The isolation is the first thing I tried. It definitely helped, but still no solid 110 degC. I'm not an isolation expert, but these are the results I obtained.
The limiting factor is the RAMPS module at this point. I once tried 4x2.2Ohm resistors in parallel and the mosfet melted through the RAMPS module
...To give some insights in my efforts:
Test1: 4x4.7Ohm resistors in parallel (default setup of Felix 1.0)
Each line adds extra isolation compared to the previous line.
- baseline, no isolation max temp 70 degC
- bottom isolation, only bubble plastic. to decrease convection losses on bottom. This increased temp of + 10 degC to 80 degC
- bottom isolation, bubbly plastic with alu foil for radiation. + 10degC to 90
- Encapsulating the heat resistors with silicone kit +2 degC to 92degC
- top isolation, aluminum foil. +13degC to 105degC. THis is unusable with foil on top, but gives insight in approx max temp with these resistors.
Test2: 4x3.3Ohm resistors in parallel. Had to include extra heatsink on mosfet to keep temps in check. So not a very safe situation.
- Temp without isolation 82 degC
- Temp with buttom isolationem isolatie 100 graden. When you start printing the temp drops to 94 degC
- Alu foil on top raises the temp 15degC. Up to 115degC
It got pretty close, I hoped a more efficient heater like the foil heater would do the trick, but it is hard to get good specs for it.
Meanwhile I made a few prints with ABS. I made the ABS solution like described before (some ABS filament in a few drops of Acetone) take an old brush and spread it thin on my Kapton covered printbed. I get the best results with the heated bed and raft, without raft it is very very very hard to remove the objects but it will also work. It is not much work in before and the solution could be removed with more Acetone. So you dont have to change the printer, dont waist money on extra parts or more electrical power, you have a new use for your raft plastic or damaged prints and you can keep the full size printarea. 
