Acrylic fabrication questions? I can help!

[Acrylics]

Odd...

I rarley see an acrylic tank that is not a bowfront...

hence my disdain for mass-produced tanks.. ugh. Most of these tanks use materials that are 30-50% thinner than they ought to be, and the reason for so many scratches. While straight acrylic acrylic still scratches easier than glass, toss in a badly bowed tank and a straight scraper and it just compounds..

BTW, nice to see you again, Sir

 

[pfoxgrover]

Paul, if this is to be a reef tank, you *may* wish to re-think it? Acrylic bowfronts are a royal PITA to scrape coralline from and you will likely get far more scratches than a straight tank; and you've got 4 of those panels to clean.. just thinking out loud

I'd form the pieces though if you want to do this. Even parking the pieces on a form in a hot car will help. Cold forming and bonding 1/2" - may not turn out as you wish.

James

James,
Yes it will be a reef tank. An upgrade to my 240 g mixed reef. I have had a bowfront before and didn't notice any big difference in removing coralline algae. you may have to scrape left to right instead of up and down to get the scrapper to sit flat against the tank.
I do have a homemade acrylic oven and I could use it to form the pieces. I thought that since I was using such a large radius that I could save the time of building a form and that the acrylic would be more pristine if there was no chance of mark-off etc.
If I were to try something in the middle to make the acrylic a little more pliable as you suggested, I'm afraid that might not work if I put it together over a period of days because once I make the first seem it would no longer fit into the oven.

At what temperature do you think would start to make a difference?

Maybe this is a bad idea. My original intent was to build a 31" radius cylinder with two vertical seems. I later decided that I don't like the distortion that a cylinder gives you so I switch to the square Idea. I thought that the tank I described might be a compromise between the two designs where the curvature would be minimal and have no real distortion effects.
have no real distortion effects but would have an interesting look.
James,
Yes it will be a reef tank. An upgrade to my 240 g mixed reef. I have had a bowfront before and didn't notice any big difference in removing coralline algae. you may have to scrape left to right instead of up and down to get the scrapper to sit flat against the tank.
I do have a homemade acrylic oven and I could use it to form the pieces. I thought that since I was using such a large radius that I could save the time of building a form and that the acrylic would be more pristine if there was no chance of mark-off etc.
If I were to try something in the middle to make the acrylic a little more pliable as you suggested, I'm afraid that might not work if I put it together over a period of days because once I make the first seem it would no longer fit into the oven.

At what temperature do you think would start to make a difference?

Maybe this is a bad idea. My original intent was to build a 31" radius cylinder with two vertical seems. I later decided that I don't like the distortion that a cylinder gives you so I switch to the square Idea. I thought that the tank I described above might be a compromise between the two designs where the curvature would be minimal and have no real distortion effects but would have an interesting look.

I appreciate the feedback.

-Paul

 

[Floyd R Turbo]

I think it would be pretty cool, very unique tank. I don't see the bend in the acrylic panels being the biggest obstacle, I see bonding the vertical seams being the toughest one. You would have to have the front laying flat on one end with the other up off the table surface on a block or something, then the vertical piece you are joining to it would have to be supported such that the edge met up with the front panel flush for bonding the joint, and the rest of the piece, which is curved, would have to be supported somehow to keep it from falling over in the direction of the curve. Then once that piece is bonded, you have to "roll" the setup so that the other side panel can be bonded on, meaning the first curved vertical panel is now hanging in such a way to stress the new joint unless it is braced properly to support the joint (and you would probably want to let the joint cure for extra time before doing this). Then putting the back panel on would be similar but slightly less difficult.

Then how do you flush trim the front and back lip? You've got an obtuse exterior angle, I see another jig needed, and probably a lot of sanding.

After that, you would have to take out the lip created from the bending process, and then you're home free putting the top and bottom on.

I'm sure there's a way that is probably easier than I am envisioning but I like thinking about how to do these types of projects...

 

[pfoxgrover]

I think it would be pretty cool, very unique tank. I don't see the bend in the acrylic panels being the biggest obstacle, I see bonding the vertical seams being the toughest one. You would have to have the front laying flat on one end with the other up off the table surface on a block or something, then the vertical piece you are joining to it would have to be supported such that the edge met up with the front panel flush for bonding the joint, and the rest of the piece, which is curved, would have to be supported somehow to keep it from falling over in the direction of the curve. Then once that piece is bonded, you have to "roll" the setup so that the other side panel can be bonded on, meaning the first curved vertical panel is now hanging in such a way to stress the new joint unless it is braced properly to support the joint (and you would probably want to let the joint cure for extra time before doing this). Then putting the back panel on would be similar but slightly less difficult.

