Just about every option possible has been mentioned in this thread. If it
were me, I'd use several coats of shellac - good stuff, dewaxed - or epoxy (there are now some plant-based varieties if you're worried about the toxicity of the stuff).
Ok, I have a test object, I will try some options. I was not happy with dilluted PVA, now I am testing acrylic lacquer and spray paint. If I will be able to get shellac, that sounds good. Epoxy other than the very basic stuff is hard to get.
I've used this stuff to repair rotten wood on shed windows etc and it does what it says on the tin. Never tried it to seal raw MDF but might try it next build as it's easier to use than 2 part epoxy etc.
Rob.
If you don't want to use epoxy then polyester would do the same (though it comes with its own problems), or use some automotive 2K primer.
I recently fabricated a wood base for a turntable I wanted to sell.
Wood recently has become hard to get in the right sizes and grain patterns, so I opted for painting.
I used the Rust-O-leum dark brown satin for the finish and it came out quite nicely.
Of course the photo doesn't do it justice.
Wood recently has become hard to get in the right sizes and grain patterns, so I opted for painting.
I used the Rust-O-leum dark brown satin for the finish and it came out quite nicely.
Of course the photo doesn't do it justice.
With MDF (I use MRMDF which takes finish a bit better as it is made to be less absorbative) I lay down 2-3 coats of waterbased matt or satin varnish with a high density foam roller and sand inbetween. By this point you can look across the surface and see most imperfections and can fill or deal with.
(the third pic above is as the varnish is fresh on so hasn't levelled itself yet so looks more orange-peeley than it ends up but the reflections in the baffle which was already done show what you can get)
After that I use whatever paint I have plumped for and roller it on with the high density foam roller. You can get these with concave ends so they leave less lawn stripes. Layer on the paint a good few times then once thick enough I sand it back down to get rid of the majority of the built up texture. The over the top of that I do a couple of clear coats with the roller which sanding in between.
If it is a small project I do the above but do a final final sand then clear coat with Rust-O-Leum Crystal Clear satin. You have to wait for the waterbased stuff underneath to cure though. Then do some wire wool action then a final spray.
Here are some brackets I made with the roller/spray/wire wool combo:
Using a roller is a skill in itself, I have a realised. It's all about pressure and as you track down a panel you want to relieve pressure from the side that is the finished edge. You can get excellent results that show no roll marks as can be seen below which is black MDF that has had LOADS of clear coats:
Rollers may not leave the uber-flat surface but it's just about what I consider passable.
(the third pic above is as the varnish is fresh on so hasn't levelled itself yet so looks more orange-peeley than it ends up but the reflections in the baffle which was already done show what you can get)
After that I use whatever paint I have plumped for and roller it on with the high density foam roller. You can get these with concave ends so they leave less lawn stripes. Layer on the paint a good few times then once thick enough I sand it back down to get rid of the majority of the built up texture. The over the top of that I do a couple of clear coats with the roller which sanding in between.
If it is a small project I do the above but do a final final sand then clear coat with Rust-O-Leum Crystal Clear satin. You have to wait for the waterbased stuff underneath to cure though. Then do some wire wool action then a final spray.
Here are some brackets I made with the roller/spray/wire wool combo:
Using a roller is a skill in itself, I have a realised. It's all about pressure and as you track down a panel you want to relieve pressure from the side that is the finished edge. You can get excellent results that show no roll marks as can be seen below which is black MDF that has had LOADS of clear coats:
Rollers may not leave the uber-flat surface but it's just about what I consider passable.
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General purpose resin works for me. Still have a roll of chopped strand mat in the garage I bought from them about years ago 😀
Cool but you are missing the most important data, WHAT wood did you use?
HOW did you prepare surface?
Sanding, sealing, how many coats, etc?
This is s practical advice thread 🙂
Thanks.
Hey Mandoman,
If you were painting this onto c-grade hoop ply, what would your steps look like? I'm strongly considering a smooth white finish over my 5 cabinets for a 5.x system, but I REALLY don't want to spend 50hrs sanding and I don't have an airgun, so I'm not really sure how to finish them off.
Cheers for any advice you have,
Depends on how smooth you want the finish. For smoothest finish I would use Boat Coat epoxy first. Follow the Boat Coat instructions. Practice on scrap first because the result will depend on how good you are with applying and leveling the epoxy. Get it wrong and you will spend a lot of time sanding. After the 3rd coat of epoxy has thoroughly cured, sand it smooth. Now brush a coat of Norglass primer and sand smooth. It does not require much sanding. Next brush on 3 coats of Norglass paint, light sanding between coats. Done. You might get away with leaving out the epoxy steps, but try on scrap first. As always, the quality of the final result will depend on surface preparation and your skills with the brush, and practice makes perfect. You can't get away with little or no sanding, but if you get the epoxy on smooth it is not too bad.
