Uniseal - How to use - For adding Vent Fitting

[Tartan34C]

First, wow, I came upon this ask an expert forum after reaserch on improving my sanitation system, and repeatedly finding references to the expert, Peggie the Head Mistress!

Thank you Peggie for your involvement here, and to the hosts of this site, I have just spent many hours reviewing 19 pages of past threads, and that has pretty much answered all my system cleaning and updating questions. (Plastic tank is fine, how to clean sludge, hose replacement, whale pump diaphram replacement, joker valve, KO, critical importance of venting, etc..)

Which brings me to the last point, venting.

I have the typical too small 5/8" vent in place, will replace all components to 1" (tank is 15g btw), and I could not find the answers to the folllowing, neither here or on the Uniseal site:

1- If I use the uniseal product for a new 1" hole, what type of fitting should I use, a threaded nylon male thread to male barb fitting, some other type of smooth walled fitting, or simply a piece of 1.5" OD PVC pipe?

http://www.aussieglobe.com/uniseal3.htm

I'm just not 100% clear on what type of connection I should use to put into the tank with the uniseal, leading to a male hose barb.

2- In addition to the uniseal, would it be wise and safest to add some silicone around the uniseal fitting to further ensure no escaping air?

3- Also, instead of Uniseal, couldnt I just drill a slightly undersized hole, and try to make a "thread" in the plastic tank wall with a 1.5" Male threaded METAL fitting, string enough to gough/thread the plastic? (Then screw in a nylon fitting with sealant tape)

The rest of the install, I think I have pretty much down pat thanks to all the wisdom shared on this forum and thank anyone with any insight on the uniseal/new vent fitting to tank aspect and options, very appreciated!

Tony -

 

[Peggie Hall HeadMistress]

Answers to your questions...

1- If I use the uniseal product for a new 1" hole, what type of fitting should I use, a threaded nylon male thread to male barb fitting, some other type of smooth walled fitting, or simply a piece of 1.5" OD PVC pipe? I'm just not 100% clear on what type of connection I should use to put into the tank with the uniseal, leading to a male hose barb.

If you want to use something barbed, you can...but it's not necessary...A piece of PVC pipe will work just fine...about 6" long oughta do it. Or, if you need a 90 or 45, use an off the shelf fitting from any hardware store. Leave enough of it showing outside of the tank to become the hose barb.

2- In addition to the uniseal, would it be wise and safest to add some silicone around the uniseal fitting to further ensure no escaping air?

Nope....a sealant could actually interfere with a good seal. The Uniseal will grip it tightly enough to get a good seal...double clamp the hose, keeping the screws 180 degrees apart.

3- Also, instead of Uniseal, couldnt I just drill a slightly undersized hole, and try to make a "thread" in the plastic tank wall with a 1.5" Male threaded METAL fitting, string enough to gough/thread the plastic? (Then screw in a nylon fitting with sealant tape)

Nope...for a couple of reasons: 1. the threads are FAR more likely to leak than the Uniseal. 2. Never use a metal fitting in a plastic tank, 'cuz metal and plastic have vastly differing thermal co-efficients (tech speak for "they expand and contract at different rates and in differing amounts)...If the tank expands more than the fitting leaves room for, you have a cracked tank..if it contracts more, you have a leak.

If we were talking about discharge fitting at the bottom of the tank, we might not even want to use a Uniseal...but it's the best thing since the pop up toaster for adding or relocating fittings at or on the top of a tank. Install it according to directions...and trust it.

 

[Tartan34C]

Thank you for the response Peggie!

Little Rock, drove through there once, pretty hills, remind me of my hometown, Quebec.

Using a simple pvc hose makes it easy, will check out O.D. of piping at Lowes (1" ideally) and order the appropriate Uniseal and hose.

I will add a new 1" vent, short run with little bend, to a through hull beneath toerail, port side, about 3 feet from the bow (in anchor locker, tank is close to that bulkhead)

Q- With regards to the through hull under toerail, I'm wondering if instead of that,
I installed the through hull vertically through the foredeck, a few inches inside the toerail, and covered with a clamshell, if that wouldn't work just as well, while removing the "cosmetic" issue of a through hull under the toerail?

Q- Would it be even better if, in addition to this new vent on the port side, I also ran the existing 5/8" vent to a similar (smaller) through hull on the Starboard side, therefore ending up with 2 vents, one on each side?

I'm also wondering, if I KO properly and have good ventilation, if I could get away with standard smooth wall (water) or even heater type hose instead of the more expensive T 148, and use the $ saved for the proper T 101 where needed (both discharges, doing this on a budget)

I have a funny feeling what the answer will be...

Tks for any further help, and I will recommend your book to all those I know who ask about head systems!

 

[Peggie Hall HeadMistress]

Answers to all three questions...

It wouldn't work nearly as well.

Nope. A single 1" vent line that's straight, < 5' long and doesn't rise more than 45 degrees is all you need to keep the tank aerobic.

Do that only if you want stinky hoses by the end of the season. People who are trying to save money tend to forget that it's always cheaper to do it right the first time than it is to do it over.

Btw...don't forget that you'll also need a new 1" thru-hull. Use a plain ol'bulkhead or "mushroom" fitting.

 

[Tartan34C]

People who are trying to save money tend to forget that it's always cheaper to do it right the first time than it is to do it over.

Yeah, learned that after a few divorces...(kiddin)

Will do the side hull vent, probably flush design painted hull color, a single line vent, and proper hose done right the first time.

Thank You