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Discussion Starter · #1 ·
Anyone ever get recones and the foam surrounds are warped from the box being smaller than the cones? All four cones had flat sides in 2 spots on the surrounds from being squeezed in. I assume this is normal, happens with every recone kit sent out as it's a standard cardboard box used to ship them.


I thought using clamps to flatten them would work but I have 2 bad recones, one so bad that it has a flat side on the surround and it makes noise.




















heres the flat side, this driver makes noise right at that spot onless I press the surround in with 1 finger. The two bad recones wouldnt lay flat on the mounting flange so they are angled and brittle.



 

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What you are seeing is pretty standard with foam surrounds. You can't really call it damage. We get boxes of new cones that come in with surrounds that way. As long as they are glued straight they'll be just fine when broken in. If you're gluing the surround down you need a solid ring that goes all the way around to put even pressure on the surround all the way around. It fits tight against the outside of the roll to help hold the right shape and flatten the surround against the frame.


Shim the coil, glue the spider first. Then pull the cone upwards lifting the surround off the landing and put your glue on the frame under the surround. This is where you need to have the coil shimmed precise enough that when you pull the cone upwards it will hold in that position. A precision gap gauge should come with a recone kit, or shimstock that is cut precisely enough to fit that gap that way. When you glue the surround, set the ring over the surround first then use the ring to push the surround down into the glue. The bottom will be flat and then you just push that part out so it is tight against the ring. Then clamp with 6-8 spring clamps around the ring. Again this takes a precision machined ring that will fit the surround right. You also want to make sure you don't have too much glue to glue the ring down. We use HDPE so the glue doesn't stick but you can use MDF if you're careful.


If you're using CA glue though gluing a warped surround becomes more difficult as it will want to stick before you can push it into the proper shape. Also, using CA glue on a foam surround isn't really a good idea. It can work and people do it, but until it dries the solvents will actually eat into the foam. In addition to that, if you have squeeze out on the inside it creates a sharp edge that can cut through the surround over time, especially where the foam has already been weakened by the CA glue. For surrounds it's ideal to have a softer flexible glue that can't cut into the foam.


John
 

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Discussion Starter · #3 ·
John, very informative, thank you! What is HDPE ?
 

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Also used for those milky white cutting boards.


I just Googled and found one source where you could buy a 24x24 inch 1/2 inch sheet for $45. I imagine you could cut a ring out of that with the right precision equipment. Maybe someone who wants a 12 inch ring could hook up with someone who wants a 18 inch ring and split the cost.
 
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