Acrylic fabrication questions? I can help!

[Floyd R Turbo]

Yes you can rough-cut the top off with a circular saw (I would use a blade made for cutting plastic/acrylic like the Diablo triple-chip or something like it) then make jig and router to make the edge prepped for bonding, but that gets pretty tricky.

Here's one I made when I cut a tank in half and put a new bottom on it





That was only for a 11" tall tank though. Just used double-stick tape. Made the template out of acrylic with paper so it would slide smoothly. Kept pressure on the guide edge and slid it down the tank with one continuous pass without stopping (which is what you need to do).

The top brace I suppose it less important as far as joint strength because it doesn't have to hold water back but it still needs to be a good solid seam.

I might be making this more complicated than it needs to be. You probably could get away with laminating a new top on and affixing plates on the inside over the cracks. Still though I think if you want to make the tank the best possible, I would put a new top on it, that's just me though. The way I see it, if you're going to put all of your investment into this thing, then it's the most important item and no need to skimp.

Before going through all of this, I would take a good long look at every seam on the tank and made sure there are no other problems. The top euro being underbuilt could be a sign of overall poor construction.

[NEReef]

ya i hear ya. Im thinking of just clamping a straight edge right underneath the seam of the top lid and just running a laminate trimmer with a pattern stright cut bit to remove the top. See any problems with this?? Ya i looked the tank over and it looks good other then the top but obviously i dont know tons about acrylic... it says clarity plus on the front of the tank i think they were/are made by Sea Clear???

[Floyd R Turbo]

You can do that too. Theoretically you could make strips and bond them on all 4 sides and use that as a guide to finish the edge also, double-stick tape everything down (intertape stuff, nothing else) and run your router around. Problem is getting everything straight and true.

SeaClear is one of the big manufacturers that generally builds to the minimum spec (thickness of material) but it should be fine. Explains the cutout cracks though.

Make sure you research before bonding on the top. I can run you through the basics so you don't have to read 400 pages.

[peppie]

Originally Posted by Floyd R Turbo

You can do that too. Theoretically you could make strips and bond them on all 4 sides and use that as a guide to finish the edge also, double-stick tape everything down (intertape stuff, nothing else) and run your router around. Problem is getting everything straight and true.

SeaClear is one of the big manufacturers that generally builds to the minimum spec (thickness of material) but it should be fine. Explains the cutout cracks though.

Make sure you research before bonding on the top. I can run you through the basics so you don't have to read 400 pages.

Come on Floyd its only 400 pages. I'll bet he could learn things he dont even need to know.... YET

[Dustin1300]

I'm 99% confident this is fine but wanted to check with others. Local club member ask if I could build a frag tank for him for frags, why not!? That being said, he wants it 24"X24"X8-10" tall.

My plans were just to use 1/4" cell cast acrylic with a eurobrace around the top. No worries about flex with this, correct? With such minimal height I'm guess no!? Thanks in advance.

[Floyd R Turbo]

Hey Dustin I'm following your 1000g build looks nice.

Using the Cyro calculator it says 24W x 10H with a top needs 0.192 so the answer is yes, but I never use anything less than 3/8" (0.354) for the walls just because it will have that much less propensity to bow (and scratch) and the extra thickness of the material means your joints will have that much less stress on them (or rather the stress is spread out better) and the tank will last much longer.

You can still do 1/4" top and bottom and I'm guessing that a 3" perimeter brace would be in order with 2" radius corners.

[Dustin1300]

Floyd, thanks for the response. I built using 1/4" on a 15 gallon cube for my frag QT tank with good success. I'm going to look into 3/8"&1/4" based on your recommendations.

Thanks again!

[Floyd R Turbo]

NP.

I would look into finding the "general purpose" 3/8" cast acrylic, it is exactly the same as Plexiglas-G except it has no print on the mask and is 20% or so less. Still made by Arkema and it's what I have been using (also have used 1/2" as well as 1/2" and 3/8" black, same thing). You have to sometimes train your acrylic supplier to look for the right thing though

[Acrylics]

Originally Posted by Floyd R Turbo

NP.

