Last night I did the bender again and started trying to do the “sliced tangent to the inner radius” exhaust tip. Now while I was building my tool and practicing bending the raw stock I was listening to YT Music on my phone, which ran the battery down so I couldn’t take pictures after I was done. But I promise pictures for tomorrow after the phone gets charged.
The tricky part is the heating of the raw stock to make it soft enough to bend without causing the tube to collapse. I ruined many bends because I overheated the tube and collapsed it. I also discovered that heating the stainless steel bolt I’m using as a bending post doesn’t work for tubing at all, unlike solid rod. If the post is warm enough to soften the plastic, the wall of the tube next to the post collapses before the outer radius starts to bend. In retrospect I should have expected that, but I was thinking in metalworker mode not plastic model builder mode. The way to go for the plastic tube is to spin the tube on its long axis with the intended bend area in the heat source (butane torch flame) until it gets soft but not floppy, then put it in the bender and make the bend. This has to be done extremely fast because the temperature spread between floppy and rigid is very small and soft enough to bend and too cold to bend smoothly is even smaller.
Anyway I discovered another reason for using the sliced bend exhaust tip, it leaves a delightful teardrop shaped opening besides directing exhaust away from the car, similar, shorter, but not exactly like when the reverse technique is used for side-exit exhaust. But I wasn’t expecting this shape from the inside bend, I was expecting a more oval shape opening. Maybe when I get a better quality bend the shape of the opening will be more oval than this attempt. But better quality requires more practice and there is a limit on how much raw stock I can waste on practice. I really need to reserve one stick of tailpipe material for the final build so I have enough length. But I will get a picture of the pretty practice tailpipe for tomorrow’s post
Witch on a Bicycle 