Can I turn a queen memory foam mattress into a sleep sofa?

No, you can't. But you can leave the sofa bed open and lay the mattress on top. Or you could put the mattress on top of the full size bed. On the back side, use tables, benches, sturdy cardboard boxes or even chairs facing into the mattress to hold the mattress up. Now IF your memory foam mattress is only foam, you could cut it any way you want, but you can't put it back together again. One more thought, many full size bed frames stretch out to queen size. I have had to put a metal box at the bottom end for more stabilization once, but that worked fine for three years. Best wishes 😇

Thanks! I don't have a sofa bed, I was wondering if the memory foam could be bent enough to make a sofa bed out of it. I just don't have room for all my beds right now, but I could use a sofa bed so as not to have to store the mattresses and get no use out of them.

Maybe this will give you some inspiration.

I've also seen the full size on done but it is just laid out and pillows were put along the back with arm bolsters on the side. Then more pillows in between.

HTH

Thanks! I thought about this, too. I guess I just wondered if anyone had ever tried it just bending the mattress in half. I may try it the way you linked, or just play with it a bit and see what I can come up with. Thanks again, both of you!