I would look into finding the "general purpose" 3/8" cast acrylic, it is exactly the same as Plexiglas-G except it has no print on the mask and is 20% or so less. Still made by Arkema and it's what I have been using (also have used 1/2" as well as 1/2" and 3/8" black, same thing). You have to sometimes train your acrylic supplier to look for the right thing though

After a bunch of research and a few headaches, found out I was given bad info on this one

The Arkema material with no branding on it at all is called "P-Max" and made and sold in truckloads only. This material is made to compete with the cheap imports and it comes with *absolutely no* warranties, certifications, tolerances, or quality controls. If you have issues with the material - the answer from Arkema is "too bad" ..essentially; you paid your money, you take your chances..

FWIW, most plastic salesmen know squat about it and even the CS at Arkema didn't know there was a difference. I had to talk to the chief technical engineer and regional sales rep to actually get the truth on this material.

That said, for sumps and whatnot, it's fine, but I after learning what I have - I would *never* recommend it for display aquaria..

James

[Floyd R Turbo]

Well, that's a kick in the nuts. Weren't you using that for a long time under the impression that they just stopped printing the mask? Have you had any tanks come back with problems?

I think I spoke to the same guy a while back, I have his name written down somewhere I thought. My local Sabic rep gave me his #, Bill something?

I think for full-size display tanks of any size, I would use G anyways. However so far I have only made tanks around the size of 40g, like a frag tank.

I'm getting ready to make a tank that is 43 x 24 and 14 high out of 3/8" P-Max, also a frag tank, do you think it's going to be OK?

Would you throw this under the "extruded" category?

[Acrylics]

Originally Posted by Floyd R Turbo

Well, that's a kick in the nuts. Weren't you using that for a long time under the impression that they just stopped printing the mask? Have you had any tanks come back with problems?

No, just used 1/4" for some display cases. I won't use anything but Polycast for tanks.

I think I spoke to the same guy a while back, I have his name written down somewhere I thought. My local Sabic rep gave me his #, Bill something?

Engineer's name was Jeff, sales rep was Pete, and the CS person at Arkema was a woman, so wasn't a Bill

I think for full-size display tanks of any size, I would use G anyways. However so far I have only made tanks around the size of 40g, like a frag tank.

I'm getting ready to make a tank that is 43 x 24 and 14 high out of 3/8" P-Max, also a frag tank, do you think it's going to be OK?

I don't see any reason it would be bad.. most of the defects I've seen are minor inclusions, surface irregularities, and thickness issues, but nothing I'd point out as being problematic for something like a sump or frag tank.

Would you throw this under the "extruded" category?

not at all, it is cell cast material and better than most, if not all, imported cast materials. Just something I wouldn't use on a display tank.

James

[Floyd R Turbo]

{wipes sweat off forehead}

[lookout888]

Hello all,
So I have made my own sumps out of 1/4 Acrylic and had not problems. I am getting a new tank delivered next month and have a decision to make. I have a 500 Gallon 1" thick acrylic tank in my garage (8’ x 3’x3’) with a bottom that has a crack in it. I bought the tank for really cheap with plans to use the acrylic. So here are my questions/decisions. Do I fix the bottom (layering acrylic on the bottom of the tank) and use it. The problem I have with this is the only place I could use it is in my garage and it get really hot in there (I live in FL). If I were to use it, I am not sure what I would use it as, I don’t want to put good lights over it... and I could not imaging the pumps I would need.. Do I cut it apart and build my sump with it. The problem I have with this is how I cut 1” acrylic. I used a router on the ¼ and it was a pain as no matter how slow I went it would gum up eventually. Should I not attempt to work with the 1” acrylic and see if I can find a local acrylic place to cut it?
Opinions and suggestions welcomed. This may be more of a "What would you do?" question.
Mike

[lookout888]

Double post..

[Floyd R Turbo]

depends on where the crack is. if it's out in the open, then you can drill a hole at both ends of the crack (to stop the crack from expanding) then laminate another piece over the bottom, which I would sand & prep well first to make sure you get full adhesion, and this is probably a case for WO40 and an extended cure time (how long I do not know) and possible something more than 1/4". Pics?

As far as cutting, I just use Diablo circular saw blades. If you're using a router bit to take place of a circular saw blade, that would explain the problems you are having. I would not do that.

[Heliman]

Floyd

I plan to drill a 1 1/8 hole in 4 " cast acrylic tube with a Unibit.

