Solvent weld as macerator pipework

[Sea Dog]

I'll be replacing my Jabsco macerator pump out toilet like for like shortly. Whilst the existing 38mm flexible sanitary pipework should make it "plug and play", that pipework is aging and probably pretty badly scaled. I could replace that like for like too, but lots of posts suggest there can be issues with flexi pipework going a bit whiffy, even if you have fitted the most expensive stuff.

 

So, I'm thinking that I might replace the 38mm flexible with 40mm solvent weld pipework as others have before me. I've trawled the posts that refer to this, but what I'm still unsure about is the mating of that 40mm rigid pipe or associated fittings with the toilet output or waste tank input which will be made to be a tight fit into 38mm flexible hose.

 

Can anyone recommend how I might tackle this?

 

[davidg]

I've used this stuff in the past:

https://www.pipestock.com/effast?gad=1&gclid=EAIaIQobChMIm5KTlef6_wIVEsHtCh3MxQqsEAAYASAAEgISHPD_BwE

 

Much more solid than domestic solvent weld and easier to get fittings from solvent to bsp to hosetails.  I use Spa Plastics in Coventry but this outfit supply online.

[matty40s]

[magnetman]

Wet exhaust hose is good. Not done a long run with it but in a short section it seemed to let less stink through than the part I did with silicone hose. 

 

Of course what one really wants is solid stainless but this is awkward to achieve if there are lots of kinky bits. 

 

 

Stainless steel T bolt clamps rather than jubilee clips. 2 for each connection. 

 

[Jen-in-Wellies]

53 minutes ago, davidg said:

I've used this stuff in the past:

https://www.pipestock.com/effast?gad=1&gclid=EAIaIQobChMIm5KTlef6_wIVEsHtCh3MxQqsEAAYASAAEgISHPD_BwE

 

Much more solid than domestic solvent weld and easier to get fittings from solvent to bsp to hosetails.  I use Spa Plastics in Coventry but this outfit supply online.

 

This sort of stuff is used in industrial scale chemistry. The material is picked to be compatible with the chemicals being processed. The solvent will be different, depending on the material chosen. I'm guessing PVC would be the one to choose for the "contents" in this case.

Edit to add:

Yes, uPVC is the pipe material to choose. It's used in soil pipes, so should be fine as a macerator pipe.

 

[Bod]

If all your pipes are rigid, and glued together, can the system be unblocked?

Without spilling the pipe contents.

 

Bod.

 

[Sea Dog]

Thanks all. Plastic is where I was aiming, but which one I hadn't really considered beyond what's available in Screwstation or Toolfix

Whichever way I go though, what I am really seeking to resolve is the interface between the tank and toilet fittings which accept 38mm inside diameter flexible and the rigid 40mm plastic pipe or it's fittings. Adaptor? Short length of something stretchy? 

[Jen-in-Wellies]

9 minutes ago, Bod said:

If all your pipes are rigid, and glued together, can the system be unblocked?

Without spilling the pipe contents.

 

Bod.

 

There are screwed together fittings, or bolted flanges with rubber seals that can be used to make it possible to dismantle for unblocking.

[Sea Dog]

Just now, Bod said:

If all your pipes are rigid, and glued together, can the system be unblocked?

Without spilling the pipe contents.

 

Bod.

 

Dunno. Since it's a macerator output it's not done that with the existing flexible so I'd not expect it to do so with smooth plastic with a reasonable fall, I suppose could add an access plug just in case now you have raised the issue.

 

I do want to be able to separate it at the end joints, which is the original point I'm looking for advice on.

 

That 40mm plastic stuff is cheap enough to just redo if it blocks though, which sounds rather better than getting involved with the unblocking!

[Jen-in-Wellies]

11 minutes ago, Sea Dog said:

Thanks all. Plastic is where I was aiming, but which one I hadn't really considered beyond what's available in Screwstation or Toolfix

Whichever way I go though, what I am really seeking to resolve is the interface between the tank and toilet fittings which accept 38mm inside diameter flexible and the rigid 40mm plastic pipe or it's fittings. Adaptor? Short length of something stretchy? 

38mm is 1.5", so the shortest length of 1.5" ID hose in to a hose tail, with a BSP thread and adaptor on to the pipework.

[PeterF]

Use swept / large radius bends rather than elbows to reduce the risk of blockage.

