Heat pump for a big bath!

[Beelbeebub]

Very cool!

 

Is the bath overflowing continuously (ie constant water input) or is it just that it is designed to be tolerant of overflowing?

 

I know wood baths shouldn't dry out or they start leaking so will you be keeping it full all the time?

 

 

[Alan Ambrose]

To me, the bath sides look a bit thin if they’re not supported? You’ve filled it with water already? My dad was a boat builder of wooden boats (which are inside-out baths). I would readily hold up my hand to the accusation of ‘mr over-engineer’ though.

[sharpener]

On 03/07/2024 at 05:58, Alan Ambrose said:

My dad was a boat builder of wooden boats (which are inside-out baths).

 

A carvel-built wooden boat of that size would have thinner planking, but also internal frames of some kind to resist the external pressure (so the fastenings would not be under tension). Also dinghies have reinforcement round the "rim" by way of gunwales or decking, and are generally curved, both of which which prevent the sides from bowing in.

 

So I think you are right, some structural calcs might be in order to see if lengthwise external ribs would be a good idea. If the sides bow out it will also tend to peel apart the corner joints over time.

 

Not easy to tell but to me it doesn't look to be very generously proportioned for 2 x 75 kg people.

Edited July 4 by sharpener

[JamesPa]

On 03/07/2024 at 05:58, Alan Ambrose said:

To me, the bath sides look a bit thin if they’re not supported? You’ve filled it with water already? My dad was a boat builder of wooden boats (which are inside-out baths). I would readily hold up my hand to the accusation of ‘mr over-engineer’ though.

Are baths inside out boats?  Boats are under mostly compression whereas baths are mostly under tension, and material properties tend to differ.  Admittedly wood and fibreglass which are common boat materials (and I guess fibreglass is a common bath material) are good at both.  Just saying!

[SteamyTea]

1 hour ago, JamesPa said:

fibreglass

It fails catastrophically (most composites do, why Kevlar used to be mixed in with carbon fibre) when buckled past the yield point.

There is very little elasticity with normal GRP compared to the tensile strength.

I think timber has other engineering characteristics, mainly the grain, with very different properties across and along it.  This, as has been noted, can cause problems at joints.

[Alan Ambrose]

>>> Boats are under mostly compression whereas baths are mostly under tension

 

Yeah, I was trying to be slightly amusing, only slightly tho.

 

I should confess that I’ve had a wooden bath for 25 years. My design and it’s a lot heavier duty than this. There were no calculations. Proof is in the pudding tho.

[Beelbeebub]

I have to say, the wooden baths I've seen seem to be a little thicker sided, though how much is necessary and how much is looks I don't know

 

[Alan Ambrose]

If you've got the bath already, there's an easy way to tell