iNTRODUCTION TO FACETING by John dyer
Indexing TIPS
Make the transition from a cutter of beginning to intermediate skill to one who can cut more rapidly and with fewer indexing mistakes. As another gem cutter once said, "Most of the cutting time is spent with the gem NOT in contact with the
lap."
So the less time you have to spend thinking about what you are going to
do or hunting for the correct index the more time you spend with the
gem actually in contact with the lap and the more efficient a cutter
you become. The
following technique has allowed me and many other professional cutters
to cut with much more efficiency than that of the beginning faceter. Read More in PDF...Dopping TIPS
If you are having trouble with gems falling off the dop when you dop with wax then I can almost guarantee that your problem is that you are not heating up the gem enough. If you heat the gem most kinds of dopping waxes will give a very good and reliable bond. I probably have about 1 out of 300 to 400 gems come loose from the wax. I have had far more problems with Super Glue although it is used with success by some.My preferred type of Dop wax is currently the Raytech brown wax but I have heard of good results with the black dop wax from Graves company.
Here is what I would recommend. (Unless it is a very heat sensitive gem.)
(Disclaimer, this works for me but I cannot be responsible for any negative results, use these techniques at your own risk. Also be careful, hot dop wax is very HOT and will burn skin and cause blisters or possibly worse if you are not careful.)
I heat the gem over an alcohol lamp's flame, turning the gem so as to heat it evenly. Much heat related breakage is due to UNEVEN heating, not just to getting the gem hot. If you watch carefully with a good amount of light you should see a vapor form on the gem of small water droplets, this means it is starting to warm but not warm enough. Then this water vapor will evaporate, this is almost warm enough. Warm a second or two more and then hold the gem about an inch or so from the flame as you heat the end of the dop wax stick in the flame.
Get the wax good and liquid and then apply a thin layer to your gem which should be still warm because you kept it near (but not directly in) the flame. I coat most of the pavilion with a layer of wax like this, paying special attention to the area nearer the girdle as I figure that holds better than the area near the culet. You obviously want to leave some space between wax and girdle but no more than necessary.
At this point you can let the gem and wax cool if you want, there is no need to but keeping the gem hot is no longer important since the gem to wax bond has already been established.
This works best as a hybrid dopping method, I do not usually use wax for the first side of the gem, I use a kind of epoxy putty that allows for repositioning and is more heat resistant than wax. Super Glue on the first dop will also work if done correctly. If you are doing a wax to wax transfer you must be careful because the gem can shift on the dop as you apply heat to it and get tilted or off center.
Now heat up your dop that you are transferring to, get it very hot and melt wax onto it. If you do not get it hot enough the wax will not bond well to the dop and your dop may rotate inside the wax. IT is a pain in the neck when that happens.
Once you have melted wax onto both your gem and the new dop you want to transfer to, then put them in the transfer jig (if they are not already in it). Now put them close together and use the alcohol lamp flame to heat the wax on the dop and the wax on the gem simultaneously until they are both liquid. Push them together and your bond is made. DO NOT PULL THE GEM BACK OUT, if you do this you will probably pull the wax away from the gem and weaken the bond you just made with such care.
Warm or somewhat hot wax can be shaped with a cool metal object such as the handle of a tweezer, once the metal heats up the dop wax will start to stick to it and pull away from the gem so it should be cooled in water periodically. You can smooth lumps and etc. in this way.
Wait until the wax has completely cooled before removing the first dop. For small gems this may be as little as 5 minutes, for large gems sometimes I leave them for 15 minutes or more because even though the outside of the wax is cool the inside can still be soft and if you transfer too early the gem can shift. If you get many gems that are crooked after transfer this may be your problem.
This technique is risky on opals, apatite and other very heat sensitive materials. With appropriate care it works for us on all the quartzes, feldspars, topaz, tourmaline and many other gems.
Hope this helps!
John Dyer
www.ultratecfacetingmachine.com