Acrylic Fabrication Q & A

[SrConejo]

Hi
Should I be concerned about the upper part of the seam in the picture below?
It's from an 1/4" acrylic sump and the seam in the picture is under the baffles so I think the volume of water in there would be small (2.2 gal max) most of the time.
The water test passed BTW

Thanks

 

[Lowell Lemon]

Hi
Should I be concerned about the upper part of the seam in the picture below?
It's from an 1/4" acrylic sump and the seam in the picture is under the baffles so I think the volume of water in there would be small (2.2 gal max) most of the time.
The water test passed BTW

Thanks

Not a big worry since it is at the top above the water line.

 

[SrConejo]

Not a big worry since it is at the top above the water line.

Thanks Lowell. Actually it would be below the water line: The sump is empty and upside down so what you are looking at is the bottom of the sump. The poodle like bubble is about 1" long.

 

[Turbo's Aquatics Verified Sponsor]

If that were a baffle on the inside, I wouldn't worry. But that looks like the bottom/front seam, bubbles on the front (outside) edge, so that could be a problem down the line.

The seam will likely hold as-is for some time, maybe indefinitely. Like you said, it's in an area with some reinforcement nearby (baffle). But, if they seam starts to deteriorate at all, that's the first area that will go.

You can fix that easily with a piece of acrylic gusset welded into the corner. Square on 2 sides, then round the corner a bit so that both sides are in contact with the panels and weld in place. It may not "seal" all along, but you're going to strengthening the area so that pressure doesn't pull apart an already weakened joint.

Then, if you want, goop silicone around that gusset to keep the water away. It's not structural so that works fine. It might peel away over time but that's fine, remove and add more. Or use silicone that adheres to acrylic and glass (they make it)

 

[NautiTang]

Hello all. I've been poking through this beast of a thread, still not all the way done yet (on page 58 now), in a planning stage for my dream tank in about 2.5 years. Dimensions are as follows: 96Lx30Hx36W peninsula style tank with a 3-4" perimeter eurobrace and 6" cross-braces spaced at 24" intervals. I intend to use 1" acrylic as suggested by Turbo and James. So naturally I found my way to this thread as I like to do stuff myself and I have a "few" questions, hopefully I don't ask you to repeat yourselves too much as I haven't yet finished the thread but here goes:
• Are the good brands still the same as mentioned earlier in the thread (polycast, plexi-G or evonik)?
• Foam underneath is bad but is the 1/4" neoprene that turbo mentioned good to use just expensive?
• I've seen several times mentioned that a thinner bottom and top panel would be ok would it help with bowing at all to keep it all 1" or not really, and if so how much do you think it would help?
• Would rounding off corners (aside from bottom corners) and the holes in the eurobrace affect structurally at all?
• Does a larger radius in the corners of the cross-brace give any additional structural benefits?
• Will the aforementioned water absorption effect the overall dimensions? 0.8% over 96" is not insignificant. I'm curious if this extends length or just thickness of the panel?
• Another question just for my curiosity as I dont intend to use such an experimental technique untill it's been tested thoroughly but would it be potentially possible to anneal a seam locally with strip heaters? Again I have mo intention of trying this in the near future but it does sound like a fun science project.
I understand that 1" is more difficult to work with amd I would practice first with a sump for which I have no specific plans for yet other than I wish to include a filter (pad or sock not sure which yet), skimmer section, fuge (probably fairly large for pod populations), and a return section with extra space for future equipment. I would also practice with some scraps of 1" if I could get it fairly easily from a plastic supplier before purchasing the 1". All this being said I wanted to see if the experts thought it would be possible for a novice to pull something this large off with an assistant or should I just pay someone like Lowell lemon to do it for me ;)

P.S. if anyone has any suggestions with the overflow as I haven't looked into designs yet; I want the overflow to have as minimalist a presence inside the tank as possible and be a coast to coast or close (like the one I believe Taylor made early in the thread) on one end

Thanks for your time and sorry for the novel.
-Best regards from Noah

 

[lapin]

Noah,
I will make a few comments here that are my ipinion;

If you go with an internal overflow be sure you leave room to access it thru the top bracing.

The mat; I dont like mats if I can help it. Its hard enough to get a tank in place without having a mat to contend with. My current tank 5' x 5' sits on 2 layers of 1" marine plywood and then a 5'6" square melamine panel I glued together myself and sanded to be sure it was perfectly flat. I would have gone with a stone counter top base but Im not rich.

You can make a tank with 1" with limited experience. After all humans are doing it so why cant you. It depends on mechanical ability, knowledge and experience.
After getting 3 or 4 panels welded if you make a fatal error those might be scrap. Mistakes can be costly as 1" is not cheap. Its going to take some trial and error. You might think about practicing on thinner (cheaper) material, then once you think you have it down, try on thicker stuff.

