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Discussion Starter · #1 ·
Hey all, need some advice on finishing my custom stand.
The stand is all MDF. I've read on here about using an oil-based primer, and I stopped by Home Depot today to pick some up. However, the guy behind the paint counter mentioned that there is a certain time frame after applying the oil based primer that water-based paint will stick to it, and if you wait too long the paint will just peel off. :confused: Is this a line of bull, or is there some accuracy to this? If its true, what time frame is it?

I was planning on 2 coats of Kilz oil-based primer, then 2-3 coats of paint. Do I need a sealer on top of that? If so, what's a good choice? Any advice on type of paint?

I'm also a paint noob. Any general advice for painting it? I'd like an ADA-like gray finish.
Some pics of the unfinished stand, which was built by a friend who is an amazing finish carpenter. (He swears this was "slapped together", but it looks pretty awesome to me!)





Thanks!
 

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First Killz makes a great shellac based sealer, with white pigment in it, so it acts as the primer. It dries very quickly, can be lightly sanded with fine paper to knock down any bumps, dust specks, etc. and it is a great primer for latex paint or any other non-alcohol based paint. There is no need to use oil based primer at all - old fashioned, not very good now with the current air quality regulations cutting way down on the volatile components in it. If you lightly sand with 200 grit paper between coats you can get a pretty nice finish with acrylic/latex paints. No need for any clear coat on top of that.
 

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I agree with Hoppy. Shellac is great for water resistance for MDF lightly sand prior to your finish color.

My personal preference is a spray on acrylic whether by a low pressure sprayer or a can. At least two coats then burn in a coat of a high quality clear furniture wax with #0000 steel wool. Wait 24 hours. Add a Japan wax and let dry. Then sparingly add another coat of the first wax with cheese cloth and polish to desired finish, lots of elbow grease with a diaper for a high gloss, down to a shoe brush for a matte finish. Will give you a long lasting finish that if water ever hits it, it will bead up like a finish on a new car. Plus if it ever scuffs you can polish it back up as opposed to a spray on clear coat.
 

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Discussion Starter · #9 ·
First, thank you both for the info. I didn't actually know what shellac was before now. After a few minutes on wikipedia, I am both enlightened and fascinated. On a side note, I'm never going to eat another skittles again without being slightly creeped out.

Hoppy - I'm slightly confused. If I understand you correctly, you're saying to NOT use oil based primer. But you also recommended Kilz. My confusion is stemming from this - Kilz Original Formula, specifically this description - "Originally developed to replace pigmented shellac sealers, KILZ Original primer/sealer..." I went through the rest of their product line, and can't find anything like you describe, on their website or locally.
So do you by chance mean something like this - BIN Shellac Base Primer?

JDowns - would spraying with a can look decent, if I've never done it before? And I will definitely try what you described with the wax. What exactly do you mean by ""burn in"?

Thanks guys, sorry if I'm being slow here.
 

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You can use any shellac. A good rule is when it stops penetrating easily. I've had the best results with multiple thin coats of thinned down shellac. A final sanding of 200 grit or greater will give you a nice smooth finish for painting.

The point for burning in the wax with #0000 steel wool is the paint will mix with the first coat of wax giving you a perfect solid color. I lightly buff with a shoe brush this coat after smoothing with steel wool. It may take multiple coats to get a perfectly smooth finish. Let dry overnight between each coat. You can consider this like color sanding a cars finish. When smooth add a coat of Japan wax, also Profix works really well and is cheaper. It takes very little of this and is quick to apply. The final coat of wax on top of this is your finishing coat and can be buffed to the desired finish. Whether it is a high gloss, semi gloss, or matte finish. The final coat of wax gives you a finish that you can just buff when scuffed and always keep that new look without any oils. I prefer this method over clear coats to avoid that plastic look. You can also use a clear coat then a simple coat of wax on top and skip the Japan wax. The wax will give the finish a sense of depth and really good protection against any moisture.

You should test whatever method you choose on a test board before applying to your finished product. This will allow you to see the finished product and work out any kinks prior to applying to your piece.

If you've never sprayed before then I would test, test, test. Light thin coats. First two coats shouldn't look perfect. The key is patience.

The bottom inside of this stand is nothing more than cheap flat black primer from Ace buffed out with a shoe brush for a matte finish. Water beads up on contact. The back is just primer with one coat of unbuffed wax, I wasn't to worried about the finish on the inside of this stand. I just added the extra protection for the bottom in case water ever spilled.

 

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Hoppy - I'm slightly confused. If I understand you correctly, you're saying to NOT use oil based primer. But you also recommended Kilz. My confusion is stemming from this - Kilz Original Formula, specifically this description - "Originally developed to replace pigmented shellac sealers, KILZ Original primer/sealer..." I went through the rest of their product line, and can't find anything like you describe, on their website or locally.
So do you by chance mean something like this - BIN Shellac Base Primer?
It has been about 5-6 years since I bought some of that primer, so I can't be sure it is still sold. It was a primer/sealer that used alcohol as the solvent, not oil. Alcohol based coatings are almost always, if not always based on shellac. Oil based primers are alkyd products using mineral spirits as the solvent. (I may not be 100% accuate with this.) Those oil based products now have to meet strict air quality regulations which greatly limit the amount of solvent in the coating, and make them a much poorer product. This applies to oil based varnish and paint, as well as primers. The professionals I have talked to about this don't use oil based products anymore for that reason. But, alcohol based products are not "oil based".

The Kilz Original Formula looks a lot like what I used to use, and if it says to clean the brush with alcohol, it may be what I used to use. The fact that it dries in 30 minutes almost guarantees that it is an alcohol based product. I would use it now if I wanted to do what you are doing.
 

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Use fasteners for what? Is this just a board attached to the wall, or part of an aquarium stand? I would always install all fasteners - nails, screws, etc. - before applying any finish coating, so I could use spackle or wood filler to fill in the holes where the fasteners are. I see no reason to finish the MDF first.
 

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I would agree with Hoppy that an alcohol based primer will work great for this. With MDF it wants to absorb anything water based and just keep swelling. Zinsser BIN primer is what you are looking for, and you can get that just about anywhere. One last thing you should do with MDF... Seal the exposed edges of it. Everything else will paint up great but you will still have rough edges. You can just use a brush to paint on 2 coats of Zinsser and then sand it smooth. After that you can apply 2 more coats to all of it including the edges again, and sand it real quick til it is smooth. And then use your top coat.
 
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