[system 4-50]

I used solvent weld on ABS piping.  The pipe going off to the left was 2.5M long.

[magnetman]

I think a 38mm ID silicone hose of some sort would probably take up the difference between 38 and 40mm fittings.  They do short lengths, elbows etc for car cooling systems. Durable stuff. 

Clamping it onto the outside of another hose is a bit dodgy though. 

 

Bicycle innertube is good but can balloon and split which us unideal in this scenario for a number of different reasons. 

 

 

[system 4-50]

and the other end. 

[magnetman]

Are there enough solenoid valves? 

 

I do like a nice solenoid valve. 

 

 

[Paringa]

This goes from 40 - 38...Could you put a piece of 38mm pipe in and clamp your flexible hose to it?

 

MCALPINE T28L-ISO COMPRESSION CONNECTION STRAIGHT CONNECTOR WHITE 40MM X 38MM

[magnetman]

Just now, Paringa said:

This goes from 40 - 38...Could you put a piece of 38mm pipe in and clamp your flexible hose to it?

 

MCALPINE T28L-ISO COMPRESSION CONNECTION STRAIGHT CONNECTOR WHITE 40MM X 38MM

That looks like a sink waste fitting. 

Not sure I would like to use that on a lavatory with a pumped discharge. 

[nicknorman]

I replaced the flexi hose of our pump-out, with solvent weld stuff, just a short section of flexi to make it all fit together. Got all the fittings from Leesan. This is the joint from the solvent weld to the deck fitting …

 

 

 

 

 

 

Edited July 6, 2023 by nicknorman

[matty40s]

51 minutes ago, Paringa said:

This goes from 40 - 38...Could you put a piece of 38mm pipe in and clamp your flexible hose to it?

 

MCALPINE T28L-ISO COMPRESSION CONNECTION STRAIGHT CONNECTOR WHITE 40MM X 38MM

That would depend on the exterior dimension of the hose, and whether it was ribbed.

[Sea Dog]

Awesome! Thank you everyone above, just the sort of help I was hoping to get. The photos are particularly useful.

The toilet is still winging its way from Xylem Europe (or not - who knows!) so plenty of time for further contributions before I get down and (hopefully not) dirty...

[Theo]

On 06/07/2023 at 22:06, magnetman said:

That looks like a sink waste fitting. 

Not sure I would like to use that on a lavatory with a pumped discharge. 

Certainly not.  Over time, with the variable pressure the joint will work apart.

 

Nick

Edited July 16, 2023 by Theo

[jonesthenuke]

54 minutes ago, Theo said:

That looks like a sink waste fitting. 

Not sure I would like to use that on a lavatory with a pumped discharge. 

Certainly not.  Over time, with the variable pressure the joint will work apart.

 

Nick

The images of screwfix etc pipe and pipe fittings are to my mind not suitable as they are domestic drain fittings and are designed to operate unpressurised. The other pictures show Durapipe and similar industrial fittings/pipe which are designed for pressurised systems (some ranges are 10Bar rated). 

As others have said use swept bends, or fit Tees in place of elbows with screwed access plugs on the unused port to allow rodding through in the event of blockages.

This will cost more, but consider the consequences of pipe failure!

 

Edited July 16, 2023 by jonesthenuke
typo

[Sea Dog]

Thank you all for your input. Just to update this thread...

 

With the new loo onboard I got the old one out to find that, apart from 2 short-ish lengths of 38mm Flexi, my system had been done in Floplast solvent weld pipe during build.

 

Useful info for future reference:

1.  15 year old Saniflo Premium flexi is still allowing absolutely no smell through.

2.  Contrary to some expectations, it seems that standard white Floplast pipework is up to the job.

[Tigerr]

I did this on my last boat and it was so much better than the flexipipe. Everything you need can be got from Leesan, and you will know it is the right quality stuff for the job. Plus the team there can give you good advise on the best way to install, corners, rises and falls, to avoid problems later. 

[Tracy D'arth]

I have used solvent weld standard waste pipe and fitting for 50 years for pump out tanks and never had a problem or smells.

I use the compression type fittings with rubber olives on layflat hose for my electric pump out kit and they never come apart even when I join 3 lengths together to get to disposal point, 75 metres in total. They have to be screwed up tight though.