Bending/shaping a heating element for water heater ?

[Externet]

Heard a long time ago, that heating elements of this type
**broken link removed**

can be custom shaped and bent when new, but not after first usage. Is that correct, incorrect or is there a proper way or brand to do it ?

 

[tunedwolf]

As far as I know, the metal tube is annealed before each stage of bending during manufacture to soften the metal as the bending process work hardens the metal again making it prone to fracturing. The mineral insulation is compacted by the bending process too and sometimes extra is added if the bends are particularly tight, ensuring that there is sufficient insulation around the bent element. So to answer your question, it can be bent to any shape you require, within reason, during manufacture, but it should not be bent again after manufacture and definitely not after being used

 

[jpanhalt]

I suspect you searched Google and found conflicting views on bending similar heating elements. Unfortunately, most of those views are not supported by anythng more than opinion, and certainly not by any information from the manufacturers.

Watrod is one such manufacturer. Here is what it has to say (https://www.watlow.com/downloads/en/specsheets/hanwat0713.pdf ):

Here's a YouTube (not from Watrod):

Another question that arises is the effect of previous use on bendability. Again, there are conflicting opinions. It is also harder to find comments from the manufacturers related to that. Unless the internal filler somehow solidifies during use -- another unsubstantiated claim made on various blogs -- I don't see how the normal use of something to heat water would adversely affect the temper of the steel sheath. Whether higher temperatures (say dull red) will lead to better or worse temper depends on what metal is used for the sheath. That is something that is easily found, once you determine the specific heater you plan to use. What you want to avoid is bending a bend. That is, the first bend will work harden the sheath. When you try to bend it again, it will not bend in that same manner as it did before, and the work-hardened metal may crack.

There are "bendable" heating elements. McMaster-Carr sells them, as do other suppliers. McMaster is a little more expensive, as usual, but it ships quickly and at least you know what you are getting.

Based on those observations, I think the device you show from HD may not be suitable to additional severe bending: 1) It has already been severely bent; and 2) It is single-ended. You have not said how much bending you need to do. Since the price is quite reasonable, this may be a case, though, where experimentation is the easiest and most cost-effective answer. If it is more than just gentle, then I would look for a double-ended heater or a heater sold as "bendable." Check the web site of whatever brand/manufacturer you use for its recommendations.

Finally, as you know, when you bend tubing it tends to collapse. That will compress the filler in the tube and may lead to hot spots, if supports for the internal heating element are not designed for such bending (See: technical papers on the Watrod site). I would suggest using a tubing bender that supports the tubing sides and reduces such collapse, particularly if you are bending more than , say, 30 to 45° or the bend radius is small.

John

 

[Externet]

Thanks, tunedwolf. Agree with the precaution of not shaping after being used.
Thanks, jpanhalt, for your elaborated reply.
Yes, did search before posting and your link and several others showed up. But none for the screw-in terminated element assemblies, all for the bare heater rod.

For a not severe bending, but one somewhat less than as fabricated in a section that has not been already bent, and using a proper bending tool, there is a chance to succeed as you say 'experimenting' to find out if such immersion heater will survive and perform.

The plan is replacing a 1500W / 120V with a longer 3000W / 240V element in a compact water heater, taking care of thermostat capabilities to match, and bending to fit as in this ----> //www.plumbingsupply.com/images/water-heater-element-2853.jpg
or as the attached picture:

 

[edthomas]

Heard a long time ago, that heating elements of this type
**broken link removed**

can be custom shaped and bent when new, but not after first usage. Is that correct, incorrect or is there a proper way or brand to do it ?

why couldn't you buy a new heating element heat it up red hot with a torch and slowly bend it into the shape you need. I have a 15.5 gallon stainless steel beer keg and I want to put in a heating element but the keg is concave on the inside bottom, I want to bend the element so it is very close to the bottom almost touching it so it will always be covered with liquid mash for distillation so that it will never run dry and burn out. Your never supposed to run those heating elements dry, they must always be submerged in liquid.

 

[DerStrom8]

edthomas Welcome to ETO.

Did you look at the date stamp on the last post in the thread before submitting your reply? This thread has been dead for nearly 4 years.