Cassette considerations

grozier

Member
Hi all,

We need to re-caulk the shower pan (again!) and have a small leak similar to that described in this thread, so it's got me thinking hard about the cassette conversion. Many thanks to autocamp, discus, and Adolphus for paving the way.

A few questions for those who have done the conversion and/or are familiar with cassettes:

1. How are you finding the odors? Do you need to use a chemical treatment? (One thing I really like about the vented black tank is not needing to use a chemical.) Has anyone installed the SOG venting system?

2. What is the thinking on the version with the separate flush tank (C402) vs the one that connects to the main water tank (C403)? Reading the specs, it seems like the fillable reservoir holds 15 liters, nearly as much as the tank itself (19L). It is an advantage to have another 15% fresh water capacity, but more trouble to fill? I suppose if you ran out without a hose nearby you could use the rear shower.

3. Finally, has anyone successfully removed the rear wall of the bath? I need to refinish the metal profile visible from the rear and it looks like the wall has to come out to do so. This would also allow a better cut for the cassette opening. Aside: Does anyone have a good US source for RAL color paints? This trim is apparently RAL 9006 - "white aluminum."

Thanks in advance for any help. It's nice to see that the cassette system is becoming more common here in the US.

Ted
 
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autocamp

un-bastardized NAFTA JC
Hi Ted,

Here are my answers.


1. How are you finding the odors? Do you need to use a chemical treatment? (One thing I really like about the vented black tank is not needing to use a chemical.) Has anyone installed the SOG venting system?

I have the C402 with its own flush water storage. It has provision for venting and my installation includes it. I never use chemical or additive. You still occasionally get some smell when driving with the front windows open and I am not sure if the odor is from the grey water tanks for the cassette toilet.

2. What is the linking on the version with the separate flush tank (C402) vs the one that connects to the main water tank (C403)? Reading the specs, it seems like the fillable reservoir holds 15 liters, nearly as much as the tank itself (19L). It is an advantage to have another 15% fresh water capacity, but more trouble to fill? I suppose if you ran out without a hose nearby you could use the rear shower.

Getting the C402 is a no brainer with the gain in water capacity is worth the price of admission. It is very easy to refill and you just have to use a garden hose with a slower stream of water. When empty in a bind you refill it with a pouring pitcher. I carry a $0.50 plastic one in case of the need. The thing about the flush water storage is it uses all the otherwise wasted space of the toilet. What this mean is the level sight glass can be very misleading for how much water remains. The biggest capacity is towards the top of the sight glass so you always want to top up the water as much as you can.

With my custom auxiliary water tank I nearly double the potable water capacity. The cassette toilet turned out to be everything I expect and more with the extra water capacity. I have in numerous occasion discharge the cassette in normal toilets and never made a mess for others.

3. Finally, has anyone successfully removed the rear wall of the bath? I need to refinish the metal profile visible from the rear and it looks like the wall has to come out to do so. This would also allow a better cut for the cassette opening. Aside: Does anyone have a good US source for RAL color paints? This trim is apparently RAL 9006 - "white aluminum."


It does not appear to me you can remove just the rear wall. I suspect the whole "wet cell" was made in one unit and install into the Sprinter.
 
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Kiltym

'05 Westy
Just FYI on the re-caulking of the showerpan.

Had to re-caulk twice since we owned it (only 2 years). The last time we used a good silcone caulk recommended by onemanvan.

We also have/had some flex at the bottom surface of the showerpan, which in turn, caused stress/flex on the sides and joints that are caulked. After removing all the caulk, and the toilet (did not remove sink), along the door edge of the pan (which is the joint that kept cracking on us), we dumped a lot of caulk down the side of the pan so the "wall" of the pan would be affixed to the wall of the bathroom. We then caulked the joint. We then put about 250lbs of weight on the floor of the bathroom while it cured (7 days).

We still have a little flex in the floor if you look carefully, but the caulk has held for about 7 months of full time use, and appears to be holding so far. Was certainly easier them removing the entire pan.

Here is a thread with more info, and the caulk we used: https://sprinter-source.com/forum/showthread.php?t=70566&highlight=caulk
 

grozier

Member
Thanks to both of you.

