I ran a shop a few years ago that was very very very into cyclocross. The owner was from Mass, just outside of Boston and was, probably still is, a cross fanatic. He is also one of the best mechanics Ive met and was privileged to work for him. Anyway...
We made our own sealant for the shop and sold it. I feel safe giving out the "recipe" now that the shop has been sold to new owners and is a totally different place now. This stuff worked so good, people would come by it from the other side of town. Now, please don't think I'm going to rewrite the book on anything here or blow your minds. Sometimes its the simple things that make a HUGE difference. With that in mind...here's the recipe for the Secret Sealant:
- Sealant of choice: Stans or Caffelatex
- Glitter...that's right Glitter: as fine as you can buy at your local craft store
That's it! Seriously. Glitter is great stuff! It helps to clog the holes faster, hence using less sealant and not allowing as much air to escape. Caffelatex wasn't around then, but now that its here and doesn't use Ammonia as its anticoagulant, which will degradate latex tubes over time. Instead they use CO2. Stans is great stuff, and my personal choice if asked, with the exception of the latex rule.
Take whatever amount you use for the tire setup, road, cross, mtb...etc and pour it in a cup before you put it into the injector. Pour in the glitter and give it a good mix, then put into the injector you're using. Ive found that the syringes used by EMT's/Firefighters that are full of saline and have a screw on/off needle tip, work the best. The only thing is, you have to have a tire/tube with a removable core. The Caffelatex injector doesn't require removing the valve core, which for using sealant by itself works great. You can custom widen the opening/tip so that the glitter moves through easier. Then gently, and firmly press the injector on, make sure theres a good seal, and plunge away. This is where you'll know if you found the smallest glitter possible. There's super fine stuff out there, just ask your local club kid friends! Once its all in, give the injector a couple of pulls and pushes on the plunger so the sealant doesn't backfire on you when you pull the end off. Wrapping the coupled valve and injector with a rag while pulling off helps to keep from making any mess as well.
Give it a try if you're having trouble, or just want to see if it works for you. Hopefully you'll enjoy the same results so many riders did when we sold it.