As for havin Lowel or some other professional build it: In my eyes the question comes down to, do you want a flawless tank or are you will to settle for a few imperfections on a DYI tank.

What ever way you chose it will be a nice tank to have.

 

[NautiTang]

Thank you for the words of encouragement, I do plan to practice first with thinner stuff and then build a sump for which I have not particular plans for. Then practice with some scrap 1" untill I feel confident.
I dont want an internal overflow if anyone knows of a good thread to look at for external overflows that would be great, if not I'll do a search on my own once finished with this thread.
-Noah

 

[lapin]

Here is a picture of my glue up of the overflow box. Its 12x12 by 48 long. A bit big. I wanted the space for frags algae ect...
Dont do this on the kitchen counter top when your wife is at home.

 

[NautiTang]

Thanks for the pro tip ;)

 

[Lowell Lemon]

Thanks for the pro tip ;)

Hey if you have access to the equipment and have the room to build the tank I think you can achieve it. I would build a couple of smaller projects first just to make sure you get the feel for the art as well as the science of acrylic. Good Luck!

Skip on the Evonic acrylic but a big yes to Polycast by Polyone or PlexG.

By the way the only way to anneal a tank is after all the fabrication and then into the oven as a finished and polished piece. So it takes a large oven. You might be able to find some one with a large poweder coating oven that might rent you time to anneal the tank.

 

[Lousybreed]

Here is a picture of my glue up of the overflow box. Its 12x12 by 48 long. A bit big. I wanted the space for frags algae ect...
Dont do this on the kitchen counter top when your wife is at home.

What type of weld are you using in the pic?

 

[NautiTang]

Thanks guys!
@Lowell Lemon my wife and I want to move to Wa near Seatle are you still in that area? If you still run your shop when I get out I will need a job ;)

 

[lapin]

What type of weld are you using in the pic?

I used a 2 part. Sci Grip # 40. In this picture I was welding the back long seam to the bottom of the overflow box. This is why it was laying at an angle The stuff needs to flow into the joint. I had attached the 2 end wings to the back already.
If you dont know I cant make bubble free joints with a solvent like #3 or 4 on anything over 1/2" thick.
I didnt want to take the time to make my own solvent mix out of Methylene chloride so I went commercial.

 

[Lowell Lemon]

Thanks guys!
@Lowell Lemon my wife and I want to move to Wa near Seatle are you still in that area? If you still run your shop when I get out I will need a job ;)

I live in Eastern Washington on the Idaho border. We fabricate counters for homes and businesses every day! The tank thing is on the side for fun these days!

 

[Shayeh]

Hello team.
I want to build an acrylic tank 160L*60W*60H in cm 64L*24W*24H in inches (55cm/22'' height the water level). What thickness i should use? 15mm or 20mm? i don't want to have any bend when i fill it.
For top bracing i need a full acrylic sheet with holes or i can do it with pieces like glass tanks?
I am thinking about sump filtration. 10mm 1/2'' i think its ok. what do you think?
All suggestions are welcome

 

[Turbo's Aquatics Verified Sponsor]

64L*24W*24H in inches

for 24" tall and under 84" long, 1/2" minimum - so 15mm (0.59") should suffice. The thicker the material, the less propensity to bow - which is a concern for cleaning, as curved surfaces mean you would have to work harder to get it clean, leading to more odds of scratching it. 20mm (0.787") would be even better, at least for the front and back panels. You could get away with 15mm for the ends, top, and euro.

For top bracing i need a full acrylic sheet with holes or i can do it with pieces like glass tanks?

Absolutely a full one-piece euro. Piece-together braces with acrylic create focused pressure points in the corners, which is where you will get cracks eventually. You might be able to get away with a strip euro on very small tanks, but this one is too big.

For the euro, you will want it to have a 3" perimeter euro and 2 6" wide crossbraces, with minimum 1.5" radius sweeps at all the corner cutouts. Then, round over the corners of all the openings (top and bottom) to remove the sharp edge - this is not only so that you don't cut yourself, but it also alleviates another focus point for pressure (sharp edges). Knocking them down with a razor blade at a 45 degree angle to the edge is sufficient.

I am thinking about sump filtration. 10mm 1/2'' i think its ok. what do you think?

Thickness is primarily a function of height (water depth) so there's not enough information here. But for reference, a 16" tall eurobraced sump with full-height interior baffles can usually be made out of 1/4" (6mm)

All of this should be prefaced on the assumption that proper parts & edge preparation techniques and solvent welding techniques are all followed.

 

[Shayeh]

20mm (0.787") would be even better, at least for the front and back panels. You could get away with 15mm for the ends, top, and euro.

For the euro, you will want it to have a 3" perimeter euro and 2 6" wide crossbraces, with minimum 1.5" radius sweeps at all the corner cutouts.

