fixing acrylic crack

[eleyan]

I accidentaly dropped my 55G acrylic tank and got a small crack in the corner. I was thinking of reinforcing the corner inside and outside with 1/8 th acrilyc. What is the best epoxy to use for this? and here can I pick is up ?

[::pete::]

Can you post a picture? It sound like weldon 4 and it can be purchased at Allied or Regal which are on the NE side of SA.

[eleyan]

here is a photo. the crack is less than an inch on one side and 1/4 - 1/2 on the other side. Any place in austin has these ? (home depot, lowes?)

[::pete::]

Ouch ... thats on three pieces not just one!!!

[SBreef]

At least it was not a Glass Tank ^_^ :roll

[matt]

Weldon #40 is definitely your best bet for this one. You want to put a small quantity inside the corner, maybe stand up the tank on that corner so the weldon will pool up (use a little bit!!) in the corner. Then you can use weldon#40 to cement a couple of small "patches" on either side on the outside, but not, of course, on the bottom. Use cast acrylic for your patches.

That "should" work, but you definitely want to leak test it outside!

[tgray]

Would it be of any help to drill smalll holes at the end of the cracks to stop the cracks from running any farther?

[eleyan]

can I pick up Weldon #40 at Home Depot or Lowes in austin, or do I have to call Glass repair shops?

[eleyan]

At least it was not a Glass Tank Happy Rolling Eyes

I know, I slipped on some water in the garage when I was carring it and it fell on my foot. scraped the hell out of it, but if it was glass it would have been much worse

[::pete::]

You will have to order it online. It has a shelf live so most plastic places do not carry it.

[eleyan]

I looked up both weldon #4 and $40 and the #4 is much cheaper ($5 vs $24). well either one work?
http://www.rplastics.com/weldon4.html

[::pete::]

The 4 is for bonding acrylic pieces together. In your case as Matt mentioned 40 in the coner and seems, but you wilkl still need the 4 to put the patches on.

[witecap4u]

Look up the plastic stores in austin in the phone book. There are a couple that carry the stuff. I've gotten some from a place on 183 by the airport, cant think of what its called, something like Interstate plastics I think. I've gotten #4 and #16 from them.

cs

[ReefOne]

order a 1" acrylic cube and use some weld-on on that corner gluing the cube in it's place on the inside of the tank. This will give you a better result as far as sealing goes. I dont believe just gluing in the cracks would work that good. You could just get a small 1/4" triangle and glue it in if it's at the top of thank so that the it wont look as noticeable as the cube.

Ram

[::pete::]

I agree with reefone a square tube up the corner on the inside with 4 will do the trick!!

Search here (http://www.mcmaster.com/) for acrylic bars. This will give you an idea of what is mentioned above.

[matt]

The 4 is for bonding acrylic pieces together. In your case as Matt mentioned 40 in the coner and seems, but you wilkl still need the 4 to put the patches on.

I'd use #40 to put the patches on as well; it won;t look as good but it will be stronger. Be careful if you buy any locally, as it has a firm expiration date; 1 year from the date stamped on the jar. It's a 2 part polimerizing cement; #16 will not work in this case. I'd forget about the cube inside the corner; it won't hurt, but just a fillet of weldon #40 will be fine and just as strong. You might want to run a SMALL bead of weldon #40 a few inches along the seam from the corner in all three directions, inside, as it's possible the shock might have weakened the joint. If that's the case, though, maybe nothing will work.

The #40 has to be mixed in the right proportions; I found an old salifert test kit worked great. Use the big syringe for the resin and the small one for the activator; 20:1 resin/activator mix. You'll have to mix up small quantities at a time; (like 5 ml of resin, .25 ml activator) first to do the inside corner, then after that dries, the patches, then the beads up each seam if you want. The stuff does not smell very nice....but it's really strong. You don't have to rough up the acrylic before hand, but you should make sure it's absolutely clean and dry.

Anyhow, that's how I'd do it. There was a guy that bought a skimmer from me and dropped it, causing some really serious damage. Although I had to replace the tube and top of the skimmer, I used weldon#40 to fix some cracks in the side of the box right near the drain, where the gate valve had slammed into the street and torqued the box enough to crack it. (3/8" spartech, no less!) Weldon#40 holding a few patches on did the trick. Good luck!

[::pete::]

The 40 is really strong stuff and strong smelling too!! I put a bulk head on a piece of acrylic and then turned and realized it was in the wrong place!! I grabbed my channel locks and could not get it off with in 20 minutes!!!

[eleyan]

Thanks for all the help. I checked out the cube Idea, but the smallest bar I can find at that place was a 1"x3"x6" and cost $66. I was able to cut three 1"x1"x1/4" from a peice of scrap acrylic I had and 2 other 1/8" pices for the outside. I don't care how it looks as long as it holds water since I'm going to use this for my sump/fuge. I'll look for the weld-on 40 in local stores tomorrow, otherwise I'll order some.

Thanks

[::pete::]

Oh ... its a fuge ... yea Id just patch it up!!

[ReefOne]

tap plastics sells the small 1" cubes. I bought them there a while back.

[eleyan]

Weldon #40 is really hard to find. I found #4 and #16 locally @ Interstate plastics and Regal Plastics. Interstate Plastics had some #40 in another location and said he can bring it by the end of the week, but wasn't sure how old it was. If its too old, should I just use #16 since I'm sandwitching both sides?

[ReefOne]

if you use 16, you have to remember that it shrinks as it dries which can cause some crazing. You could use some 4, followed by a real thin amount of 16.

[eleyan]

Well, I ended up using Weld-on #16 and it seems to have worked, here is a shot