posted
I have a job that has gone on forever for various reasons, trying to get the last part done and I'm having a problem with the finish blistering. Went to install (5 hours one way)and arrived through a rainstorm and had blisters in the finish. I thought it was because of the wet ride to the job site. They went away after the sun came out but I wasn't comfortable leaving them that way. Brought them back to re-finish.
Details:
Duna board HDU Cleaned with spray of water after fabrication. Sprayed on coatings of Jay Cooke's Primer 220 grit sanding Gloss acrylic latex top coat.
Had a large fan going to dry the signs and thought maybe that I had caught moisture in the finish, maybe thinning with water to spray left too much moisture for good curing? So this time, after sanding down with 80, then roller coating Cooke's right from the can, sanding between with 120 grit (better tooth?) let cure overnight. Take outside today and rinse off with the water hose, leave in the sun for a few hours, roller a thin coat of gloss acrylic latex finish and in a few minutes...
Blisters form:
Break it open and pull waht is loose off:
I have finished signs for years this way and with these products and have never had this problem. Hundreds and hundreds of dimensional and sandblasted signs with acrylic finishes...I need this job finished and looking GOOD. Any thoughts?
-------------------- John Byrd Ball Ground, Georgia 770-735-6874 http://johnbyrddesign.com so happy I gotta sit on both my hands to keep from wavin' at everybody! Posts: 741 | From: Ball Ground, Georgia, USA | Registered: May 1999
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posted
Hve you always used Duna board? I have a friend who is local to my area and he had the same problem with an HDU sign which was Duna. Just wondering. He'd used Sherwin-Williams paint. What did you use?
-------------------- Amy Brown Life Skills 101 Private Address Posts: 3502 | From: Lake Helen, FL, USA | Registered: Feb 2001
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posted
John, For starters, I went to your website. Nice work you're doing!
As for your problem...have you contacted the paint manufacturer? You might ask them. It looks like the paint is lifting off of the primer, in which case it might be a bad batch of primer.
Also, the last picture looks like you maight be coating over Bondo. Is this correct. If so, I've had similar issues when overcoating Bondo that has not yet fully dried. I give mine at least overnight.
That's all I've got. Frankly, with your level of experience, I doubt I could really help you any further.
Good Luck.
-------------------- Brian Oliver Paxton Signs Fort Collins, CO paxton@peakpeak.com www.paxtonsignsofcolorado.com Posts: 237 | From: ft. collins, colorado,usa | Registered: Mar 2001
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posted
Was posting more out of curiosity really. When it comes to things like this a quote from an old freind of mine that also did alot of custom paint jobs on automobiles... "It's paint" which means, sometimes it does the unexpected. Sand it off and start again. My concern comes from experiencing all things oil based change so dramatically over the years, and you would know that they changed their formula when a job went south. The first thing that popped into my head was -here we go again, now they're doing it to the water based paints. Anyway, I do think it was a little moisture caught behind the first primer coats. Thanks for the compliment Brian! And no, that's not bondo showing. That's white primer and green Duna board showing.
-------------------- John Byrd Ball Ground, Georgia 770-735-6874 http://johnbyrddesign.com so happy I gotta sit on both my hands to keep from wavin' at everybody! Posts: 741 | From: Ball Ground, Georgia, USA | Registered: May 1999
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posted
John have'nt experienced the same exact thing, but have noticed paint just not wantin' to absorb into HDU. I'm telling you it's like there's too much plastic or plasticizers, or silicone in the HDU. The old foam board I used to get 10+ years ago used to ABSORB the paint. I notice primer just kind'a beads up on this new stuff.
I'll never believe it's any paint or primer problem . . . it's the HDU.
-------------------- Signs Sweet Home Alabama
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"Look like a girl, act like a lady, think like a man, work like a dog" Posts: 5758 | From: "Sweet Home" Alabama | Registered: Mar 2003
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posted
Dale, that tells me right there they have a variable, unstable, erratic, fallible chemical formula in production of this stuff. That's all the 'clean' adjectives I can come up with at this time.
It's maddening because these are the high-end signs of our business and we should be able to finish them in a high-end LONG LASTING way and the foundational material is no good??!!
