DIY Aluminum stand advice: can frame be larger than the tank?

[the register]

I'm working on spec'ing out a new tank and stand. The tank will probably be 48in x 24 x 24 +- an inch or two. It will be setup as a peninsula. There are a lot of options in that range, but the main issue I have is I don't want a modern style, industrial, flat panels flush with the tank, painted glossy, stand. That doesn't match anything else I own, and I'd prefer something that looks more like furniture. This IM site picture for instance is closer to what I'd want:

Heading researched options, I really like the idea of a T-slot stand. However, all the examples I've found have been the flush look.

I have no structural engineering design skills, so I'm wondering what my options on building this are. Let's say my ideal is:

• tank is 48in long, 24in wide
• stand is 60in long, 28in wide, 30in tall
• sump under stand

Should I expect the stand to be an AL box the size of the stand, or do I need the AL box to be the size of the tank?

My assumption is the vertical legs need to be approximately under the edges of the tank, and it's better for the legs to be slightly inside the edges of the tank than slightly outside. That'd imply I need to build an AL box 24in wide, 48in long, and then build an outer box surrounding it that the actual tank sits on.

However it'd be a lot easier if I could just build a 60x28 box and set the tank on it.

Anyone have guidance, or know of an AL extrusion stand place that'd give me good advice?

 

[Biglew11]

I would make the support frame the same size as the tank and build it out from there.

 

[stinkydavis]

I would make the support frame the same size as the tank and build it out from there.

+1. Build the outside dimensions to what you want with the main support in the inside. You can do the load bearing legs internally. So tank dimensions and use that to figure out the two internal door sizes. You will use the support legs to hang the two doors. Then make sure that the length on the other end will be that door size. So if you are doing 1/2inch overlap with the doors you total stand length would be 100+ in. 25in per door wide by however tall your stand is plus 1 inch for the 1/2 over lap. Feel free to PM me and I can give you my number to explain over the phone to be more clear.

 

[Reefer Reboot]

Is something like this what you had in mind? (Just basic layout)

You can clad the outside with an appropriate looking wood skin.

 

[the register]

Is something like this what you had in mind? (Just basic layout)

You can clad the outside with an appropriate looking wood skin.

Thanks all!

This is a great visual, and I hadn't considered the legs being offset from the end. That makes a lot of sense for length extension.

The width is where I was especially concerned. If the edge of the aquarium is internal to the frame, is that ok? I don't have enough structural sense to know.

My intuition is it shouldn't matter, because there's going to be a deck on top of the frame and the tank is on that. I'd expect that as long as the deck itself doesn't deform, and the tank is centered, that the weight would be evenly distributed across the legs regardless. The deck would be supported by the cross bracing, so it too I'd expect to be stable.

Said differently, it's not a point load or a rotational one, it's a very well distributed load. Both because the tank itself is a pretty even weight distribution, but because the deck spreads it further.

However I don't trust my intuition...

 

[the register]

Here's the list ridiculous mspaint'esque drawing ever (using a kid drawing app I had handy), but here's kinda what I mean when viewed from above.

Tank centered left to right, and the edge of the tank aligned with the legs.

 

[Reefer Reboot]

Exactly, if we were to view it with the table top remove, the left and right sides of the tank align with the internal front to back cross beams. The table top would disperse the weight evenly across the stand.

Quick rough calculations, your tank, 48"x24"x24" = 27648 cubic inches = 119 gallons times 8.5 lbs. (saltwater weight per gallon) = 1017 lbs. Double that for safety factor and run a load of 2,000 lbs. through the 80/20 load calculator with fixed two ends. Using 80/20 profile 1530-S, the long front and back beams with 2000 lb., load evenly distributed gives a calculated load sag in the middle of .0129". Now add in the rigidity of the tank and more importantly the rigidity of a strong table top and blah blah blah..... yeah, no problem!

 

[the register]

Exactly, if we were to view it with the table top remove, the left and right sides of the tank align with the internal front to back cross beams. The table top would disperse the weight evenly across the stand.

Quick rough calculations, your tank, 48"x24"x24" = 27648 cubic inches = 119 gallons times 8.5 lbs. (saltwater weight per gallon) = 1017 lbs. Double that for safety factor and run a load of 2,000 lbs. through the 80/20 load calculator with fixed two ends. Using 80/20 profile 1530-S, the long front and back beams with 2000 lb., load evenly distributed gives a calculated load sag in the middle of .0129". Now add in the rigidity of the tank and more importantly the rigidity of a strong table top and blah blah blah..... yeah, no problem!