I wanted to go for 15mm because the budget is not enough for 20mm. You think the 15mm will bend? if i go front and back 20mm and bot eurobrace and sides 15mm it will be safe?
Can i go with 1 crossbrace at the middle? I was thinking 4'' perimeter and 1 crossbrace in the middle 8''. What do you think about it?

The sump will be 26''L*14''W*16''H. i was thinking about 8 or 10mm with the bafles 5mm.Only 3 bafles will go to the top but they will have 1'' gap from bottom.total 5-6 bafles. Sorry about the thickness measures but in my country i find these.

After long read i think you suggest pin method. Why you don't like the other method? it looks easier than pin method especially if you have no help like me... I saw somewhere that for pin method you dont need smooth edges and rough ones are better is that correct? weldon 3 or 4?

 

[Turbo's Aquatics Verified Sponsor]

I wanted to go for 15mm because the budget is not enough for 20mm. You think the 15mm will bend?

deflection will likely be minimal.

if i go front and back 20mm and bot eurobrace and sides 15mm it will be safe?

yes. 20mm on front & back is not necessary, but you will have slightly less deflection in the middle

The sump will be 26''L*14''W*16''H. i was thinking about 8 or 10mm with the bafles 5mm.Only 3 bafles will go to the top but they will have 1'' gap from bottom.total 5-6 bafles. Sorry about the thickness measures but in my country i find these.

8mm should be fine. You could use 6mm also, and 5mm for baffles is fine

After long read i think you suggest pin method. Why you don't like the other method? it looks easier than pin method especially if you have no help like me...

pins allow for solvent to soak and dissolve material for a period of time so that the bond is strong. Do NOT use the capillary method. This results in very weak bonds. The shimming & pinning method is a critical thing that you need to learn and practice.

I saw somewhere that for pin method you dont need smooth edges and rough ones are better is that correct?

I'm not sure where you read this. You need perfectly straight, square, sharp, router-prepped edges for solvent welding. You might be thinking of 2-part bonding, where you want some roughness to the bonding surfaces, but this would be after prepping the edges with a router (as if you were going to solvent weld them). Also 2-part (Weldon 40) is not necessary for anything under about 2" thick, and I don't recommend this unless you really know what you are doing (and don't let others tell you this is a "better" technique)

weldon 3 or 4?

If you can get Weldon #4, that is better than #3, but either will do. Ideally you can use Methylene Chloride and mix in 5% Glacial Acetic Acid, but it all depends on whether or not you can get these in Greece.

It sounds like you haven't done any acrylic tank building before - if this is the case, start with the sump, or even something smaller using some scrap material and practice. Parts preparation is critical, you need the right equipment and tables, etc. For instance, in order to put a parallel edge on a 64" long piece of acrylic, you need a router table that is on the order of 120" long and a long, perfectly straight fence. There are other ways to do it but it injects error factors.

 

[Shayeh]

Be sure my friend that i haven't done any acrylic tank this size. I did one 10g breeding tank many years ago with 5mm thickness with capillary method with no edge preparation. But this size is different and i want to make something good.
I wanted to build the sump first to see what is going on and if i fail it will be small loss. i will take some scrap pieces too to learn. The good think is that the shop will prepare the pieces with a router for me. So for this part we will be sure.
i will order weldon 4 then. i can't find any of this here.
i will try to go 20mm front and back if my pocket allow me :D
About the 1 crossbrace what you think? 4'' perimeter and 1 crossbrace in the middle 8'' ?
You have any video to see?

 

[Turbo's Aquatics Verified Sponsor]

The good think is that the shop will prepare the pieces with a router for me.

That's good. One thing to keep in mind though is that many places will cut to square and the run a router on the edge using a small table (which is basically like a jointer). This doesn't necessarily produce parallel edges or square corners, or square parts for that matter. The ends have to be perfectly square and match dimensionally. The front/back/side panels have to have the exact same height dimension. The best way to perform this last step is to use a router table where you pass the parts between a long fence and the router bit, which is not a standard way of routing; most of the time, the fence is on either side of the router bit so that it make one edge straight, but this does not keep that edge parallel to the opposite edge.

Your shop might know this, but I would check with them.

i will order weldon 4 then. i can't find any of this here.

You may not be able to obtain it at all. As far as I know, most every effective solvent welding chemical is restricted in the EU.

About the 1 crossbrace what you think? 4'' perimeter and 1 crossbrace in the middle 8'' ?

If you want only one crossbrace on a 64" tank, I would bump the perimeter euro to 4.5" and the crossbrace to 8"

You have any video to see?

I just took some video of this last night actually when prepping parts for a custom sump. It might take me a while to get around to editing it and posting it, or someone else might do it for me