What I wanna REALLY WANNA KNOW IS - what was wrong with the gator foam?? HUH??? I NEVER had any problem having paint stick to IT. Still have signs up 10 years later that STILL look good - NO peeling problems because paint ABSORBED INTO the material.
I just can not stress enough the importance of that. If you have a pourous material, paint is NOT gonna adhere to it by just sittin' on top of it, whether its HDU, plywood, MDO or whatever. The primer HAS GOT TO SOAK IN on the first coupl'a coats and that stuff just won't let it.
I swear . . . I hate to add HDU signs to my very short list of signs I HATE to do . . .
Who's the HDU REP around here? Someone needs to get a chemist and sign painter together so this problem can be fixed.
Do I seem sufficiently irate and over-indulgent pertaining to this ON GOING primer adhesion problem with HDU?????
That's cause there is really no end of 'heads comin' in here with this SAME problem . . . it's the most ridiculous problem we can possibley have; for the FOUNDATIONAL coat to NOT BE STICKING because the MATERIAL IS UNSTABLE . . . and it is unstable in the name of trying to make this stuff SOOOOOOOO long lasting, when what I'm tellin' you, dear manufacturer, is the OLD MATERIAL was LONG LASTING AND primer ABSORBENT.
FIX this stuff!
-------------------- Signs Sweet Home Alabama
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"Look like a girl, act like a lady, think like a man, work like a dog" Posts: 5758 | From: "Sweet Home" Alabama | Registered: Mar 2003
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-------------------- Brian Oliver Paxton Signs Fort Collins, CO paxton@peakpeak.com www.paxtonsignsofcolorado.com Posts: 237 | From: ft. collins, colorado,usa | Registered: Mar 2001
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posted
Sheila, any HDU is cellular in structure & no finish can get beyond the first layer of cells. However, this allows it to never be sanded really smooth so any primer or any paint will have a good physical bond provided it's clean. Any time you have an adhesion problem on HDU it's either because of surface contamination (either dust or chemical) or one layer has not cured properly. High humidity is more often than not the culprit.
-------------------- Rodger MacMunn T.R. MacMunn & Sons C.P.207, Sharbot Lake, ON 613-279-1230 trmac@frontenac.net Posts: 475 | From: Sharbot Lake, Ontario | Registered: Nov 2003
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posted
I have had this exact problem on HDU...however the exact problem also on wood...so it's not the material in my case...so I think my problem is impatience...I need to allow more drying time before recoating...I know for a fact I recoat way too soon...but only occassionally get the blister.
This is a heartbreaker problem. I've also had the same adhesion problems. Glad you posted such good photo's. They really reveal the situation.
It's true HDU doesn't absorbe anything. It's a closed cell materials. Which means proper priming is very important.
My first adhesion problem was due sanding dust. I hadn't properly blown off the dust. Thanks to this froum I now wash down my panels. However that wasn't the end of it. Like Rusty suggested, I've also been too impatient. And re-painting several coats witout letting the base coats harden off.
My solution, which has worked like a dream so far, Automitive High Build Primer. It quickly fills, sands like a dream, and is dry in minutes.
The down side is, it requires spray equipment.
Hope someone has a better solution.
-------------------- Joe Crumley Norman Sign Company 2200 Research Park Blvd. Norman, OK 73069 Posts: 1428 | From: 2200 Research Park Blvd. | Registered: Sep 2001
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posted
What a bummer! At some point we have all been there...or will be there someday. That doesn't make the experience any easier, just common.
There will be as many solutions presented here as there are people here, me included.
Joe and others are right - HDU can't absorb anything because of its cell structure. That's the reason for making sure there is no dust or chemicals on the surface.
HDU does not need a primer but most of us use one anyway. Almost anything will stick to it provided that the surface is clean. Gary Anderson has been using 100% acrylic without a primer on HDU for years without a problem.
Acrylics have the capacity of "breathing" and staying somewhat elastic. That's why they work so well on houses.
What happened in John's situation would only be a guess on my part. Since he has been using the same procedure for years without a problem until now, this just might be one of those flukes that happen to all of us from time to time.
