by Stu Brennan in the December 2002 RootesReview:
When I replaced the paper defroster tubes in my Tiger, I came across a solution that you might want to consider. I had wanted to complete the project in one weekend, but was disappointed to find that my local auto parts stores had nothing close to the original type tubes in stock. But… as I left the last store I tried, something shiny caught my eye. This something shiny proved to be the solution. Check out those aluminum accordion replacement tubes used to route hot air to the air cleaners of newer cars. Most auto parts stores have a good selection of them, including the 1.5″ size that was about right. Mine cost about $5 each.
The new tubes were exactly the same diameter as the right heater outlet and defroster spreaders they were supposed to fit over, so I had several choices. I could slit them where it wouldn’t show and slide them over the ends, securing them with clamps. Or, I could try to stretch the tubes to fit over the outlets. Neither of these options seemed attractive. Also, the tubes would not fit into the rubber 90 degree left heater outlet. So I had to invent an internal adapter out of the cardboard center of a roll of paper towels. I cut the cardboard tube into several sections and dipped them into polyurethane varnish, saturating them. The next day, I had some fairly rigid adapters.
The aluminum tubes bend and stretch easily and hold their shape when you are done. Unless you want the “Zeta Ray Duct” look, the next step is painting. Give the tubes a good pre-paint cleaning, since mine seemed a bit slimy–probably from their manufacturing process. I sprayed flat black Krylon over some primer, and they looked like the paper originals. My installation was simple. I used some GE RTV to glue the cardboard adapters into the outlets, the spreaders and the aluminum tubes. Everything pressed into place, requiring no clamps or supports while the RTV cured. The installation looks great, since I was able to bend these tubes to fit better than the originals.