How best to eliminate LP warps

I have used the Vinyl Flat plates and heating bag on at least 20 LPs. I was very satisfied with the results. I have used on both vintage and new releases. If the device doesn’t completely remove the warp, it can reduce the warp to barely noticeable. 
 

I purchased the system to 1) Avoid dealing with LP returns, 2) flatten a number of already owned LPs. I am completely satisfied with the results. 
 

www.vinylflat.com

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.

OUTER RING. It will flatten out pretty much anything while you play it. Who cares what it looks like in the sleeve.

A must on my rig.

OUTER RING

+1

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.