DYI Stand - which plywood?
 

I have the frame of the stand done and ready to go.

I was thinking of using 3/4" plywood for the top sheet and if I have enough of it left over use it for the front. The rest I would like to use 1/2" depending on price.

My wife wants to paint the stand out white.

Which type of plywood would be best for painting white? What I am looking for is something without grain popping through.

I found mahogany was fairly inexpensive with a good finish for paint. 1/2" is fine for sides, I doubled that for the top. Last stand I did didn't use a top at all, the tank sat on the 2x4s

stand
 

birch is 10 dollars less than mahogany here an has a smooth finish ,1/4 inch mahogany is all you need for the sides

It's depends how beefy your framing is. I'm happy using 1/8" for the back and 1/4" for the sides. If you're using European hinges they require the mounting surface and the doors to be 3/4" plywood for easiest installation (many others require this too) since typical kitchen cabinets are 3/4". If you're using magnets to hold the panels instead of fabricating doors, then sometimes 1/8" works better because the magnets are stronger than the wood's ability to warp, but 3/4" is much more durable. I've always just used standard sanded plywood.

I use birch or maple for skinning. Both will finish well with paint, although I recommend a higher tooth saw blade for cleaner edges. Im sure 1/2" would be fine