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Dayton CX150-8 Coaxial Project

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  • #76
    Originally posted by emilime75 View Post

    Not sure, I just assumed since both are from the same line, so I could be wrong. PE photos aren't much help. Maybe 4thtry could verify?
    Yes, I can see vents.
    Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build
    Plan-Tanic: http://techtalk.parts-express.com/sh...ght=Plan-Tanic

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    • #77
      Originally posted by tomzarbo View Post
      Looks good Bill.

      How do you like particle board to work with compared to MDF. It's a lot nicer, right? I need to use it more often, it doesn't make dust like MDF and it doesn't smell so funny.

      I like the idea of using the scraps to make a clamping fixture, great call there. Not sure if I did that or not on any of my projects, but I probably should have if I didn't!

      TomZ
      Thanks, Tom. For this project, I changed from MDF to particle board for a number of reasons:

      1) Particle board is roughly 1/2 the cost per 4x8 sheet
      2) Particle board is slightly lighter than MDF (not much, maybe 10% or so, based on my crude bathroom scales measurements). I wanted to keep the cabinet from getting too heavy, as I intend to do a double thickness 1.5" baffle board. It will be a composite of 3/4" particle board and 3/4" solid walnut. Solid walnut is very dense and heavy stuff.
      3) As mentioned, MDF is very dusty stuff.
      4) This is subjective, but recently the MDF that I have purchased has tended to be somewhat flaky. I remember years ago using 3/4" MDF and when I routed the baffle recesses, the recess was very clean. Recently, my baffle recesses using MDF have been very flaky looking. At first, I thought I had a dull router bit, but installing a new bit produced the same results. Not sure why this happened to me, maybe I just got a bad batch of flaky MDF or something.
      Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build
      Plan-Tanic: http://techtalk.parts-express.com/sh...ght=Plan-Tanic

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      • #78
        Originally posted by JavadS View Post

        It's all I used when I was a kid doing speaker building, but I remember it was pretty crumbly, MDF holds a very sharp edge and is very machinable (though it's weak as heck if you bump or hit it), the dust is horrible though which is why I'm a plywood and solid wood guy for the most part these days. I noticed Bill is good with the bondo though, interested to hear your thoughts Bill.
        I must have gotten some bad MDF. In the past MDF was always very machinable with a sharp edge. And I always use a good dusk mask with MDF.
        Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build
        Plan-Tanic: http://techtalk.parts-express.com/sh...ght=Plan-Tanic

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        • #79
          Originally posted by 1100xxben View Post
          Bill, I think you'll be surprised how much stronger a laminated, curved side is. I built a pair of stentorians a few years back and used 6 layers of 1/8" HDF on the sides. In hind-sight, I could have easily gone with 3-4 layers and the cabinets would have been significantly lighter and the side walls would have been more than stiff enough. Of course you're more than welcome to use 6 layers, but I'm just letting you know that I don't think it will be necessary to go with that many.

          Also, I built a "Dr. Seuss" bookshelf for my sister recently and made the curved sides with 3 layers of 1/8" hardboard, just like you're doing. I scuffed each layer by hitting it quickly with some 40 or 60 grit on the random orbit sander, just to take the shine off the smooth faces and make sure the glue has a chance to soak in. I used Titebond Extend wood glue, which has an extended working time for applications such as this. When I made my forms for gluing/clamping, I put some weather-stripping on the edge and left the paper attached to the "outside" of the weather stripping. This gave a smooth surface that would flex a little as it gets clamped down. Otherwise, as you add layers, your curve actually changes shape slightly and you're no longer applying clamping force to all the areas necessary. The weather-stripping helps keep clamping force on the entire area. It's not a perfect solution, but it works better than just using the cutoff piece as your clamping surface. For some reason I chose to use weight, which was barely enough. If I build another, I'll use ratchet straps.

          Attached are a few pics of my jig setup, but you cannot see the weather-stripping in these pictures. If you want to see it, I can take pictures tonight that show the detail of the weather stripping. Even though it's not speaker building, I might make an OT post on that bookshelf and show how I went about it, because some of the techniques I used are applicable to curved cabinets, and sometimes it's always fun to see a wood-working project other than a speaker box
          Thanks for all the great suggestions! I knew I was copying my curve shape from somewhere, but couldn't place it. My curve, however, is a little wider toward the bottom.

          My tentative plan is to line my compression fixture edges with self-stick felt. And as you suggest, I think I will add a thin 1/16" thick self-stick layer of foam rubber underneath the felt, to fill in the gaps created by the multiple layers. I am going to do several "dry" runs, bringing the clamps down slowly, without glue, to see how the first 3 sheets of 1/8" material tend to squirm under pressure. I may need to add a number of "alignment" clips along the edges to keep the panels in place as I apply the pressure.

          I will be using 3 layers on the first clamp up. As you suggest, maybe this is good enough. I'll give it the knuckle rap test before adding the second 3 layers. My plan is to lightly sand the smooth side as you suggest. Good tip on the Titebond Extend wood glue; I will check for this locally. Will post some pics of my "sandwich" clamping fixture when I get that far.

          How thick was the weather stripping that you used? Was it the spongy open cell type or the denser closed cell type?

          Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build
          Plan-Tanic: http://techtalk.parts-express.com/sh...ght=Plan-Tanic

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