like solvent pop. But when you all said blisters, I looked again, and sure enough, they can look like blisters as well. That changes things a little. Most likely not solvent pop, but moisture issues instead.

 

[BruceK]

Enlarged, they look like humidity bubbles. Had it on a car roof, on a new refrigerator door, and have seen it other times on cars. Likely the result of moisture trapped under paint.

 

[Osprey69]

Not sure of everyone else....but having used Brightside for the last 40 years on many boats and had the same bubbles in every place from shower pans (before my knowledge of constant wetness and bubbles) to decks to cabin tops and sides..... I can tell you those bubbles look very common to me.

Even when I was sure I did everything right, anytime something that attracted/cause moisture, even something like a boathook laying on a cabin top for days with dew, caused bubbles sometimes. Can't say for sure, but moisture seems to be a common cause.

If the paint was fine for weeks, then bubbles after a week of rain...sounds possible to be moisture.... though we all know it shouldn't be. The million dollar question is...."is it possible moisture could be getting behind the paint?".

Just curious...if bubbles have re-occured over 40 years with Brightside...why keep using it?

 

[psneeld]

Just curious...if bubbles have re-occured over 40 years with Brightside...why keep using it?

Not re-occurring in the same spots that I know of...I have just seen the same thing happen on many different boats over all those years.

And as I posted before, it generally doesn't do it unless you put something on it that stays wet for days on end. Most of the time when you take it away, the bubble disappear and all is good.

I like the product and it generally does the job...the bubbling occurs in other brands of polyurethane paint as far as I know.

 

[Bmarler]

Just curious...if bubbles have re-occured over 40 years with Brightside...why keep using it?

I sure wouldn’t. While I have experienced various types of issues with many different paint systems, I can certainly say that I wouldn’t regularly use a coating that I didn’t consider pretty bulletproof.
Bright side is one of those paints you can use straight from the can and have fairly consistent results. Or, you can customize it a bit and have a higher performance coating.
The issue pictured is a result of an application error of some sort, and has been stated many times, moisture is the likely culprit. Where it got introduced into the coating is what hasn’t been answered, as we never got any feedback on what the process was.

 

[Finestkind]

Tiny Bubbles…

One year after rebuilding mast step (cut back to inner skin, dug out surrounding core, long drying time & layer cake of Coosa & glass/epoxy to surface) my cured & cleaned step was painted with multiple coats of Interlux single part… a Pox was cast upon my project! Slowly small spots rose about 1/16” max & over time many would pop off completely! Others would crack 3/4 around & lift up a bit.
All times followed, proper foam brushes (as this paint in Notoriously fussy) and protected…
SO…. When my sliding hatch needed love & support I tried again. After roughing up some tooth on the inside gel coat I epoxied a layer of unidirectional carbon fiber tape into/across the ‘ridges’ of the hatch. Cure, wait & paint with the same formula Brightsides… 2 coats. Turned it over & gave the chalking top a good sanding, prep & paint (3 coats in all) and a year Later than the step, I start to have tiny pinpoint spots appearing only on the slider sides…
Years back bootstripe in just one area would blister a bit days after application (foam roller) and when prepped again a totally smooth surface…
I’m done with Brightsides.
We did use Interlux 2 part on our hull. “Super resistant red fuzzy rollers” for 2 part paint… and I flocked the transom! How fast can YOU get the rags & solvent flying!!! In the end we got a great result with 18% reduction added to 2-part After Proper mixing; and sanding after 1st 2 coats using foam ‘hot dog’ rollers. As soon as they would start to swell a ‘hair’ switch roller & continue. Mirror like finish with NO bubbles or tipping.
The Admiral said Never Again…

 

[rslifkin]

Thinking about it... Are those having trouble with Brightside thinning it? If so, it's possible that's related. Even in cold weather I've only used it straight out of the can or mixed with the appropriate flattening agent.