LEE filters are warped. Can they be fixed?

<p>I recently discovered that 3 of my big 4x6 LEE Resin filters are warped quite badly. I attempted to flatten them out by placing them under a lead brick and leaving them for a week but it seemed to have no effect. I also tried heating them with hot water and placing them under the weight but that did not work either. I was planning on trying again with boiling water but I am afraid of melting the filters.<br>

Has anyone experienced this?<br>

Have you successfully re-shaped them?<br>

Thanks.</p>

<p>From a plastic resin perspective ...<br>

If Lee filters are made of PET resin (typ polyester), that melting point is 250 C, far above your water. So, without comment as to the softening point, you won't melt it in boiling water.<br>

The glass transition temp for that material is 75 C., so you'll need to be hotter than that. Also, it wouldn't hurt to heat the surface upon which you will place the plastic so it doesn't 'instantly' cool off the filter upon plopping it down.</p>

<p>Beware of scratches and manhandling tho.</p>

<p>Jim</p>

<p> </p>

<p>Boiling water worked. I just laid the filters on a flat clean surface and poured boiling water over them. The flattened out all by themselves.</p>

<p>Just curious: How did they end up warped in the first place?</p>

<p>I have no idea. I got them out of my camera backpack to use one of them and noticed that they were all warped. I store them sandwiched between the hard plastic cases of my screw in filters to protect them from just t his sort of thing. I can only guess that it may have happened last week when I was at the park. I walked around all day in the sun with the bag on my back and the the temp was 92 degrees.</p>