SeaPerch Remotely Operated Vehicle, Руководство по монтажу

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SeaPerch ROV Construction Manual
– Version 2010-04NW
2.6-1
Tips on Wax Melting – Safety and Techniques
Wax Melting Safety Reminders:
Eye Protection: Always wear safety glasses or goggles when working with potting wax.
Wax Handling: Bowl ring wax is made from petrolatum
– basically the same type of material that, when more
refined, becomes common petroleum jelly. It is safe to handle when cooled, but quite sticky, and difficult to
remove if it solidifies on clothing. After handling bowl ring wax,
wash your hands with very warm water and
soap. Do not ingest the wax.
Don’t Get Burned:
Bowl ring wax usually melts at a rather low 150 degrees Fahrenheit (F). The wax-melting
approach used for SeaPerch ROVs is to melt the wax in a water bath, usually employing an electric skillet to
heat the water (and wax).
It is important NOT to let the water evaporate (keep adding water to maintain it
at about ½” to 1” deep); otherwise, the wax can get VERY hot
. Although its flash point is over 500
degrees F, the manufacturers usually recommend not exceeding 200 degrees F. Obviously, if the wax is
allowed to get too hot, serious skin burns are possible; more sensitive skin or large quantities of hot wax may
cause burns. In case of a burn, quickly rinse the area with LOTS of cold water and seek medical attention.
Don’t Have a Melt-Down:
Too-hot wax, such as from using a hot plate without a water bath, has been shown
to actually melt the thruster housings! For this reason, and the safety reasons noted above, use of a
thermometer for the wax cup(s) is recommended. If a thermometer is not available, the best advice is to keep
the water bath below the boiling point, and adjust the skillet temperature to low or medium, so that the wax just
reaches its melting point, or a little higher, about 160 degrees F. The goal is for the wax to be hot enough that
it will not harden immediately when poured into the thruster housings, but cool enough to avoid burn hazards.
Wax Melting Technique Tips:
1. To facilitate cleanup, put a drop cloth on the work bench, on the floor below it, and on the wall behind it.
When installing caps, stand back to avoid getting wax on you or your
(or others’) clothes.
2. Start the wax melting early, at least an hour before class time on motor-potting days.
3. Put small weights (such as lead sinkers) in your wax-melting cup(s), to prevent floating in the water.
4. Try to find metal cups with insulated handles that can hang over the side of the electric skillet or other water-
bath heating device. This makes handling and pouring much easier than using tongs or gloves on a hot cup.
5. One wax ring will pot about six thrusters, but plan on some spillage; have extra wax on hand!
6. Should wax run short, spilled wax can be scraped up from the potting holder, table top, or even the outside of
the cooling thruster housings and returned to the cup(s) to be re-melted.
Example of a Student’s Safety Glasses Saving the Day!
Watch Out for Squirting Wax: Wax can
squirt quite a distance when the caps are
pressed onto the thruster housings if the task
is done very quickly (wax can jet out of the
hole in the cap). Wearing an apron and
gloves (latex, nitrile, etc.) during the motor
potting process is recommended.
Holding a
paper towel over the cap as it is pressed on
will help to prevent wax from squirting beyond
the area of the housing.
The inside-seal type
housings (some film canisters) tend to squirt
wax farther than the outside seal types, but
either can be a squirting hazard. The picture
to the right says it all; wear that eye protection!