Vinyl flattening combines art and science, and often requires experimentation. Vinyl composition varies dramatically by record, and every warp is truly unique.
To fix a warped record, you need three things:
In this post we will talk about Heat, which is the most important variable to control with precision to get flatter results with less risk of damage. While we will not get into vinyl chemistry thermodynamics in this post, the key thing to understand is quite simply… controlled heat accelerates the process of flattening out warps.
When it comes to flattening vinyl, at Record Pi we refer to the 2 C’s of Temperature:
- Curve – What is the shape of the temperature curve of the heating process?
- Control – How much does the temperature vary from target during flattening?
Every heating/cooling session has a Temperature Curve when you graph temperature against time. When flattening records, you want the temperature to gradually increase until it hits the target flattening temperature, and then hold temperature steady until completion, when the record gradually cools.
We call this the Tabletop Curve because it looks like this…
The Tabletop Curve (for the math geeks, it’s technically called a Sigmoid function) minimizes risk of damage, while also maximizing the softening effect of the heat on the vinyl that is necessary for flattening out records.
What you do NOT want to see are rapid increases or decreases in temperature, or significant fluctuations from the target flattening temperature. When using manual techniques such as the “two panes of glass in the oven” method, you will typically see a Temperature Curve that we call the Devil's Fingers because it looks something like this…
This brings us to the 2nd C, Temperature Control. The Devil's Finger curve is risky. If the temperature spikes too high the vinyl grooves can be damaged or destroyed. The spikes in temperature also result in a less flat record because you are softening and hardening the vinyl in short little bursts, which is not ideal for vinyl softening given it’s composition.
Once you reach the target temperature, you ideally want to maintain the temperature within 1°F of the target. The Record Pi achieves this out of the box.
This brings us to a final question… What is the best target temperature to flatten records?
Although we hate to say it, no single ideal target temperature to flatten records exists, as it depends on the record, the warp, your tolerance for risk, and your patience.
Every Record Pi system comes preconfigured to target 125°F for flattening, which is a relatively safe temperature for vinyl records. We recommend starting with a 2 hour heating session at 125°F to seeing if the warp improves. If the warp has not improved, we typically recommend keeping the target temperature at 125°F and increasing the time for an additional session.
We do know that many records can be safely flattened up to 135°F, particularly those of heavier weight. However, some vinyl may be damaged at that temperature, so we always recommend increasing time before attempting to increase your target temperature.
But ultimately that decision comes down to how bad the warp is, your personal tolerance for risk of vinyl damage, and your patience.
With the Record Pi vinyl flattener you have a tool that you can optimize for your unique collection, while maintaining complete control over the variable of Heat.
- Mark @ The Record Pi Team