A friend of mine is getting into Cyclocross and has decided to put slime tubes in the tires. He has a Redline bike with Velomax wheels. He called last night after changing the tube, putting the tire on and inflating it, he said at 35 psi he got slimed. Slime came out of the valve and even into the pump. I don't know much about slime tubes any ideas as to why this would have happened. He does have deep rims on his wheels and the tubes had a short stem. Any idea as to what happened? Or has anyone else had this happen? He is now leery of inflating the other tire. Thanks.

Sounds like there is too much slime in the tube. I have had the same thing happen a few times. Always air up the tire with the valve in the eight-o-clock to four- o-clock position (when looking at the wheel) If the valve is close to the ground, and the tube is empty or low the slime puddles up at the valve and things get messy.

could be a valve failure...? was it a presta stem or Schrader stem? I'm pretty sure that bad things can happen if you slime a presta stem (i.e. slim explosions ) anyhow if he plans on racing his cross bike he really shouldn't be using slime as it adds weight to the wheels (the last place you want to add weight to) and normally races have wheel pits so flats are not a big issue.... anyhow it's all just MHO

Unless he's riding in goathead thorn territory, slime isn't going to do him any good. From my experience, those "pre-slimed" tubes use too much goop, and they go waaaay off-balance when the weather gets cold and all the goop solidifies in one area.
Tell him he's lucky-he could've had slime come out and ruin a good wheel-like it did for me! The stuff stuck everywhere except the hole it was supposed to plug!