Good consensus when i wrote 50°C that were in the dial of the oven and don't need be the real temperature..
But yes time is on your side.
How best to eliminate LP warps
I own about 2500 LPs, and I like to think they're flat. Furthermore, I espoused the view that warped LPs ought to be discarded. But lately I have found 2 or 3 of my LPs that do have warps but sound too good and are too precious for the music recorded on them to throw away. So I am in the market for ideas on how to remove warps. I am aware that there was a device on the market that looked like a large waffle maker, to be used for warp removal. I think Furutech made it, but I never see it advertised these days. I am also aware of the DIY method of placing an LP between two glass plates and heating the ensemble. The question there would be how hot and for how long? Any suggestions are welcome, especially opinions on the efficacy of the Furutech. Thanks. Please no comments on vacuum hold down; I think it's a great idea but none of my five turntables has that feature.
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The vinyl disc is manufactured using a compression molding process. Theoretically it is a process that will induce the least amount of "molded in" stresses in a plastic part like a record disc. There are a variety of reasons why a vinyl disc made like this will warp. From the process itself, from discs not stored properly, etc. To remove the warp you need to apply a type of annealing process where you want move, or reposition, polymer chains. This can be done in an oven. You will need to set the temperature control to the desired temperature and apply a force. After time the disc should be flat. The glass transition temp of PVC is 83C so this is the target temp. You will need to be at or just above this temp to get the polymer chains to move. If you place the vinyl between two aluminum plates and place a weight of 1kg on top this should work. Place a thermocouple in the oven and determine what setting is necessary to achieve 83C. It will take time to come up to temperature and then there will be a necessary dwell time to make the disc flat. The time can be determined through a little experimentation. And it will also depend on thickness of the vinyl disc. I did this before and it worked well. |
@drbond thanks for the info on Mockingbird. I saw an Orb listed here on Audigon recently, but it was almost the price of a new one, so I passed. It did get snatched up pretty quickly. Agree with those that mentioned using an outer ring. If your table will accommodate one, that's a great way to go. I had one with my VPI Classic 2 and it worked great. I don't think it would be a good idea to put one on my Sota Sapphire with it's suspended chassis, which is why being able to flatten my records is appealing. I have the Sota clamp which works well, but doesn't do much for warps where the outer edge is bent upwards. |
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