Center Brace Reinforcement Question

[jwcarlson]

I bought a used 125 that was actively holding water when I bought it about a year ago.  I am finally getting around to cleaning it up.  I resealed it 72 hours ago.

When loading it I slipped and thought I broke the center brace, but when moving it in I could not find an issue with the brace.  While resealing I really flexed the brace because I am paranoid and found that the seam from the injection mold had cracked, but not completely through.  Obviously I cannot fill it like that.  So tonight I got a sheet of 1/4" acrylic and cut a strip the same width as the brace.  And attached it with four nylon bolts.  I am leaning towards putting four more bolts in, the over worried part of me thinks it is a good idea, but the engineer in me thinks it is probably totally unnecessary.   What say you?

 

Pics to show what I did.  Stainless nuts will be replaced with nylon ones when I can locate some.

 

Edited December 24, 2023 by jwcarlson

[lefty o]

should work, though tops may be difficult.

[jwcarlson]

On 12/23/2023 at 9:09 PM, lefty o said:

should work, though tops may be difficult.

Yeah, it's going to jack with the tops a bit, but I'll survive.  Or figure something else out.  I could externally brace the tank and I am not too worried about the appearance.  I'll crop the pictures well. Haha

Or maybe I'll make a false top or something somehow.  

Edited December 24, 2023 by jwcarlson

[nabokovfan87]

On 12/23/2023 at 4:58 PM, jwcarlson said:

When loading it I slipped and thought I broke the center brace, but when moving it in I could not find an issue with the brace.  While resealing I really flexed the brace because I am paranoid and found that the seam from the injection mold had cracked, but not completely through.  Obviously I cannot fill it like that.  So tonight I got a sheet of 1/4" acrylic and cut a strip the same width as the brace.  And attached it with four nylon bolts.  I am leaning towards putting four more bolts in, the over worried part of me thinks it is a good idea, but the engineer in me thinks it is probably totally unnecessary.   What say you?

Bond the acrylic to the plastic. Then also have the mechanical attachment holes with the bolts. If you don't bond it, then you're loading everything to the bolts.

Option 2 is to just eurobrace it.

[jwcarlson]

I was thinking about this last night and I think I arrived at the same conclusion, @nabokovfan87.  

I don't think there's much sheer concern on the bolts, but if the acrylic itself cracks then the whole ball of wax is going.

Thanks!

[jwcarlson]

The question is how to bond it, I think.  Silicone doesn't adhere to acrylic well, right?  Are any of the JB Weld type products aquarium safe?

[nabokovfan87]

On 12/24/2023 at 5:59 AM, jwcarlson said:

The question is how to bond it, I think.  Silicone doesn't adhere to acrylic well, right?  Are any of the JB Weld type products aquarium safe?

3m has some stuff they sell at home Depot that can pretty much bond anything to anything. There's a few but I think it's called DP100. DP100FR is the same thing but fire resistant. There may be a marine or water install version.

https://www.3m.com/3M/en_US/p/d/b40066435/

I can't say it's fish safe, but there is a method to bond it that should give you multiple methods of ensure attachment.

1. Rough the surface on each piece, clean and prep it appropriately.

2. Drill holes in the acrylic so that whatever bonding epoxy used can seep through those holes and stay put. Any forces will then be multidirectional to resist the tearing. It will be a lot more rigid and take a lot more strength to break and shear apart. It sort of acts like a bunch of rivets and distributes the load.

3. Make sure it has the proper cure time and ventilation.

Found this:

https://adhesives.specialchem.com/tech-library/article/maximizing-the-efficiency-of-adhesive-joint-designs

Edited December 24, 2023 by nabokovfan87