PVC Taboo - Myth or Reality ?

[jr_spyder]

I can tell you that Trident 101 sanitation hose definitely won't glue into a PVC fitting. The otter layer of the hose is more like a canvas wrap, not plastic. It's also a slightly larger diameter that the same spec PVC pipe. It''s easy enough however to get an adapter which is a PVC slip on one side and a barbed end on the other to slide into the flex pipe and clamp down.

[Lancerbye]

There are a few different qualities of PVC pipe. Buy good quality and it won't crack or break easily. Most of my sanitation and bilge pump drain pipe is done in PVC. Using proper fittings and doing a quality job will give you a trouble free, odor free instalation that doesn't have dips and droops to collect waste in.

[boatsmith]

PVC will become brittle exposed to uv. But there are many, many solar pool heating systems that use PVC pipe to run up the walls and across the roof and they don't fail very often at all. I installed thousands of these systems over a 15 year period in Southern Cal and never had a pipe failure of the pipe due to a fracture. You can heat PVC pipe with a heat gun or a torch( difficult to keep from scorching). You can also hook-up a piece of pipe to the exaust of a car and run it at fast idle for about ten minutes switching ends once and you can have a 20' piece of PVC pipe that is like a noodle. You can then lay the pipe out to a line and let cool or while itis still hot you can snake it through the holes you need to go through and let it cool in place. The ends might be a little distorted but the main body of the pipe will stay round. When we plumbed the main drain for a pool one guy would cook the pipe and when it was ready he would come running back dragging the pipe calling for help and the help would jump into the pool hole and guide the hot pipe between the dirt and the rebar. We also bent the pipe into 7-8' diameter for the spa jet plumbing. This reduces the number of fittings and increased flow. We did this for thousands of gunite spas and pools and never once did we have a failure of the pipe or a glue joint onto the heated pipe. For the best possible PVC joint sand the pipe and fitting with 80grit to break the glaze and use primer vefore the glue. I prefer the heavy body glue. Nowadays I will heat PVC to use for molds for fiberglass. You can also buy flexible PVC pipe.

[peghall]

You can also buy flexible PVC pipe.

Yup...#148 white sanitation hose (the $3.50/ft stuff sold at WM etc) is flexible PVC...which has -0- resistance to odor permeation.

Whyizzit that NO ONE would even consider buying the cheapest boat made, or the cheapest electronics...but only want the cheapest equipment and materials for the system that's used the most, can do more to ruin a cruise if it fails, and has the most potential to sink the boat: the toilet and sanitation system.

Some day I gotta ask a shrink about that one...

[thinwater]

Originally Posted by peghall

Whyizzit that NO ONE would even consider buying the cheapest boat made, or the cheapest electronics...but only want the cheapest equipment and materials for the system that's used the most, can do more to ruin a cruise if it fails, and has the most potential to sink the boat: the toilet and sanitation system.

Some day I gotta ask a shrink about that one...

Uh... I don't know about that first point. There are a bunch of Bayliners out there.


BTW, what is the experience with Raritan's Saniflex? It certainly is a bunch easier to bend than Trident 101, which can be a bugger in some spots.

[foggysail]

Originally Posted by David M

You just don't want to use PVC in situations where if it failed it could sink the boat. PVC is too brittle. A hose you can step on or drop something on it and not break it.

Really??? Have you ever used PVC? Heck, I have even used PVC pipe as an extension lever to free large bolts. Just try breaking the stuff. It will bend but I have never had a piece fail using it for a pipe lever. Yeah, sure, you can whack it with a hammer I guess.

I plumbed my old Hunter 30 completely with the stuff except for a 6" hose that made connection to the head. I replumbed the waste lines on my current boat, Silverton 40' with PVC. Total hose length used was less than 2' and that was to connect to two heads and the holding tank.

PVC in my opinion is the ONLY way to go. It is stronger than many believe it to be; schedule 40, 1 1/2" pipe has a maximum working pressure of 330 psi at 73 degrees F. Does stink hose have that kind of rating???

I could care less about its low temperature ratings because we don't use the boat in cold weather.


Foggy

[barnakiel]

On our boat the hose is rubber (sanitation hose - I guess more than one layer of material(s)), fittings are bronze. Been living aboard many years and noticed no bad smell except when head is not used over a longer period - e.g. in port or winterized. If so, I sprinkle some house-grade and biodegradable thing and flush the head a couple of times and it is again good as gold for a time.

Offshore, since we use the head, we have never ever had any issues.

b.