Do you suggest that it is wise to use a drill lubricant (such as Trefolex or similar) or not

Can you advise please.

[Floyd R Turbo]

I've never used a Unibit on acrylic, I just use a standard bi-metal hole saw. I don't use any lubricant, I just drill a pilot hole with a 1/4" acrylic bit, then do the hole saw (with the pilot bit), wait until it's about 1/2 way through, then switch to the other side. I run the drill at medium speed and 'roll' the cutting edge around, stopping every 10-15 seconds to clear the chips. For thicker material (over 3/8") I usually let the bit cool or blow it off with air for a while.

Once when a friend and I were drilling a larger tank (1/2" or larger, I believe, and Polycast) the bit got very hot and I just stood there with a spray bottle with water and kept the bit wet. That one still took a while and we had to let the bit cool several times.

Just don't stop the bit in the hole. I suppose if you want to use some kind of lubricant that would be fine, but I would test it on a scrap piece first to see if the lubricant affects the acrylic or anything, I wouldn't think it would.

[Floyd R Turbo]

I've never used a Unibit on acrylic, I just use a standard bi-metal hole saw. I don't use any lubricant, I just drill a pilot hole with a 1/4" acrylic bit, then do the hole saw (with the pilot bit), wait until it's about 1/2 way through, then switch to the other side. I run the drill at medium speed and 'roll' the cutting edge around, stopping every 10-15 seconds to clear the chips. For thicker material (over 3/8") I usually let the bit cool or blow it off with air for a while.

Once when a friend and I were drilling a larger tank (1/2" or larger, I believe, and Polycast) the bit got very hot and I just stood there with a spray bottle with water and kept the bit wet. That one still took a while and we had to let the bit cool several times.

Just don't stop the bit in the hole. I suppose if you want to use some kind of lubricant that would be fine, but I would test it on a scrap piece first to see if the lubricant affects the acrylic or anything, I wouldn't think it would.

[jimmyj7090]

Originally Posted by Floyd R Turbo

As far as taking it to a plastics shop, unless they work on aquariums I wouldn't trust them any more than a DIYer. Aquarium work is a specialized subset IMO and most acrylic shops don't know it well enough. It's not that easy to take the top off an existing tank and put a new one on correctly esp if you've never done it before, x2 with a tank this big.

FWIW Marc (the rock guy, marcorocks) found a shop somewhere in the new england area that was able to cut his tank down yrs ago and they did a very nice job with it (later that tank was Liam's if you follow the locals...). If you are looking for a pro in the area you might want to e-mail Marc and ask if he can point you in the right direction.

[jdcook72]

Working on my first acrylic projects, sump and internal overflow box. I’m using 1/4" cast acrylic. I started with the overflow box, much smaller 1x7x11, good practice. Everything seemed to go fine, turned out ok I think. I didn’t use pins, just set the pieces on and applied WO4. It wicked into the joint and seems fine, a few tiny bubble here and there. Does this seem like it will be ok even with a few bubbles? All the bubbles are in the center regions, none at the edges.

For the sump, roughly 20”x16” by 18” tall again 1/4" cast, will this same technique work or should I use the pins? Why are pins used, is it because of the weight of larger pieces preventing the solvent from wicking into the seam? What is gained from this over just setting the piece in place?

All pieces were cut on a tablesaw with a Freud 80 tooth plexiglass blade. I scraped the overflow edges with a razor blade to get them smoother before bonding. I think I will router the edges for the sump before bonding those. Will that make any difference as for using pins or not?

[peppie]

Originally Posted by jdcook72

Working on my first acrylic projects, sump and internal overflow box. I’m using 1/4" cast acrylic. I started with the overflow box, much smaller 1x7x11, good practice. Everything seemed to go fine, turned out ok I think. I didn’t use pins, just set the pieces on and applied WO4. It wicked into the joint and seems fine, a few tiny bubble here and there. Does this seem like it will be ok even with a few bubbles? All the bubbles are in the center regions, none at the edges.

For the sump, roughly 20”x16” by 18” tall again 1/4" cast, will this same technique work or should I use the pins? Why are pins used, is it because of the weight of larger pieces preventing the solvent from wicking into the seam? What is gained from this over just setting the piece in place?

