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  • MDF enclosure

    Hi I am building a MDF enclosure and just thinking about the finish. It will either get painted or use some sort of wood-like sticker/wrap around it. If I go down for the route to paint the MDF, should I assemble and glue together the parts first then paint or the other way around? Does the MDF need to be primed before using those wood wraps ? Thanks.

  • #2
    Originally posted by Cruciata View Post
    Hi I am building a MDF enclosure and just thinking about the finish. It will either get painted or use some sort of wood-like sticker/wrap around it. If I go down for the route to paint the MDF, should I assemble and glue together the parts first then paint or the other way around? Does the MDF need to be primed before using those wood wraps ? Thanks.
    Welcome to the forum!

    I guess how to finish it sort of depends on how you Construct it. If you plan to have a complete box with standard openings for drivers, then for sure, assemble, sand, paint. But if, for example, you were planning on making a basic box with decorative sides, then it probably would be a good idea to prep and paint those, then add to the box near the end of the process.

    Also, you didn't ask, but.... I've used the vinyl sheet wood-look veneer and it was actually very difficult to get it to look right. trimming edges was tough to get perfect, and if you sliced in a bit, the cabinet underneath showed through, which I didn't like. Also, corner seams are just hard to get looking nice. At least for me. I have a much easier time using veneer. Though it's much longer time-wise to apply, it's basically a lifetime finish if done correctly.

    The one and only time I used vinyl wrap, I didn't do anything to the MDF. Maybe I should have at least sealed the end grain with glue or something first, but I didn't.

    TomZ
    Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF

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    • #3
      Sealed or painted MDF works best with wraps imo. When priming MDF don't use anything water based for the first coat. Water based anything makes the MDF swell. Use oil based or shellac based BIN primer for the first coat. +1 on the veneer
      John H

      Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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      • #4
        Glue lines are a problem if you use the wrong glue. PVA will sink in after time. Use powered resin glue. Stronger and won't sink in.
        I use polyester resin for fiberglass as my sealer. 2 coats. It can then be sanded without fuzz perfectly smooth. Then prime and paint as your choice. Best finish is of course high built 2K primer and 2K color coat with clearcoat but that is expensive. You can do very well with a few rattle cans.

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        • #5
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          MDF and rattle cans...however, this is a lot of effort....the following to be exact

          Coat of sanding sealer
          Sand (240)
          Coat of sanding sealer
          Sand (380)
          Coat of primer-filler
          Coat of primer filler
          Sand (400)
          Coat of black
          Coat of black
          Wet Sand (400)
          Coat of black
          Wet Sand (800)
          Coat of clear
          Coat of clear
          Coat of clear
          Wet Sand (800)
          Coat of clear
          Coat of clear
          Coat of clear
          Wet Sand (1000)
          Coat of clear
          Coat of clear
          Coat of clear
          Wet Sand (2000)
          Polish
          Wax

          I would hate to do this on a whole box!! And warning - rattle can enamel paint doesn't really cure that hard so you'll be handling the speakers with velvet gloves for the rest of their lives.

          With MDF definitely use a sealer (as mentioned a non-water based version). I use Feast Watson Sanding Sealer (but this is an absolute pain to sand and I'd like to find a better alternative).

          If you have any exposed 'end grain' of MDF you must seal it really well. It will react with moisture and one day you'll be looking at your veneer wondering why the edge join line appeared. With exposed edges I would go so far as to seal them up with a smear of builders filler as a final step before sanding down the boxes.

          I have a current project under way made with a layered construction of mdf (so all edge grain down the sides of the box). I've applied a layer of cheap "backing" style veneer to the boxes first which will be followed by the final veneer. You will be surprised how much even the smallest imperfection will show through a layer of veneer (and that's timber veneer) - the micro thin plastic stuff will be even worse.

          I use contact adhesive for my veneer and edge grain mdf actually requires two coats of the glue before you apply the veneer. So one coat down, allow to dry but not cure, then apply the glue coats to both surfaces and bring together.
          Last edited by DeZZar; 01-21-2021, 09:11 AM.

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          • #6
            Very purty though !

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            • #7
              link to Brad's MDF box finishing techniques, there are 3 videos in the series. https://www.youtube.com/watch?v=Ixui...annel=Hifiside
              John H

              Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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              • #8
                That's true. Sealed or painted MDF works best with wraps imo.
                2048

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