Tank Drilling

[wrangler99tj]

So i was a little bored today after i got home from work so i decided to try to drill my 10 gallon tank for practice and i failed...there is a perfect hole but there are some crack coming off the hole.....what did i do wrong??

 

[elephen]

http://reefcentral.com/forums/showthread.php?s=&threadid=751988

Check out that how-to, very good.

What did you use to drill it, a dremel or a drill? Did you keep the surface and bit cool/cold while drilling?