Drilling Seamless Braceless Acrylic Tank?

[PhysicsDude]

Hello, I'm picking up a tank tomorrow off craigslist which is pretty unique.

Its a 100g tank made from 1/2" acrylic. Its 84" long, and 16" wide and 17" tall.

Its rimless, and has no bracing on the top! Its used and holds water. I want to drill bulkheads in the SIDES of the tank for filtration. Plan is to put Two 1" bulkheads on one side, and Two half inch bulkheads on other side.

I'm worried that this might hurt the integrity of the tank too much since there is no center brace.

Also, is there a danger of drilling the holes too high or too low? I've heard to keep holes in the top 2/3rds of the tank or else it hurts the integrity.

Also its for a freshwater setup if that matters.

Here's a picture of the tank:

For a variety of reasons, I really do not want to drill holes in the bottom or install overflows. Tank is to sit flush against a wall, so do not want to drill rear of tank either.

Thanks!!!

 

[Andyroo]

No response... mine neither.
I've got nothing useful to offer vis-a-vis information to your query, only moral support.

However, what I hear of acrylic is that you can drill it much like wood. So long as you've got good (tight) bulkheads you should be OK as a good tight bulkhead is a structural aspect.
If you're worried, get a brace of some sort for the top. It's only holding lengthwise, so it needn't be too thick- one or four x 2" wide strap of 1/4" from Staples might do it. "They" say that the glue you use for acrylic is very strong and easy to use- particularly for an application such as this. Failing that, your worry is bowing- drill a couple of little holes at the top and use a stainless steel cable with a tightening nut of some sort.
If you're worried about the hole(s), glue in a plate of the same 1/4" and drill through both, then set the bulkhead over it all.
NB: read above- I have no idea what I'm talking about!!!

 

[PhysicsDude]

No response... mine neither.
I've got nothing useful to offer vis-a-vis information to your query, only moral support.

However, what I hear of acrylic is that you can drill it much like wood. So long as you've got good (tight) bulkheads you should be OK as a good tight bulkhead is a structural aspect.
If you're worried, get a brace of some sort for the top. It's only holding lengthwise, so it needn't be too thick- one or four x 2" wide strap of 1/4" from Staples might do it. "They" say that the glue you use for acrylic is very strong and easy to use- particularly for an application such as this. Failing that, your worry is bowing- drill a couple of little holes at the top and use a stainless steel cable with a tightening nut of some sort.
If you're worried about the hole(s), glue in a plate of the same 1/4" and drill through both, then set the bulkhead over it all.
NB: read above- I have no idea what I'm talking about!!!

Thanks for the reply. I realize this is kind of a specialized and unique question.

I'm not afraid of drilling the acrylic, I'm a contractor and I use hole-saws all the time. I'm just paranoid that because the front and rear sheets of acrylic (7 foot span!) are essentially only "braced" by the 2 sides, and I'm afraid taking away integrity from the side pieces might make the front bow too much or something. But, my understanding is that 1/2" acrylic is pretty beefy, so this thing is definitely pretty strong, and at 17" it is not that deep.

I like the stainless steel cable idea I might try that if the bowing looks really bad.

I'm pretty excited though, a seamless acrylic tank is a pretty "exotic" type of aquarium that you don't see often. I was going to go with a typical 125g, but then I saw this tank on craigslist and couldn't pass it up. I also want to build a 3D background and put in some large pieces of driftwood, so no center brace makes that MUCH easier!

 

[wednesday13]

Drill away...Only thing that will cause structural issues in the side panels themselves is if you place the holes too close together, theres a chance of that thin piece inbetween the holes cracking. Nothing will change the front or back panels by drilling the sides they will bow on their own regardless with no braces lol. You should be more than fine with that size hole. Have you filled it yet and measured the difference in the center? i'd glue on a full top sheet with hole/lid cutouts or atleast some permitter/center bracing. Heck even a nice wood/metal frame will stop the bowing. As for hole placement, just keep them a couple inches away from the seams and eachother. This is more particular for glass tanks than acrylic so you shouldnt be worried of doing any damage. Flip the tank up on its side and drill from the inside out with a wood backer and hole saw with a guide bit, Smaller teeth the better but they all work. This will prevent the tank from moving/flexing while you drill, lowering your chances to crack anything. Ive drilled acrylic tanks while there full/empty and without a wood backer just the same but if i can use the wood behind on the ground i do. By "seamless" do you mean the front sheet is bent at the corners? Its small enough it could have been cast or vacuum formed but ive never seen one outside of small retail displays using cast cubes/rectangles with thin material.

 

[PhysicsDude]

Drill away...Only thing that will cause structural issues in the side panels themselves is if you place the holes too close together, theres a chance of that thin piece inbetween the holes cracking. Nothing will change the front or back panels by drilling the sides they will bow on their own regardless with no braces lol. You should be more than fine with that size hole. Have you filled it yet and measured the difference in the center? i'd glue on a full top sheet with hole/lid cutouts or atleast some permitter/center bracing. Heck even a nice wood/metal frame will stop the bowing. As for hole placement, just keep them a couple inches away from the seams and eachother. This is more particular for glass tanks than acrylic so you shouldnt be worried of doing any damage. Flip the tank up on its side and drill from the inside out with a wood backer and hole saw with a guide bit, Smaller teeth the better but they all work. This will prevent the tank from moving/flexing while you drill, lowering your chances to crack anything. Ive drilled acrylic tanks while there full/empty and without a wood backer just the same but if i can use the wood behind on the ground i do. By "seamless" do you mean the front sheet is bent at the corners or was the whole tank cast in a mold? Its small enough it could have been cast but ive never seen one outside of small retail displays using cast cubes/rectangles.

Thanks for the reply. I did pick up the tank yesterday and cleaned it/filled it this morning. Its a custom made tank, and its basically 5 sheets of 1/2" acrylic glued together. No top piece or bracing.

It does bow quite a bit. I don't think its going to fall apart or anything, as the tank feels really sturdy, but it bows about 5/8" on the front and back (1.25" total bowing when measured in the center), 5/8" of bowing accross a 7 foot span doesn't seem unreasonable to me considering there is no top bracing. I will brace it though. After I get the background set in the tank, I found a plastics company really close to my house and the plan is to put Three 4" braces, equally spaced across the top. I don't think the tank is in danger of falling apart or cracking, but it will help the bowing, and I'll get some thin pieces of acrylic at the same time to make lids/covers as well.

I really love the tank though. Really excited to get it set up in the upcoming week.

 

[wednesday13]

Thanks for the additional info and nice pickup. I agree the tank most likely isnt going to blow apart or anything. Those couple 4" strip pieces for the top should work well for you.