How strong is a stainless steel bar?

[reddal]

Hi,

 

I have a wine cellar about 2.9m wide - which I want to also use as a drying room for cured meats. I want to install several rods spanning the width of the room - which I'd hang all kinds of chorizo etc whilst its curing.

 

The question is what to use for these rods - given they will only be supported at the ends - and there might be quite a bit of weight distributed along them (each needs to support at least 20kg - of distributed weight - maybe 50kg if I go mental).

 

Something like this looks like it might do the job - but is 10mm diameter steel bar strong enough to hold the weight without deforming? If not what diameter would do the job, or is there a better solution altogether?

 

Summary of problem :

 

 

If I have to I'll work out a way to also support the bar in the middle - but it would be nicer if it didn't need that.

 

thanks - reddal

 

Edited May 14, 2017 by reddal

[daiking]

On the phone so can't multitask but someone will be along shortly to solve.

 

Sounds weak to me but I'll check later. pipe/tube would be much better 

 

http://www.roymech.co.uk/Useful_Tables/Form/Stress_Strain.html 

Edited May 14, 2017 by daiking
link added

[Russell griffiths]

2.9 m is a long span for any rod bar type material, it will deform without a shadow of a doubt, 

how about buying some ex butcher shop hanging bars they are normally a rectangular shape as there is more strength in the deeper profile than a round bar. 

[Russell griffiths]

http://pages.ebay.com/link/?nav=item.view&alt=web&id=192179325902&globalID=EBAY-GB 

[Onoff]

How about a length of st/st Unistrut? Plenty of pre drilled slots. If you fitted it toes up you could hook over the edge.

[daiking]

http://www.efunda.com/formulae/solid_mechanics/beams/casestudy_display.cfm?case=simple_uniformload#target

[daiking]

59 minutes ago, daiking said:

http://www.efunda.com/formulae/solid_mechanics/beams/casestudy_display.cfm?case=simple_uniformload#target

 

Ok so I've even checked it by hand as I didn't believe I'd done the calculator correctly. The deflection would be so great it breaks the formula - for a 50kg load, the deflection works out as over 1.5m. A 20kg load, 0.63m. These are nonsense figures so I'm afraid you need something much better - akin to a scaffold tube over that span.

 

That supplier does a tube, 30mm dia, 1.5mm wall thickness, which even then would have a deflection of 57mm.

 

So, bigger tube and/or thicker wall again or build in the beam to control the ends and reduce the deflection by 80% - but then you might need to look at the stress as well as the deflection. 

Edited May 14, 2017 by daiking

[PeterW]

1 hour ago, reddal said:

 

 

I have a wine cellar about 2.9m wide - which I want to also use as a drying room for cured meats.

 

 

Oh crap ..!! Now you have me thinking ..!!!

 

What ventilation have you got in there ..? I've not got any but may put a small PC fan to circulate air around. 

 

Just had a quick look and the curing room at the local place from the photos has 25mm Ish tube but it looks like it's supported every metre or so from the photos. 

[Jeremy Harris]

The thing here is to increase the area moment of inertia.  Forget about the tensile or shear strength, it's irrelevant in this application.  Choose a material with a high Young's Modulus (i.e. any type of steel over aluminium, or better still carbon fibre) and then choose a section with a high area moment of inertia in the axis of the applied distributed load.  Hollow sections or I beams are far stiffer than solid rod for a given mass.

 

I can run something through BeamCalc as soon as I'm back on my Windows machine if you want (BeamCalc doesn't work well on Linux/Wine).

Edited May 14, 2017 by JSHarris

[reddal]

Hi,

 

Many thanks as ever for all the advice. Seems like you probably saved me some time and money as what I was plannnig had no chance of working.

 

Seems like I probably have to support the length in the center - which should make the problem much less of a challenge. There is a beam in the ceiling in the middle of the room so I could attach hooks to that and drop some rope from those to take the weight at the center of the span.

 

Following the Unistrut idea from @Oneoff - maybe this would work (assuming I support it in the middle)? However it doesn't look like that is stainless or galvanised - and there is going to be a fair amount of humidity in the room (about 75% rh) so I guess it might corrode over time? The stainless / galvanised Unistrut looks a bit expensive at first glance.

 

1 hour ago, PeterW said:

 

Oh crap ..!! Now you have me thinking ..!!!

 

What ventilation have you got in there ..? I've not got any but may put a small PC fan to circulate air around.

 

Until now I've only been using the cellar for wine - and as its in the basement the conditions are not bad and I didn't bother doing anything special to control the environment.

 

However curing is a whole different story and I need to control the temperature and humidity carefully. I'm installing a cellar conditioner to keep the temperature at 12c - and will have a humidifier / dehumidifier controlled by a humidistat to keep the humidity at 75% rh. The hardest part is probably going to be stopping the humidity getting too high - a load of wet meat product gives off a lot of moisture. I'm also going to install a couple of extractor fans - one pulling air into the room - one pushing it out - which will both get turned on if the humidity gets too high.

 

The nice part is the environment for drying cured meat is also just about perfect for wine - so I don't have to get rid of that :).

