Leaky Uniseals...help!

So I just built a nice RDWC system and went to to fill some of the buckets and discovered that they are leaking around the bottoms of the Uniseals. I disassembled the thing, made sure it was dry, made sure there were no burrs or imperfections around the holes. They are round Home Depot buckets, and I know square ones are ideal, I just couldn't get any. I slathered the inside and outside of the buckets at the junction between the Uniseal and side of the bucket with "aquarium safe" silicone, which is quite expensive btw. I let it dry for 48 hours and tested again. Most were okay but I still had a few leaky ones. When I pulled away the silicone to fix it and reapply, I discovered that it just peeled away very easily, meaning that the silicone doesn't adhere very well to the plastic of the bucket or the rubber of the Uniseal. I'm not sure what to use other than the aquarium safe silicone; everything seems to have hazardous chemicals in it. What should I do? Just gloop on more silicone excessively until it doesn't leak any more? I can't be the only one that has had this issue with Uniseals and curved buckets.

As a waterproofing agent silicone is 100% useless , it might last 50 yrs but it isnt a good waterproofer due to it's poor adhesive characteristics , also something even seasoned construction workers aren't aware of is that in order to get silicone to properly adhear to the surface a liquid silicate based primer is supposed to be used before applying the silicone , good luck finding the primer at home depot , lowes or ace hardware as they've never heard of it's existance , for some unexplained reason johns mannsville makes the primer but it's only available to JM approved contractors , nowdays most architects spec Vulkem Sealent & allow Sika Flex 1-A as a substitute for waterproofing applications , your situation is of a waterproofing nature .

Sealing flat surfaces to round buckets is a perfect application for Vulkem sealent , you can get it at most custom glass shops which include companys who cut & install home & commercial window glass , it's expensive at about $10 a tube but it will stick to any dry surface & you'll play hell getting it off , just be sure to rub it into the surface of the bucket with your finger then apply a bit more so it's thick enough to create a pressure seal & it wont ever leak again .

Do a google search for Vulkem & you should be able to order a tube or locate a supplier near you , any large commercial roofing company in your town will have some on hand & you could ask them to sell you a tube , it's the absolute best sealent on earth bar none & it's a polyurethane sealent not junk silicone or latex .

Thanks panhead, great info! Do you think that the Vulkem would leech chems into the water? I read the ingredients, and there is some pretty nasty stuff in there. In fact the label says it contains several compounds known to cause cancer. Not that silicone, or anything else wouldn't also, but that made me a little uneasy in the pants. Otherwise I'd say it's a go.

You're so right on the silicone. It doesn't stick to shit. 4 out of my 7 buckets are leaking where I applied silicone. There's $25 down the drain. I was even thinking of trying out a bulkhead, even though they're expensive, and just tightening the shit out of it until it basically flattens out the bucket a little. even if I have to steam the bucket or use boiling water to soften the plastic. If that doesn't work, I might try the Vulkem.

Did you check for burrs? (sorry, not insulting you just eliminating the obvious)
...and for minor leaks, plain ole Vaseline does work and does last for a while and isn't toxic

JohnnySocko said:

Did you check for burrs? (sorry, not insulting you just eliminating the obvious)
...and for minor leaks, plain ole Vaseline does work and does last for a while and isn't toxic

Click to expand...

Huh, interesting. I never would have thought of the Vaseline. Maybe it's worth a try though I always thought petroleum would have some downside like either getting the pump if a little bit were to break loose, or coating the roots, but maybe not.

I did check for burrs and there were a few, but using a 3" hole saw, there's just no way to avoid at least some burrs. I dealt with them as best I could by using a paint scrapper and smoothing out the rough spots. I figured that the pressure of the PVC outwards on the uniseal would expand the rubber enough to kind of fill the small burrs if that makes sense. Obviously this theory was incorrect.

I'm reading some stuff on DIY bulkheads using shower drains or other PVC parts so I think I'm going to give that a shot first as bulkheads are super expensive

I've used uniseals before, what I do is 1st use a x-acto and carefully go around the hole, then I take a lighter and VERY quickly go around the hole again...
I slap a lil vaseline on the thing and screw it in....
also sched 40 PVC works a lot better than the 120 PSI stuff

...and I also de-burr that PVC with some 220 grit

Also i have had good results with marine Goop but it is somewhat permanent. But I would try the vaseline first. All of my connections are on flat surfaces and I use marine thru hull fittings, so not much help.

So I ended up scrapping the whole Uniseal thing because they just wouldn't seal properly with the curved buckets. Instead, I went with DIY bulkheads made from toilet gasket seals and PVC couplers. They seem to be holding up so far. No leaks and haven't had to apply any silicone!

I think Uniseals are a great idea and very affordable, but they just aren't really designed for curved surfaces. You live, you learn.

if you rough the plastic up a bit with a small file or sandpaper the silicone will adhere much better.

also make sure you use denatured alcohol to clean the area thoroughly.

I used to build aquariums and that aquarium caulk is some badass stuff.

there is another product called Ultima. It's an elastic sealant. you put it on with a brush. THat stuff is badass get it at most of your bigger box stores.

vulkem might not be a good idea

Sustainability SolutionsRenewableLow VOCsGreen ConcreteAir & Moisture InfiltrationThermal PerformanceIndoor Air Quality[h=1]Vulkem 116[/h][h=2]One-Part, High-Performance Polyurethane Sealant[/h]Vulkem® 116 is a one-part, moisture-curing, gun-grade polyurethane sealant with superior primerless adhesion to porous substrates. It is durable, flexible, offers excellent performance in dynamic joints and is an excellent choice for sealing expansion joints in commercial construction applications. Vulkem 116 is also suitable for certain water immersion applications and is rated for 25% movement capability.
WARNING! Contains chemicals known to the State of California to cause cancer, birth defects and/or other reproductive harm.
FOR INDUSTRIAL USE ONLY! For use only by trained and experienced professional applicators.

[h=2]Basic Uses[/h]

• Designed for use on poured and precast concrete, masonry work, window and door perimeters, and similar types of construction joints.
• For use on exterior applications only. Do not use this product inside an occupied building even if there are no occupants present during use

joe macclennan said:

if you rough the plastic up a bit with a small file or sandpaper the silicone will adhere much better. also make sure you use denatured alcohol to clean the area thoroughly. I used to build aquariums and that aquarium caulk is some badass stuff. there is another product called Ultima. It's an elastic sealant. you put it on with a brush. THat stuff is badass get it at most of your bigger box stores.

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Good stuff Joe! I wish I knew that sandpaper and alcohol trick when I was applying my silicone. Is the aquarium caulk you are referring to the same as this? http://www.dap.com/product_details.aspx?BrandID=67&SubcatID=27 That's what I was trying to use, but unfortunately it just peeled right off the plastic of the buckets. Ultima might be something I would look into if I need to caulk the bulkheads. I'm assuming it's aquarium safe since you are an aquarium guy

TWS said:

vulkem might not be a good idea

Click to expand...

That's what set off the alarm in my head

we never used the ultima in aquariums. the stuffs great though and cures kinda soft and flexible. I will almost guarantee it'll bond to your plastic perfectly. We use it to seal up aluminum boats and stuff and the aluminum flexes a lot and the ultima is yet to pull off. I'd still rough the plastic and clean with alcohol tho.
It does stink to high heaven while curing which takes about 24 hrs but after that you are good to go.

as far as the aquarium caulk type we used...I can't remember. It's been over a decade since I built aquariums honestly.