Vince, I found your vent install post. So the vent is just a passive design like the original Bravura? That seems to work well except with the front windows down. Am I seeing it right that the vent is at the bottom of the tank?

Ted
 

autocamp

un-bastardized NAFTA JC
Thanks to both of you.

Vince, I found your vent install post. So the vent is just a passive design like the original Bravura? That seems to work well except with the front windows down. Am I seeing it right that the vent is at the bottom of the tank?

Ted
Passive vent. I consider doing a active vent but you have to manually turn on a switch unless you get really creative and turn it into a production.

In the post I only identified and confirm its option use. It's been so long now. I remember I have to cut a hole on the subfloor to reach it. Finding a fitting for it turned out to be impossible as I suspect it is metric. It is also thin soft plastic so you can't put much stress on it.

What worked was using a piece of the body tubing of a common caulking like the one you need for the job.:hmmm: That is why I can never throw anything away. Not even an expired silicone caulking tube. :lol:

I then supported the weight of the James Cook hose with a cable tie to release the stress that would otherwise impart on the round port.

 
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OldWest

2004 T1N Westfalia
https://sprinter-source.com/forum/showthread.php?t=53942&highlight=Vent

The link in the above thread to the James Cook Friends Forum photos does not work. The photo showed a vent opening in the driver side taillight area floor, like a twin to the TNeuer passenger side floor.vent originally used to cool the Kerstner Meanwell converters and recycled as a floor tank vent.

You could also put a 360 siphon vent cap at the bottom. I believe you can install them upside down.

https://www.lci1.com/360-siphon

I think a driver side floor vent would be nice. There would be a shorter exhaust hose length. Also, you could install fan inside the exhaust hose, using the 12v electric wires to the rear storage light. You could run the control switch back inside the bathroom.

Note: There is a Sprinter Body Builder Manual or something like that which specifies what aftermarket mods can be made to the Sprinter body. A small.floor hole probably wouldn't be covered but you can doublemcheck.

Note 2: Although Autocamp prefers the cassette to a composting toilet like Foster did, a composting toilet would work in the boonies where there's no RV dump or toilet of any kind.

The James Cook Friends Forum even has a thread on DIY composting toilets. One owner made a very nice bench composting toilet to fit the original cassette toilet, with the liquid wastes going into the graywater tank.

http://forum.james-cook-freunde.de/viewtopic.php?f=16&t=6157
 
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autocamp

un-bastardized NAFTA JC
Since I removed the Kerstner AC and its abundance of electronic guts behind the water heater I repurposed the cooling air duct for the switch mode power supply that is the size of a nuclear reactor. I retained the brushless fan and added a switch to control its on/off.

It serves two purposes:

  • help circulate the stale air underfloor and chassis and remove any potential moisture
  • help introduce cooler air when Brunnhilde is parked and unoccupied to supplement the custom extractor fan that I made

the on/off switch located on the aluminum panel


the custom automatic extractor fan to help reduce cabin temperature when park


Prolong excessive temperature is the leading cause of shrinkage of the plastic molding on the cabinetry in Westfalia including the Vanagon campers.
 

OldWest

2004 T1N Westfalia
Autocamp:

Clever idea to reuse the floor vent.

Did you reroute the air duct in the rear compartments? Any photos?

With the upper window vent fan (and the underfloor storage door open), do you get a good airflow chimney effect?

One concern is whether any exhaust would be pulled into vehicle when driving (any difference with Meanwells and other equipment in place)?