Then how do you flush trim the front and back lip? You've got an obtuse exterior angle, I see another jig needed, and probably a lot of sanding.

After that, you would have to take out the lip created from the bending process, and then you're home free putting the top and bottom on.

I'm sure there's a way that is probably easier than I am envisioning but I like thinking about how to do these types of projects...

Thanks Floyd. I have given some thought to the jigs required. I attached a very cude drawing of my idea for gluing the seams.

As for trimming the verticle edges, the flush bevel bowl bit I mentioned in my first post would make the 100 degree cuts for the sides and also flush cut them.

 

[adambowersva]

James, thanks for the extra reply on the Interstate tape and tips. Tried to send you a PM to see if we can talk "shop" sometime, but naturally your box is full =P. Not surprised though...as sometimes I think about doing that intentionally hehe.

Off the wall question...have you ever looked into doing any of the AGE type hybrid builds?

Currently I build almost exclusively acrylic tanks for my customers (sometimes glass if they REALLY want it and its less than 100gal), but as a strong majority of my customers are saltwater guys, there is of course a large proportion that leans towards glass simply for perceived ease of maintenance in cleaning.

I have been pondering the potential of making a test tank of all acrylic, but with a glass front panel for test purposes to see how it holds up.

 

[subshop]

subshop, any 1/2" flush cutter will do the job, no need to buy an expensive one for this, unless you plan on doing more acrylic work.

I'm assuming you're using a handheld router, if correct - you want route going from your left to your right. I other words - counter-clockwise. If you go the wrong way, the cutter will grab and want to take you on a little ride.. you'll know real quick

James , how much material can I cut away with the router. One last dumb question, I hope ! Since the bottom and sides need to be trimmed, Do I trim the bottom piece first and stop at the corners? THEN DO THE SIDES TO FINISH THE BOTTOM CUT ! neil

 

[Acrylics]

James, thanks for the extra reply on the Interstate tape and tips. Tried to send you a PM to see if we can talk "shop" sometime, but naturally your box is full =P. Not surprised though...as sometimes I think about doing that intentionally hehe.

send me an email if you want. the PM thing drives me nuts.

Off the wall question...have you ever looked into doing any of the AGE type hybrid builds?

Of course but glass work gets into a whole 'nother ball game and tooling I don't have.. and more importantly - time I don't have.

I have been pondering the potential of making a test tank of all acrylic, but with a glass front panel for test purposes to see how it holds up.

I've been asked to do it and have pondered it as well, just make the front as a frame and silicone the front panel in before gluing the bottom on. Nothing difficult, but again - just time, space, etc.. maybe this fall if the opportunity presents itself

James

 

[Acrylics]

James , how much material can I cut away with the router.

as much as you can handle. I take routers through 1" on a daily basis. Using a 1/2" flushcutter, you can easily take off 1/4" without it grabbing at all. Once you exceed the radius of the cutter - it starts to pull you through the cut - which works to your advantage when you learn to control it

One last dumb question, I hope ! Since the bottom and sides need to be trimmed, Do I trim the bottom piece first and stop at the corners? THEN DO THE SIDES TO FINISH THE BOTTOM CUT ! neil

More than likely, you're going to need to do a coupla passes at it. Personally, I'd wrap a piece of tape around the bottom - where the bearing will ride, and route the bottom. Pull off the tape, this will leave a very small lip (~.005") which is easier to route "cleanly."
Do the same tape thing on the sides, then pull off the tape and make your finish pass on the sides, then the bottom. You *might* end of with a little tit of material on the sides, near the bottom. You can either route this off or sand it off if more comfortable.

So; rough cut the bottom with tape, rough cut the corners with tape, finish cut corners with no tape, finish cut bottom with no tape, sand/route as needed/desired. done

HTH,
James

 

[Acrylics]

Paul,
Obviously you can try it, but my gut tells me it won't go as planned
Personally, I'd form all 4 pieces and build a "cradle jig" that would hold 2 pieces in a "V" and cast the joints using WO 40/42. This will require mitering the joints, but no flush cutting -just some sanding of the corners.

