what thickness of plywood for top of stand on rimless tank?

[Devaji108]

guys what thickness to use for the fallowing? 1/4 or 1/2 inch

2x4 stand
rimless 90 gallon 36x24x24
tank will be on matt
matt will be on plywood top
ply. top will be on 2x4 stand...
not looking for support as i will have a center brace and using rockets temple so it's plenty strong. just look for a smooth even top of the stand. I am most likely over thinking this...ans 1/4 will be fine. just want to dbl check.

should I use 1/4 or 1/2 or does it really mater?
was going to cut my 2x4 today but this effect the high for my trim with I already have gone...

 

[sfdan]

Since the tank is rimless that means the weight is going to be distributed equally along the whole surface, so you are going to want the plywood to distribute the load evenly regardless of how much bracing you have.

1/4" plywood is really weak and is going to sag very quickly instead of distributing the weight. Really thin plywood also isn't going to be as flat or stable as thicker plywood.

My guess is 1/2" plywood is fine, but I don't have any formulas which could confirm that. Personally I put 3/4" plywood on top of my 4'x2' stand.

 

[Devaji108]

hmmm Damn I just made up the calculations for the 1/4 plywood. yeah I know it not as strong. there will be a brace mid way at 18 inches I was going to screw in to..

guess i could always but a brace every foot.

another reason I was thinking the 1/4" it not as ugly on the side when i take of my trim. with will be 3 side removable. not the biggest deal in the world and could be over come.

 

[Bogue Chitto]

I would go with 3/4 and have peace of mind.

 

[JohnnyHildo]

i just built my stand for a 48x24x24 without bottom trim and used 1/2" plywood to top it. http://www.reefcentral.com/forums/showthread.php?t=2553977 to check it out.
edit: i just wanted to add that if you are running a bottom plumbed tank to make sure you have room for the drain and if you are running a sump also build it so you have clearance for a skimmer between those cross braces. i planned for it but lucked out a little too.

 

[Devaji108]

yeah thank for the heads up johnny. I do have plans to run a 40br sump with access from the side if I need to take it out of the stand for what ever reason and will be plenty of room for the skimmer. might not even run one to be honest...

OK i'll just go with 1/2 to be on the safe side

 

[davocean]

I always use 3/4

 

[Manfredo]

I used 3/4" inch for the top and then added a 1/8" inch neoprene pad for the tank to sit on. The pad helped even out any uneven spots and it barely noticeable.

 

[civics14]

just wondering, how makes that tank? 36x24x24? That is the exact tank dimensions I am looking for, but I'm finding it to quite rare.

 

[MelloW33]

I've always used 3/4" but 1/2" will be fine. I like to cut it a little big and then sand it down to size in order for the edge to look cleaner.

 

[slief]

I always use 3/4

Me too.

No reason to skim on the thickness of the top regardless of what the calculators say. I would use 3/4" plywood.

 

[JohnnyHildo]

just wondering, how makes that tank? 36x24x24? That is the exact tank dimensions I am looking for, but I'm finding it to quite rare.

while i can't speak for this gentleman in my case my lfs has a tank builder that will design a tank to whatever specs you require. might be an option for you as that isn't a common size and finding one might be like hunting a unicorn.

 

[don_chuwish]

Definitely 1/2" or higher. Even more importantly, good quality, minimal voids, and straight when you buy it. Any tendency to curve can get even worse after cutting to size. Sure, once screwed (and glued) down to the frame it SHOULD be forced dead flat but.... so much easier working with flat & straight.
I 2nd the idea of cutting about 1/8" proud on all sides, then using a trim router to even up the edges perfectly. But of course that assumes you have a router of some kind!
Pre-drill and countersink for the screws so they don't have any chance of being slightly proud or causing a swell in the surface.

 

[reefer1970]

3/4, anything less will warp and buckle and probably delaminate

 

[davocean]

Anything less probably wont warp or buckle(unless it's not sealed and you flood it a few or more times) but the whole purpose is for it to ride across deviations.
If your frame is coplaner not really much of an issue.
It's more critical on a trimless tank.
1/2" is ok, it's just not optimal, if you already did it I wouldn't bother w/ redoing it, but for future builds or bigger and trimless tanks or to others reading, like Slief said, if you are going to bother w/ doing it do it right.

 

[Ruckus16]

3/4" for me too

 

[saybng]

3/4" for me here...but I've also used 1/2" 13 ply in the past with no issues..good luck.

 

[Devaji108]

OK I found a 1" pice in the barn I Am going to use. adds a lot of weight but on well.
might be over kill but its free!

starting on cutting today...

 

[Devaji108]

just wondering, how makes that tank? 36x24x24? That is the exact tank dimensions I am looking for, but I'm finding it to quite rare.

SC aquariums make it, its a 90 gallon. 3 side starphire glass.
amazing company, great built quality and CS is just great can talk to real people. and prices are great!!
there are a few builds going on now in the build thread section of RC. there are a few pic of the 90 there. once I get it i'll most likely do one to.

 

[don_chuwish]

Free is good! Yeah the 3/4 I used had been sitting behind a cabinet in the shop for over 30 years. Very nice stuff.