Vacuum bagging looks like a hassle, so I'm trying this. Gotta do the same thing you'd think?

I think that technique is called "Ball Bagging"

This is very clever. Water balloon might work too.

Thats an awesome idea for sticking a new footpad down but apart from that i agree its 'ball bagging' nice one PC

I use a similar technique with a large piece of mattress foam and an anvil.
I did try covering a small item in plastic and immersing it in water, trouble was the item punctured the plastic, and water didn't improve the epoxy setting.

I also don't bag small repairs

I cover in plastic then put a sandbag on it that is stuffed really full so it conforms to the surface but is still a bit rigid if that makes sense..........then tape all around, as tight as I can, with plastic packing tape
Applies every bit as much pressure as bagging

The problem is if you want to apply pressure to something lower than the deck - like a layer of divinycell that sits say 2mm lower than the deck before u glass it later. Your bag, ball, etc will also sit on the deck and apply less pressure at the edges of the repaired area. So I cut a bit of d'cell, cardboard, whatever, the same size as the repair and lay then on top of the d'cell before applying the weight.

Been thinking about a plastic bag full of lead shot, easy 5-10kg and conforms nicely...

I would like to try a baby hippopotamus. Just for giggles..everything else I've tried is a bit boring

Adam I look like one so could come sit on it if you wish...

So you have a crushed rail, nose, or tail that needs to be repaired, but that last part, wrapping the final glass cloth around the repair can be a frustrating pain.

Lay up the resin socked glass over the repair, and wrap it around the rail, but it won't want to stay. Just let it hang as you get a piece of wax paper, big enough to go beyond the glass, and lay that over the wet glass, then wrap it around again using tape to tape the wax paper onto the dry parts of the board beyond the repair. Use lots of tape, covering the entire patch job, taping it down as tight as you can, wrapping around the rail.
Come back later after it's cured, remove the tape and wax paper, the patch will look like it was vacuumed bagged, solid with no bubbles. Just sand down any ridges and finish as desired.

Serve warm with a nice Chianti and some fava beans.

^^^
Or you can use clear builder's plastic. It has the added benefit that your tape will actually stick to it so it's easier to apply.

^^^ Or just put the board on edge so the rail is uppermost

^^^ if gravity was strong enough I would, but then again you still wouldn't get the compression that vastly improves the lamination.