Glue – DP190Gray
All Michigan chambers with old Heim tubelets are coated with DP190 epoxy around the end of the half jumper. Epoxy is applied with a pneumatic dispensing syringe using long bent needles or with small swabs (3mm diameter foam tip).
Some tubelets have epoxy pre-applied along the length of the tubelet body to seal cracks that are away from the bulge area.
Techniques:
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| A small artists brush or swab is used to apply epoxy to a tubelet body starting 10mm from the bulge and going past all the bends. |
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| Tubelets are assembled and installed on a gas bar on jig. Pre-assembled gas bars are stored for later use. |
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| Just before a gas bar is installed on a chamber epoxy is applied to the half-jumper/tubelet region using a syringe and swab. The gas bar is installed on the chamber while the epoxy is still wet. |
Applying epoxy to tubelets which are already on a chamber uses the same techniques, however it is not always possible to see whether a full epoxy coat covers the hidden side of the half jumper. It is helpful to use a swab or brush which is bent near the tip for accessing the back of the half jumper. Of the 10 chambers at Michigan which were done this way we found 2 tubelets which still leaked, due to inadequate epoxy coverage.
Questions can be addressed to
cweave@umich.edu