One time we had a similar problem and found out that the HDU (not Duna) has some chemical on one spot and nothing would stick to it. It must have come to us that way, but was only about a two inch circle. We sanded down the paint, used some high powered cleaners and reapplied the paint...and it worked.
We have been using Corafoam (Duna USA) for years with no problems, but then my next job may find the same problems that John did.
This is a lot of words to say that the underlying problem may never be found. My guess would be that somehow moisture was trapped between the HDU and the paint layers...possibly because of the the rain on a freshly painted surface. It would further by my guess (and only a guess) that if you had not peeled up the paint that it would have corrected itself over time. Back when we were using redwood and acrylics, sometimes moisture would migrate out of the wood and form blisters under the paint. Over a few days the moisture would work through the paint layer and everything would be fine. I've got a mailbox post in front of my studio that did that 17 years ago and the paint is still on it.
One thing I've learned from this: I don't want Sheila mad at me...about anything.
-------------------- Chapman Sign Studio Temple, Texas chapmanstudio@sbcglobal.net Posts: 6306 | From: Temple, Texas, USA | Registered: Nov 1998
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posted
There is some HDU company I got an email from were they actually push the primer in with I think a sgueegy. Don't know if that is to hide the open cells or promotes adhesion. But I had the same thing happen too. And when you think about it doesn't the same thing happen to treated 4x4x8's when you try and paint them. Could be chemical could be water.
-------------------- Jonathan Harvey Harvey's Signs and Designs 214 N. Main Newton,KS 67114 316-283-2424 (no telemarketers) Posts: 63 | From: Newton, KS | Registered: May 2006
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posted
Come to think of it...Raymond is right about the blisters correcting themselves...I had the same experience...although I have peeled off, sanded, and repainted the occassional blister...while driving through a nearby town I noticed a couple of major blisters on a sign that I had recently installed at the library...they were in the worst possible location...the faces of 2 children reading a book that I had used...since this job was out of town...and I hadn't been notified by the librarian...I let it ride until I was in the area again...this time I came prepared with whatever I thought I might need to make the repairs...but only to find that the blisters were gone...and are still gone to this day...that must have been 15 years ago.
Did the blisters occur where the paint was "thickest?"
The reason I ask, is I had a situation where I was painting a border with gloss latex (like I had many times before) and I layed-down too thick of a coat in a few areas and rushed the job out the door the next day and installed it in the rain. Later that day I had a few bubbles in the paint right where the drops of water were sitting.
My guess is that I layed-down too thick of a coat, the surface dried but the paint below was still curing and out-gassing. When the water was sitting on the surface, it may have softened the top coat and allowed some outgassing, causing bubbles. They eventually layed down by the end of the day. The sign has been fine for 8 years so far.
Just my guess though.
Since then, I do several thinner coats and cure for a few days. No problems since then.
Best of luck, Bob
[ May 13, 2009, 11:51 AM: Message edited by: Bob Kaschak ]
-------------------- "The 3-4 minute mark of "Freewill" by Rush.
Bob Kaschak Artisan Sign And Design Peru New York Posts: 1873 | From: Upstate NY | Registered: Jul 2002
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posted
It was raining or about to during the whole painting process the first time around and I had my 'Tornado-on-a-stick'
fan going to try to keep the project moving. Probably trapped some moisture in the first primer coats and it's been a problem since. Think I've got it licked now. Spraying thin coats and watch paint dry. I will say that this kind of weather has me thinking of the 2-part high build primers Joe mentioned.
-------------------- John Byrd Ball Ground, Georgia 770-735-6874 http://johnbyrddesign.com so happy I gotta sit on both my hands to keep from wavin' at everybody! Posts: 741 | From: Ball Ground, Georgia, USA | Registered: May 1999
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posted
John, the Jay Cooke primer will cause you problems during humid spells as well. I've had no problems as such since I switched to Fresh Start........it sands out much better too.
