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-# JerrycanGasCaps
+# JerrycanCaps
+
+Lost or broke your jerrycan cap? Just print a new one with my generic 3D design.
+
+## Disclaimer
+
+Let's begin with the obvious part: fuel is flammable. Any leak can thus become a hazard.
+Due to print and material qualities, I can not guarantee that my design is leak free and strong enough in your particular setup.
+Even if the cap does not leak when tested, over time it might still develop a leak.
+Always obey the maximum fill line of the jerrycan, store the jerrycan so that the cap is not touching the liquid, 
+and never store a jerrycan filled with fuel in an enclosure which is not ventilated to the outside.
+
+## Software
+
+This 3D design file is made by FreeCAD. You need this free open source program to configure the dimensions of your Jerrycan Cap.
+
+## Dimensions
+
+In the FreeCAD file is a spreadsheet. The following entries, all in millimeters,  need to be edited:
+
+- Diameter. This is the diameter of the filler neck of the jerrycan, excluding the (male) thread.
+- Thread. This is the depth of the thread. This can not be more than half of the Pitch.
+- Pitch. This is the pitch of the thread. This is the distance between two adjacent "ridges".
+- Heigth. This is the height of the threaded part of the filler neck of the Jerrycan.
+
+## Materials
+
+Please do not use PLA. It can not deal with long term exposure to fuel, UV, and temperatures above 40 degrees Celsius.
+
+### Cap
+
+I use PETG for this, as it is a bit flexible, can withstand UV, does not react with fuels and additives, and can deal with temperatures up to 65 degrees Celsius.
+
+If you plan to have the jerrycan permanently exposed to the sun, I recommend to print the cap with ABS/ASA instead.
+
+Dry the filament before use to obtain the correct strength.
+
+I used the default settings of my slicer software, i.e. 2 walls, 15% infill. 
+Stronger is not necessarily better: in my design I rely on the cap to be a little bit flexible, so it adjusts to small angle deviations of the filler neck.
+
+### Gasket
+
+Although I added a spring like construction in the inside of the cap, for minor unevenesses you probably want to add some sort of gasket.
+
+You can either cut a piece of rubber sheet with the correct diameter, or print my "Gasket" design.
+If you cut it from a piece of rubber, make a small hole in the middle so it fits over the pilar in the middle. This serves to retain the gasket.
+
+If you print the gasket, use TPU for this. I used TPU95 and that proved to be adequate.
+Anything else than TPU is not an improvement over the cap itself.
+
+### Holder
+
+Obviously, this is an optional part, to prevent the cap from becoming lost when the jerrycan is opened. I used TPU95 for this.
+
 
-Lost or broke your jerrycan gas cap? Just print a new one with my generic 3D design.
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