Hello, I am looking for a company to replicate the piece pictured below. This a cooling coil/heat exchanger for the air system on our 1929 trolley. It’s primarily made of 1-7/8” OD/1-1/2” ID steel or iron pipe. Fin size (square) would be approx 3-1/2”. Any recommendations?

Thanks

Probably a custom piece and require plenty of $$, minimum lot size etc.

https://www.fintube.com/products/stamped-fins/

Perhaps you can find a hot water baseboard heater with the right length and remove the enclosure around it. Might need to use 3 or 4 baseboard heaters to get the equivalent flow.

Depends on your priorities, function or looks.

Look for a commercial steel pipe fin tube heating element, commonly available in 1.25" or 1.5" steel pipe sizes. A good commercial/industrial plumbing/heating/AC supply house should be able to source this. You'll probably need to cut a section to your desired length and thread the cut end.

Howard P.

Since it's part of the air system the pipe would need to be rated for about 150 psi. That may limit my options. Thanks

Those sort of look like the radiator elements on SP 9010, though much smaller, originally made in Germany but wrecked by scrap metal thieves. The SP 9010 crew sourced new ones from a radiator supplier in California, and I would guess those would tolerate 150 psi. A radiator supplier in your area might be able to produce them (I worked for Universal Auto Radiator as a driver in Denver, their home office was in Pittsburgh PA, they made the radiators for the Model T but I believe are out of business due to some sort of financial scam): https://www.facebook.com/profile/100064 ... 20Radiator

The company suggested by NYCRRson might be your best bet since they appear to manufacture tubes similar to what you need if you don't mind spending some $$$ for a finished product. I can personally attest to https://www.unitytube.com/ , I have used them multiple times for custom made tubes for rebuilding very early tractor radiators. I'm not sure that they do square fin type stuff but they are worth contacting at a minimum. They might have suggestions even if they can't do it themselves.

On the practical side though, it looks like you just have 2 lengths of normal sch 80 1-1/2 pipe that are 5 ft long with a bunch of simple, flat fins added on them. With a couple fresh pieces of pipe, I don't think it would be unreasonable to get some new fins made and make the assemblies yourself. A sheet metal shop that's any good could easily cut you a bunch of square pieces of sheet metal to match what you have. And for the hole in the center, it would be cut probably about 1/8-1/4" under the OD size of the steel pipe. The hole would then be extruded with a mandrel which gives you a lip that provides contact surface to the pipe and helps align the plate correctly. The final hole size after extrusion should be just a tiniest bit under the size of the pipe so that you can bump them onto the pipe but they hold themselves in place and make good contact to the pipe surface for good heat transfer. The pipes should be cleaned down to bare, shiny metal before putting the fins on and after assembly, the fins should be soldered or brazed in place which can be done using a variety of methods. Really not that hard once you know how to break it down. Might think about it a bit since you only need two pipes like that. Commercial outfits are going to want to charge a fortune for that, unless you want a couple hundred of them made...

Some quick research also indicates that there are some off the shelf products that could potentially be modified to fit what you need. However, they all seem to only go up to 1-1/4" sch40 steel pipe. If you don't mind dropping down a size (which would actually match the plumbing at either end of the finned tubes) and can safely use sch 40, its worth the consideration. The fins wouldn't be the same size either though, looks like they're usually 4-1/4" square instead of 3-1/2". You'll have to decide how much you're willing to spend and how important it is to you whether or not it is perfectly accurate to original. I guarantee you that the public would never notice the difference on these components unless you told them. It's all up to your group's preference. Throw some emails out there and maybe one of these companies might surprise you.


Here's a few links to help your research:
https://www.slantfin.com/wp-content/upl ... ta-916.pdf
https://slantfin.weareslightlymad.com/p ... -elements/
https://indeeco.com/products/industrial ... -elements/
https://www.afsupply.com/slant-fin-1030 ... n-5-l.html

This is the closest readily available product I think that you'll find if you can live with a few differences but want to save some money by only spending a couple hundred dollars:
https://www.afsupply.com/slant-fin-1060 ... n-5-l.html

Thanks, Ryan - between Slant and Unity Tube, I think we can probably come up with a replacement.