You are seriously the man/woman! Lmk if I can pay it forward somehow!

I'm officially going to order all this tomorrow now and can stop dawdling!

 

[the register]

You are seriously the man/woman! Lmk if I can pay it forward somehow!

I'm officially going to order all this tomorrow now and can stop dawdling!

Also @Reefer Reboot I see from your profile you're in CA. I'm in NorCal. Do you know of any extruded AL suppliers in the area or generally CA?

 

[Biglew11]

I know if you contact 80/20 stuff they will let you know who in your area supply's there stuff. I get emails from them all the time.

Distributor look up towards bottom of page.
https://8020.net/customer-support

 

[thatmanMIKEson]

Exactly, if we were to view it with the table top remove, the left and right sides of the tank align with the internal front to back cross beams. The table top would disperse the weight evenly across the stand.

Quick rough calculations, your tank, 48"x24"x24" = 27648 cubic inches = 119 gallons times 8.5 lbs. (saltwater weight per gallon) = 1017 lbs. Double that for safety factor and run a load of 2,000 lbs. through the 80/20 load calculator with fixed two ends. Using 80/20 profile 1530-S, the long front and back beams with 2000 lb., load evenly distributed gives a calculated load sag in the middle of .0129". Now add in the rigidity of the tank and more importantly the rigidity of a strong table top and blah blah blah..... yeah, no problem!

Very nice, very helpful

 

[Reefer Reboot]

Hi @the register, you're welcome for the sketch. I (man ) don't have any specific info on local dealers but I know there are a lot. Still, I get most of my raw material off Amazon. I would suggest going through the manufacturers websites to learn of all the profiles of t-slot style beams and hardware. Be aware it does come in fractional and metric sizes.
I can make up the sketches in <5 minutes, so if you want to change/modify anything or get a closer/better view, give me a shout.
Let the adventure begin and be sure to post the progress and final build!

 

[Tenecor Aquariums]

I would make the support frame the same size as the tank and build it out from there

Agree. The design below is not the strongest your tank should sit on the perimeter. You can easily build out from there as per @Biglew11 . With the design below you will compromise strength and I don't see any easy way to add leveling legs. See this post for another opinion

 

[Tenecor Aquariums]

Exactly, if we were to view it with the table top remove, the left and right sides of the tank align with the internal front to back cross beams. The table top would disperse the weight evenly across the stand.

Quick rough calculations, your tank, 48"x24"x24" = 27648 cubic inches = 119 gallons times 8.5 lbs. (saltwater weight per gallon) = 1017 lbs. Double that for safety factor and run a load of 2,000 lbs. through the 80/20 load calculator with fixed two ends. Using 80/20 profile 1530-S, the long front and back beams with 2000 lb., load evenly distributed gives a calculated load sag in the middle of .0129". Now add in the rigidity of the tank and more importantly the rigidity of a strong table top and blah blah blah..... yeah, no problem!

15/30? I wouldn't build this with no less than 45/45 and 45/90. It's not just the load sag calculations you need to consider

 

[Reefer Reboot]

15/30? I wouldn't build this with no less than 45/45 and 45/90. It's not just the load sag calculations you need to consider

Okay, let's debate/discuss this. When I ran the calculations I used almost double the weight as a safety factor. I only added a few connecting brackets on the bottom of the sketch just for the idea. My main goal was to figure the load capabilities of the beams. Running the load calculations on the 80/20 websites load calculator, for a span of 45 inches (the length between the insides of the vertical legs of said sketched stand) with a load of 1,000 lbs. (2,000 lb. safety # divided by two for front and back beam) comes up with the following load deflections for each profile.
Fixed two ends, Loads evenly distributed,
Profile 1530-S = .0129" deflection
Profile 45-4545 = .0707" deflection
Profile 45-4590 = .0096" deflection
Only Profile 45-4545 is just slightly better by a difference of .0033". The width of a human hair is, according to professor google, on average .0040".
Prices for just one 60" beam,
Profile 1530-S = $85.20
Profile 45-4545 = $48.01
Profile 45-4590 = $113.69
Using Profile 45-4590 over Profile 1530 would add over $100.00 to the cost of the stand and only add less than the width of a human hair in rigidity.
As per the leveling feet, there are a lot of different styles available that could easily be used. I personally prefer to have the entire beam making contact with the floor to distribute the weight, especially on a non slab floor. Any leveling can be accomplished by adjusting the length of the legs or using shims between the legs and the horizontal beams.
For proof of concept from first hand experience, my tank is 173 gallons, larger than OP's. I made mine with Profile 1530 legs and only Profile 1515 horizontal beams. The tank does not sit on the perimeter of the stand. It's been up there for over 5 years and a couple of earthquakes and hasn't budged.
If someone wants to make a stronger stand, I have no problem with that. Is it necessary to under estimate the strength and over engineer the stand, unnecessarily raising the cost? In my opinion, no. But as I said, that's just my opinion and everyone is entitled to their own.