 

- reddal

 

p.s. if anyone is thinking about trying to make slow cured meat products - note - these conditions are only for the final part of the process - the final drying. Before that theres a whole different process of fermentation and initial drying which requires very different conditions. I wouldn't want someone to read the above and just hang some raw pork+spices in their wine cellar for a couple months then eat it - as that could easily kill you :).

[Nickfromwales]

?

Sorted

?

[AliG]

All the kinds of steel section you could possibly need! One of them must work.

 

https://www.metals4u.co.uk/mild-steel/c6

[Russell griffiths]

http://pages.ebay.com/link/?nav=item.view&alt=web&id=162508877130&globalID=EBAY-GB 

[Ferdinand]

I think if I were looking for this I may be (subject to modern regs) talking to trad-looking butchers' shops to see if any still had their backyard slaughterhouse fittings that I could purchase. I like the continuity.

 

I looked at a property last year that was two butchers shops and the old slauighterhouse at the back - decent sized site. I ran away because of the amount of immediate cash needed and the potential ground contamination.

 

That still had the rails and meat hooks extant after being unused for decades and being in a collapsed state.

Edited May 15, 2017 by Ferdinand

[PeterW]

8 hours ago, reddal said:

The nice part is the environment for drying cured meat is also just about perfect for wine - so I don't have to get rid of that :).

 

I may have to look at this a bit more as my drying / conditioning unit is a converted wine chiller ..! Humidity is the issue and I was wondering how to get the air in and out as mine is a "proper" cellar - basically it's the old garage pit converted with with a concrete capping before having the insulation and floor cast over it...! I should get some residual heat from the ufh downwards and then the ground temps from around the sides. 

 

Have you tried home smoking too ..?? (I can see this heading OT...!)

[Jeremy Harris]

OK, I'm on a machine with BeamCalc running now. 

 

Starting with the 10mm solid stainless steel bar mentioned, assuming 316 ("marine grade" stainless steel), an evenly distributed load of 196 N (20kg mass at 1g) over a length of 2.9m, with simply supported ends, then we get the following figures:

 

Average shear stress = 1%

Peak bending stress = FAIL (exceeds allowable material bending stress with no margin or SF)

Maximum centre deflection = -1.871m (this is how far down the centre would bend if loaded like this and if it hadn't failed under the bending stress).

 

Lets try the same bar but with a centre support, so we now have two simply supported beams with the load evenly distributed on both.  Only one half needs to be analysed:

 

Average shear stress = 0% (it's too small for BeamCalc to worry about)

Peak bending stress = 51% (still too high, there needs to be a margin of at least 2, preferably 3 or 4 for something like this)

Maximum deflection at the centre of each side = -0.0585m (each side will bend down by around 58.5mm at its centre)

 

For sake of another example, say a length of standard 15mm stainless water pipe was used, with a centre support:

 

Average shear stress = 0% (it's still too small for BeamCalc to worry about)

Peak bending stress = 29% (acceptable, the margin is a bit over 3)

Maximum deflection at the centre of each side = -0.0223m (each side will bend down by around 22.3mm at its centre)

 

So, I reckon that a bit of 15mm stainless water pipe would be just about OK if supported in the centre.  If you wanted to have a bit less deflection and a better margin, then you could look at using 22mm stainless water pipe.  I'll leave BeamCalc open, just yell if you want me to run any different section through it, it only takes a few seconds.

Edited May 15, 2017 by JSHarris
typo - misspelt "there"

[Tennentslager]

Google. Images for "gas pipe handrail" for lots of inspiration

[Jeremy Harris]

As I had the programme open, I've just run the numbers for 22mm stainless steel water pipe, both with and without a centre support.  First, with a centre support:

 

Average shear stress = 0%

Peak bending stress = 11%

Maximum deflection at the centre of each side = -0.0056m (each side will bend down by around 5.6mm at its centre)

 

Next, with a centre support but with the load increased to an evenly distributed 490 N (50kg at 1g):

 

Average shear stress = 0%

Peak bending stress = 27% (OK, the margin is over 3)

Maximum deflection at the centre of each side = -0.0141m (each side will bend down by around 14.1mm at its centre)

 

 

Finally, a single 2.9m length of 22mm stainless water pipe, with a 196 N (20kg at 1g) evenly distributed load:

 

Average shear stress = 0%

Peak bending stress = 86% (unacceptably high)

Maximum deflection at the centre of each side = -0.18m (the centre will bend down by around 180mm under load)

 

My view is that using 22mm stainless water pipe, with a centre support, would be best.  It's readily available in 3m lengths, you can adapt stainless pipe clamps as supports, and it would be OK even with the worst case of a 50kg distributed mass hanging from it, with a reasonable margin and acceptably low deflection.

[reddal]

1 hour ago, JSHarris said:

My view is that using 22mm stainless water pipe, with a centre support, would be best.  It's readily available in 3m lengths, you can adapt stainless pipe clamps as supports, and it would be OK even with the worst case of a 50kg distributed mass hanging from it, with a reasonable margin and acceptably low deflection.

