How bad of an idea is this? PVC for burner leg extensions

[Punx Clever]

I just hope that anyone else reading this thread and considering this option listens better to the realistic and reasonably thought out reasons why your approach is completely stupid.

Personally, I think its a great idea for YOU to use it, figuring that Darwinian processes might strengthen the human gene pool here. However, I wouldn't want others to think that your guidance is anything but ridiculous.

So, you've been to his house to check on the stability of the burner with a full kettle on top? No? Are you an engineer? Do you have any legitimate method other than dogpiling on with others to determine the safety of this setup?

Honestly, some of the stuff I see on this forum scares the bejeesus out of me: two-by-four contraptions to strap angle grinders to kegs, hlt's full of scalding hot water perched precariously atop whatever junk happens to be laying around, modifying pressure cookers to act as steam boilers, putting water heater elements into tubes with the wrong threads and hoping the controller doesn't fail... the list goes on.

To be honest, what he did is pretty tame.

 

[Homercidal]

+1.

It's not what I would have done, but I have much better access to all kinds of metals and a welder.

 

[usfmikeb]

I guess there's simply a level of common sense that I expect to be normal, and others have a lower threshold.

 

[starman]

Here's a test: grab the legs from the very bottom and try to pull them apart to test the resistance of the leg to bending at the top joint, I bet you will be surprised at how easy it is to bend now that the legs are twice as long. Also, keep in mind that when the metal is heated it will reduce its resistance very significantly.

Most tall lanky chairs have supports that connect all the legs at mid height somewhere to stabilize them and prevent this kind of failure.

Snicks is right. The 1 1/4" pipe is probably strong enough but youve added a big lever to the leg. Because the legs arent plumb it is introducing a force that wants to twist the legs out as the weight of the kettle pushes down. You can make this whole thing significantly safer by adding a brace to those legs. This will keep them from scooting farter and farther out of plumb.

The greater the distance the legs are out of plumb, the more torque thats put on the original frame... which makes the legs push farther out... until the frame gives up and youre out a batch of wort (or worse).

To demonstrate, hold something that weighs a couple pounds up to your chest at shoulder height. Now extend your arm, keeping it at shoulder height. The farther out you get, the greater the strain on your shoulder. Try it with your arm fully extended.

There are some easy ways to cheaply tie those legs together and make that set up safer.

For example, make a capital "I" out of a 2x4 the same size as your burner. Simple lap joint with 4 nails or screws at both intersections. Drill 1.5" holes in it at the corners. Put it on the ground and set the legs in the holes. Cost ~$3.00 for materials.

 

[Homercidal]

Anyone want to perform a structural analysis and give a report based on it?

I think knowing the basics of conduit properties, angle of deflection, weight and force, etc. should make it an easy assignment.

 

[Punx Clever]

Anyone want to perform a structural analysis and give a report based on it?

I think knowing the basics of conduit properties, angle of deflection, weight and force, etc. should make it an easy assignment.

Depends...

What temperature is he brewing at? How much of a temperature increase will the stand see during brew day? How much of a temperature increase will the leg extensions see? What type of steel is used in the stand? How many times has the stand been cycled between hot and cold? What exactly is the conduit made of?

If you really want to get technical:
How large of a batch is he making? What is the specific gravity of his wort? What is the rate of boil off? How long of a boil? What kind of impulses are caused by the movement of wort as it boils?

Do we get to use Finite Element Analysis? Or will a simple model do?

One could really over-engineer this problem

 

[carrolte]

drill holes near the bottom of the legs and wire all four together with some bailing wire, so they don't do the splits.

 

[starman]

Lets see... roller connection for the bottom legs. Moment frame at the top with some kind of goofy pin where the EMT thinwall laps the legs... plastic deformation as the frame and tube deflect.. uh... hmm. Ill go with statically indeterminate for $1,000 Alex. My magic structural moment frame 8 ball aays Call a SE if you really want quantify how bad of an idea this is.

 

[Huaco]

Lets see... roller connection for the bottom legs. Moment frame at the top with some kind of goofy pin where the EMT thinwall laps the legs... plastic deformation as the frame and tube deflect.. uh... hmm. Ill go with statically indeterminate for $1,000 Alex. My magic structural moment frame 8 ball aays Call a SE if you really want quantify how bad of an idea this is.

Bwahahahaha.... funny stuff man!

 

[Punx Clever]

uh... hmm. Ill go with statically indeterminate for $1,000 Alex.

No reason to let that get in the way...

 

[Mjolnir]

you may want to tie those legs together some how to sure it up a bit

 

[ekjohns]

add cross bars! I spilled a little bit of water at 170ish on my arm and hand a few months ago and it still haunts me. I have since over done safety wherever I can

 

[usfmikeb]

I have since over done safety wherever I can

I follow that approach as well, better to be safe than sorry. I also have helped many new brewers get started, and you want to show them the right way to do things. Shortcuts can haunt you...

 

[ekjohns]

my little spill was resulting from a hose on my ball valve not being clamped tight with a hose clamp. After running water the hose loosened up and slipped off. Just a quick blast with water and I had 2nd degree burns across the top of my right hand and all my fingers and 1st and 2nd degree burns on my left arm. That was just water heating up for brew day and needless to say brew day was called off and I spent the next few weeks nursing my burns. All because I was missing a $1 part. Piece of mind is always worth the extra few bucks or a new perspective of things when it comes to safety

 

[usfmikeb]

Yep, I used to be a plumber, and have a very healthy respect for hot water and the source of the heat. I've had to fix things where people took shortcuts like the above leg modifications, and have seen people that were hospitalized for their desire to save a buck or two.

 

[freshhoarse]

So, you've been to his house to check on the stability of the burner with a full kettle on top? No? Are you an engineer? Do you have any legitimate method other than dogpiling on with others to determine the safety of this setup?

Honestly, some of the stuff I see on this forum scares the bejeesus out of me: two-by-four contraptions to strap angle grinders to kegs, hlt's full of scalding hot water perched precariously atop whatever junk happens to be laying around, modifying pressure cookers to act as steam boilers, putting water heater elements into tubes with the wrong threads and hoping the controller doesn't fail... the list goes on.

To be honest, what he did is pretty tame.

This. BUT... It doesn't look too safe. That 1 in 100 chance that it fails is going to hurt.

 

[johnnybrew]

Jumping in to say my peace: it doesn't look bomb proof. I wouldn't brew on it.

Chance favors the prepared. Be safe.

 

[TBaGZ]

I don't want to come off as "that guy" on my first post so this has been edited and I am going back to browsing.

 

[passedpawn]

So, you've been to his house to check on the stability of the burner with a full kettle on top? No? Are you an engineer? Do you have any legitimate method other than dogpiling on with others to determine the safety of this setup?

OP asked for opinions. He didn't ask for us to come to his house and measure anything.

 

[blksabbath]

Back on track.

I have the same burner with leg extensions I cut from two old steel fence posts. The burner It raises the burner up to carboy height and is very stable, no wobble whatsoever. I've had my burner set up like this for 6 plus years.

Yeah, pvc is sketchy, but metal tubing of some sort works great.

 

[barhoc11]

Back on track.

I have the same burner with leg extensions made from two old steel fence posts. The burner It raises the burner up to carboy height and is very stable, no wobble whatsoever. I've had my burner set up like this for 6 plus years.

Yeah, pvc is sketchy, but metal tubing of some sort works great.

Thanks for an objective post using facts from a real life experience.