Hi,
Well like Simon said it probably be much safer and easyer to just buy the aspern. Now lets say your pet shop didn't have any aspern for sale then there's acouple of things to consider befor you make it.
1) make sure you disinfect it. Now I'm no experit heck i'm just a kid but this is just my small 2 cents ok a basic rule to follow when disinfecting is first boil it in HOT water for 30 mins then (now keep an eye on the wood) but it in the oven on 275 for about 1 hour. as I said befor that's what i do for my corns logs make sure it dosen't burn.
2) Next, make sure that they are not sharp. try and some how rounding the edges so that it won't cut it's self and make sure there big enough so that your corn will not mistake it as a posiible food sorce.
3) Let them cool down befor you place them into the cage.
that's just how i disinfect my wood items. Also i could be a little bit off so if any of you see something I may of mistaking something in the disinfecting process plz tell me i'm still learning
To save your self a lot of trouble i would probably just buy the aspern but anyway i hope that helped.