Flattening 3D cards

[Paul S]

Is there any proven way to flatten 3D cards? I have a set of (I forget which) that are curled in arcshape that I bought in the late sixties. I keep reading that they will crack. etc. Also, I don't grade my stuff -- although I might in this situation -- but how do TPGers get them in holders? Is there some guarantee that they will remain "untarnished" thoughout that encased existence?

[steve B]

I don't know of any way to flatten them without some sort of damage. They curl because the plastic shrinks and the paper it's bonded to doesn't. As the plastic dries and shrinks it also gets a bit brittle, so flexing it can cause cracks and/or coming loose from the paper.
If the plastic is still pliable it might work to put them in screwdown holders. But that will flatten the ridges.

Of the 3-d stuff I have, the Kelloggs have done ok if kept out of light The sets in the original mailer have curled the least, ones I bought at flea markets have done the worst. A 3-d basketball set I have in screwdowns is doing just fine.

I have some non-card 3-d stuff. Some large 3d pictures by the inventor of the process are doing really well, no problems at all and only a hint of curl- maybe 1/4 inch over 14 inches. Some 3-d Postcards are doing very poorly, when I got them they were curled nearly back over themselves along the edge. They probably got lots of light exposure.

Steve B

[Exhibitman]

I wonder if putting them in a low heat oven for a short time would relax the plastic enough to allow the cards to be pressed flatter without cracking. Probably worth a common or two to experiment.

[darkhorse9]

I have stored my Kelloggs cards in nine pocket sheets, but have placed the cards in rigid top loaders and trimmed the sides off of the loaders first. They now reside between two hard plastic sheets inside the sheets. They haven't curled a bit in years and display very well

[Paul S]

All great replies. If I had several curled beaters I would try all recommended remedies: ovens, trimmed loaders, et al. This is a complete set, pretty sure it's Topps, but not in my possession at this time due to boring marital reasons.
But what about sending them curled to TPGers? Would they just insert them inside holders and I would have to pray for mercy throughout the years?

[ALR-bishop]

I have never collected the Kellogg cards but do have a set of the Topps 1968 3D cards. They don't have a bending problem but can crack. I don't have the courage to try Adam's low level oven heat but maybe I can convince Bob (bobsbbcards) to try that on some of his :-)....or maybe soaking them :-0.

I have always liked the Kellogg cards. Do all of them bend over time, or just some ?