Like the Ford Explorer Police Interceptors.

https://autoweek.com/article/recall...estigated-exhaust-leaks-after-2700-complaints
 

autocamp

un-bastardized NAFTA JC
I had never gave any thought to the potential introduction of the exhaust gas. The fan is like only 3" and very low CFM so I won't lose any sleep over it. In the original arrangement the vent expel air. There is a rectangle port below the original power supply but I blocked them to keep the sub-basement warmer. I reverse the fan so the vent pull cooler air in since it is at the lowest spot. I kept the plastic bracket which house the fan from the Kerstner power supply so everything looks factory.
 

onemanvan

Active member
In December 2017 I had suggested an alternative cassette toilet installation that would not require modification of the shower pan.

https://sprinter-source.com/forum/showpost.php?p=609347&postcount=9

Subsequently I found this webpage where Manfred documented how he had already done this.

https://www.ermel-freizeitmobile.de/westfalia-umbauten/

I snapped a photo of the area where the pass thru on the driver side of the van would be. The only obstruction in this path - other than side of the van and the shower wall - are the flexible vent tubes for the holding tanks.
 

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autocamp

un-bastardized NAFTA JC
Vince, your blog is so helpful, thank you. I see in Part 9 the nice work you did on the fiberglass modification of the pan. Do you remember how far toward the sink you extended the fiberglass? Did you do the whole pan?

An alternative is this as a potential drop-in replacement shower pan: https://www.leisureshopdirect.com/water/caravan-shower/caravan-showers/cp-shower-tray

I have asked for a shipping quote.
This is all from memory. I cover the top side with 2, may be 3 layer of cloth. It is very important to have cloth overlap (bridge) on top and bottom of the void where the American toilet behind. I didn't try to do a pristine job and just try to do a reasonable job without turning it into a major production. I had a pretty good idea what is adequate from my home made fiberglass projects.

A few tips if you've not done fiberglass lamination before:
  • It is not as hard as it seems as long as you pay attention and understand the techniques.
  • Make sure you choose the right resin and in this case polyester rather than epoxy. Polyester will dissolve and bond to the shower pan to form a strong bond. Epoxy relies on mechanical adhesion and will fail in my judgement.
  • Make sure you have all the material on hand.
  • You will want a pigment to mix into the resin, and I used white.
  • S or E fiber cloth would suffice.
  • If you never work with fiberglass you should do a lamination exercise onto a cardboard box etc to learn. You will learn how the resin wets the cloth and how to spread and squeeze out excess resin. You will learn to judge how much resin you will need. You will experience the gel time and pot time to know how much time you have to work before all is too late.
  • Always keep a coupon of resin so you can check without messing up the work.

It is imperative that you heed the correct amount of catalyst to use - polyester resin is very forgiving.
 

autocamp

un-bastardized NAFTA JC
When I embarked on the cassette toilet Westfalia has an eStore that you can order the European shower pan. The only problem is they are not set up to sell across the pond. Despite my attempts to contact them I went no where. I seeked high and low for other shower pan that may work as well as custom manufacturing. All are just a big waste of time dead ends. Projects like this you have to take the matter into your own hand. There will be no existing pan with dimensions that remotely come close.

If needed, I can fabricate a pan from scratch. It is just how much time and effort that I am willing to invest. My approach is one that is most practical and least costly monetarily and time wise.
 

onemanvan

Active member
I guess if you wanted to keep it really simple then this porta potti might suffice.

Functionally it's the same as a cassette toilet.
A fraction of the cost and very easy to install.

The obvious downside is you have to carry the cassette through the kitchen to get it outside.

The not so obvious downside is there's no provision for venting to the outside:
1) don't be surprised to arrive at the top of a mountain pass and see it rolling around like a beach ball
2) you'll need to actively control odor by adding some chemical - bleach is the cheapest solution

https://www.amazon.com/Porta-Potti-White-Thetford-Corp/dp/B07CKR3VYT/ref=dp_ob_title_auto

I can't find the dimensions for the floor plate but it might be about the same footprint as the Bravura.

https://www.amazon.com/Thetford-924...ZZXRFJ3DN46&psc=1&refRID=V602V7H5YZZXRFJ3DN46

The floor plate would be screwed to the raised pedestal where the old toilet was. The new porta potti would snap onto the floor plate - preventing it from sliding around.
 

