Acrylic fabrication questions? I can help!

[Acrylics]

So, James and anyone else, any advice??

IMO, stick a fork in it.. you've got fractures in the vertical panels and you're not going to be able to transfer stresses effectively from those areas.. already have at least 2 issues going on...

Hey all just have a question on a Acrylic Technor tank it is a 300gal 96x24x30and the seller said he thinks it is made out of 1/2 is this heavy enough or should I pass on it thanks

I'd pass.. If this is to be a reef tank, you're not going to be happy with it...

James

 

[The Computer Ox]

I picked up a SeaClear 46g tank for next to nothing that is in pretty good condition. I was about to clean up any scratches when I decided to do a leak test first. The tank holds water, no leaks, but it is bowing out in the front and rear about 1/4 inch when it is full. I have always had glass tanks, so I am not sure if this is "normal" for acrylic tanks. It is approx 36x17x20 and made of 1/4 inch acrylic. Should I be concerned about this much bowing? Also, the tank does have a euro style brace.

thanks in advance.

TCO

 

[dahenley]

does the top bow, of the middle of the viewing panel bow?

 

[The Computer Ox]

I really tried to get a picture without any luck. The viewing area of the front and rear panel area bowing. However, when I was looking at the euro brace the front looks fine while the cutout over the rear of the tank is bent slightly. Meaning the access area where you would install a center overflow is bowing approx 1/8 inch. The euro brace in the area is only 1/2 inch.

 

[Floyd R Turbo]

seaclear is one of those tank makers that makes tanks with the minimum materials. Acrylic is very stong, so while I would not even consider making a tank 36 L x 17 or 20 tall out of 1/4" material, they do it all the time, with no or little warranty of course. Thinner material means it will bow which makes it difficult to get clean, but hey they make lots of them...right?

sorry...being a little sarcastic here. you are right to check for signs of damage and do a fill test. It might be too thin to do too heavy of a sanding though.

 

[dahenley]

also, if a tank is made of too thin material, and you put a external overflow, the solvent and the rigidity of the overflow with the thinner bowing of the tank will cause major problems.
i wouldnt do it.... but maybe one of the professionals here can chime in with real advice.

 

[Floyd R Turbo]

Just looked back up in this thread and you were looking at doing a beananimal type overflow on this tank?

I don't see there being a huge problem with solvent welding an overflow box to the back of the tank, but I would make it out of thick material, like 3/8", and make sure the edge is very well prepped and bonded well to the back of the tank. That would actually make the back panel stronger if done right. If you bond a box to the inside as well you increase the strength more. Make sure you let it cure for a while, like a week before putting water in it. And make the box then bond it to the tank, not the other way around.

 

[The Computer Ox]

I called over to FarCo on Friday and they have 1/2 inch scrap cuts. I could probably get all of the material to make a new tank for about $100. I am going there tomorrow before I move forward with this tank. I just don't want to risk a blowout that could kill everything inside and possibly even injure, or worse, my children.

Just a note: I am not affiliated with Farco, just have had great success with their materials and prices.

 

[sean04]

Slot cutout in back of tank?

Slot cutout in back of tank?

I want to cutout a slot on the back of my 48" long tank instead of having an internal box and an external box. I would rather have a slot and an external box 25" wide centered across the back of my tank. Since, cutting out a slot will weaken the back I wanted to know how long of a slot I can cut?

Notice the top bracing. Since the top has a 15 3/4" cutout near the back side, I wanted to know if my slot should be the same size? Or can I make the slot wider? How wide would would be considered too risky? I'm worried that if I go wider than the 15 3/4" cutout it would considerably weaken the effectiveness of the top bracing.

 

[Floyd R Turbo]

The potential weak spots in that tank appear to be in the 4 corners of the back slot. Since the euro center brace does not connect directly to the back of the tank, the load stress on the front of the tank is transferred to the 4 corners of that rear slot. Cutting a slot on the back of the tank would probably relieve that stress and transfer it to the ends of the slot you cut.

If you going to cut the slot, you're going to want to reinforce that top euro along the back edge with something. Bonding the external box to the back of the tank should re-inforce the slot, but IMO it wouldn't be enough to make it safe.

Err on the side of caution when doing this. Take this into consideration - James always suggests making a 2" radius on the corner cutouts for the access holes to adequately distribute the stress at these points. The pump-them-out tank makers do not do this. As a result, they are more prone to developing stress cracks at these points, so extra care must be taken when doing any modifications. These tanks are usually built to a minimum standard compared to the way James (and other great builders) make them.

 

[juststartingout]

Looking for acrylic thickness recommendations for a 96l x 36w x 30h tank. Is 3/4 all around good or should the front/back be 1". Looking to go with Polycast, so it would be a true measurement of thickness. The back would contain an external overflow box. Probably will not do drain teeth, just a couple of slots. I'd like to stick with the 3/4 as the magnetic pump mounts would work better at this thickness.

