Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Snagged this Elektro engine on eBay last week and discovered it had a burned out heater when I got it.
I made a new heater for it today and now it runs pretty good, although the crankshaft bearing is extremely worn and make the flywheel appear wobbly along with creating some noise. Still a great piece.

that is really great - it would be wonderful if you made a dedicated post on just making the heater with list of supplies (part numbers / source sites) - perhaps even with a video.  Looking at your last photo it looks like a simple-ish task.

Nice repair Mike! I see you even marked the new one to get the exact same wraps as the original

...

Do you remember what ohms/ft. nichrome wire you used for the new heater?

Paula

Yes, please Mike - the details on the Nichrome Flat Heater Wire would be great - would love to have the supplier/part number :-)

Did some figuring on this...

I have an old heater from a B30. The heating wire itself is good, but the aluminum terminals have rotted off. The electrical info, from the nameplate reads:

110 volts, 375 watts.

If I = P/V, then the current = 375/110 = 3.41A

If R = V/I, then the resistance = 32.3 ohms (The ACTUAL resistance measures 28.5 ohms, for whatever that's worth)

The number of turns is approx. 34, at 2.5"/turn, which gives a heater ribbon length of 85"

85" = 7.08 ft., 32.3 ohms would require a wire resistance of approx. 4.6 ohms/ft.

I measure the wire ribbon size at .004 thick X .031" wide.

This source has wire available in 5.15 ohms/ft, .0035" thick, and 1/32" wide, which would work:

https://jacobs-online.biz/nichrome_ribbon_wire.htm

It's the first size listed, with various lengths available.

Paula

Did some figuring on this...

I have an old heater from a B30. The heating wire itself is good, but the aluminum terminals have rotted off. The electrical info, from the nameplate reads:

110 volts, 375 watts.

If I = P/V, then the current = 375/110 = 3.41A

If R = V/I, then the resistance = 32.3 ohms (The ACTUAL resistance measures 28.5 ohms, for whatever that's worth)

The number of turns is approx. 34, at 2.5"/turn, which gives a heater ribbon length of 85"

85" = 7.08 ft., 32.3 ohms would require a wire resistance of approx. 4.6 ohms/ft.

I measure the wire ribbon size at .004 thick X .031" wide.

This source has wire available in 5.15 ohms/ft, .0035" thick, and 1/32" wide, which would work:

https://jacobs-online.biz/nichrome_ribbon_wire.htm

It's the first size listed, with various lengths available.

Paula

You’re on the right track! I got my nichrome ribbon from wireoptim.com. I use two sizes, 0.8mmx0.1mm and 0.5mmx0.1mm, 4.15 ohms/ft and 6.57 ohms/ft respectively.
I also use mica insulation sheet that is as close to the thickness of the original mica as I could find. It’s much easier to work with compared to regular mica. I cut it on a regular paper cutter and it seems to hold up well to the heat so far. I bought what I have on eBay.
I try to re-use the aluminum lugs when I can, but I have also made new ones from aluminum and copper.
These heaters are fairly simple to make, but you have to get the resistance right and also make sure you can get the right number of windings on the substrate.
Here’s a calculator I like to use.
 https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html
I’ve attached a few pics of the dispenser I made for the ribbon. It works well, but has to be clamped down to the work surface.

Excellent! We've nearly got this down to a science!

BTW, for Mica sheet that I got before this project I am trying to do now.

McMaster - #85825K42 Flexible Electrical-Insulating Mica, 23" x 39", 0.008" Thick $18.66 and you get a ton of it.  It comes in a rather large flat box!

This is how it is coming out on my cutting board - just unsure if I need even more sheets cut.  There is one now for the base, two strips, and the a cover to go over the strips.  I don't know if I should do one or two more.  BTW, this photo is for an Empire #90, which I been talking about this same topic (heater creation) in my post.

I also need to figure out how to attach the two sides.  They are wrapped individually and then are tied together with a little bit of metal (I think the same as the power tabs).  But the one on this heater just fell apart when I tried to lift up the tabs.  Now I haven't anything in my "supplies" to tie the two halves together.