Based on some of the earlier discussions, when I was testing paints and methods, I cut up some scrap Home Depot "hardwood plywood" (softwood plywood with an extremely thin birch veneer) square samples on the order of 150-200mm square and routed 3 edges with different bits to test different paint tpyes and brush / roller methods with. Among the samples I did were epoxy + primer + paint vs just primer + paint
On my samples that I prepped with epoxy vs. just primer (using Benjamin Moore Advance primer). I saw no significant difference other than the epoxy one was extra work. End painted surface was identical, provided adequate prep / sanding. I did an informal dent test, as I thought the epoxy base might offer a bit more hardness, but didn't see much difference between the two. Presumably the epoxy version does better when things get wet, but I think it would take a lot more water than speakers typically see for this to matter. Perhaps also the epoxy base coat is better when using a lower hardness paint, but I was testing the kind of paint I wanted to use (BM Advance,) which cures quite hard.
The BM Advance primer is expensive,, but for my tests, I came to the conclusion that the epoxy is an unnecessary step. Bonus is that the water base means it's really easy to clean-up and you don't have to trowel it or throw away brushes like with epoxy. I did use 2 coats of the primer (in both cases.) The primer did go onto the epoxy surface better, obviously. The bare grain soaks up the first coat and you must sand the nubs... but you get the same thing with the first coat of epoxy. Perhaps you could get away with one coat of primer on epoxy? Both that primer and the epoxy sands well, though the epoxy loaded the sandpaper a lot more than the primer did, it took a lot more cleaning off the sandpaper on the epoxy samples.
On my samples that I prepped with epoxy vs. just primer (using Benjamin Moore Advance primer). I saw no significant difference other than the epoxy one was extra work. End painted surface was identical, provided adequate prep / sanding. I did an informal dent test, as I thought the epoxy base might offer a bit more hardness, but didn't see much difference between the two. Presumably the epoxy version does better when things get wet, but I think it would take a lot more water than speakers typically see for this to matter. Perhaps also the epoxy base coat is better when using a lower hardness paint, but I was testing the kind of paint I wanted to use (BM Advance,) which cures quite hard.
The BM Advance primer is expensive,, but for my tests, I came to the conclusion that the epoxy is an unnecessary step. Bonus is that the water base means it's really easy to clean-up and you don't have to trowel it or throw away brushes like with epoxy. I did use 2 coats of the primer (in both cases.) The primer did go onto the epoxy surface better, obviously. The bare grain soaks up the first coat and you must sand the nubs... but you get the same thing with the first coat of epoxy. Perhaps you could get away with one coat of primer on epoxy? Both that primer and the epoxy sands well, though the epoxy loaded the sandpaper a lot more than the primer did, it took a lot more cleaning off the sandpaper on the epoxy samples.
In my latest attempt with mdf i came to an issue with place where i had roundover: the raw/ 'naked' mdf was thirsty with primer ( obviously!).
I didn't find a good way to have a proper finish so asked some woodworker friend how i could deal with it to have a constant behavior of mdf.
I've not tried it but he suggested to use some 'wooden floor vitrifier' ( i don't know it it is the exact term in english...this kind of stuff: https://www.v33.fr/passages-extremes-r-vitrificateur-parquet-escalier.html ) : 3 coats on the router processed location : first/second thick layer, third and final coat light layer on the whole cabinet.
Sanding after each coat obviously. Then paint after a waiting time of 1/2 weeks.
He showed me some furniture he did this way and with satin pu paint finish ( roller/brush applied) outcome was great. The guy is talented and experienced so i expect less stellar results than what he get but i hope it'll solve the issue i had.
I didn't find a good way to have a proper finish so asked some woodworker friend how i could deal with it to have a constant behavior of mdf.
I've not tried it but he suggested to use some 'wooden floor vitrifier' ( i don't know it it is the exact term in english...this kind of stuff: https://www.v33.fr/passages-extremes-r-vitrificateur-parquet-escalier.html ) : 3 coats on the router processed location : first/second thick layer, third and final coat light layer on the whole cabinet.
Sanding after each coat obviously. Then paint after a waiting time of 1/2 weeks.
He showed me some furniture he did this way and with satin pu paint finish ( roller/brush applied) outcome was great. The guy is talented and experienced so i expect less stellar results than what he get but i hope it'll solve the issue i had.
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Hmm, interesting translation from the link ... paint with balls.
In North America I'd use fresh, dewaxed, shellac but if you can't find it/don't want to mix it, then I'd use this:
https://www.rustoleum.com/product-c...shellac-base-primer/b-i-n-shellac-base-primer
In North America I'd use fresh, dewaxed, shellac but if you can't find it/don't want to mix it, then I'd use this:
https://www.rustoleum.com/product-c...shellac-base-primer/b-i-n-shellac-base-primer
Lol.
It's not really a paint, more like a varnish but water based, it is the product we use to renovate wooden floor, stairway,...after sanding. The nano ceramics balls are supposed to protect from shocks from the product blabla.
Anyway results i've seen were great. Same level of quality as pricey 'design' furniture. Worth a try for my issue.
He told me he used it with ply too.
It's not really a paint, more like a varnish but water based, it is the product we use to renovate wooden floor, stairway,...after sanding. The nano ceramics balls are supposed to protect from shocks from the product blabla.
Anyway results i've seen were great. Same level of quality as pricey 'design' furniture. Worth a try for my issue.
He told me he used it with ply too.