-------------------- Rodger MacMunn T.R. MacMunn & Sons C.P.207, Sharbot Lake, ON 613-279-1230 trmac@frontenac.net Posts: 475 | From: Sharbot Lake, Ontario | Registered: Nov 2003
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-------------------- John Byrd Ball Ground, Georgia 770-735-6874 http://johnbyrddesign.com so happy I gotta sit on both my hands to keep from wavin' at everybody! Posts: 741 | From: Ball Ground, Georgia, USA | Registered: May 1999
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posted
Between what I've read has happened to others, and what I've read on proper painting techniques, it seems that the problems always occur when an attempt is made to speed up the painting process by using a fan or putting the sign out in the sun, or cheating on time between coats.
With alkyds, it is perfectly acceptable to apply a fan on the substrate once a solid film is present to accelerate out gassing, and automotive paint and lacquer is often baked or heated to accelerate drying.
But one article I read stated that in waterborne paint, the pigment lays down in layers like shingles on a roof. The "solvent", in this case water, is trapped more easily and takes longer to dry than with hot solvent paints. Add this to the fact that wood will absorb some of the moisture in the paint where HDU does not, so the water has to come through the top surface only, which increases drying time even more.
My rule of thumb is to not push it with waterborne paint. I've never had a blister yet, not saying I never will, but I feel safer using quality paint, cleaning the HDU with my pressure washer after machining, and giving the paint longer to dry between coats than the manufacturer recommends when painting HDU. Most instructions for paint assume you are painting wood.
[ May 14, 2009, 09:26 AM: Message edited by: Dave Sherby ]
-------------------- Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 sherwoodsign@sbcglobal.net Posts: 5397 | From: Crystal Falls, MI USA | Registered: Apr 1999
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posted
This is a very interesting thread. I would also agree that moisture is the culprit. Sanding the primer with a heavy grit is going to open up the primer. Washing it down with water is going to allow a ton of moisture to get down into the primer. Setting it out in the sun to dry is causing the moisture to migrate to the surface. This migration will continue after the top coat is applied. I would replace the washing with blowing it off with air follwed by a tack rag.
-------------------- George Perkins Millington,TN. goatwell@bigriver.net
"I started out with nothing and still have most of it left"
posted
I have had this happen with MDO. For what it's worth, here is my experience. Panels primed with waterbased primer. 2 coats Frazee Acrylic which is a quality waterbased paint I believe is only sold in the Southwest. Finish got rained on after paint was dry overnight but not fully cured. Blisters where water was allowed to sit. After sitting in the sun an hour they flattened ot to where I couldn't tell. I was still concerned the paint wasn't adhered well where it blistered. I went ahead and installed them knowing I may have to replace them. They have been up years without a problem. Once the paint is cured a few days then gets wet it does not blister. I have seen this a few times. I have not had to replace or repaint one yet. I have no explanation.
posted
George, I didn't mean to wash the primer. We pressure wash the raw HDU after machining. There is enough static in HDU that blowing off with air doesn't get all the dust off. When the panel is completely dry we start painting.
-------------------- Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 sherwoodsign@sbcglobal.net Posts: 5397 | From: Crystal Falls, MI USA | Registered: Apr 1999
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I don't do a lot of sandblast work, but I deal with static a lot, mostly when working on fiberglass and plastic parts on vehicles.
Just thinking out loud here...
To beat the static, I soak a rag or paper towel with water and place it somewhere on the surface away from where I'm painting. The static charge heads into the rag. When I don't have a rag handy, I spray or sprinkle water onto the back of the surface and it does just as well.
Like George, I'm thinking blowing it dry would at least take some of the water out of the process, but if static is a problem, it might be worth a little experiment.
Maybe a damp rag on the back or one corner would cut the static and blowing it off would work better. Another idea would be to stick a screw in the back and ground it with a wire.
Maybe I'm over thinking this... Rapid
-------------------- Ray Rheaume Rapidfire Design 543 Brushwood Road North Haverhill, NH 03774 rapidfiredesign@hotmail.com 603-787-6803
I like my paint shaken, not stirred. Posts: 5648 | From: North Haverhill, New Hampshire | Registered: Apr 2003
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posted
The letterheads need to have a symposism on the subject. I don't think it's the primer, paint or dust, but I also use a damp chamois to clean up dust. My one time experience with this problem was on a rainy day and I wasn't present when the installers loaded the truck. What happened was like formica cement that has dried to the right tack. Latex paint has the same effect if it is not dry. The installers stacked the post and panels paint to paint and when they separated them they stuck together, thereby creating "pull-apart" bubbles.
