A question for those who "converted" standard rims to tubeless. What, if anything did you use to seal the valve to the rim tape with? I've just taped up a Mavic Askium One, 2 layers of packing tape over the original Mavic vinyl tape. I made a small cross cut through the tape to install the valve, and used CO2 to get the bead seated - a track pump wouldn't do the initial expansion quick enough. Seated the bead, deflated the tyre, added sealant, re inflated (with track pump) only to have a leak around the valve stem as evidenced by bubbles from the soapy water Id used to aid installation and bead seating. I've used pliers to tighten the valve stem nut, added extra sealant and "bounced" the tyre to splash it about around the valve area, and seem to have slowed the loss of air (it dropped from 6 to 2 bar overnight before I added extra sealant this morning). It may just be a case of letting the valve seat bed in to the tape until all flexibility has gone, but something to give an initial seal would help - and I need to be able to remove the valve roadside to use a spare tube in emergencies, so an overnight valve stem nut isn't desirable - I was thinking maybe Vaseline, or a non setting mastic?