I'm new with the blue foam and refilling those tiny liquid cups. I've tried different ways but still get leakage. Should the atty be touching the blue foam. Mine always touch.
Riva 510 is a clone of the eGo, there is much debate as to which is better either will work fine for you. as for the foam there are several ways to cut it. You can cut it the same size as the filler that comes in carts or a little wider or even shorter, but never pack it tightly, such as folding it over. The juice will go to the area that is the most compressed, its a capillary action thing, when I was beginning to use carts and moved to foam I started with the foam the same size as the filler, then moved into an A shape with the top the width of the cart and the bottom about 1.5 times the width to make it wick toward the atty better, then moved into a plug style where the foam was about 1/3rd the length of the cart and almost twice as wide. Just play with it you will find a way that works best for you.
The atty will push the foam up into the cart each time you use it, when you refill it make sure the foam is at the end of the cart again so the atty can push it to the right place.
If strictlyejuice.com wasn't recently hacked I would send you there to get precut blue foam for 510 carts. They seem fine now and may have upgraded their site:
https://strictlyejuice.com/index.ph...ducts_id=222&zenid=4qbte46p51qer5e4qs98in2n37
The blue foam should be shorter than the inside of the juice cup, just enough wider to stay in place but not so wide the foam holes are pressed closed because that will make it not wick. And tapered on the inner end.
Re shorter - I tend to be cautious and just go with 3/4 the inner depth of the cup. Some people are extreme and go with 1/3 the inner depth of the cup. I also only fill the juice cup 1/2 way. Then I stick the foam in and press the foam down into the juice all the way to wet it. (an unbent smooth paper clip is handy). Then I reposition it at the top edge of the juice cup and top it off with 1-3 drops - whatever it needs to look damp but not a puddle on top.
BTW - after not too long you will probably get sick of carts and switch to cartomizers and/or dripping like most people do. I like Boge cartos (standard resistance because I am using slim batteries. A fat battery model can use standard or LR low resistance)
And yes the atty bridge needs to touch the foam, then the white wick in the atty bridge wicks the juice to the coil