Wetman,
Their site states the product is inert, which is chemically important. As to food safe, they did say "isn’t certified as food safe yet, but we’re working on it.". I bet catheters are not certified food safe either Let's be honest, there is a high risk is what we are talking about here. This sort of play is not for the timid, nor the dumb. I'm very aware of what risks I'm taking and I accept them.
The retention bulbs I made too large, however I sanded them down after curing to 8mm (I can take up to a 24FR catheter, so 8mm is max for me at this stage). For the tether I used fishing line, I don't remember the strength, but probably around 15lb test. To be extra safe (ha ha) I tied one end of the fishing line to the outside edge of the catheter then measured out enough to reach outside of the body then doubled back and tied on to a second point. This redundancy is useful in case one knot slips, breaks, etc. I'm not sure what you mean by position? Where did I attach the line to? I used a sewing needle to go through the catheter if that is what you're asking
I do have photos, but not handy right now. It's pretty much what you see in the drawing I posted yesterday. Taking a photo is always a good idea in case you have to go to the ER
Your idea is interesting. I've never been good with heating and stretching stuff, too hard to replicate my work so I've avoided that. Let us know how it turns out.
Questions are awesome.