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autocamp

un-bastardized NAFTA JC
In December 2017 I had suggested an alternative cassette toilet installation that would not require modification of the shower pan.

https://sprinter-source.com/forum/showpost.php?p=609347&postcount=9

Subsequently I found this webpage where Manfred documented how he had already done this.

https://www.ermel-freizeitmobile.de/westfalia-umbauten/

I snapped a photo of the area where the pass thru on the driver side of the van would be. The only obstruction in this path - other than side of the van and the shower wall - are the flexible vent tubes for the holding tanks.
I have came across Manfred's installation after I completed my project. To be fair it certainly is an alternative but not an attractive one as it involves cutting two panels, and worst leave the unsightly outside access door. For me there is no doubt modifying the shower pan is easier and less risks.

We are lucky the shower pan is made of material a resin bounds strongly to. Had it be polypropylene we would have been screwed. Though you can always use the pan as a fabrication mold so not to relying on bonding to the existing pan. Just a lot more work and skills.
 

grozier

Member
Well, it's in! It was a lot of work, and there's no way I could have done it without the pioneering efforts of Autocamp, Adolphus, Discus, and others (Mike Sisk?) who were brave enough to go first, as well as others (Zach Woods, Theo Engbrink) who did the original research.

Approach
First, the toilet itself. I snagged one for $499 delivered from this eBay shop: https://www.ebay.com/str/cmeboating. Thetford calls it the "Right" model (the orientation is as if you're sitting on the toilet) but be careful, because I have seen some confusion on various sites. The model delivered was the C402C, which differs slightly from those others have installed -- and that shown in the eBay picture -- in that it only has a "full" indicator, rather than the three levels for flush water (it uses its own reservoir) and waste. I believe the fancier model is the C402X. The one I received does have the cassette with passive venting and a provision to install a vent through the floor.

I had never worked with fiberglass, so I was very nervous about modifying the shower pan. In particular, I was not confident in my ability to fabricate a "dam" at precisely the right spot of the toilet end of the pan, especially given that half the reason of doing this project was because of shower leaks. As a family of four, our shower gets heavy use, sometimes in all four seasons.

With that in mind, I took a different approach, building atop the pan rather than cutting it. As you'll see below, I still had to remove and patch the “half moon” of the NAFTA toilet platform, but did so in the confidence that the area is flat and can mostly be substituted with the material removed.

This process was tedious, and if you count my labor at much more than minimum wage, it makes the €420 custom pan from Germany look like a bargain, provided you can get it delivered. (The best shipping option for that thing, as far as I can tell, is to fly to Düsseldorf and take a mini-vacation to get one, because Deutsche Post/UPS/FedEx won't ship it, and the freight routes are probably even more expensive. While you're there, stop at any camping shop to get the different drain needed for that pan. You might even get your 19% VAT back if you fill out the right forms.)

Disassembly
Getting everything apart was easy enough. I found I was able to remove the pipe into the black tank by cutting the Sikaflex seal at the top of the tank and working it back and forth with some dish soap and patience. Likewise, I was able to disconnect the outlet by raising the black tank and carefully removing the four 10mm bolts that hold the slide valve in place. Fair warning though: one of these bolts was so corroded from leaks at the slide valve that it snapped. If that happens, you have no choice but to tear everything apart; I was then able to remove the broken bolt with vice grips, but this would not have been possible in situ.

Behind the black tank I found a bit of narrow drain hose not connected to anything. I gave it a tug and it came off in my hand. Any idea what it or the riveted drain tube it attaches to is? The A/C condensate drain is outboard of the toilet wall, so that’s not it. Maybe something from the A/C retrofit done on our van, #121?

Once the toilet, cabinet, and drain (don't remove its strainer, if you can avoid it) are out of the way, and the perimeter is scraped clear, the shower pan just popped out. I feared a struggle with the adhesive between it and the floor, but time (and leaks?) gave it trivial grip. Fortunately, even despite significant water leaks (on our van, there is corrosion on the brackets supporting the floor, and flaking paint on both ends of the silver trim visible at the rear doors) there was no damage whatsoever to the plywood floor, as it's covered in a waterproof laminate.