 

Many thanks for your advice - that sounds ideal. Would this do the job? Thats a 21.34mm Outside Diametre x 2.11mm wall grade 304 Welded Stainless Steel Pipe - for £38 ex vat. Not cheap - but not as much as some of the options were looking like.

 

10 hours ago, Nickfromwales said:

?

Sorted

?

 

True - but buying nice chorizo can be expensive - look at this I saw in my local M&S recently :

 

Thats £20 for 120g - or £167/kg! If all goes to plan I will be selling some of mine - but not for that much!

 

2 hours ago, PeterW said:

 

I may have to look at this a bit more as my drying / conditioning unit is a converted wine chiller ..! Humidity is the issue and I was wondering how to get the air in and out as mine is a "proper" cellar - basically it's the old garage pit converted with with a concrete capping before having the insulation and floor cast over it...! I should get some residual heat from the ufh downwards and then the ground temps from around the sides. 

 

Have you tried home smoking too ..?? (I can see this heading OT...!)

 

The biggest issue might be it getting too hot. The ground temps might be close to what you need (12c - or thereabouts) but if the ufh + heat given off by humidity equipment heats it a way beyond that it could be too hot. Putting cooling into that underground space might be hard...

 

To control humidity, first you need a controller - something like this, which measures humidity and gives power to devices you attach to lower or raise the humidity. Adding humidity is easy - a small ultrasonic humidifier is fine - however you probably only need that to get initial levels up - after that the meat gives off a lot of humidity and your problem is to keep it down. Two ways to lower humidity - a small dehumidifier, or exchange some air with the outside (lower humidity space). The tricky part is anything you do to control one variable tends to muck up the other so it takes a bit of fettling to get it balanced.

 

Happy to start a new thread on this stuff if there is interest in discussing it? I'm not an expert by any means - but I spent a year or so experimenting - so its just about possible (for once) I might not be the most clueless person here on this subject :).

 

- reddal

[Jeremy Harris]

12 minutes ago, reddal said:

 

Many thanks for your advice - that sounds ideal. Would this do the job? Thats a 21.34mm Outside Diametre x 2.11mm wall grade 304 Welded Stainless Steel Pipe - for £38 ex vat. Not cheap - but not as much as some of the options were looking like.

 

 

As a single 2.9m length, with no centre support, then it's not really up to it.  The numbers (for 20kg distributed evenly) are:

 

Average shear stress = 0%

Peak bending stress = 71% (not OK, as there's not a big enough margin)

Maximum deflection at the centre of each side = -0.154m (the centre will bend down by around 154mm under this load)

 

Adding a centre support makes it OK though:

 

Average shear stress = 0%

Peak bending stress = 9% (OK, the margin is over 10)

Maximum deflection at the centre of each side = -0.0048m (each side will bend down by around 4.8mm at its centre)

 

with a centre support and 50kg distributed evenly:

 

Average shear stress = 0%

Peak bending stress = 22% (OK, the margin is over 3)

Maximum deflection at the centre of each side = -0.012m (each side will bend down by around 12mm at its centre)

 

[reddal]

1 minute ago, JSHarris said:

Adding a centre support makes it OK though:

 

Average shear stress = 0%

Peak bending stress = 9% (OK, the margin is over 10)

Maximum deflection at the centre of each side = -0.0048m (each side will bend down by around 4.8mm at its centre)

 

with a centre support and 50kg distributed evenly:

 

Average shear stress = 0%

Peak bending stress = 22% (OK, the margin is over 3)

Maximum deflection at the centre of each side = -0.012m (each side will bend down by around 12mm at its centre)

 

 

Perfect - thanks a lot.

[daiking]

@JSHarris Is this all modelled as simply supported? What does built in look like? (I'm just being lazy and don't want to do it by hand myself).

 

It's overkill but I'd keep it to structural sort of values so a 1/500 max deflection would need to be quite a substantial rail...

 

I'd start at 50NB Sch 40 and go up from there!

 

Edited May 15, 2017 by daiking

[Jeremy Harris]

It is just simply supported at the ends, yes. This programme can model cantilevers, but not a beam constrained at both ends.  I used to have a finite element programme that could model 3D structures with constraints, as an add-on for AutoCad, but I seem to have lost it when my old machine went down.

[reddal]

1 hour ago, daiking said:

@JSHarris Is this all modelled as simply supported? What does built in look like? (I'm just being lazy and don't want to do it by hand myself).

 

 

At one end is a wall made of double width concrete blocks - so I was thinking I'd just drill a deep hole in that and shove the pipe in - should be very secure.

 

At the other end is a stud wall. I was planning screwing a length of timer into the stud wall and drilling holes to feed the pipe into. So at this end it will take the weight - but it wont be as strong in terms of flexing.

 

Thinking about it - I'll get something like this to make the ends look nice and help keep it all secure.

 

It doesn't need to be built like a battleship - I just want to be reasonably confident its not going to fall apart.

 

- reddal

 

 

[Temp]

What size tube is available for SS car exhausts? Perhaps that's the cheapest size tube?