Ooops! Acrylic tank rebuild.

[thediscobandit]

Stupid me, i had one of my new acrylic tanks perched precariously up high whilst i was cleaning out my garage. Tank fell onto the floor below. Looks like one corner took the brunt of the blow.

I searched the tank thoroughly but the damage seen on that corner/end is pretty much it. Im looking for ideas on how to salvage the tank.

My first inclination is to saw cut the entire end off---6" will take out all of the chipped and crack portions and leave me with a 24x24x20h tank instead of the 30x24x20 it is now.

Then replace the end with a new piece of acrylic. Then i want to use whats salvageable from the sawed off end (that big crack extends almost 12" down) to make an external coast to coast overflow for the tank which if all goes right will be 5-6"wx24"lx8"h.

I have experience making repairs and patches on acrylic tanks but im pretty new to actually putting tanks together. Any advice or input would be appreciated. If anybody well versed in acrylic tank construction sees any problems with my plan please let me know before i cut into the thing.

Thanks.

 

[ndrwater]

I know that Joey "The King of DIY" has a bunch of videos on YouTube about doing stuff like this. Might do a quick search and see what you can find.

 

[albano]

If you cut off 6", how much of the top 'surround' is left on that side?

 

[thediscobandit]

If you cut off 6", how much of the top 'surround' is left on that side?

The top bracing? There will none at all left on the end, but the two sides will still have 4" to bond to. That was one of the last things i had thought of. Any ideas on how to brace it?

since i was planning to add the overflow box on the outside, i was thinking it would be easy enough to attach a piece of acrylic to the top of the overflow box, back seam, and existing bracing. It just wouldnt be pretty im betting.

 

[Foothill Corals]

Sounds very do-able, I would remove the center brace if you are making it shorter and add a euro brace to the new side.

 

[Matthew Frost]

My biggest concern would be getting the edge of the tank, the joints, machined well enough and square so you get a good weld.

 

[Foothill Corals]

Rough cut with a saw, finish using a router and a guide. Measure off the opposite sides to make it square.

 

[albano]

I think it would be better to leave an inch or 2 of the top so that you have a solid top piece to ‘weld’ to. Tank being 26” long vs 24” is not a bad thing.
For the record, I’ve had acrylic tanks since 1991, and have cut some of them down... I ‘trimmed’ a 20 yr old 27” tall 130g down to a shorter 90g which I use as a QT reef. My current DT is a 6’x5’ 500g mainly softie tank.

 

[thediscobandit]

I can typically do pretty well with a rip fence and circular saw. But yeah i was worried about getting each side perfect. ill probably cut the top first, then set the rip fence on the sides off of the kerf from the top cut.

Thanks for the advice. I have weldon 16 i used for some patches, will that work for this application?

 

[Foothill Corals]

I'm not sure if #4 would be best but I would not use 16

 

[thediscobandit]

I think it would be better to leave an inch or 2 of the top so that you have a solid top piece to ‘weld’ to. Tank being 26” long vs 24” is not a bad thing.
For the record, I’ve had acrylic tanks since 1991, and have cut some of them down... I ‘trimmed’ a 20 yr old 27” tall 130g down to a shorter 90g which I use as a QT reef. My current DT is a 6’x5’ 500g mainly softie tank.

Ah i see. The problem im running into is that the damage to the top extends 4-5" up the side, and the bracing is only 4" so even if i only cut 4" out i would take out all of it. Do you think a 4" wide overflow box would still work? Plenty of room for 1" bulkheads? The opportunity to make a nifty overflow box out of the scraps was the only positive i could really pull out of this debacle.

Id be interested to hear any tips you have for bonding the new panel on since you are indeed well versed in these kind of fixes.

Thanks!

 

[Matthew Frost]

After looking really closely at the tank, that side is an internal seam. Meaning the front, top, back and bottom lap over the side. That's virtually impossible to "patch" in another piece. Cutting the side the exact size and getting a good weld would be almost impossible. You will have to have the side lap over the front, back, top and bottom. The good news if you choose to do that is it will be easy to finish the edges. You still have to get a clean coplaner edge to weld that side to.

 

[thediscobandit]

After looking really closely at the tank, that side is an internal seam. Meaning the front, top, back and bottom lap over the side. That's virtually impossible to "patch" in another piece. Cutting the side the exact size and getting a good weld would be almost impossible. You will have to have the side lap over the front, back, top and bottom. The good news if you choose to do that is it will be easy to finish the edges. You still have to get a clean coplaner edge to weld that side to.

Yeah thats what i intended to do, cut the top, bottom, sides flush and bond a piece of acrylic 24x20 onto it. I wouldnt try to cut a piece to fit into the damaged section. That would be very tedious and like you said, impossible.

 

[Foothill Corals]

If you wanted to make the new panel the back, then you could just cut slots into the top and add an external OF box.

 

[thediscobandit]

If you wanted to make the new panel the back, then you could just cut slots into the top and add an external OF box.

Thats the plan. I was just gonna trim all the cracked, damaged part of the chunk of tank that i cut off and use that as the box instead of buying an of box.

 

[FishKeeper01]

Do you have any video about this? Would love some tips too - thanks!