How to achieve the "best" black satin paint job without a lot of sanding?

I have had some veneered MDF with exposed edges due to roundovers by routing and just varnished the lot, and it comes out nice.

Yes, if I thought it through, I would have done that. I noticed that routing the edges after painting leaves a really nice look on the previous speakers I've built. Painting is really a pain :mad: And my speakers smell like pickles because my sanding sealer is stored in a jar that held pickles. Why is it you can't get rid of the smell of pickles from a glass jar no matter how many times you wash it?
 
Iv'e had excellent results using satin black paint and a roller with light sanding inbetween coats.

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peterlo

Member
2007-06-18 10:38 am
Some great finishes shown here which reflects a good deal of experience.
But the original question is not well addressed.
My 2 cents would be that there is no easy method for the DIY'r.
A good finish always means lots of work & a fair bit of skill & patience.
How about asking the previous posters to estimate the man hours just to (decoratively) finish their examples.
 
I was thinking of maybe using a roller to roll or paint on the primer at least. I've used a roller for speakers before. It came out okay, but not that great. I think it was interior latex paint.

It is a lot of work. I already have about 10 coats of sanding sealer on them right now, lol, so that's good, I think.

I should have built a speaker out of plywood or at least veneered them. Looks like I didn't give finishing much thought. I don't like the look of wooden speakers, looks archaic, but I know there's wood under all that paint anyway, so what's the point, lol? Not sure why that was an lol, I think it's the sanding sealer fumes, which I've now gotten use to and find quite pleasant. Is that bad? :D
 
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peterlo

Member
2007-06-18 10:38 am
Jimmy,
I also have tried roll on undercoats.
Alas despite experimenting with oil & acrylic based undercoats & with different solvent content, the results were frankly poor, & worse, none of the undercoats i tried were genuinely "free sanding" so obtaining the required smooth finish was very time consuming & difficult.
I recommend anyone trying this approach first find a genuine "free sanding primer-surfacer". They are available but not in your average home paint supplier depot.
 
Wow, sanding and painting speakers in your living room is really bad idea. Speaker fell into my plasma tv and cracked it :rofl: Now my apartment smells like sanding sealer, primer and paint and there's dust everywhere. I was being super cheap buying MDF when I started this project, but it is really worth it in the long run (maybe it might even be cheaper) to purchase plywood and finish the plywood with some clear coat or stain then clear coat, if you don't mind that look. I should know better by now. I guess I never learn :D
 

peterlo

Member
2007-06-18 10:38 am
Jimmy
Yeah, .................. I once, when first married & living in our first small home, brought my 12 foot sailing dinghy through the sliding windows/doors of our living room. And we (Wife & I) sanded, stripped, & fibre-glassed the seams, before undercoating for a friend to spray elsewhere.
Well I guess you do what you have to, but never again!
As for MDF: it's hard to avoid it's use, especially in speaker cabinets. But you need to be careful to have at least the mediun density grade & allow for extra bracing as well as increased wall thickness. That's if you wish to emulate the sound of plywood which is much more expensive when one face is paint ready.
Also be aware that MDF seams will always show unless you use epoxy glue, not sure why this is; PVA is strong enough & easy to use but those damned seams will show after some time.
Clear finishing plywood or MDF is unlikely to give a pro standard finish. But if you use marine ply or veneer yourself then you should have the potential for a clear furniture finish
 
Never sand down MDF of plywood without areally good dust mask on.

Always use a "cork" or "rubber" sanding block with your sandpaper for flat surfaces.
Use silicon carbide wet and dry. Dry with wood and wet with paint finishes. Always use a little soap in the water when using wet and move the sanding block in a circular "random orbit" manner. With a rubber block often the weight of the block alone gives enough pressure for the cutting action to take place, so try to sand down surfaces when in a horizontal position; this also keeps the water on the surface.

I would avoid using MDF on health grounds. Use Marine or Birch plywood instead.

Have your finish coat done professionally.
 
Never sand down MDF of plywood without areally good dust mask on.

Always use a "cork" or "rubber" sanding block with your sandpaper for flat surfaces.
Use silicon carbide wet and dry. Dry with wood and wet with paint finishes. Always use a little soap in the water when using wet and move the sanding block in a circular "random orbit" manner. With a rubber block often the weight of the block alone gives enough pressure for the cutting action to take place, so try to sand down surfaces when in a horizontal position; this also keeps the water on the surface.

I would avoid using MDF on health grounds. Use Marine or Birch plywood instead.

Have your finish coat done professionally.

I didn't do any of those things :D

Yes, MDF is awful. It is bad for you, if you breathe the dust. I should know better by now. I would have been much better off with plywood.

That Rustoleum textured finish needs a lot of coats to look right I think. Four cans were not enough for my speakers. But I'm going to leave them as they are, lol :D
 
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To get a decent finish on MDF all you need is a thick quick drying water based primer. Paint on several coats, then sand flat. Spray on your paint of choice and you're done.

The MDF doesn't need to be sanded, unless it's really uneven. Simply paint a primer on with a brush and build up a few substantial layers.

The water based one I used recently dries very quickly if you apply a very thin coat. I chose to apply a couple of very thin coats immediately to the MDF then put on two-three thick coats. The thick coats needed about 3-4 hours to dry. Leave over night and the primer is completely dry. Now you have to sand it flat, the bonus with the primer that I used is that it is quite soft and very easy to sand, 240 grit made light work of it until the paper became really clogged. I used an orbital sander to do most of the hard work and it's dust extraction facility prevented the paper from clogging. Of course you have to hand sand if there are any round overs to etc.

After you've sanded flat, it should only require a small amount of paint for you to end up with a decent finish. If you want, I can take some pictures of something I did recently to show you the results.
 
Trying to finish MDF without coat(s) of primer is definitely a losing game. Sanding is a joke unless the primer is completely cured so that it cuts without loading up the paper. A couple days getting turned around in the summer sun gives everything enough heat and thermal cycles to help the last coat of primer cover things that will probably not move much again if you let them rest for a couple more days after "baking". One or two coats and then sand the rest individually at least a little. The sanding is not so hard if you can actually get a lot of cutting and less friction for it. I've sprayed high grade exterior latex paint, black satin actually, and it looked good enough. Most of the speakers came out with no visible seams, second up from bottom grade wood glue. It seems like rushing a finish job is what causes the most headache, which would be odd for a DIYer, since that's the cheapest resource so long as you're free to do something else for most of it.
 
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