Crack in trim

[Prickly Magoo]

My 75 gallon has a crack on the front left of the trim, not the middle part but on the front. Can i still fill it up and use it or is it not a good idea?

[mynameisnobody]

@Prickly Magoo I wouldn’t risk it. 

[Biotope Biologist]

It’s fine the trim does nothing other than hide crudely cut glass so they don’t have to sand it or anything- it is not structural.

Despite what many think

[Tanked]

If the center strip is intact, you are probably ok.  For peace of mind, I would probably invest in a tube of plastic weld/epoxy to repair the crack. Replacement frames are also available. 

[nabokovfan87]

75G is a lot of water.  I'd repair it or replace it with some sort of a eurobrace style thing.

They do have those new 60B tanks that are pretty awesome in dimensions and might be easier to work in.

It sounds like the (and looks like) the tank was on storage or something and got damaged. I would definitely go through it with a fine tooth comb before setting it up in a permanent situation.

On 8/27/2023 at 9:19 PM, Biotope Biologist said:

It’s fine the trim does nothing other than hide crudely cut glass so they don’t have to sand it or anything- it is not structural.

Despite what many think

A 75G has a cross brace. I imagine in some aspect it is structural at least to stop Blowing? Not all aspects are structural and your explanation is exactly why, it hides some flaws.

[Biotope Biologist]

On 8/28/2023 at 7:49 AM, nabokovfan87 said:

A 75G has a cross brace. I imagine in some aspect it is structural at least to stop Blowing? Not all aspects are structural and your explanation is exactly why, it hides some flaws.

It says that on their website, but I have a feeling it’s a liability thing. Glass is not very flexible and if the water were to exert enough pressure on that plane to get the glass to bow it would snap very quickly after that. A thin sheet of plastic would not hold it together or prevent those forces to begin with. 
 

I don’t know how they manufacture these tanks but I have a feeling the trim is used in the final silicone molding stages to make sure that the glass stays put while the silicone cures. A 75g has 2 long sheets of glass so a center brace in the trim prevents the middle of those sheets from walking out during that process. 
 

Rimless tanks do just fine without any bracing or trim. But they use higher quality glass and thicker sheets typically

[JChristophersAdventures]

I would certainly agree with @nabokovfan87 if you are going to use it, I would clean the cracked area, so the repair will stick, and use an epoxy for repairing cracks specifically in plastic... work it well down into the entire length of the crack. And, whatever the cure time says on the label... I would double that just to make sure it is ready to go. If you are worried about how it looks, then just smooth it well before it drys and/or sand it down after it cures and touch it up with some flat black or low gloss black paint.

If you don't care how it looks, and you really want it super strong, then after filling the crack, consider finding a stout strip of similar scrap plastic and weld it across the front with the same epoxy (you could do the same with the top and inner surfaces, but it might interfere with your lid, if you are using one). My only other thought is a question: Why is it cracked? If it cracked on you while in use, then I would make sure the surface/stand you are using didn't contribute to the problem before filling the tank again. Hope that helps. Thanks.

Edited August 28, 2023 by JChristophersAdventures

[dasaltemelosguy]

I would agree with @Biotope Biologist that the trim crack is insignificant insofar as being a structural support is concerned. However, trim cracks like these can have another annoying property if the water level is high enough or if there’s enough condensation or splashing such as being under an air stone or other bubble source. They can fill with water and behave not unlike a mini siphon, funneling small amounts of water up and over the edge. I had a 120 with two similar trim cracks do exactly this. I would find small puddles every morning. Although small, those cracks also soon became filled with algae or a similar muck as well. I lowered the water line and filled in the cracks with silicone although their suggestions of epoxy sound like a better idea than my approach.

[nabokovfan87]

On 8/28/2023 at 8:35 AM, Biotope Biologist said:

It says that on their website, but I have a feeling it’s a liability thing. Glass is not very flexible and if the water were to exert enough pressure on that plane to get the glass to bow it would snap very quickly after that. A thin sheet of plastic would not hold it together or prevent those forces to begin with. 

I seriously wish the 29G's had one.  I think 37's do, but I've never seen one in person. 

 

On 8/28/2023 at 8:35 AM, Biotope Biologist said:

Rimless tanks do just fine without any bracing or trim. But they use higher quality glass and thicker sheets typically

100%

A "happy medium, is this method.  Really cool to see this process.
 

 

 There's also some vids of people using plastic fill and heat to "solder" or heal the cracked rim.

I think the cracked trim might be a symptom and not the only thing going on.  As mentioned before, if it was sitting for a while in storage be sure to go through it with a fine tooth comb.

[Tanked]

I can't say for certain what purposes the tank trim is supposed to serve. I can say: that when measured at the center, my big box 55 gallon expands by 1 " when filled.  The center strap is missing.

[JChristophersAdventures]

@Tanked Personally, I would fashion a replacement like the video above shows. 1" is a lot of flexing that glass is not designed to do... the bottom edge has support, being attached to the bottom glass all along the front, but the top edge doesn't without that center brace. Rimless tanks are built to different specs because they know from the start there will not be a rim to support them and they require a lot more support from the stand you put them on, in contrast to tanks with rims. My newer 75g has a center beam support across the bottom as well as the top, which I think was a smart move on Aqueon's part. The rest of the trim serves as protection for the edges of the glass panes which are very vulnerable to damage (especially the bottom glass which is tempered on larger tanks and can explode if it comes into contact with metal or stone objects). Thanks.

[Prickly Magoo]

I'm just not gonna use it. Thanks for all the replys.

[Tanked]

On 8/29/2023 at 8:35 AM, JChristophersAdventures said:

@Tanked Personally, I would fashion a replacement like the video above shows. 1" is a lot of flexing that glass is not designed to do... the bottom edge has support, being attached to the bottom glass all along the front, but the top edge doesn't without that center brace. Rimless tanks are built to different specs because they know from the start there will not be a rim to support them and they require a lot more support from the stand you put them on, in contrast to tanks with rims. My newer 75g has a center beam support across the bottom as well as the top, which I think was a smart move on Aqueon's part. The rest of the trim serves as protection for the edges of the glass panes which are very vulnerable to damage (especially the bottom glass which is tempered on larger tanks and can explode if it comes into contact with metal or stone objects). Thanks.

I agree.  This summer, mandatory things to do has pushed aside all of the optional stuff.  The tank is not currently in use, It was being leak tested in June.  When a different question concerning a cracked center trim strap came up, I decided  to take some measurements.

[Galabar]

On 8/29/2023 at 5:29 PM, Prickly Magoo said:

I'm just not gonna use it. Thanks for all the replys.

Good decision.  I would do the same thing.