The quality is excellent and we overengineer them.

I'll let the math and science speak for itself, but then again, I don't sell
them.
On the flip side, I also don't have to defend myself against frivolous lawsuits when someone does something they shouldn't have.
So regardless of how this may have first sounded, I do see your point.

 

[Tenecor Aquariums]

Okay, let's debate/discuss this. When I ran the calculations I used almost double the weight as a safety factor. I only added a few connecting brackets on the bottom of the sketch just for the idea. My main goal was to figure the load capabilities of the beams. Running the load calculations on the 80/20 websites load calculator, for a span of 45 inches (the length between the insides of the vertical legs of said sketched stand) with a load of 1,000 lbs. (2,000 lb. safety # divided by two for front and back beam) comes up with the following load deflections for each profile.
Fixed two ends, Loads evenly distributed,
Profile 1530-S = .0129" deflection
Profile 45-4545 = .0707" deflection
Profile 45-4590 = .0096" deflection
Only Profile 45-4545 is just slightly better by a difference of .0033". The width of a human hair is, according to professor google, on average .0040".
Prices for just one 60" beam,
Profile 1530-S = $85.20
Profile 45-4545 = $48.01
Profile 45-4590 = $113.69
Using Profile 45-4590 over Profile 1530 would add over $100.00 to the cost of the stand and only add less than the width of a human hair in rigidity.
As per the leveling feet, there are a lot of different styles available that could easily be used. I personally prefer to have the entire beam making contact with the floor to distribute the weight, especially on a non slab floor. Any leveling can be accomplished by adjusting the length of the legs or using shims between the legs and the horizontal beams.
For proof of concept from first hand experience, my tank is 173 gallons, larger than OP's. I made mine with Profile 1530 legs and only Profile 1515 horizontal beams. The tank does not sit on the perimeter of the stand. It's been up there for over 5 years and a couple of earthquakes and hasn't budged.
If someone wants to make a stronger stand, I have no problem with that. Is it necessary to under estimate the strength and over engineer the stand, unnecessarily raising the cost? In my opinion, no. But as I said, that's just my opinion and everyone is entitled to their own.

I'll let the math and science speak for itself, but then again, I don't sell
them.
On the flip side, I also don't have to defend myself against frivolous lawsuits when someone does something they shouldn't have.
So regardless of how this may have first sounded, I do see your point.

I lived in SF Bay area for many years and sailed there almost every day. My boat was an Islander 36 affectionately referred to as an iron bathtub. Not the fastest. but it was solid. About 30 miles outside the Golden Gate are the Farallon islands, also known as The Devil's Teeth. I would sail out to them about once a month and never fails, the weather would turn really ugly. Back to the boat. The Islander has what is called a keel stepped mast meaning the mast is sitting and attached to the keel. This in comparison to a deck stepped mast, where the mast ends and sits on the deck. Many boats have deck stepped masts because it opens the cabin below and makes it more spacious. Another feature of the Islander is the thru hull bolts holding the deck and hull together. Imagine a clamshell with the deck and hull as the shells. In the same boats with deck stepped masts, the deck is attached to the hul with screws. Another design difference is the forestays and backstays on the islander versus shrouded rigging on the "other" boat. The other boat looks great at boat shows. spacious, beamy. Just like a clorox bleach bottle. Great for staying dockside or a nice chardonnay sail. But past the gate is another story. It gets ugly fast. BTW, the Farallons are also one of the premier great white shark habitats... We were rounding the islands one day one we heard a May Day distress call. A boat had demasted and was in big trouble as they were heading into the shoals. Coast Guard Golden Gate was out there in about 30 minutes in a Sea Stallion and luckily the crew made it out ok. Not so much for the boat.

My point is that boat was engineered to spec and what happened should not have happened. Until it did. I appreciate your analysis and logical conclusions. You also stated the additional cost was about $100. For perspective, a comparable Tenecor stand would cost less and still be more sturdy. Our philosophy is to make this hobby more affordable without cutting corners. And we learn a lot from hobbyists here. Your design has already given us some insights on other features we will be adding. All the best. Below is one of the nastier days we sailed past the gate. That handsome fellow closer to the pointy end of the boat is yours truly.