Here's how I make my bags....
For the purple bag above I used about 300g - it's quite good to split the colours in half so you know you have the same for each side.
I put one or more pieces of sari silk onto the resist.
Then holding the top layer of bubble wrap, the felt, the resist and the bottom layer of bubble wrap I flip everything over.
So in total there are six (fairly thin) layers each side with six overlapping layers.
When all the layers are finished and folded over I start to rub everything, alternating rubbing with my hand and rubbing with a scrunched up plastic bag. I pay particular attention to the sides. I then roll it up around a piece of pipe insulation and roll from all directions until the resist begins to buckle.
I cut the top open which allows the resist to come out a little but I leave it in and continue to roll.
When it is quite well felted I remove the resist and carefully turn inside out. I then roll some more, followed by carefully dropping on the table onto bubble wrap - I sometimes go and do this in the bath - the felt in the bath - not me!
I then roll some more and when it is fully felted I roll it with a rolling pin since I like to get it as smooth as possible. Then whilst it is still wet I mould it into the shape I want my bag. If I'm using a frame I put it in at this stage since the felt does shrink a little as it dries.
Here's the finished bag.
I was surprised how purple it turned out - I had used some grey under the resist but like the effect.
And here are a few pictures of another bag - I got a bit carried away with the making and didn't take many photos.