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Bit of irony; oil based primer and paint!
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Author:  Les Beckman [ Sun Jan 07, 2018 1:18 am ]
Post subject:  Bit of irony; oil based primer and paint!

Recently in the thread entitled "2017, A Year of Accomplishments", I posted some things we had done at the Hoosier Valley Railroad Museum" this past year. I included a couple of photos, one of which was of our Purdue crane that was painted in the Spring of 2017. Got a note from Mark Knebel who was brave enough to venture out to the museum on another frigid day. Mark took photos of a couple of items, including said Purdue crane. As you can see, the south facing thin metal construction cab side must have shrunk in the severe cold this past week and when the sun hit the surface, the oil based primer/paint expanded and it popped right off. Mark says that in his 29 years at the museum, he has never seen this happen before.

Incidentally, it also happened to the south face of a building at the museum that is also of a thin metal construction, although this structure had actually been painted about 3 years ago.

Les

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Author:  Ron Travis [ Sun Jan 07, 2018 11:22 am ]
Post subject:  Re: Bit of irony; oil based primer and paint!

What is the manufacturer and product description of that finish paint and primer? I would like to have the manufacturer take a look at that photo and tell us why the finish failed in less than a year. It seems to me that paint performance is loaded with surprises these days.

Author:  Pegasuspinto [ Sun Jan 07, 2018 12:47 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

IMHO this is an adhesion failure. The temperature might of been the catalyst that finished it, but there was a lack of adhesion for some reason. I've seen this when incompatible paints have been used. It really resembles the paint failures you get painting galvanized steel.

Author:  Les Beckman [ Sun Jan 07, 2018 2:25 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

Ron and Robert -

Thanks for the comments. I'm not sure what paint and primer Mark used, but I'll see if I can find out.

I've also included the photo of "the Erie shed" that had the same problem. This shed has the same type of thin metal walls that are in the cab of the Purdue crane, but this was painted about 3 years ago, and there were no problems until this latest sub-zero cold snap and subsequent bright sun. Again the problem has only occurred on the south sides.

Les

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Author:  robertmacdowell [ Sun Jan 07, 2018 2:47 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

I would look at the level of gloss of the rejecting surface, and for any contamination. My SOP is to scuff-sand and wipedown with the paint's solvent right before paint. Passive environmental stuff like the sap from trees can really getcha.

I know the temperature changes seem extreme, but we also set our "zero" scale right around there, which does not reflect actual physics of things not water based. The midwest normally ranges from 255-305 degrees Kelvin, and of late it has ranged from 250-310 K.

Author:  Pegasuspinto [ Sun Jan 07, 2018 4:56 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

The building appears that it IS galvanized, and it's showing exactly what I've seen in the past from painting galvanized metal. It's sort of a tricky surface to paint to.

Author:  Mount Royal [ Sun Jan 07, 2018 5:05 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

I’m going to go with surface prep as the culprit here.

Author:  crij [ Sun Jan 07, 2018 6:37 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

With the crane, how long between priming and finish paint? Some primers only state finish must be applied within X days for proper adhesion. If primer finished hardening before the finish coat than that would be the reason it didn't hold fast.

Did you use a primer on the crane? Could be the digital interpretation of the color, but it looks a bit off.

Rich C.

Author:  Les Beckman [ Sun Jan 07, 2018 8:12 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

Mark points out that we have painted the crane a number of times since it was first donated to the museum by Purdue in 1992. Its yellow cab was originally painted with Van Sickle yellow, later painted silver, still later painted yellow again at least twice. What paints and primers have we used over the years? As a small museum in a farm community, we have used many different brands through the years; Van Sickle, Rustoleum, Richards, MAB, Sherwin-Williams. Perhaps others. Yes, the crane was primed before the last finished coat. Mark points out that it appears that the original Orton paint may even have come off. The next time I'm at HVRM, I'll see if I can find a piece of the flaked paint to see how many coats had been put on. Mark still thinks it's a result of our frigid weather and then sun, since the sides other than the south facing side appear to be okay. Stay tuned.

