Acrylic Tank Repair

[tike]

Hey Gang!

I bought Erik's 60 gallon sps tank a few months ago. While we were disassembling it we crack it . The crack comes off one of the holes drilled for the closed loop. I am a amatuer at repairing acrylic (but a pro at glass! )

So my questions for you acrylic pros is......what is the best way to go about this?? I know that Weld On is the cement of choice but other then that I'm Lost! Any suggestions would greatly be appreciated!!!

I am attaching a few pics of the crack so you get a cleaner picture about what i am talking about.

Thanks!!
Willie

 

[james734]

I'm not a expert, But I've seen others patches for similar things. Basically I think you would take out both bulkheads there and get a big piece of arcylic and cover the whole area. Then re-drill the arcylic in the same location as the existing holes and reinstall the Bulkheads.

Basically just cover up that whole area with a new piece.

 

[tike]

Cool! Now, should i glue the new piece to the inside or outside??


willie

 

[mattseattle]

I'd do it on outside and do as James described above. I'd get a piece of acrylic the same thickness as your tank and weldon it to the outside of your tank in the damage area. I'd let it dry then re-drill out the bulkheads. You could paint the back black before you do that though and that'd hide the sheet of acrylic but then again coralline will cover it eventually.

 

[tike]

Okay....now for the weld on. Where do i get it??? I have tried Home depot but they don't carry it. Also what type of paint is best for acrylic?

 

[mattseattle]

http://www.tapplastics.com/

they have local stores so you can just go in. i'm sure there are other places as well so maybe someone else knows of a place in/around Tacoma.

 

[tike]

Thanks Matt!!!!


willie

 

[DonW]

Kel Tech on pine just of 38th by the Tacoma mall. Forgot the name but there is another place behind the humane society on center street.

Don

 

[Brenden]

Just my 2 cent: I would not waste my time painting it.

 

[tike]

Why Brenden???

 

[tike]

This is what the tank looks like full shot.

 

[big t]

Don't paint it, it will probably stress out the acrylic to the point of craizing and possably cracking. PSI is the place over by the humane society. I would stop drill the crack and then put on the patch like discribed above. Use weldon 16 and it will be a easy job.

 

[tike]

thank big T!! O.K.......what's stop drill?? Man i feel dumb! LOL

 

[big t]

A stop drill is when you drill a small hole at the end of the crack to "terminate" it. It will make a stopping point so the crack will not extend any further.

 

[liveforphysics]

Exellent advise BigT. That was going to be exactly what I told him, and I'm actually really suprized that DonW didn't tell him earlier.

If it were my own, I would make a 1/4" stopdrill hole, then slide a 1/4" acrilic dowel chunk in the hole coated with weld-on. Then I would either use very thin acrilic cement with a toilet plunger ready on the back side. I would lay a bead over the face of the crack, then use the plunger and capilary action to draw the weldon clear through the crack.

After that, I would do the most important step, removing the bulkhead and smoothing the whole inside of the circle to remove future stress riser points which enabled that crack to form.

If I was slick with the plunger setup, I would not add a reinforcement plate afterwards, unless I had a way to make slick feathered edges on it, otherwise you are createing another stress riser point when the aquarium is flexed again to crack.

 

[les]

I would drill out the end of the crack then lay a bead of Weld On 40 down filling in the crack and the drill hole. WO 16 isn't as strong and anything else would just run out of the crack anyway.

 

[big t]

Ok a plunger? Have you used a plunger before do draw thin weldon into a crack before Luke?

Les the crack will not accept any weldon 40 becuase it is not a gaping crack, it is a hairline crack. Also it could cause a lot of crazing on a used tank. I suggested using the 16 because it is easy to find, easy to use and will be plenty strong for that type of fix.

Anway you can use thin weldon to fill the crack and it will draw the weldon thru capilary action (no plunger required), however once it cures it will be full of bubbles and will not have much of a bond along the edges becuase as the thin weldon's cure they contract and draw air into itself. When building a tank you use pins to spread the joint apart and it mixes up with the acrylic that is being joined. When you pull the pins the joint settles and creates a fillet along the edge. While curing the fillet will get drawn back into the joint and if done right there will be no bubbles.

Anyway tike if you need a patch I can provide one from my scrap pile for free, and you can borrow some 16 too.

 

[DonW]

I'm actually really suprized that DonW didn't tell him earlier.
I would make a 1/4" stopdrill hole

Matt already stated how to fix the tank. 1/4 stop hole?? 1/16 is more than enough 1/32 is even better. Its only a 60 and the crack is at the top of the tank.

Patch it and get water in it. It looked great when Eric had it, hope you have the same.

Don

 

[Brenden]

Sorry I just now saw your question to me but Big T already answered. Besides it will be covered in coralline soon. Use the smaller hole as Don stated. I also agree with Big T.... leave the plunger in the toilet where it belongs.

 

[tike]

Hey that is really cool big t for the offer! I will pm you about a good time for me to come by.

You Rock!!!

willie