Public Aquarium: 3" acrylic panel cracked; can it be repaired from outside with Weld-on #40?

[HawaiiAquarium]

Tried to start one of these threads a long time ago and no one seemed to believe me about the quality of this glue and its purpose in the aquarium industry. I am more than glad to know people are now catching on and following my advice and practices of using #40. I know some people are probably tired of hearing about it but I've been getting a lot of p.m.'s about this product and how to use it. #40/#42 is the only glue anyone should be using to repair an acrylic tank, it is 30 times stronger than weld on #4 and 60 times stronger than #16 (this information is provided by the weld-on company themselves not me). It is a two part epoxy that is simply mixed and applied. #42 is #40 being sold in the smallest "kit" they make, it pre mixes for you like when you buy an epoxy from home depot in the plastic tubes. If you have an acrylic tank chances are it was built with #40 in the first place. A lot of people build with #4 or #16 and it is good for small applications like when using 1/4",3/8",1/2" if your good lol.... I've built many acrylic tanks with #4 and #16 for years but still reinforce the inside of them with #40 to prevent any crazing or seam popping down the road. Tanks 15-20yrs old came "stock" with #40 tip and poured on the inside of them and I really don't understand where this practice was lost on tanks being sold today. My opinion is newer tanks are being made cheaper and newer builders just don't know about the product or are making more profit by using cheaper acrylic cements. #40 first and foremost can be used to weld together any thickness of acrylic with crystal clear seams. Its second purpose is using it for inner reinforcement that looks similar to silicone on the inside of a glass tank. #40 can prevent and repair any seam "crazing" or separation. Any used acrylic tank I buy, I take the time to reinforce them with #40 just to never worry about them lasting for my lifetime. I have tanks over 20yrs old that were made this way and there still going stong today. That's enough backstory I guess lol, anyone with questions about the product or how to use it feel free to ask here. Also feel free to post pics of the work/repairs you've done with #40 to help out the rest of our community. Boring read I know, but it will help a lot of us. i'll get some pics together of tanks ive done with it and the "tip and pour" method of reinforcement. Some people may think reinforcing tanks is "overkill" but it sure helps me sleep sound at night and I honestly prefer the look of it on an acrylic tank. #40/#42 can also be used to "butt joint" two pieces of acrylic on end next to eachother to make longer lengths of acrylic. That's how strong it is. #40 is comprised of the same chemical properties of the acrylic itself. It is more or less liquid acrylic. Just the same as what they mix when casting sheets of it.

Can I use #40 on the outside of a large scale cracked acrylic tank? The crack/leak is minor, and has been stable for an extended duration. The leak is on a functioning public aquarium shark tank display. The acrylic is at least 3 inches thick, and I am unable to drain the water as there is no relocation for the sharks. Does #40 cure while wet? Can I take a piece of acyclic, and slap it over the crack with the #40 on the outside, and inside of the aquarium while it is still filled with water? Thank you.

 

[wednesday13]

Can I use #40 on the outside of a large scale cracked acrylic tank? The crack/leak is minor, and has been stable for an extended duration. The leak is on a functioning public aquarium shark tank display. The acrylic is at least 3 inches thick, and I am unable to drain the water as there is no relocation for the sharks. Does #40 cure while wet? Can I take a piece of acyclic, and slap it over the crack with the #40 on the outside, and inside of the aquarium while it is still filled with water? Thank you.

Thats a tough one… any cracks should be drilled out to prevent “running”… ur in a bind tho and ive been there also. I have used 40 and a patch on a tank that was up and running before on the outside as u propose. It will still cure if it touches water but it could very well still leak and allow the water through the patch as it cures. Look into Hutton Products “gold label aquarium and pond sealer”… it is a silicone that will cure under water. Use it on the inside of the tank 1st to stop the leak. Once the leak is stopped ur idea with 40 and the patch on the outside will stop it from leaking permanently. If you cant get ahold of the gold label in hawaii a good “regular” brand silicone will also cure under water contrary to popular belief. It should b enough to stop any leaking/tear dropping to get through ur outside patch. In my case it took 3 patches on the outside to stop any tear dropping from getting through as the glue cured. U have to stop or plug the leak from the inside as best u can 1st, get it dry on the outside and then, u should have a pretty good shot at solving the problem ?

 

[fishdance]

Not sure what type of public aquarium this is but adding external patch sounds like a liability lawsuit risk.

If you can't move the sharks, you can fashion a temporary coffer dam out of wood & canvas, etc. Wall off the crack area on inside and use a high volume submersible pump on float switch to keep enough water out until the patch is dry. I always place a spare pump, piped and plugged in beside the working pump (float switch set just a bit higher).