[jr_spyder]

Peggie, I agree with your price issue entirely. The truth is that if PVC cost more than Trident 101 I'd still use PVC for where it is best suited in the system, and 101 for the places where flex pipe is best suited. The fact that PVC is so much cheaper is a remarkable benefit, but not a determining factor. It's also a joy once in a very rare while to find an inexpensive alternative to a solution that is not a compromise, and even has other merits. I hope you can agree with that in the case of PVC, and it's why I started this thread in the first place - to find out if PVC was really a legitimate solution. Clearly the consensus is yes!

Finally, on the list of reasons why boats sink shouldn't we rejoice at a pipe joint that is more reliable than a hose with two clamps on a barb? There are many such failures. I had one myself only last month where 100+ gal for fresh water drained out of my water tanks into the bilge due to a failed clamped joint well hidden away. Granted that would never have sunk the boat since all that water was already onboard and the bulge pump was easily keeping up, but it was a reminder of the unreliability of clamps, and made for some very exciting moments about 10 miles offshore until we figured out where the water was coming from.

JR

[dohenyboy]

PVC is also quite useful for a couple other applications
1. Distribution manifold. For example, under the galley sink I run a fresh water line through a filter and then a UV sanitizer. Off the sanitizer, I needed to branch off to feed the icemaker, the flybridge icemaker, the hot water heater, and the cold side of the faucet. I tried using a bunch of bronze tees-- what a mess. Instead I took a foot of 1/2" PVC, cut it into short sections and used them to glue to 5 tees and made a great manifold.
2. You can make a cheap and great working mini holding tank. Lets imagine you are not a liveaboard and need a holding tank just to be legal and for the rare occasion you might need it while in the marina. But you do not have the space for a traditional holding tank. Take some 4" PVC, glue a 1 1/2 fitting to the top and a pvc valve and fitting to the bottom. You have a great working holding tank for less than $20.

I always worry about pipes breaking, melting, etc. You have to expect the worst. That is what thru hull valves are for. As long as you secure PVC against vibration, it works great. Don't put it where it can be stepped on, unless you shield it.
That being said, as the purchaser of a number of used boats, I no longer am surprised by the unsafe and inappropriate materials used by DIY owners and even some professionals. But there is nothing wrong with using something inexpensive if it works better. I use drugstore denatured alcohol to clean not Grey Goose vodka.

[Therapy]

Originally Posted by Dame.n.Jess

You will not regret it, just remember to apply to much joint goo and they will not leak, the goo does smell like strong chemicals but will set hard after a few hours and can be painted over to deal with the smell. Also when you build the system, dry fit everything together and draw a mark over each join so that you can glue them on the right angle.

Regards
Damien

Also remember that when dry fitting the pipe it usually does not go all the way together. Once the cement melts the PVC it will go all the way together. These small amounts (in length) can cause irritation in the extreme.

Yes you can dry fit it all the way together but schedule 80 all the way together (are you sure it is actually to the stop?) try to take it apart again.

I learned these one time............

[onestepcsy37]

i used 1 1/2" pvc fittings at some bends in my system. having used it for five or more years i've had no problems. i would probably use more pvc pipe in my system when it comes time to rebuild it.

[cat man do]

delete.
difference in cost between 101 and pvc already pointed out

[Cheechako]

I have had sched 80 grey PVC pipe and fittings fail in a commercial environment. It's not bulletproof, but in the right well thought out situation, I wouldnt hesitate to use it for long runs in a boat. I've thought of using it before, but by the time I figured in all the fittings, adaptors etc and the related potential clog points.... just decided to use good hose.

[Tellie]

Ditto on the grey pipe. Forget the white sprinkler crap. I've used the grey sch80 pipe for direct bury conduits for years. Of course nothing is bullet proof but as Cheechako says "but in the right well thought out situation, I wouldnt hesitate to use it for long runs in a boat" I'd add as a few other above have said to get a good heat gun and form the pipe to the curves of your boat. The PVC glue smell, even un-painted, will disapate in a few days or weeks.
As far as sinking your boat... do I have to re-school you in what position a thru-hull valve should be in when you leave a your boat?

[peghall]

I don't know who makes Raritan's these days. They changed suppliers about a year ago, haven't heard anything pro or con from anyone who's used it.

I can say though that it's been my experience over the years that when it comes to single wall flex PVC, the softer it is, the more susceptible to odor permeation it is.

Hoses should never be bent tighter than they want to bend willingly...and especially never heated to make it bend tighter than it wants to...'cuz that causes the outside of the radius to stretch past the tearing point and/or the inside of the radius to collapse and possibly kink. If the hose doesn't want to bend enough, break it and insert an inline 45 or 90 fitting.