# trial theory on pre primed wood



## IHATE_HOMEDEPOT (May 27, 2008)

I am with the opinion that some, not all, of the factory prime coats that come on a pre-primed wood/mdf these days actually starts to melt when you try and brush the initial coat. I have noticed this for some time. It makes brushing the first coat really difficult and I don't care how much I cut it.

On top of all that some of it is a really garbage for a substrate. I loaded some trim on my truck the other day and it got rained on just a bit and when I got to the job it was wiping off right down to bare wood and I mean without any trouble. There is no doubt better qualities when it comes to this material but I guarantee you the GC/Carpenter is not going to investigate this. Just for an experiment next time you see a scrap pick it up and see how well it holds up to a wet rag.


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## Mantis (Aug 4, 2008)

it's complete garbage. I tell everyone that uses it that unless they allow us to reprime it, they are basically only getting 1 coat of finish. Since the first coat of finish gets soaked in, we treated as primer anyway.


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## Rcon (Nov 19, 2009)

IHATE_HOMEDEPOT said:


> I am with the opinion that some, not all, of the factory prime coats that come on a pre-primed wood/mdf these days actually starts to melt when you try and brush the initial coat. I have noticed this for some time. It makes brushing the first coat really difficult and I don't care much I cut it.
> 
> On top of all that some of it is a really garbage for a substrate. I loaded some trim on my truck the other day and it got rained on just a bit and when I got to the job it was wiping off right down to bare wood and I mean without any trouble. There is no doubt better qualities when it comes to this material but I guarantee you the GC/Carpenter is not going to investigate this. Just for an experiment next time you see a scrap pick it up and see how well it holds up to a wet rag.


Pre primed stuff, lately, has been crap here as well. Lots of problems with it not adhering to the substrate. Don't know what causing it but can't say i'm happy with it. Proly comes from home depot. 

Doors have been fine as usual but the boards haven't been so good.


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## plainpainter (Nov 6, 2007)

Clapboards that are primed with a grey colored primer or trim that has been primed with a white colored primer seem to be fine - although I reprime.

The stuff that is an atrocity is trim, door casings that's been factory primed with this eggshell like brown color to it. That stuff is utter garbage, and god forbid if your clients let it weather a few years. Even pressure washing all the chunks loose, and then going over with a primer like maddog - it will lift the remainder of the primer off the wood within a year causing it to peel in sheets.


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## IHATE_HOMEDEPOT (May 27, 2008)

Ah, good point plainpainter interior trim is what I was talking about and there does seem to be a diff. One more thing I forgot to mention is that I HATE Home Depot.


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## johnpaint (Sep 20, 2008)

Yeah, it seems to have very little binders in the primer. White wash almost,Tom Sawyer kind of thing.


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## Roadog (Apr 18, 2007)

I always figured that the pre-primed wood was more for transportation reasons of the wood to help get it from point a to point b in a better condition. I mean......why would the lumber industry pretend to be giving the paint industry a head start? Cause they like us? :no: Re-prime! :yes:


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## johnpaint (Sep 20, 2008)

Roadog said:


> I always figured that the pre-primed wood was more for transportation reasons of the wood to help get it from point a to point b in a better condition. I mean......why would the lumber industry pretend to be giving the paint industry a head start? Cause they like us? :no: Re-prime! :yes:


I think it's mostly for the anti warping qualities.


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## plainpainter (Nov 6, 2007)

A good factory prime is only to protect wood from UV degradation once installed - is already 'back' primed, so cannot be affected from water intrusion from behind - and it keeps all mildew and dirt particulates on the surface from growing into the wood.

These are all very worthy attributes - however, factory primed surface does not mean it's 'paint ready'. To me that's what separates the hacks from the professionals which seems to be a 85/15 ratio these days. 

Of course this is from an exterior point of view, from an interior point of view - the reason to reprime is because contractors have a ton of pencil/pen marks all over the wood from measuring, and it will bleed right through the paint. If these issues don't exist - and you are going with an oil trim paint - then there is enough allowance, imo, to go ahead and apply direct to the primer.

However, the realities being what they are, in today's scumbag world of low low pricing - you can kiss every estimate away if you either bid for oil trim paint or re-priming. These jobs are only priced for a quick two coats of Aquaglo, no finish sanding between coats - and then head over to the next job. I think for anyone who thinks the world 'quality' and 'painting' can be contained in the same sentence, let alone the same paragraph are in for a rude awakening.


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## Paradigmzz (May 5, 2010)

This is why you should always prime factory primed wood (10 years later).


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## jack pauhl (Nov 10, 2008)

Paradigmzz said:


> This is why you should always prime factory primed wood (10 years later).


Looks like finger-jointed oak. We see factory primer peel away from certain pieces before we begin doing anything with it. We have also seen peeling occur back to bare when we pulled tape and in some cases completely removing all the primer!

I was discussing in another thread about applying Gardz to pre-primed MDF or factory primed trim in general. I'm testing to see if applying Gardz can in fact make the factory primer stick better by penetrating the prime coat like Gardz suggests it does over cheap flat wall paint. 

One thing for certain, Gardz is easier to apply to pre-primed MDF vs your first coat of paint. You can apply it with a pump-up sprayer too, it just dissipates away into whatever you apply it to. Pretty awesome. You can imagine how fast it takes to seal a cased door jamb with a pump up sprayer... ummm 15 seconds.

EDIT: just remembered why I replied. I dont believe repriming pre-primed trim can make the failed factory primer stick any better. The failure is already there, we've sent stuff back for replacement trim. I think your best shot at getting a failed factory primer to stick might be by thinning an oil and hoping it penetrates the factory coat.


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## DeanV (Apr 18, 2007)

On a couple jobs I have primed the pre-prime MDF and had tape pull all the layers off down to the raw MDF when it was removed.

The primer is just a cheap clay coat product. A rep from the mdf company blamed it on us for using primer lol. The real problem is that if the base layer is a crappy product, it does not really matter that much how good of a primer you use. The base layer determines the adhesion of all the layers above.


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## jack pauhl (Nov 10, 2008)

DeanV said:


> On a couple jobs I have primed the pre-prime MDF and had tape pull all the layers off down to the raw MDF when it was removed.
> 
> The primer is just a cheap clay coat product. A rep from the mdf company blamed it on us for using primer lol. The real problem is that if the base layer is a crappy product, it does not really matter that much how good of a primer you use. The base layer determines the adhesion of all the layers above.


Dean, man those reps get under my skin with their back peddling of why their products fail. I would have been like... here is a piece without primer, now what is your excuse why your factory finish comes off? Get the  outta here and go fix your product!


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## briancreary (Oct 12, 2010)

*maybe*



johnpaint said:


> I think it's mostly for the anti warping qualities.


 
I think it's so they can finger-joint their junk wood and still sell it to us.


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