Slight Gap(?) Under Rimless Tank

[Mas0n]

Whats up R2R, just setup a 120g rimless on a custom Aluminum stand, with a 1/2inch piece of PVC board on top.

Now that the tank is filled, I'm seeing this on the bottom glass pane, what appears to be air bubbles? Water? under the glass.

No dripping or leaking anywhere.

I can slide a .1mm feeler gauge under it on a small part of one edge. All of the corners have no gap.

Seems like the tank isn't sitting fully flush on the PVC board. Is that small of a gap a serious concern?

 

[UncommonSense]

That is unusual…

It is possible that the board isn’t consistent thickness across the entire span, or that there’s a proud spot on the top of the aluminum extrusion framing (joints between framing not being flush would be most likely!

— more importantly, though… rimless glass tanks should really have a closed cell foam pad under them, between stand top and tank bottom! (I believe the factory mat with the Fiji95 I did a little while back was 1/8” [3mm] thick)

— I’d recommend a 1/8”-1/4” thick neoprene mat! Get one a bit too large, install it under the tank, then trim the mat flush with a razor! (If you cut it to exact size prior to install you need two burly people to hold the tank up while a third person tries to get the perfectly fitted pad sitting in the exact right spot; it’s a nightmare!)

 

[Mas0n]

That is unusual…

It is possible that the board isn’t consistent thickness across the entire span, or that there’s a proud spot on the top of the aluminum extrusion framing (joints between framing not being flush would be most likely!

— more importantly, though… rimless glass tanks should really have a closed cell foam pad under them, between stand top and tank bottom! (I believe the factory mat with the Fiji95 I did a little while back was 1/8” [3mm] thick)

— I’d recommend a 1/8”-1/4” thick neoprene mat! Get one a bit too large, install it under the tank, then trim the mat flush with a razor! (If you cut it to exact size prior to install you need two burly people to hold the tank up while a third person tries to get the perfectly fitted pad sitting in the exact right spot; it’s a nightmare!)

Could be a combination of both!

I definitely should have used a mat. Oof... Kicking myself now.

Thanks for the input

 

[UncommonSense]

Could be a combination of both!

I definitely should have used a mat. Oof... Kicking myself now.

Thanks for the input

I recommend checking across the top of the stand with a level or other straight edge to try and pinpoint the highest spot while the tank’s off!

The leveling mat is primarily for very small imperfections like grits of rock in ambient dust… it can only do so much for a stand top with a proud spot! (If it’s a joint in the aluminum framing, now would be a good time to get it nice and flush before it’s stuck like that for the lifetime of the tank in that location!)

 

[Mas0n]

I recommend checking across the top of the stand with a level or other straight edge to try and pinpoint the highest spot while the tank’s off!

The leveling mat is primarily for very small imperfections like grits of rock in ambient dust… it can only do so much for a stand top with a proud spot! (If it’s a joint in the aluminum framing, now would be a good time to get it nice and flush before it’s stuck like that for the lifetime of the tank in that location!)

Found the issue, the PVC board has inconsistent thickness. Some areas are +- .1mm.

I drained the tank and added a mat, which removed most of the inconsistency. There is a low spot that I shimmed between the frame and PVC board.

I think this should be fine long term as the shim is below the PVC board and mat, so there is still room for the mat to do its work and not create a point load.

Thoughts?

 

[exnisstech]

There should never be shims between the stand and tank. The only place that shims should be used is between the stand and floor. I would remove the the PVC board and just have the mat between the stand and tank. JMO

 

[rtparty]

Don’t remove the PVC board!

A rimless tank needs full support underneath it. Sitting on the rails of the stand is not a good idea even with a mat

 

[exnisstech]

Don’t remove the PVC board!

A rimless tank needs full support underneath it. Sitting on the rails of the stand is not a good idea even with a mat

Interesting, my WB 330.7 sits directly on the aluminum stand with just a leveling mat. Its glass rimless 84x30x25" but does have a top eurobrace.

Edit:

 

[Mas0n]

This is what I'm looking like right now:

Unfortunately, I am not able to drain and move the tank again.

 

[commod0re]

all I see is blue… got any pics under whites? What does the opposite side look like?

 

[Mas0n]

all I see is blue… got any pics under whites? What does the opposite side look like?

Haha, non deep-fried with blue!

 

[commod0re]

Looks fine to me! The majority of the edge pane surface area is still directly supported

 

[UncommonSense]

Haha, non deep-fried with blue!

I don’t see any air gaps here, and .1mm isn’t particularly significant when the mat is at least 3mm thick!

Where is this shim at? — could we get a good look at that area?

 

[Mas0n]

Haha, non deep-fried with blue!

I don’t see any air gaps here, and .1mm isn’t particularly significant when the mat is at least 3mm thick!

Where is this shim at? — could we get a good look at that area?

Absolutely.

The shim is a small single layer piece of PETG that I 3d printed.

 

[UncommonSense]

Absolutely.

The shim is a small single layer piece of PETG that I 3d printed.

Ah, now I see how you did that!

Okay, so the PVC board was perfectly flat on top with that spacer added, when you ran a straight edge across it, correct?

If so, the primary concern here will be the unsupported/free floating PVC adjacent to the shim sagging over time… could you switch to a smaller printer nozzle to make half-height shims which slide in next to the full layer height shim? That would help to prevent that long-term sag…

 

[Mas0n]

Absolutely.

The shim is a small single layer piece of PETG that I 3d printed.

Ah, now I see how you did that!

Okay, so the PVC board was perfectly flat on top with that spacer added, when you ran a straight edge across it, correct?

If so, the primary concern here will be the unsupported/free floating PVC adjacent to the shim sagging over time… could you switch to a smaller printer nozzle to make half-height shims which slide in next to the full layer height shim? That would help to prevent that long-term sag…

I can, that’s a great idea. Thank you for all the help