 

[juststartingout]

Take this into consideration - James always suggests making a 2" radius on the corner cutouts for the access holes to adequately distribute the stress at these points.

What if the corners aren't a square cut w/ 2" radius, but leaving a 45 degree in the corner?

 

[gveng]

thinking about building a 48"x24"x12" tank.

I'm trying to get quotes on material right now but not quite sure what I need. I'm trying to keep this tank on the cheaper side.

any help would be greatly appreciated!!

 

[gveng]

thinking about building a 48"x24"x12" tank.

I'm trying to get quotes on material right now but not quite sure what I need. I'm trying to keep this tank on the cheaper side.

any help would be greatly appreciated!!

 

[Acrylics]

Looking for acrylic thickness recommendations for a 96l x 36w x 30h tank. Is 3/4 all around good or should the front/back be 1". Looking to go with Polycast, so it would be a true measurement of thickness. The back would contain an external overflow box. Probably will not do drain teeth, just a couple of slots. I'd like to stick with the 3/4 as the magnetic pump mounts would work better at this thickness.

3/4" is fine, but I would advise using 1" on the front and ends if you can swing it. The front to keep deflection down and the ends just to look consistent. The 3/4" for the back should be beefed up a little if you're going to be removing structural material so I would personally make the overflow out of something thicker than 1/2".

James

 

[Acrylics]

thinking about building a 48"x24"x12" tank.

I'm trying to get quotes on material right now but not quite sure what I need. I'm trying to keep this tank on the cheaper side.

You can "get away" with 1/4", will need a 3" perimeter flange (aka euro-brace) and a cross-brace. That said, should use something thicker as the deflection bugs me, personally.. If you use 1/2" with a 3" euro-brace, forget the cross-brace

..you can get the whole tank out of a single sheet.. make it count

James

 

[gveng]

You can "get away" with 1/4", will need a 3" perimeter flange (aka euro-brace) and a cross-brace. That said, should use something thicker as the deflection bugs me, personally.. If you use 1/2" with a 3" euro-brace, forget the cross-brace

..you can get the whole tank out of a single sheet.. make it count

James

so in retrospect i could also use 1/2" and a 3" cross brace down the middle?

also, what kind of acrylic should i be asking for when i call for pricing?

thanks again!

 

[Acrylics]

so in retrospect i could also use 1/2" and a 3" cross brace down the middle?

yes, but the euro-brace is key to long life and limited deflection

also, what kind of acrylic should i be asking for when i call for pricing?

I would only use Polycast or Plexi-Glas G. Polycast will be more expensive and in this case - not sure it's worth the extra investment.

James

 

[sean04]

The potential weak spots in that tank appear to be in the 4 corners of the back slot. Since the euro center brace does not connect directly to the back of the tank, the load stress on the front of the tank is transferred to the 4 corners of that rear slot. Cutting a slot on the back of the tank would probably relieve that stress and transfer it to the ends of the slot you cut.

If you going to cut the slot, you're going to want to reinforce that top euro along the back edge with something. Bonding the external box to the back of the tank should re-inforce the slot, but IMO it wouldn't be enough to make it safe.

James (Acrylic), Floyd,

If I cut a slot the same width (15 3/4") as the top cutout as pictured in my original post. How can I reinforce that top euro (taking into account) that my external overflow box will be 25" wide centered across the back?

 

[DUPioneers]

Sump/Fuge Build Questions

Sump/Fuge Build Questions

To the acryli-nuts out there...

So, I was able to pick up a 60G acrylic tank from a dude on craig's list for a song. The tank had originally been used as a wet/dry filter set up for a freshwater cichlid tank, but I'm intending on converting it to a sump/fuge for my 180 gallon reef tank build.

Before I get too far into this and screw something up, I've got a few questions:

1) The guy I bought it from was a total tool and put his baffles and such in with as much aquarium silicone as he could use to ensure a (semi) water-tight seal. Yes, I'm serious. I have since ripped everything out and scraped as much of the silicone residue off the walls and floor of the tank as possible without gouging the crap out of the acrylic, but there is definitely more left. My question is: What should I do about that silicone residue? I'm assuming that my new baffles and dividers won't bond to it when using Weld-On, so it has to come off...any suggestions of how to get it off? Or, should I just design around those places that have the goo?

2) Since the tank is, well, a tank...and, has three sides, what is the best procedure for welding my new baffles and dividers in? i.e., weld the bottom first, then one side, then the other...or, weld one side, then the bottom, then the other side...or ??? Also, what's the best way to apply even weight/pressure to my joints when working inside a tank that I can't take apart?

3) Finally, given the above, what's the best product to use for my purposes? I'm thinking Weld-on #16, since I don't care (much) about bubbles or appearances...but could definitely be persuaded to use something else.

Thanks tons in advance for any help/suggestions/admonishments!!! :wave: