I did a search and couldn't find an answer so I thought I'd ask. I hope this hasn't been talked about before - If so, please give a link.

Years ago I had several Desert Hairy Scorpions that I had bought as adults and kept them on a sand substrate and everything was fine, but I have never kept baby Desert Hairy Scorpions. When they are really young, like 1-2 inches, how do you keep them? What type of substrate do you use?

There are actually quite a few combinations people have tried in order to get their scorpions to molt properly or to allow the substrate to hold burrows.
Some mix coco-fiber with sand, other with sand and excavator clay.

You can try 2/3 sand and 1/3 excavator clay for a good burrowing substrate.
Since you have babies, you should read this thread: http://www.arachnoboards.com/ab/showthread.php?t=190082&highlight=Hadrurus+arizonensis+substrate

He was able to get it to molt due to allowing it to have a tunnel to burrow in and allowing for some humidity for the molting process. You need a really deep substrate level, at least 6 inches worth, I'd guess. If it doesn't work, remember that it's a very difficult task that few hobbyists have done.

Here's another thread that may be worthwhile: http://www.arachnoboards.com/ab/showthread.php?t=170430&highlight=Hadrurus+arizonensis+substrate

Here is a thread dedicated to desert hairy scorps: http://www.arachnoboards.com/ab/showthread.php?t=142949&highlight=Hadrurus+arizonensis+substrate

Hope this helps