Fabrication
I tried to no avail to remove the rear wall of the bath, as I figured it would be much easier to cut the cassette-access hole with that board out of the van, as well as refinishing the silver trip piece at the bottom. I also see that the Euro vans don't use a hole as such, but a large notch instead, which I figured would be easier than trying to cut a perfect rectangle in such a tight space. (See the first photos below of the Euro execution of the cassette access.) But even after removing all the screws (inside and out), the sealant in the rear corners of the bath, the hand towel rail, and cutting the mastic between the rear shampoo shelf and the plywood wall, I couldn't get it to budge. I suspect the walls are bonded together, or there are a couple of invisible, inaccessible brackets. I fished around with a powerful magnet, but couldn't find anything. Save your effort and leave that wall in place!

I was able to cut the hole just fine with some carefully triple-checked measurements and a simple jig saw, from the outside. There was just enough room. I used a fine wood blade, but in retrospect, a metal blade and tape over the cut line might have made a smoother edge. I used a bit of garage door weatherstripping and a staple gun to make it neat.

Incidentally, the sealant in the corners of the bath is apparently made of something unobtainable in the U.S. like https://www.otto-chemie.de/en/homepage-construction/ottoseal-s-100 in Crokus or Jasmin, depending on which source you read. I used Sikaflex 221 in Colonial White, (not regular white) and found the match acceptable. For the floor, I used the Dow RTV-739 as recommended by Onemanvan. But I'm getting ahead of myself.

The shower pan had a sticker on the bottom suggesting it is made of polystyrene. I have a few bits of scrap left to send out if anyone can do a chemical analysis on it. The drain protrudes below the floor, so you need a thick board with a hole to get it to sit level. From here, I made a couple of observations: the toilet platform is molded so as to be level when there is a 52mm spacer beneath. The plywood platform in the van is only 49mm. As a result the platform is under stress, evident in tiny cracks around the edge. Having these measurements correct was essential to getting a level surface for the cassette toilet.

So, on with it. I measured out a generous platform (I think 28+ cm from the back wall, or about half an inch more than the depth of the cassette) and got at it with an oscillating tool. (After reading Autocamp’s praise for his Fein Multimaster I have a new favorite device. I bought the inferior but much less expensive Harbor Freight clone. You’ll need this to make a dent in the plywood platform anyway; don’t even bother trying a pry bar, because you will get no closer to removing it and will chew up the floor in the process.) With careful work, I kept as much as possible of the half moon intact.

I then found that one of the plywood supports for the black tank fit just perfectly below the platform. I carefully trimmed it down to 52mm wide, then screwed it into place. A couple of scraps of 3mm laminate floor between the platform and pan will fill the aforementioned gap.

I cut a hole for the vent. More on that later. Then, I went about filling the sides, carefully cutting 1/4” plywood plates with a jig saw, gorilla gluing them together into two solid chunks, and bonding them in place with “Liquid Nails.”

I did a test on scrap and found that hot glue adheres well but also comes off without damage. I glued a piece of plywood to the top of the shower pan with a piece of cling wrap over the half-moon hole, then placed the half moon back into place with Bondo. Cling wrap is low-density polyethylene, which like the HDPE yogurt tubs, won’t bond to polyester resins.

After a bit of sanding, I got to try my hand at fiberglass for the underside of the half moon. I used the same stuff as Autocamp: “Bond Coat” polyester laminating resin from Tap Plastics. Two layers of their modified twill cloth went down well enough.

I used some expanding foam clamped down under cling wrap to fill the gap between fiberglass and the plane of the bottom of the pan.

Then Theodoro’s Body Shop of Horrors got to work. It took just more than a quart of Bondo to get everything filled in and curved right. I made a little template to copy the edge profile across the new section. It’s all a bit of a guess because the floor is sloped so all sides aren’t the same height. I checked and double-checked for level.

During the sanding of the top side I found a hairline crack about four inches long on the edge of the pan by the rear wall. How it got there, I have no idea.

