All these years, whenever I have finished an enclosure, sanded it, and painted it, I've just assumed there was nothing I could do to keep certain parts of the wood from absorbing about the first 4 coats of paint, and therefore making the entire enclosure lok uneven. Then the other day I read somebody say something about an MDF sealer or something that preps it for being painted so it doesn't have that problem. Is this a real product, or were they just talking about a sandable, paintable wood filler, or something?
I have seen primer paints in DIY stores labelled for use on MDF. I'm not sure if these really are 'special' or different, or merely another ruse to get money out of our pockets and into the till.
I would have thought that any good wood or general purpose primer would do the job.
I would have thought that any good wood or general purpose primer would do the job.
I have used oil-based primers on MDF and they work well. I use a brush so if it's priming for paint its another sanding job.🙁 I'm leery of using water based anything on MDF but I note that a lot of people here do it. So I suspect that's just my paranoia.
eStatic
eStatic
I used 'mdf primer' for one of my projects, and it was like white emulsion (water based paint) mixed with 'unibond' (pva sealent - used in plastering etc)
If I want to seal mdf again I'll just mix water based wood glue 50/50 with water, and roller on with a sponge roller.
Cheers
rob
If I want to seal mdf again I'll just mix water based wood glue 50/50 with water, and roller on with a sponge roller.
Cheers
rob
Wouldn't sanding sealer work OK for this? It is often used on hardwood floors before staining, but it should work to seal MDF. I found a can of it at The Home Depot.
Cheers,
Zach
Cheers,
Zach
What about Kilz primer? http://www.kilz.com/
It an oil-based paint that is designed for use in applications where you need to cover something up. I.e. If you want to paint a black wall white, you could paint it with Kilz (which is white) and then paint it with a top coat.
1 gallon of the Original formula is $10 at Lowes. http://www.lowes.com/lkn?action=productDetail&productId=45551-000000807-153-4833
-MC
It an oil-based paint that is designed for use in applications where you need to cover something up. I.e. If you want to paint a black wall white, you could paint it with Kilz (which is white) and then paint it with a top coat.
1 gallon of the Original formula is $10 at Lowes. http://www.lowes.com/lkn?action=productDetail&productId=45551-000000807-153-4833
-MC
MDF Sealer
The purpose of this stuff is to fill in the " end grain " on the MDF. A couple of things do work well. If you are painting then zinser primer works well. Some car primers work especially well if they are two part. If you have a lot of problems I sugest using zinser primer and then fill any blemishes with a water based putty. Sand this smooth and prime again. Sand it once more. Clean it off with a rag that is either a tack cloth or slightly dampened with water. Look closly at your finishing job at an oblique angle. Face the music and give it another primer coat. Then with a block and some fine wet and dry paper, some slighly soapy water and a lot of elbow grease sand your surfaces really smooth allways using the soapy water in a squirt bottle to lubricate the work. This method works exceedingly well and you finnishes will be at the pro level if you have acess to spray equipment.
Hope it helps!
Mark
The purpose of this stuff is to fill in the " end grain " on the MDF. A couple of things do work well. If you are painting then zinser primer works well. Some car primers work especially well if they are two part. If you have a lot of problems I sugest using zinser primer and then fill any blemishes with a water based putty. Sand this smooth and prime again. Sand it once more. Clean it off with a rag that is either a tack cloth or slightly dampened with water. Look closly at your finishing job at an oblique angle. Face the music and give it another primer coat. Then with a block and some fine wet and dry paper, some slighly soapy water and a lot of elbow grease sand your surfaces really smooth allways using the soapy water in a squirt bottle to lubricate the work. This method works exceedingly well and you finnishes will be at the pro level if you have acess to spray equipment.
Hope it helps!
Mark
Try PVA primer. It's used to prime drywall before the finish latex paint. It seals up the paper (absorbant like MDF) and plaster so the finish paint adheres evenly to the whole works without soaking in.
At Napa ( and other auto parts places, I've seen sealer primer (only seen it in grey). I've used it, and it works pretty well. It took 3-4 coats of regular primer to seal off the MDF i was working on, and only 2 coats of the sealer primer to seal it.
Of course it's also sorta expensive at almost $5 a can, something like the Glue paint, or pva primer would be a much more economical alternative.
Of course it's also sorta expensive at almost $5 a can, something like the Glue paint, or pva primer would be a much more economical alternative.
We use an oil-based primer for MDF, works fine. On a side note, MDF doesn't really have "end-grain". You can pretty much cut it to any shape, sand it, and everyting will turn out the same.
I f you want to seal it from moisture most primers and then a top coat will do ok. But if you really want it to be sealed you really need to use a slow dry oil so that the primer will soak farther into the wood and give a better bond and seal.
The problem will all spray enamel primers and oil based primers such as kilz123 and the rest is that they flash too quickly. That is they are drying so quick that it will not sink into the wood. Just look at the can of primer and look for something that requires 24 hours before a top coat can be painted over it. All major paint companies make them.
Miller, Behr, Benjamin Moore, Parker... etc.
If you are looking for a product that will make the MDF take a stain and you want a nice even coat then the product is Benite. All quality painters use it on real wood products to allow stain to absorb evenly and protect the wood from bad stains (fingerprints, grease, smears etc.) till it is stained. The problem with Benite is that the MDF will soak it up very quickly and will require obscene amounts of it to do it well.
When doing wood working I will always do my steps in this order.
1. Final assembly
2. Rough sanding prior to priming.
3. Slow dry oil primer.
4. Second sand to get rid of any imperfections in primer.
5. Bondo and nail and screw holes.
6. Sand.
7. Spot prime bondo areas with any oil based rattle can primer.
8. First coat of paint or adhesive and veneer.
The problem will all spray enamel primers and oil based primers such as kilz123 and the rest is that they flash too quickly. That is they are drying so quick that it will not sink into the wood. Just look at the can of primer and look for something that requires 24 hours before a top coat can be painted over it. All major paint companies make them.
Miller, Behr, Benjamin Moore, Parker... etc.
If you are looking for a product that will make the MDF take a stain and you want a nice even coat then the product is Benite. All quality painters use it on real wood products to allow stain to absorb evenly and protect the wood from bad stains (fingerprints, grease, smears etc.) till it is stained. The problem with Benite is that the MDF will soak it up very quickly and will require obscene amounts of it to do it well.
When doing wood working I will always do my steps in this order.
1. Final assembly
2. Rough sanding prior to priming.
3. Slow dry oil primer.
4. Second sand to get rid of any imperfections in primer.
5. Bondo and nail and screw holes.
6. Sand.
7. Spot prime bondo areas with any oil based rattle can primer.
8. First coat of paint or adhesive and veneer.
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