All pieces were cut on a tablesaw with a Freud 80 tooth plexiglass blade. I scraped the overflow edges with a razor blade to get them smoother before bonding. I think I will router the edges for the sump before bonding those. Will that make any difference as for using pins or not?

In my experience the way you assembled your overflow box will be just fine. As for your sump, I would for sure use the pin method after you have used the router to dress the edge. The pins allow for the solvent to come into contact with both edges of the panels. It also allows for more solvent to help "melt" the acrylic of the edges. When you pull the pins there will be a fillet on both sides of the seam. If you dont use the pins you will starve the seam of the solvent needed to react to both edges and will not create a fillet.
This is just my experience!
The pros will chime in and correct my post if is not accurate. Good luck.
BTW I use a "down cut spiral cutting bit" on my router table to dress my edges. It works great for me.

[Moffy]

Dear friends! This is probably my first post on RC.. The best and the ultimate forum for lot of things, including acrylic work.. I have been reading a lot of this thread.. I have built quite a few aquariums but always used wo40... But now I wish to move to the proprietary mix of methylene chloride, acetic acid etc.. (basically for cost) .. What I haven't found properly is a diagram showing where shims and pins are kept? I m not able to get what are shims exactly and where to place them. After reading almost all pages I m lost on this, a diagram would help, sincerely, moffy!

[Moffy]

Hello friends any reference to a diagram of shims and pins method ? Thanks a lot for any help

[Floyd R Turbo]

Here is a couple pics that shows the pins method





A quick description:

Take strips of MDF and apply camper shell foam to both sides.

Clean both areas to be bonded with denatured alcohol and blow of with compressed or canned air.

Put horizontal sheet on top of foam strips. Make sure the area under the joint has foam under it, as much as possible.

Place vertical piece in joint position. Leave a 1/8" lip. Secure in place with angle bracket.

Insert thin shims between foam and horizontal piece to snug the joint up as evenly as possible. There should be no visible gaps, or as close to that as you can possibly get. Some recommend inserting shims under each pin. IMO if your table is flat enough you only need them where it is necessary.

For pins, I use 28 gauge picture hanging wire from Home Depot, cut a length about 6-8" and loop & twist so you can have a 'handle'. Also I use a good wire cutters to get a clean cut end on the part that is inserted - the cutter that comes with the wire sucks.

Push down on the lip and insert pins. I do every 6", roughly. Only insert far enough to create the gap, 1-2mm should do it. For thicker material (1/2-3/4") I go a little further.

Once all the pins are in place, go around and gently tug on each one. If one pulls out easily (or falls out while putting in other pins) then shim that spot. Don't push it in too far or you'll have pins falling out in other places - sometimes far away from the one you just shimmed (this is more likely on a top/bottom joint). Repeat until you can go all the way around the joint without tugging a pin out.

Take canned air and blow out the joint. This will also reveal loose pins. If they move, that's probably OK. But if the air blows them out of the joint then that one was a bit too loose. I don't use compressed air here because it's too much pressure.

Apply the solvent to the joint. I keep some 28 gauge insulin syringes handy. If you blow a bubble into the joint, you can scoop it out with the needle before pulling the pins (don't bother trying to suck it out with the syringe, just 'sweep' it to the edge) and continue applying solvent.

Depending on the length of the joint, solvent used, time taken to apply solvent, ambient temp & humidity, etc, you may need to start pulling pins right away after you're done.

Adjust joint as necessary to get alignment right. You don't have long to do this, maybe 15 seconds after you pull the last pin.

If it's a top or bottom joint, the first thing to do after you pull the pins is to check for drift. If your table is not 100% flat and level, then the whole thing will slide and you had better correct this right away, well before the joint starts to set.

If you have to hold the piece in place, you should only need to do so for about a minute, maybe 2 at most.

I put weight on when bonding the top and esp the bottom joints. I just lay strips of wood across the top and put whatever I have on top. Like this.



or this



Ok maybe not the soccer balls.

[Moffy]

Hello Floyd, This is Brilliant. Thanks a ton for such meticulous info into one post. I'm taking a printout out of your post and putting in my garage as I've done with some of James post. I like to know each and every details perfectly and then start the practice.
RC rocks!