Flattening warped lp's with Seal dry mount press

Photon46, your efforts are promising.

If the Seal press works for you, I may copy your efforts so I can flatten out those few warped LP's in my collection that are otherwise perfect.

It's likely that you must hit the exact heat and cool ratio to achieve success (as suggested by other posts here).

You might even test your Seal with an oven thermometer to determine the exact temperature. That would verify the control on the Seal has not gone off the mark over time.

Interesting concept. I know a fair bit about dry mounting but don't know if any of the same information may apply to flattening LPs. With boards and paper it is always good to use a heavy, flat steel plate immediately upon removing the hot board from the press. This allows the heat to dissapate more evenly and quickly while continuing to be under the pressure of a heavy plate. Without the plate If the hot board cools too quickly and or unevenly it will tend to curve. Also, I'm not sure if they are still available, but Seal used to produce "temperature indicator strips" to quickly and conveniently gauge the temp of the press. These were made at with two colored 'buttons' of some plastic-like material. Each color melted at a specific temperature. They were made for to accomodate the more specialized low-temperature mediums for dry-mounting which would make a mess at higher temperatures. I can't recall the temps they'd indicate. My best recollection is 120 and 160 degrees. It was in the lower range for sure. There is also "release paper" which is a heat-resistant paper with a thick glossy coating of some sort that does not stick to dry-mount medium. It is is non-reactive at high temperatures. It is made to be put between the metal platen and the materials being mounted. You can also do this with a piece of white mounting board since you are not using the messy mounting material. But do check each time you use it that no loose dirt or debris gets embedded in that cardboard or you may be pressing it into the grooves of your LP. The Release paper is very resistant to holding any dirt since it has a somewhat glossy coating to it. I'd imagine that a softer buffer, like the cardboard, and or release paper, between the warped LP and the hard steel platen might be safer for the grooves. Keep it clean though!

Neat idea...good luck!

Marco

As an addendum to my post, here is one source for some of the dry mounting supplies I mentioned. They don't seem to have the temp indicator strips, but I like Albert's idea better anyway.

The presses themselves can be had on eBay at any given time for much less than new. I own two of them and the smaller, older one is ideally sized for an LP. If this thing turns out to work well for LPs I'll sell it to whoever may be interested for a good price. I no longer have a record collection so it won't serve me in this respect. Keep in mind, in seeking one out, they are a bit heavy to ship, so a local purchase is best. I think the smaller one I have must weigh about 40 lbs.

Marco

My Seal press had a dial thermometer (very accurate I might
add) built into the top platen and the heat was thermostaticaly controlled at any setting. Perhaps this was only on the larger models?

Ok, round two in the saga, much better results this time. Thanks to all for the input and suggestions. Nsgarch, I thought your ideas about the possible problems with acrylic warranted removing it for this experiment. I also thought that if the lp is sandwiched between two pieces of glass, there is going to be a small void between the raised label and the raised rim that might allow the small ripples to form in the groove area on cooling. So I used this material sandwich from the bottom layer up: 3/8" glass, 1/4" paper surfaced "foam-core" mounting board, 2 thick sheets of artists' drawing mylar (smooth sides facing the lp which is between these mylar sheets,) and last, a 4 ply cotton rag mounting/mat board (ordinary mat board would work too.) My thoughts were that the slight deformation of the softer foam core and mat board would cushion and support the thinner groove areas of the lp on cooling. I used my digital darkroom thermometer to make sure that the thermostat was accurate and heated the press to 140 degrees f. I preheated the boards to drive out moisture (less expansion/contraction,) made sure the mylar surfaces that would contact the lp were clean, and then put everything in the press for 15 minutes. No clamping, just the weight of the platten pressed things. After 15 minutes, I turned the press off and didn't open it for 4 hours as it cooled off. I don't think you would want to try and remove the lp to cool under a weight because the vinyl cools, contracts, and warps very quickly when it's soft. By the way, this was a THIN lp, not a thick 180 gr. lp. If you were working on thicker, heavier lp, I'd think you would want to heat things a few minutes longer. This time, everything worked like a charm. The vinyl is perfectly flat, no radial runout, no groove damage. It plays fine with no increase in surface noise or other audible defects. I will repeat this on a few more warped lp's to make sure things are repeatable and predictable and report back. Thanks again for the ideas, Will.