Flash points for oils

Jewelry Discussion
1

Hi everyone, I make jewelry from my home where, because a member of
my household has Multiple Chemical Sensitivities, its imperative
that I use chemical products very carefully. I’ve chosen to use
Coconut Oil rather than a petrolium oil in my "inch rock saw – so
far I haven’t had problems with the oil congealing. I am concerned
though, about weather the flash point of coconut oil might be low
enough to be a fire threat – sometimes when the oil is too low I
get sparks (I am cutting chalcedony) and that worries me. Does
anyone know about the flash point of vegetable oils versus synthetic
oils? And what to watch out for when it comes to preventing your oil
from catching fire in general?

THANKS!
Susan H.

2 
 I've chosen to use Coconut Oil rather than a petrolium oil in my
"inch rock saw -- so far I haven't had problems with the oil
congealing. I am concerned though, about weather the flash point of
coconut oil might be low enough to be a fire threat -- sometimes
when the oil is too low I get sparks (I am cutting chalcedony) and
that worries me. Does anyone know about the flash point of
vegetable oils versus synthetic oils? And what to watch out for
when it comes to preventing your oil from catching fire in general?

Hi Susan, I hope this’ll help to allay your fears, a bit… The
sparks you’re seeing “when the oil is too low” are the same sparks
you’d be seeing if you were cutting in plain water, if it ran too
low. Whenever you use diamond abrasives (as you are when the leading
and side edges of your sawblade come in contact with both the gem

  1. If you’re using a “Dolphin” (brand) or other stainless
    steel-cored sawblade, create a 40:30:30 solution of your coconut oil
    with water and glycerine and shake well before refilling your saw’s
    sump reservior. This’ll enhance the surfactant (wetting) ability of
    the oil, and thereby help reduce that sparking you’ve seen. (The
    glycerine enables the miscibility of the former two. Since neither
    the glycerine nor the oil are as prone to evaporation as is the
    water, and since all are well tolerated by those of us with M.C.S.,
    you’ll be able to cover all bases pretty easily.) Whenever the watery
    mixture runs low, just top it off with water from a bottle kept
    nearby for just such an occasion. (FWIW: I find that those pump-top
    shampoo and lotion bottles are ideally suited to this.) You’ll also
    appreciate the glycerine’s catalytic ability to intermix with the oil
    and water when time comes to clean up the area from overspray!

  2. The other “antidote” to your sparking problem has more to do with
    approach than chemistry. (And if this applies to you you, don’t feel
    alone in it…) Most, if not all, of my lapidary students have tended
    to push their roughs into their saws’ paths – and I mean really
    lean on the roughs – in order to finish the job faster. You can
    readily tell if this applies to you by simply running a fingernail
    across the surface of the finished cut; if there are waves and ridges
    further than 0.5mm apart on the two sides of the cut, you’re pushing
    too hard. The idea is to let the blade gently “sand” its way through
    the rough, rather than more forcefully “dig” its way through. Doing
    so takes a little longer, but has its benefits in at least two ways
    that more than compensate you for that time investment: first, it
    relieves the stresses on the material being cut, which reduces the
    presence of incipient fissures (especially adjacent to cleavage
    planes) and all but eliminates gem rough “breakout” at the back end
    of the cut. Secondly, it prolongs the life and usability of the tool
    receiving the wear-and-tear, so it reduces your operating expenses!
    (And every little bit helps, right?)

Finally, where flash flame-outs are concerned, the only times you
really need to worry are those in which you’ve ignored your saw’s
lubrication needs for so long that it’s pumping/slinging a thick
enough slurry that you’re actually seeing smoke. If that’s
happening, you not only need to be concerned about a flash fire, but
also about the replacement costs of both the rough and the equipment!
Remember, Susan, the coolant protects both the rough and the blade;
let the first one leave and the other two will soon follow. (I hope
I’ve been of help!)

All my best,
Doug Turet
Lapidary Artist/Designer
Another Bright Idea!
anotherbrightidea@hotmail.com

3

You might consider bying a new saw blade designed to run in water.
Check the advertizements in Lapidary journal. If not try Kingsley
North , phone (800) 338-9280. They are a good outfit.