Then two more layers of fiberglass, this time on the top side, and with the white pigment from Tap Plastics. Work from the center out, using a disposable brush. Trim it carefully after it gels but before it gets really firm. I found that the gel time was about right — 25 minutes or so — but the time to solid was overnight; longer than I expected. I didn’t sand between coats. I put one last coat of pigmented resin on with Tap’s surface cure styrene/solvent stuff but not sure it made the cure any harder. I sanded the edges for fit but left the rest as-is; it looks a bit rough up close but I fear that sanding it will expose the glass fibers. Any advice now that it’s in place? Experts, please weigh in on how this job should be done! It's not too big a deal now that it's covered in Duragrid again. (I was able to fit pieces together to fill the space again, with the aid of some zip ties that are out of view under the sink.)

Assembly
The toilet attaches to the back wall with four number 6 by 1 1/2” wood screws, not included. There are optional brackets but I don’t think they are needed. Not sure what the Euro version uses, but there’s an extra outside screw on the pictures I have seen. Unless you have a very long drill bit, you won't be able to drill pilot holes using the toilet as a guide. I used the screws to mark the wall, freehanded the drill, and put it together, and it seems to be working.

I spent $16 including postage for the special “vent kit” from the UK. Save your money, as it’s just a flimsy tube and a foam seal. I managed to connect it with some pool vacuum hose to the original black tank hose. Fine for now, but Autocamp’s method is better; should some liquid come out of that vent, it will drain to the gray tank rather than collect in the tube.

For the power flush, I just tapped into the feed for the propane detector. It’s right there and easy. I agree that the hack of the black tank sensor is more elegant.

I still have to finish closing the hole in the floor. There was a lot of rust there, due to the leak. I cleaned it up and hit it with Hammerite, then Owatrol oil between the metal and plywood. A sheet of aluminum is now Sika'd into place. I am hoping to due a "skin graft" of the gray rubber floor somewhere for a plywood patch.

Overall impressions: (+/- vs NAFTA Bravura)
For
+ The power rinse swirl is much better.
+ You can fill the flush tank with RV antifreeze and use it all winter.
+ You can keep the tank clean by back-flushing it every dump.
+ All the water you would have used for toilet flush is bonus, and not out of the main tank.
+ The seat does a much better job of staying up, and I don’t think I will need to install the little magnets that kept the Bravura from falling mid-stream. (That engineering sign-off must have been done by a Sitzpinkler.)
+ Wet cell is easier to clean without nooks and crannies.
+ You get a ton of new cargo capacity -- enough for a large hard-sided suitcase, several crates of beer, etc.

Toss-up
+/- The capacity of the cassette is about half the original black tank, but you can dump anywhere (without moving the van!) so that’s a wash in my mind, if not a slight advantage for the cassette. The thing is heavy when full but not too bad since you only have to lower it to ground level, not the other way around.
+/- Odors and mess: (All without chemicals.) During use, because the opening of the valve is a separate operation from the flush, there is a hint of odor. For comparison, try flushing the Bravura with the water switched off. Closing the lid eliminates the smell. When dumping, you are closer to the mess (i.e., you can shove the sewer hose down a hole several feet away) but on the other hand, you don’t have to walk through a puddle of someone else's sewer or face backsplash on the ground.

Against
- You lose two little areas in the bathroom on either side of the toilet that are good for flip-flop storage.
- A foot flush is more convenient than the hand valve and button flush.
- When installed on the raised platform, it is exactly the same height as the original Bravura. The seat, however, is much smaller. (See photo below compared to a standard residential toilet.) Men who are particularly well-endowed or have a few extra pounds may need to “throw a line over the bow,” so to speak...
- A clear disadvantage is the lack of a reserve capacity when full. In the NAFTA version, you can literally fill this toilet to the top of the bowl. This isn’t recommended, because you’re relying on a couple of soft seals, but you can do it in the middle of a stormy night. With the cassette, the slide valve comes with you to the dump, and anything in the bowl will leak into the cassette compartment. Heed the “full” light well! You have only 1.5 liters left, which is about two to four good pees.

Supplies
I am happy to give a plug for Tap Plastics here, because their videos were helpful and their products worked well for me. You need almost two quarts of polyester resin, one small bottle of hardener, 2 bottles of pigment, and 3 yards of modified twill cloth. (You will have some left over.)

As usual, I will give updates on this modification and am happy to answer questions here or at Westyfest. Pictures coming soon.

Ted
 

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