[timreg2]

I'm looking for a way to put a 1x1/2" OD drain pipe thru the van floor that is watertight but removable. This might be similar to putting a heater hose thru a firewall.

I'm wondering if a Uniseal, typically used for plastic tanks, is a good option. Or maybe there is something specific to the automotive industry. Or maybe just a big grommet?

 

[gregoryx]

We did it with one of these. Then either a plug like this or elbow like this depending whether it's in use or removed for our removable shower.

Thing I like most about this setup is it's really just a female-female union - so no leaks - and the outer is to lock it in place. Downside: not super easy to get it cranked down just right; but it has been working well for a year or so now.

 

[timreg2]

We did it with one of these. Then either a plug like this or elbow like this depending whether it's in use or removed for our removable shower.

Thing I like most about this setup is it's really just a female-female union - so no leaks - and the outer is to lock it in place. Downside: not super easy to get it cranked down just right; but it has been working well for a year or so now.

View attachment 184692


View attachment 184693


View attachment 184694

Thanks @gregoryx. I can imagine a few scenarios where that fitting would be very useful. In my case though, I need to be able to slip-fit a 1-1/2" OD pipe thru a watertight fitting in the floor. So I'm pretty sure I need a rubber fitting with a 1-1/2" ID hole. That's why I'm leaning towards the Uniseal.

I'll be using the fitting below to screw into the finished floor and slip thru the van floor (thru the Uniseal). Then connect to the drain line under the van.

https://a.co/d/2ium4wS

 

[greenvan]

grommet works fine, mcmaster car has any size you want

 

[gregoryx]

Thanks @gregoryx. I can imagine a few scenarios where that fitting would be very useful. In my case though, I need to be able to slip-fit a 1-1/2" OD pipe thru a watertight fitting in the floor. So I'm pretty sure I need a rubber fitting with a 1-1/2" ID hole. That's why I'm leaning towards the Uniseal.

I'll be using the fitting below to screw into the finished floor and slip thru the van floor (thru the Uniseal). Then connect to the drain line under the van.
View attachment 184721

https://a.co/d/2ium4wS

I can see the Uniseal working. I'll be curious how well it works with how the Uniseal works: I could see even the rather small movement between the van floor and the finished floor not working well - Uniseals want to be solid. Hopefully, it works!

We did something like the above for our (now removed) propane locker: similar fitting without the threaded cap. But it was just a "close fit" where it went through the van floor and a ring of silicone. Probably leaked, but it didn't matter as the fitting went down below the bottom of the van.

 

[timreg2]

I can see the Uniseal working. I'll be curious how well it works with how the Uniseal works: I could see even the rather small movement between the van floor and the finished floor not working well - Uniseals want to be solid. Hopefully, it works!

We did something like the above for our (now removed) propane locker: similar fitting without the threaded cap. But it was just a "close fit" where it went through the van floor and a ring of silicone. Probably leaked, but it didn't matter as the fitting went down below the bottom of the van.

That's my concern as well, with both the Uniseal and the grommet. Though I hope to have very little movement in the floor, as I'm assuming movement = squeaking.

I'm now looking at some boot type fittings like this one:

 

[Sams stock van]

If you want to try a grommet or two I have a few 1 1/2" ID. Just let me know. Stack a spare on the pipe it there is room.

 

[gregoryx]

That's my concern as well, with both the Uniseal and the grommet. Though I hope to have very little movement in the floor, as I'm assuming movement = squeaking.

I'm now looking at some boot type fittings like this one:
View attachment 184746

I'd say that or the grommet (with room to "slide" just a bit) would probably do it for me.

 

[timreg2]

Turns out Uniseals wont work with this type of deck fill fitting. These deck fillers have a real 1-1/2" OD. Where as the Uniseal has a nominal 1-1/2" ID, which is more like 1-7/8", so it won't seal.

 

[timreg2]

If you want to try a grommet or two I have a few 1 1/2" ID. Just let me know. Stack a spare on the pipe it there is room. View attachment 184747

Thanks @Sams stock van.
I just visited a couple of local marine supply houses to see and touch some of these components, and the "1-1/2" Uniseals they both had (Uniseal & Dometic) were almost exactly 1-1/2" ID. Those won't create a tight seal on a 1-1/2" OD pipe. They are intended for 1-1/2" pvc, which is about 1-7/8" OD.

 

[Sams stock van]

I'd be tempted to make one out of a flexible membrane sheet. Attach it to a frame to hold it flat to the underside and cut the size hole you need for a tight fit. Much like the rooftop flange that slips over the vent pipe and gets shingled down.
Options depend on where the seal to the pipe can be positioned. Just tossing an idea out there. Good luck.

 

[timreg2]

I'd be tempted to make one out of a flexible membrane sheet. Attach it to a frame to hold it flat to the underside and cut the size hole you need for a tight fit. Much like the rooftop flange that slips over the vent pipe and gets shingled down.
Options depend on where the seal to the pipe can be positioned. Just tossing an idea out there. Good luck.

We think alike🙂. I've got several different types of neoprene rubber sheets I'm considering. I'll want one thick enough to be tough while still being thin enough to handle the small movements.

 

[orton]

Does the penetration need to seal?

 

[timreg2]

Does the penetration need to seal?

Yes. And be removable. Here is the direction I'm leaning:

The deck fill will sit on top the finish floor, going down all the way thru the van metal floor. The rubber boot will go up thru the metal floor and seal around the deck fill pipe. Rubber boot will screw into metal floor from the bottom.

I may consider replacing the boot (or in addition to the boot) with a flat piece of butyl rubber and square metal frame screwed up to the bottom of the metal floor.

This setup let's me disconnect the plumbing drain pipe from the deck fill from under the van. Then lift out the finished floor (or the deck fill) from inside. It also allows for some slight movement between the finished floor and the van metal floor and drain lines.

The deck fill needs to sit flush with the finished floor as it will be the drain for my removable shower pan.

Also note that using the boot allows the seal to go up into the floor, leaving more room for attaching a right angle drain fitting as close to the van floor as possible, maximizing the angle drop into the gray tank.