# Factory primed MDF test.



## PACman (Oct 24, 2014)

I've come across an interesting development at my hillbilly test lab. I bought 4 pieces of factory primed MDF from four different box stores. I took plain water, put some on each of the pieces, let it set for 5-10 minutes. Then i was going to do a pencil hardness test, but there was a problem. Each of the primers could be scratched off quite easily with just a fingernail! This is NOT something you would want to put a water based paint directly over top of!

I also painted each one of them with a few different paints, Ultraplate, Proclassic hybrid, and Marquee, just to get a mix of products. Every one of them causes the primer to soften and scrape off again with just a fingernail. (paints were tinted so i could tell what was primer and what was paint). Every one of them had bubbling and the start of some alligatoring.

I'm sure some of you may have experienced this and some haven't, as factory primed trim is sold just like regular lumber and is a wholesale commodity product. There are hundreds of manufacturers around the country and over seas and it is next to impossible to know where any one piece was made or how good of a primer it has on it. I strongly recommend priming ALL factory primed MDF AND straight wood, and at the very least do a simple water test on it before topcoating without applying a known quality primer.

The paint departments at each of these retailers where the MDF was purchased said that no additional primer was needed and to just topcoat with any acrylic paint. Bull.


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## Brushman4 (Oct 18, 2014)

PAC, a while back I asked you about the main differences between Ultra and Ultraplate, I can't remember if you ever replied?


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## Eagle Cap Painter (Nov 14, 2016)

You should run this test again with a variety of WB primers.


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## PACman (Oct 24, 2014)

Brushman4 said:


> PAC, a while back I asked you about the main differences between Ultra and Ultraplate, I can't remember if you ever replied?


Ultraplate is a unique product. The Ultra line is the California premium line. It is made up of the best technologies from Graham, Muralo, and California. It's a pretty damn good product line and Cali claims it is very close to the Ultraplate, but I don't think so. Ultraplate has a urethane modifier. Ultra has ceramic pigments and "nanotechnology" whatever the heck that is.


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## PACman (Oct 24, 2014)

Eagle Cap Painter said:


> You should run this test again with a variety of WB primers.


I actually did a similar test last summer using 12 different water based primers and topcoats. At that time i was trying to see if any particular product was better than the others. What i found out was that any water based product i tried, primer or topcoat, micro bubbled over the factory primer. Well, micro bubbled would be the generic term. Some of them bubbled on a little larger scale then micro. The ONLY products i tested that didn't were true oil/alkyd products like the Alkyd Proclassic and the P&L Cellutone(Red Seal alkyd for you youngins'). Those two, and the P&L multisurface oil primer were the only products that didn't bubble.

At that time i didn't think to check to see what was happening beyond whether they would bubble or not. But the cause of the bubbling and the softening of the factory primer when wetted is the same. Cheap, no volume solids primer that will re-wet when a waterbased product is applied over it. It is a travesty that this bad of a product is being sold as a "premium" over unfinished by the box stores! 

My Cali rep has told me that he frequently sees the "grain" of the MDF raise quite badly when a WB topcoat is applied. The moisture of the topcoat is being absorbed directly into the MDF because the factory "primer" can't even seal the water out! Of course the people that make the trim will say that the issue is the paint, but.......i seriously doubt that, especially after this plain water test.


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## Woodco (Nov 19, 2016)

Remember my thread about the preprimed MDF doors and the everlasting wood grain? This explains it... The latex undercoater I used was raising the grain big time. All future contracts will have a clause about this.


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## PACman (Oct 24, 2014)

I just showed my test to my 13 year old grand nieces. They couldn't believe how crappy the primer was. You can wet it, let it set just a minute or two, and it will rub right off on your fingers. You can scratch it like it is a thin film of Play-do or something. Then if you let it dry, it gets hard and you can't touch it with your finger nails. I'm even worried if a decent water based primer would help at all! The only thing i have that will work on primed MDF from four retailers is oil based primers.


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## futtyos (Aug 11, 2013)

*Hillbilly, my a__! More like Thomas Edison*



PACman said:


> I've come across an interesting development at my hillbilly test lab. I bought 4 pieces of factory primed MDF from four different box stores. I took plain water, put some on each of the pieces, let it set for 5-10 minutes. Then i was going to do a pencil hardness test, but there was a problem. Each of the primers could be scratched off quite easily with just a fingernail! This is NOT something you would want to put a water based paint directly over top of!
> 
> I also painted each one of them with a few different paints, Ultraplate, Proclassic hybrid, and Marquee, just to get a mix of products. Every one of them causes the primer to soften and scrape off again with just a fingernail. (paints were tinted so i could tell what was primer and what was paint). Every one of them had bubbling and the start of some alligatoring.
> 
> ...


PACman, I am sure that most here value your "hillbilly" tests. If the various paint companies were smart, they would be trolling Paint Talk and checking out the posts, especially yours. I recently did a "hillbilly" test of my own for a roller cover I had never used before. 

After reading about your test, I think I may have been lucky at what I did on a job about a year ago that I cannot find photos for. Marina Towers in Chicago. Jeld-Wen doors, if I recall correctly. They had one panel per door that was recessed with a beveled edge. I looked at them carefully and felt the primer. Remembering all the talk here about priming already primed products, I thought that this might be in order. I also remember painting door trim on an earlier Marina Towers unit that had some MDF trim that literally sucked the paint into the surface so fast that I thought that the paint was glueing to the trim - really freaky, at least to me.

