Sump Construction pics

Is that a DIY CNC?

 

Nice. If I didn't have access to a 5' x 10' router table I would so want one.

Also I noticed that you made that sump out of Chemcast. Doesn't that worry you?

 

No, it's not recommended for aquarium use. I don't mean to burst your bubble but I can't help but add my 2c based on what I've learned. One of the very first posts I read on RC when I was getting into acrylic fabrication was a post from James Steele ("Acrylics" on RC, owner of Envision Acrylics, 25 yrs+ experience) and he was breaking the same news to someone.

Chemcast is an inferior product that for some reason does not hold bonded joints well. It is inexpensive compared to most other cell cast acrylics, thus the reason it is attractive. There was one company that started making tanks with this stuff and their prices were fantastic, but then tanks started having catastrophic failures (literally tearing apart at the seams) without any particularly predictable pattern, and the company went under due to warranty coverages. Ever since then, it's the black sheep of all acrylic products. Who knows if they have fixed the issue or not, I've seen tanks made with a mixture of CC and Polycast (400g bowfront on LA Fishguys for instance) and time will tell but I won't touch the stuff. Plexiglas and Polycast are all I will ever use, won't use Cyro/Acrylite either because anything under 1" thick is now made in China and there is not much history of the product with tank manufacturers yet.

If you're looking for a less expensive product, get Arkema/Plexiglas "general purpose" or p-max / pmacs which is cell cast with a paper mask without any print, basically the same stuff at Plexiglas-G (print on the mask) without the warranty (which is void as soon as you machine it anyways) I get it from Sabic in Cedar Rapids, costs about 25% less than -G.

Also I saw in some of your pics that your vertical seams looked like they had a lot of big bubbles, am I seeing this right? Are you doing the welds using capillary action, or are you using the pins method? If it's the former, that in combination with Chemcast is not a good combination. I am fixing a sump right now that someone got given to them after it had a catastrophic vertical seam failure (joint literally came apart like it wasn't ever bonded) and it was done via capillary action (pieces flush together, solvent ran in). This is not the correct method for tank assembly. You need to use the pins method and let the solvent 'bite' into each side, otherwise your joints will be very weak, and while this may not be an issue when the sump is in operation mode, when the power goes out and it fill up, that's when you're going to be putting maximum stress on the joints. Top it off with the absence of a top euro and it's really a triple whammy.

You might consider putting some triangle rod in all the corners. That's what I'm doing for the busted sump, 3/4" triangle rod bonded in with Weld-On 40.

It's your call, but I would at a minimum give that a good, long fill test.

 

Post on this thread about Chemcast, or search through the 2 splits for James' posts about it

http://www.reefcentral.com/forums/showthread.php?t=1056956

I would not discount the possibility that the problem has since been fixed, I would think it would be in the best interests of Chemcast to address the issue. From James' posts, he says the factory in Mexico that makes it is quite literally right next to another one, both factories built by the same company with all the same equipment, yet one produces material that causes tanks to fall apart, while the other one is an industry standard recommended product (Plex-G I think)

Ridout is my source for rods also. Just bought a bunch of the 3/4" triangle rod and WO40 from them.

I personally don't like 16, it is not a gap filler, it dries to a thin profile similar to #3 or #4, so it will 'suck air' in at the edges as it dries. But it would probably work well for your build, where the seams haven't failed yet and it hasn't seen water. I'm using 40 because I don't trust the seams on this old tank at all, I want a full bond and all gaps filled.

What I did was order enough triangle rod to do all the vertical and horizontal seams, then in the corners I was planning on taking 2 pieces of triangle rod and welding them together to form a square rod (because square rod is more expensive, at least 3/4" is) and cutting blocks for the corners to butt the triangle rod up to. I am also bonding on a couple sections of snapped-off eurobrace and gusseting the entire top seam again, and then bonding slats of acrylic on top of the old euro. Should be fun.

 

Rather than post here I started another thread

http://www.greateriowareefsociety.org/Forums/tabid/78/aft/30679/Default.aspx

 

Triangle rod will go a long way, if CC has fixed the issue, 1/2" gussets will really firm up the tank.


Adding a top euro will help as well, this will reduce the tendency of the walls to bow outward. The first sump I made was a low-profile rimless and it runs 1/2 full all the time, and it has bowed more than I would like.


How thick is the wall material?

 

I think you could get away with 1/2" triangle actually, since it's a clean build. I wanted extra reinforcement since I was not sure what material was used, and the joints were really weak. Hence the WO40 as well. If you wanted to save a few bucks you could do the 1/2", ridout doesn't bill out the order right away so you have time to change it. Extra strength definitely doesn't hurt though /DesktopModules/ActiveForums/themes/_default//emoticons/smile.gif

 

It was actually more like half of the tanks they made were literally falling apart. It really gave the product a bad name...