My Sump Leaks!!!!!!

[LoneStar]

pretty ghetto, and it hangs funny, but i dontn care it works

:roll

[dan]

if you can find the leak in your sump it can be fixed with some 1/2 x 1/2 square rod and some weldon 3. i'm sure your leak will be on one of the sides, where the bottom meets the sides. if you have any questions send me a pm.

[Flobex]

ok thanks. im acctually going tro go fill it with water now, i hope it worked!!!!

[Bug_Power]

I'm not really following what you want to do, but if you're asking if silicone will seal an acrylic/PVC joint, the answer is no...silicone will not bond to acrylic, and probably not to PVC.

Got any prof that silicone will not bond to acrylic or pvc. you do realize that the overflow boxes are acrylic, abs or pvc sheeting glued to the side of your glass with silicone right? Silicone does not BOND to glass eitheron a chemical level. If the surfaces are prepared correctly they will and do STICK quite well! We have a 150 gal and a 180 gal setup with silicone holding the center ACRYLIC brace on!

[Flobex]

well it worked, the seems felt really thin, so i just juiced em up withh a buuncho' silicone, works like a charm

[matt]

I'm not really following what you want to do, but if you're asking if silicone will seal an acrylic/PVC joint, the answer is no...silicone will not bond to acrylic, and probably not to PVC.

Got any prof that silicone will not bond to acrylic or pvc. you do realize that the overflow boxes are acrylic, abs or pvc sheeting glued to the side of your glass with silicone right? Silicone does not BOND to glass eitheron a chemical level. If the surfaces are prepared correctly they will and do STICK quite well! We have a 150 gal and a 180 gal setup with silicone holding the center ACRYLIC brace on!

Silicone holds overflows in place because the water pressure tends to push the acrylic/glass joint together, not pull it apart. I've never heard of an acrylic structural brace held to glass by silicone. Usually they're glass braces siliconed to the glass sides, sometimes with plastic trim parts that are somehow connected. I'm not sure what you're looking for in terms of proof, but I bet the cyro site has something to say about it. I do know from experience that silicone does not stick well to acrylic, and I certainly would not trust it to hold back a leak in an acrylic sump. There are cements designed for use in bonding PVC to acrylic, weldon #40 in water bearing situations and weldon #16 in non-water bearing situations. IME, weldon#16 does a very poor job of bonding PVC to acrylic with any strength, while weldon#40 does an excellent job.

[Bug_Power]

I'm not sure of this cryo site your talking about but consider this. Silicone does not BOND to glass. Bonding as I'm defining is on a chemical or molecular level. What happens is on a CLEAN DRY SURFACE the silicone sticks to the glass. Silicone is especially good for smooth surfaces. while you can use Weldon to chemically bond the surfaces together if you are doing Acrylic-Acrylic joints. If that wasn't available you could make the same aquarium using silicone just the same way glass aquariums are made. The reason Weldon is used is because a chemical bond (which makes the pieces basically 1 piece) is stronger then the physical bond from the silicone. This doesn't mean that silicone doesn't work on acrylic. I have 2 aquaruims a 150 and a 180 both using a siliconed top brace in them. These braces are less likely to crack or break then the glass. Plus I have cut open the top section of the brace to allow light/access to the middle of the tank. Instead of simply saying something won't work, ask yourself WHY wouldn't it work? When comparing the surface of Acrylic and Glass besides glass being of a higher harness scale, they are identicle.

[matt]

The cyro site is: www.cyro.com They're a major manufacturer of acrylic and the site has all sorts of good info, like an aquarium wall thickness calculator and a section on cementing acrylic. IPS corporation, which makes weldon products, also has a chart showing which solvents and cements work with which products.

But that doesn't really matter. I can tell you from my personal experience with acrylic, which is pretty extensive, that silicone is not a good choice when trying to attach PVC to acrylic in an application that must be watertight, which is what the original question was. It doesn't work well, period. If you want to build an acrylic aquarium using silicone to hold it together, fine.

[Bug_Power]

Here's a link from Cryo listing using Silicone in the article to bond thier sheets to fiberglass boats.
Once again.....if you're going to say something DOESN'T work please be able to back the claims up with proof. Otherwise others will begin to take it as fact, and then a lot of good products can be bashed on hear-say.
Here is a link from cyro's site specifically stating use of silicone as an adhesive for acrylic. http://cyro.custhelp.com/cgi-bin/cyr...hp?p_faqid=622
Further more, this joint is not under much/any pressure as it is simply an over flow from one tank to the next. Honestly if he wanted to simply clean and dry the joint well, he could silicone the crack in the sump and run it as is. without the need for having his hex in there and ruining it. If he's wanting to attach PVC to acrylic another way BONDING them together they sell a multi use glue that I have used when building about 4 skimmers that bonds acrylic to pvc sheet. It actually melts each substance and they mix together. It's not as strong as an acrylic/acrylic or pvc/pvc joint, but it is definatly water tight and strong. I can lift my FULL skimmer up by the acrylic neck with no problems.
***edit****
You have to remember silicone has been used for years in auto/homebuilding and other fields and has had much more exposure them the aquarium relm.

[matt]

The article you cited does not use silicone to bond acrylic to fiberglass; it uses it to seal between the acrylic and a frame which is bonded to the fiberglass and holds the acrylic in place. I read that article before I posted last time. Please do your homework a little better if you're going to criticize my comments, which are based on personal experience, as I said, address the original question, which was regarding the use of silicone to bond PVC fittings to acrylic in a leakproof manner under some water pressure. My answer, not matter what you want to say about it, is it will not work well.

I'm finished on this thread.