I decided that the Jeld-Wen doors I had to paint were primed with an inferior primer that would "wet" with any water based primer or paint that I might apply. I figured that if the factory primer was porous, a coat of Gardz would wet the primer and darken it just as a coat of water would. I took a leap of faith and applied a coat of Gardz. The primer darkened just as I suspected it would, but miracle of miracles, the Gardz did not raise the wood fibers of the MDF! I was able to top coat the doors with very little problem.

After reading your take on all the variables that one might have painting factory-primed MDF, I consider myself lucky that things went as well as they did for me.

Fructose


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## lilpaintchic (Jul 9, 2014)

futtyos said:


> PACman, I am sure that most here value your "hillbilly" tests. If the various paint companies were smart, they would be trolling Paint Talk and checking out the posts, especially yours. I recently did a "hillbilly" test of my own for a roller cover I had never used before.
> 
> After reading about your test, I think I may have been lucky at what I did on a job about a year ago that I cannot find photos for. Marina Towers in Chicago. Jeld-Wen doors, if I recall correctly. They had one panel per door that was recessed with a beveled edge. I looked at them carefully and felt the primer. Remembering all the talk here about priming already primed products, I thought that this might be in order. I also remember painting door trim on an earlier Marina Towers unit that had some MDF trim that literally sucked the paint into the surface so fast that I thought that the paint was glueing to the trim - really freaky, at least to me.
> 
> ...


Frutcose....roflololol 

Anywho, anybody whose played the game of not repriming the preprimed has learned the lesson to ALWAYS REPRIME THE PREPRIMED. That (in my book anyway) applies across the board. And yes solvents don't raise the grain (or fibers...whatever) and sand easier (imo). Unfortunately, the EPA is doing their best to eliminate the good stuff and paint manufacturers are left trying to give us an inferior product at a reasonable price for (somewhat) unreasonable people (us). Mdf looks best in oil, looks adequate with a waterborne undercoater and a nice, satin finish. I've never had a problem doing it this way anyway....if a ho wants a flawless finish they're paying for it and the trim will be shot in shellac (very seldom) or coverstain (9.5 times outta 10).

Thanks for confirming yet again the importance of a reprime. Especially when the coatings from the door company may vary considerably from that of the trim company. Some manufacturers have a high build plasticy coating that an average finish won't stick to without a lot of stuffing (at a minimum) or a good tightly bonding primer, preferably both. I just shoot em in oil and keep going....
Different strokes for different folks though. I've just always found that the "short cut" is the longest and most expensive route to take.



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## slinger58 (Feb 11, 2013)

You can thank CA for hanging the Fructose moniker on him. 


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## cocomonkeynuts (Apr 14, 2017)

futtyos said:


> If the various paint companies were smart


BM just spent a couple million to match perfectly all superdeck colors in the coronado maxum line. Advertising this year will be focusing on taking jabs at the box store "one coat" and "paint and primer" marketing gimmicks. 'Do it right, do it once' will be the focus this year. I would also expect to see some gennex marketing.

Paint companies are multi billion dollar _smart_ and you can be sure they employ people to read PT and other various social media.


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## Brushman4 (Oct 18, 2014)

They may read but can they comprehend, capiche, comprende, verstehen?


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## lilpaintchic (Jul 9, 2014)

Brushman4 said:


> They may read but can they comprehend, capiche, comprende, verstehen?


Yes, they can. They just stopped caring. Why stay loyal to us when a diyer will pay more and bitch less because they're ignorant to the industry?

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## PACman (Oct 24, 2014)

I'm going to repeat the test on pre-primed pine, although i expect the same results. An interesting couple of side notes;

The lumberyard across the street from me (Builders First Source) refuses to sell ANY factory primed trim. Won't even special order it.

I went to my new favorite box home improvement store (Lowe's, in case you missed my brush rant a couple of weeks ago.) to buy a piece of pre-primed pine trim. Asked the guy in the lumber department if i needed to prime it again. "oh no, just use any latex paint on it". And again i asked the woman in the paint department if i needed to re-prime it-"no, just paint right on it" (Me)-"what would you recommend? It's just for a repair in a basement." straight to the top of the line Sw! For basement trim. $24.00 for a quart. RED FLAG!

So i bought the SW to try it directly on it, and i fully intend on returning it AND the trim if it fails. Why wouldn't I? I have been given an expectation by their salespeople and if it doesn't live up to the expectation i am going to get my money back.


And yes of course almost ALL paint companies have people that read this site, i have even forwarded the sight to some of them. But, why would a paint company or retailer that is selling all the paint they can handle change anything because of something that is posted on here? As long as consumers and YOU, the professional painters keep buying from them, why would they do anything differently? That's NOT good business in their minds. So where will that mentality eventually lead us?


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## sayn3ver (Jan 9, 2010)

Pac,

I had micro bubbling happen on some preprimed fjp crown when sprayed with a fast drying acrlyic primer recently. 

Still have a local yard that sells unprimed, solid wood mouldings. I would never buy fjp personally anynore and would never buy preprimed mdf mouldings. I think mdf is better for paint than fjp. But get it raw and do it right from the ground up. 

The fjp nowadays has joints every 6-8" and it's just total junk.


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## PACman (Oct 24, 2014)

sayn3ver said:


> Pac,
> 
> I had micro bubbling happen on some preprimed fjp crown when sprayed with a fast drying acrlyic primer recently.
> 
> ...


And the joints aren't sanded worth a crap either. Then they prime over them.


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