Hi, cfries!
We are talking about 2 different things here.... But, first, when I initially fill a carto, I use the "condom" method. You add about 22 drops of e-liquid into the silicone carto covering. Insert battery side first and slowly push down until all liquid is absorbed. You may also add a few drops to the top to saturate it. Blow out the center hole, in case any liquid is inside....
That will hold about 1 mil in a regular sized carto. When it starts to get a bit dry, I just drip a few drops on the top of the filler material and repeat until totally gunked.... lol!
When cleaning, this method uses syringes with NO needles.... Actually, you need a bit of tubing, a neighbor set me up there.... SOme people use aquarium tubing, but this is the same stuff used in medical applications. Just take a few inches of it and put it over the end of the syringe. It will fit snugly. Then, insert your carto onto the other end of the tubing, that will be snug also and create a nice seal! At that point, you will be flushing it with hot water. Be careful as the steel of the carto will get hot. I'm not sure how ShogaNinja does it, but you want to draw up clean hot water into the carto, through the tubing and then flush it back out.... He claims to do it 50-100 times. I haven't done it that many times, so I did have some left over gunk. I believe there are places that will sell you an item like this, but they are way more expensive than what you could get for yourself.... I watched the vendors video and they filled the carto using this method, too. Great idea, but since I have had a lot of luck filling with the condom, I never tried it as it would be more work.....
So, basically forget about the needles, they are not needed. The only thing you would need a needle for would be to fill certain types of tanks or clearomizers. Dripping to fill a carto works just fine, but it is more time consuming than using the condom method....
Hope this helps!
I've seriously considered using the syringes to do the refill (although right now I'm just dripping into the carto and letting it absorb). Worse comes to worse, just fill two or three cartos at once, use one and have one "on deck" that way you're never panicking.
I looked at the syringes in the first few months I was really trying to re-use the cartos as long as I could. My conclusion was that, if you want to use a syringe, the syringe you really need is a 28-30 gauge needle, instead of the 18 gauges sold on most e-cig sites. A 30 gauge needle is so thin it would fit into the edge of the carto, or possibly even be able to pierce the absorbency stuff without "bending" it and breaking the element.
30 gauge blunt tip needle/syringes are typically sold at home supply sites, as opposed to the e-commerce portals for e-cigs. Again, no warranties are implied, nor am I recommending it. I haven't even tried it myself, but like I said, if you really want to pursue the needle fill, it's going to probably need to be the smallest, blunt tip needle you can find. That's probably the most precise instrument you'll be able to buy online without some type of license.
Can I post a link to one of the syringe sites here, or are we confined to e-cig links only?