Doing it your way may work out fine, definitely worth the effort I just don't see the material "wanting" to warp that much without some undue stress on the material. Keep in mind that the material, right now, "wants" to be straight and will continue to keep this memory, so will put stress on your joints without even adding water.

In either case, one of the difficulties will be tolerance stacking due to thickness variations in the material, and keeping everything square. Angles, whether they be as you are describing, or mitered, add a new complexity to the mix. In the end the tank needs to sit flat and on tanks like this - requires some careful planning and looking at all variables.

As for temps, even 150F in a hot car will help quite a bit without adding any mark-off. Take a note from how they do airplane windows; cut pieces and lay them over forms in a warehouse in Arizona. In not too much time, the pieces will "relax" on the form and naturally anneal themselves while taking the form of an airplane window. You can do this in an oven as well, just heat the material over a longer period of time at a temp low enough so the material doesn't become pliable or "plastic" at all. This will keep mark-off from occurring Maybe try some test pieces at 200F or so and see how it goes.

Hope I didn't confuse the matter more
James

 

[110galreef]

Quick Question.....

Which weld on for a frag tank. will be 3/4 acrylic...60x30x12

Weld on 4?

Thanks,

 

[adambowersva]

4 will work just fine

 

[WillM]

I bought a 72Lx36Hx20D 230G acrylic tank a few years ago. I've never set it up and now have a basement and want to, but the dimensions seem bad for a SW set up.

How hard would it be to cut the top off of it and replace the top with a fresh sheet of acrylic then cut holes in the "front" and make it the top of the tank? Basically turning the tank on it's side so the 20" side is the height.

The main thing I don't know how to do is cut the top off and get it even, if there are any tips on doing that, that would be fantastic.

 

[Acrylics]

I bought a 72Lx36Hx20D 230G acrylic tank a few years ago. I've never set it up and now have a basement and want to, but the dimensions seem bad for a SW set up.

How hard would it be to cut the top off of it and replace the top with a fresh sheet of acrylic then cut holes in the "front" and make it the top of the tank? Basically turning the tank on it's side so the 20" side is the height.

The main thing I don't know how to do is cut the top off and get it even, if there are any tips on doing that, that would be fantastic.

It's "doable" but as a generality, I'd advise against it for several reasons. IMO sell the tank and get one that works better for you.

James

 

[WillM]

It's "doable" but as a generality, I'd advise against it for several reasons. IMO sell the tank and get one that works better for you.

James

Thanks, I wasn't sure it would be possible and if it's complicated then I really don't even want to attempt it. Good call,
w

 

[adambowersva]

Hey Will, first off, yes...its possible as James said and also not generally recommended.

However, in case you want to know the basics even with that in mind for education sake here you go. I have done similar tasks for a few customers before with them understanding some of the potential drawbacks. 2 examples are one customer who had a 72" long sump that needed to be 62" long for his stand and another who had a tank that was 24" tall and wanted to shorten it to be 21" tall due to a new home and its intended location.

In both cases, the way I approached it was by first rough cutting everything but about the last 1/8" of what needed to go with a circular saw. Setting up a temp "fence" and ensuring maintenance of square and assuring a straight cut are PARAMOUNT here.

After that, I setup my fence on the router table to machine a new weldable edge to the new dimensions. The cut was performed, new piece was prepped and machined to desired spec and welded on.

The problem you would likely run into though is that I am using a router table configured for acrylic tank building. As you would see from this thread or otherwise its not the same setup as a woodcraft router table and the table needs to be quite large to handle projects like this as well.

Anywho, that is the general gist if you were still wondering, but as James said...not necessarily advisable.

 

[johnd651]

Hey all...its been a long time since i have been last on... but I finally am getting back into the fish. i just picked up a 240 gallon acrylic tank, and have never worked with acrylic before so i thought i would post in here to get some answers

the tank is a 240gallon 2ftx2ftx8ft made out of 1/2in on the sides, and 3/8in on the front back top and bottom. it has a one piece euro brace top with two overflows on the back. the bottom is drilled with 4 holes.

i will be building the stand out of 2x4, plywood and foam for the top.

the tank has scratches, some deep, so i will be using this 1,2,3 formula (3 separate bottles cant remember the name) that is supposed to 1 take out deep scratches, then 2 is for fine scratches and 3 is a shine and buff paste.

it was used for salt water before, and i think the guy dropped some rock work and had it heat buffed or had a heater melt it a little in one spot (about 4-6inches long) i did try to get a picture, but i cannot get it to show up on any camera. there is what looks like two tiny (nail head size) spider web type crack things in the acrylic at that point

-can this tank be used?
-would you modify it?
-is a 2x4 stand ok with a plywood with thin foam top ok?
-i was thinking about closing off the holes in the bottom... should i just acrylic plates down or put in bulk heads with ball valves... etc.

any other ideas...questions...comments?

