off-the-shelf tube needed for dummy load bank

Hello,
The three pdfs attached depict the “chimney tube” resistive load bank, which here is for 48V,6.5A (312W)
It is an el-cheapo load bank, easy and quick to make.
We just need to find the tube itself……we’d like it to be metal, but will settle for plastic.
Do you know of any off-the-shelf tubing like this? (we can cut the air intakes out ourselves).
It can be round or square cross section..or “any-side-oganol” for that matter...approx at least 16 cm long….approx 6cm radius.
..or any length (we can cut it to size)

Pringles tube?

Baked bean tins?

JimB

Personally, I'd use bigger wattage resistors. 100W 24R resistors will easily handle your requirements.

Mike.

I'd use a tube from a chain-link fencing post.
Also, when you solder the resistors to the copper clad board, don't clip the leads, instead, run them across the board and touch the lead of the resistor across the board. The copper leads of the resistor conduct better than the solder-covered board.

Finally, what is the story behind the 68 ohm resistor on pdf1?
the left and center columns of resistor each make 2.5 ohms (5 total). The rightmost column makes 2.41 ohms. The total is 7.41 ohms. 7.41/7.5 = 98.8 ohms. Are your other resistors 1% or less tolerance that one 68 ohm resistor makes a difference?