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Cutting painted baffels without destroying them. What's your technique?

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  • Cutting painted baffels without destroying them. What's your technique?

    Pre-made, painted baffels like the ones that come with Dayton cabinets. Curious to know how other amateur speaker builders are cutting these without scratching or chipping the paint. These Dayton baffels are beautifully finished with satin black paint, but they are also really fragile. So fragile I've found it's even difficult to remove pencil marks without visible change to the finish. IMHO, to cut and drill holes in them without damaging the finish poses a whole new set of challenges than cutting an unfinished baffel. The required precautions and extra steps in my experience also add a significant amount of time and effort to the process.

    With respect to cutting holes I'm really talking about two different kinds of of cuts: The first type would be your basic cutout for a drop-in driver where the mounting flange sits on top of the paint. For this type of cut one only needs to worry about the size of the hole, and of course generally avoiding damage to the paint. The second type of cut is a shallow depth cut needed to recess the driver into the face of the baffel. In this case we're talking about leaving a visible, painted edge around the circumference of the driver, one that obviously needs to be perfectly sharp and without any chips in the paint.

    I'd really like to hear from other speaker builders about the techniques you've developed to cut painted & finished baffels without damaging them. Because who knows, my current methods may be completely off the mark (ha ha).

    As a starting point for the discussion, I'll try to briefly describe my current methods.

    For all my cuts I'm using a Jasper circle jig, a 1/4" plunge router and a 1/4" spiral upcut router bit. I should mention here that I plan to upgrade to a 1/2" chuck plunge router soon because I've found the 1/4" bits are not stiff enough (they can flex enough to impact the shape of the hole). For basic (drop in driver) holes I've been cutting those from the
    back (unfinished) side of the baffel. I got a tip early on (I'm fairly new to woodworking) that the key to sharp holes is to cut with another board pressed flat against the surface you're trying not to wreck. The general idea is to cut a little bit deeper than your baffel on your final pass so that the bit cuts into a "sacrificial" piece of wood below. Obviously you can't just put the painted surface of the baffel face down on a sacrificial piece of MDF without scratching the **** out of the paint. So what I've been doing is using a piece of the white protective foam the Dayton speakers are shipped in as a protective layer between the sacrificial board and the painted face of the baffel. Using four 1 1/2" deck screws I literally screw the baffel to the sacrificial board (with the screws inserted in the pre-drilled holes in the corners of the baffel. The heads of the deck screws when screwed down tightly sit flush enough in the holes that the Jasper jig can pass over them without getting stuck. Next I drill my 1/8" pilot hole and begin making a series of shallow cuts about 1/4" at a time until I cut all the way through the foam into the board below. Note: The second you penetrate that last little bit, be very careful not to let the router bit wander off into the finished edge you've just cut because the center of the circle your router is attached to is now perfectly free to move in the wrong direction... This generally leaves a nice clean edge plenty clean enough for a drop-in driver, though probably not quite clean enough for a recessed baffel cut.

    Recessed cuts are a different animal. For obvious reasons, these cuts have to be made from the painted side of the baffel. So we need a way to protect the paint and make cuts while another piece of wood is pressed firmly against the painted surface (to prevent chipping). Here's how I've been doing these. While the white foam is great for protecting the paint, it still has some thickness to it which would in theory result in a rougher (painted) edge than we'd get if the paint was pressed directly against a sacrificial piece of wood. So what I've been using is that green protective cling wrap you can buy at Home Depot. It's basically a giant roll of Saran wrap. I carefully wrap the painted baffel in the green stuff so that there's only one layer of the wrap laid perfectly flat on the front of the baffel. This protects the paint as long as you are very careful not to let any sawdust or debris get smashed into your clean, wrapped surface. A piece of blue tape across the seam where the wrap overlaps on the back seems to help keep the wrap from falling off. Before wrapping the baffel in plastic however, I carefully mark the centers of my holes on the back of the baffel. Because visibility is not so good after wrapping, I also make a small indentation with a center punch. Next I cut a piece of thin, finished plywood to be slightly larger than the dimensions of the baffel. Home Depot sells pre-cut "hobby" sheets of plywood. One of the products they offer is a thin, inexpensive plywood about 3/16" thick. I think they call it underlayment or something like that. It's smooth like finished plywood but not so pretty. Next I lay the baffel face down and centered on the thin piece of plywood. Again using four, 1 1/2" deck screws I screw the whole assembly to the sacrificial board. The screws go through the four pre-drilled corner holes into the plywood. Using a hand drill with a drill press attachment I drill my 1/8" pilot holes all the way through both boards. Next I remove the screws and flip the whole assembly over. Using a couple of 1/8" drill bits for alignment, I insert the 1/8" bits into the pilot holes. Then I re-insert the deck screws to secure the assembly to the sacrificial board. The heads of the screws need to be slightly below the surface of the plywood, so tighten them just enough to do so. Now you can begin making your first recessed cut. Note that the first cut needs to be deeper than the thickness of the plywood and deep enough to penetrate the painted surface at least 1/8" or so. Cutting the recess requires setting the jig to make multiple, progressively smaller holes. It's easy to check your progress because the thin plywood circle will come off with your jig. Be sure to keep putting the loose plywood circle back into your hole so that the jig sits flush at all times. After you cut the recess you can set the jig for the hole that needs to be cut all the way through the baffel. The "through" hole can be cut from the front this way as opposed to the method described above.

    I can't speak for others, but in my case this whole exercise is tedious and time consuming; and mostly due to the need to protect the paint.

    Please share your feedback, ideas and the techniques that have worked successfully for you. Looking forward to hearing from others!

  • #2
    Lots of painters tape.
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    • #3
      Originally posted by Pete Schumacher View Post
      Lots of painters tape.
      +1
      -Kerry

      www.pursuitofperfectsound.com

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      • #4
        Use shelf liner - there are 2 kinds, a heavy stick and a light stick.
        Use the light stick kind and cover the baffle.
        It will tend to tear out a bit while you are routing circles, but works well in my experience.

        Something like this:
        https://www.amazon.com/Light-Adhesiv.../dp/B002IXDJ3W

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        • #5
          Originally posted by Pete Schumacher View Post
          Lots of painters tape.
          +2 works like a charm
          .

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          • #6
            painters tape, shallow first cut and a sharp bit. i.e. new sharp down-cut bit is best for the first pass.
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            • #7
              Contact Paper. Peel and stick shelving paper.

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              • #8
                I have also used the white light stick shelving paper. It worked great and the white color made it easy to pencil in drilling locations.

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                • #9
                  Wow, thanks guys. It hadn't occurred to me that adhesive tape alone would be enough to prevent the painted edges from flaking and chipping. The down-cut spiral bit on the first cut makes sense as well. I plan to try all of the above...

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