 

[johnd651]

...

 

[WillM]

Hey Will, first off, yes...its possible as James said and also not generally recommended.

However, in case you want to know the basics even with that in mind for education sake here you go. I have done similar tasks for a few customers before with them understanding some of the potential drawbacks. 2 examples are one customer who had a 72" long sump that needed to be 62" long for his stand and another who had a tank that was 24" tall and wanted to shorten it to be 21" tall due to a new home and its intended location.

In both cases, the way I approached it was by first rough cutting everything but about the last 1/8" of what needed to go with a circular saw. Setting up a temp "fence" and ensuring maintenance of square and assuring a straight cut are PARAMOUNT here.

After that, I setup my fence on the router table to machine a new weldable edge to the new dimensions. The cut was performed, new piece was prepped and machined to desired spec and welded on.

The problem you would likely run into though is that I am using a router table configured for acrylic tank building. As you would see from this thread or otherwise its not the same setup as a woodcraft router table and the table needs to be quite large to handle projects like this as well.

Anywho, that is the general gist if you were still wondering, but as James said...not necessarily advisable.

Thanks Adam, The other issue with the tank is the top piece I was planning on cutting off is cracked, so I doubt I'm going to get what it's worth out of it without replacing the top side. I researched how much a piece of 3/8" acrylic would cost it was quite a bit more than I could ask for the tank used. I guess this thing can just stay in storage until I can afford to run two 400W MH lights :thumbdown

 

[adambowersva]

Thanks Adam, The other issue with the tank is the top piece I was planning on cutting off is cracked, so I doubt I'm going to get what it's worth out of it without replacing the top side. I researched how much a piece of 3/8" acrylic would cost it was quite a bit more than I could ask for the tank used. I guess this thing can just stay in storage until I can afford to run two 400W MH lights :thumbdown

Oh goodness, you just opened a whole new can of worms. A 230g tank that is 36" tall AND 72" long with only 3/8" acrylic on top?!?!? Whats the rest made from???

That is just plain SCARRRYYYYYY!!! I would never ever ever ever build a tank that big with 3/8" acrylic. For 36" height I would recommend to my customers 1" acrylic for AT LEAST the front and back panels and 3/4" everywhere else. 1" all the way around and 3/4" on the bottom would be the "best bang for the buck" in the long run of happiness in my opinion.

If someone asked me to build a tank to that spec I simply would kindly decline...not worth the dig to my reputation. If they were on a serious budget the absolute minimum I would build that tank with and put my name on it would be 3/4" for the sides and top and 1/2" for the bottom.

Naturally, at 20" height things would be substantially different, but its not currently that height...

Its no wonder it has a crack in the top. Who made this thing???

 

[Acrylics]

John,

I personally wouldn't use it. The front will bow far more than you really want to see. My *guess* is that it's a tank someone made at home as 3/8" for the front is far too thin and I know of no mfr that would use 1/2" on the ends and 3/8" everywhere else - it doesn't make any sense. IMO 1/2" on a tank that size at a minimum and I wouldn't use less than 3/4".
As a secondary issue; due to the deflection (this will be the case) you're gonna have a hard time scraping coralline. Flat scraper on a concave surface..

FWIW, 2x4 stand with plywood on top is fine, forget the foam, unless it's buna or neoprene. Styrofoam is useless on an acrylic tank, it's not gonna hurt anything, but serves little to no purpose provided there's no nail/screw heads protruding from the deck.

Novus 3 will not remove deep scratches unless you spend an eternity working them. They'd have to be sanded out with (probably) 240 grit sandpaper and then worked all the way up. Novus 3 is "ok" for light abrasions but anything you can feel well at all will take a long long time. It's akin to trying to remove deep scratches in your car with Turtle Wax.

JMO
James