Les

Author:  dbbii [ Sun Jan 07, 2018 8:32 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

I've worked for a commercial painter for a number of years. I've done things ar Disney World. I've done food service processing facilities. [color=#80FF00][/color] Think of things like water towers. They are very difficult to do so you want to get 20 years of life out of your paint job. Thats why the paint is $400 a gallon.

Sherwin Williams has a commercial / industrial line. It has really good paint but most of the stores dont know anything about it. Plus they only want to sell it to painting contractors that know how to handle it. In addition some poducts can not be sold in certain states ( VOC limits)

Try to find a commercial painter in your area who is maybe willing to help you out. Not a house painter. Get the paint rep out to make a recommendation and tell you why it failed Thats their job.

Author:  Rick Rowlands [ Sun Jan 07, 2018 8:51 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

This was caused by the extreme cold. It has happened a couple of times to me. Once was inside a troop sleeper with paint that had been applied decades earlier. It adhered fine for all those years until the cold temps shrunk the steel more than the paint and the shear forces placed on the coating was more than it could take.

In my years doing maintenance painting on old rail equipment, rusty metal seems to hold on to paint much better than new unrusted metal does. This paint peeling never happens on sheet metal that had some surface rust. Better adhesion.

Author:  Rick Rowlands [ Sun Jan 07, 2018 8:55 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

In a related story about what the cold will do. About 3 years ago six 1" bolts in the crane girder of a large industrial building popped out. The cold created so much tension in the girder that the bolts could not handle the strain and they all failed. That was in a building that was built in 1906 and those bolts lasted over a hundred years. This extreme cold does some really weird stuff!

Author:  jayrod [ Sun Jan 07, 2018 9:59 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

Definitely looks like an adhesion problem somewhere among the layers of paint. It would be good to know between which layers the adhesion failed as that would be where you start before you repaint. Also, as old oil-based paint weathers and/or ages, it can lose its flexibility, get brittle and can shrink. The cold finished the job. I note that the black underneath also has shrinkage cracks but doesn't appear to have much adhesion failure - yet. It boils down to surface prep which is 90% of a paint job. If one of the layers underneath was badly deteriorated or was not prepped properly, then an adhesion failure was inevitable.

The shed looks galvanized. That takes special prep and likely etching. Similar to aluminum, the oxide film doesn't hold regular paints. With aluminum, there's an Alodine conversion tyipcally used which then allows a baked-on finish to be applied. There's probably something similar for zinc.

When it comes time to paint our wrecker, one industrial product I'm considering is "Rust Grip" as a primer. It encapsulates rust and can be used as a sealer over lead based coatings. Kinda expensive but has a 15 - 20 year life, doesn't require a hazmat suit to apply, is air dried and can be brushed, rolled or sprayed. Has anyone tried this stuff?

Author:  Dennis Storzek [ Sun Jan 07, 2018 10:25 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

I agree with Rick and Jay... I've seen this before, on the inside of steel passenger cars that have been in unheated storage for years. Typically all the paint pops off, leaving bare metal, and often with that swirl pattern that matches the size of the flakes that came off. The swirls are likely the last little bit of paint that still had adhesion. I'm sure the cold is responsible, making the steel shrink more than the paint, also the fact that each successive layer of paint makes the paint more solid and less able to accommodate the change. Since the point of failure is the first, factory applied coat of paint, there is really nothing that can be done during prep for later re-coats to prevent it other than the decision that there is too much paint on the surface, time to sandblast it to bare metal and start over. The surface left by sandblasting will help prevent the same thing in the future.

Author:  filmteknik [ Sun Jan 07, 2018 11:58 pm ]
Post subject:  Re: Bit of irony; oil based primer and paint!

Meanwhile the paint on the Highliner behind the building, what we can see of it, seems to be holding.

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