-------------------- Mark Baty Mark 1 Studio 1980 SE Leeann Drive Waukee, IA 50263 Posts: 45 | From: Waukee, Iowa | Registered: Aug 2008
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posted
If you think about acrylic latex for house paint has been around only since the 1940's, but oil paint technology is at least 500 years old. I guess the paint mfgrs need to research dryers. Most house paint is never touched after the house painter walks away from the job.
-------------------- Mark Baty Mark 1 Studio 1980 SE Leeann Drive Waukee, IA 50263 Posts: 45 | From: Waukee, Iowa | Registered: Aug 2008
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-------------------- Joe Crumley Norman Sign Company 2200 Research Park Blvd. Norman, OK 73069 Posts: 1428 | From: 2200 Research Park Blvd. | Registered: Sep 2001
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Most of the observations and suggestions are probably correct..
My experience is that you can't "force dry" a water based paint without experiencing problems in the future. Latex paint "dries" real quick, but takes a week or more to actually really "cure".
2 part epoxy or acrylic enamels will "cure" at their own rates. It's a "chemical thing" A bit of warmth will speed up the process slightly but not much. But it shouldn't be speeded up.
Paint should cure from the inside out, not form a skin.
Any change from the manufacturer's suggested methods will probably come back to bite ya in the butt!
Spray, roll, brush whatever paint ya want..then have a nap and wait till it is ready for whatever comes next!!!
Napping is better than re-doing what ya did yesterday or the year before!!!
-------------------- Dave Grundy retired in Chelem,Yucatan,Mexico/Hensall,Ontario,Canada 1-519-262-3651 Canada 011-52-1-999-102-2923 Mexico cell 1-226-785-8957 Canada/Mexico home
posted
I'll second Rodger's plug for Benjamin Moore Fresh Start, it is great on aluminum composite as well. I just purchased Aura paints for a mural and my Benjamin Moore dealer said you can't use them with other paints. With all the different formulations and variants in different brands it makes it hard to know what you can or can't combine. It isn't always feasable to buy a quart of paint for an accent colour. If I like them I may just switch completely to the Aura line once this mural is completed. Sorry, I guess I've strayed a little off the original question.
-------------------- “Did you ever stop to think, and forget to start again?” -Winnie the Pooh & A.A. Milne
Kelly Thorson Kel-T-Grafix 801 Main St. Holdfast, SK S0G 2H0 ktg@sasktel.net Posts: 5496 | From: Penzance, Saskatchewan | Registered: May 2002
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posted
Joe, how's it goin? Look forward to seein' ya at a meet soon!! Somewhere! Someday!
I think Mr.Baty said first of all, we should have a synposium on these matters, but Mr.Baty, this is primarily 'it' except for attending a Letterhead meet and then Joe, he went on to tell about similar problems with paint adhesion when he stacked some signs together upon which paint had not cured, they stuck together - (but, Mr.Baty, even paint that's been drying for a month could do that - best to use something like blankets or card board or something between every panel to prevent the signs from touching)
Next Joe, Mr.Baty is advocating the use of strictly oil-base paints since they've proven themselves for centuries over latex paint, although he suggests a 'dryer' might help.
(Mr.Baty, I agree and I also prefer oil-based paints . . . I often I use a few drops of automotive hardner in my regular oil-based paint which works as a 'dryer' which will not cause the finish to be 'flat' or compromise it's exterior life (like japan dryer can), and many here including myself often use only automotive piant on signs.
Joe, this had been a deciphered message for your clarity . . . Should you need further translation please do not hesitate to call . . . BR-549
-------------------- Signs Sweet Home Alabama
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"Look like a girl, act like a lady, think like a man, work like a dog" Posts: 5758 | From: "Sweet Home" Alabama | Registered: Mar 2003
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