Hello everyone,
I am doing a project and need some advice. I have only had very
rudimentary training in wax carving in the form of night classes at
FIT, and I read a couple of books, but I cannot seem to get past this
one problem I am having. Whenever I have a ding or hole that needs
filling I use my wax pen to deposit melted wax into the spot. The
melted wax fills the hole, and I can even sand it down and it makes a
smooth surface where the ding once was. The problem is that the spot
that was fixed now appears lighter under the surface than the rest of
the model. Is this air bubbles or just the way wax appears when you
fix it? All the books tell me to fill the void in this manner, but no
one mentions the wax appearing lighter under the surface. I am
presently using purple wax and have mended my model with the same wax
used to carve it. I get the same result no matter what color wax I am
using. Am I missing something? Do I need to buy special “fixing” wax?
I am so confused and tired of trying to figure this out. Please
advise.
Thanks,
Augest
Augest,
I sympathize with your frustrations. Wax working can be a tricky
beast. From what you describe, if you are working with a purple
carving wax, you may not be getting the wax hot enough to “bond” with
the surrounding wax you’re working with. Try a hotter tool, and when
you “stab” the tip SLOWLY into the hole you want to fill, being sure
to have an extra deposit of wax on your tool tip, remove the tip
very, very slowly, and you will avoid getting any air bubbles in the
cooling wax. Leave a small bump of wax on the repair, and file it
down after it cools. I would use the exact same type of wax to fill
that hole as you are carving, unless it is an extremely small pit or
scratch, at the very end of your carving process, in which case you
can use a fill wax, like disclosing wax, or Patch-Eze, by just
rubbing it into the hole and smoothing it out carefully. I use my
finger…
Good luck!
Jay Whaley
Hi Augest,
It is just the way wax appears when patching areas. It is normal for
wax repairs, and can a good thing to keep track of how many errors
you make on pieces. I believe it occurs due to the difference in
molecular structure and in the way light is reflected. The marks
become more apparent if the pieces are cast waxes, or prefab sheets
or ring wax, as they were cast at a different temperature and
solidify in a different way in comparison to the repair wax you’re
filling divots with (warmed by hand or by heated tools).
The marks will show up in the wax, but will not show up in your
final metal design. It can be a pain at times to be sure of accuracy
with the shape you desire when you have lighter blotches of wax in
areas, it just takes time to know when its corrected by feeling the
surface for a smooth surface.
I can’t stress enough how important it is-- if you are unsure if
you’ve properly filled the divot, it is far better to overfill the
divot than underfill it. You can always sand down excess metal, but
it is a nightmare to remove a divot when after it is in metal.
A little more detailed than necessary, but hope that helps!
Jim Sprague Jr.
I am not an expert on this, but I have also noticed this happening
when I use wax at work (I’m a dentist). I think the lighter colour
is caused by very small amounts of air getting into the wax.
As long as there aren’t any larger voids that affect the smooth
surface of the wax, it shouldn’t make any difference to your
casting. You should still get a smooth surface when you invest and
cast it. After all, all the wax is for is to create the shape you
want for your final product.
-Andrea
Augest,
Filling holes and repairing carving wax can be frustrating at times.
Some times the addition of repair wax will trap a bubble under the
surface. This can lead to the lighter color of the wax at the repair
spot.
One can check for air pockets in the wax by pulling a vacuum on the
model. The air pockets will pop out if they are close to the surface.
If the surface of the bubble does not break away under a vacuum the
bubble will not be a problem when vacuuming the investment.
The wax used to fill a hole MUST be melted into the model. The model
wax and the added wax must be melted together. The joint between
added wax and the model will be very weak if the base wax is not
melted.
Some times the repair will leave a recessed area next to the repair
spot. The hot tool melts some of the border of the repair and the
melted wax flows into the main body of the repair. These areas can
be repaired by loading the wax pen with wax and causing the melted
bead to flow into the recessed areas while all the repair spot is
still hot.
Round tips on the wax pen works better. I mentioned a battery powered
hand soldering tool (not the one advertised as an instant cool tip
when turned off) in a previous post. It has a bullet tip and works
better for repairing problems than any tip of my wax pen.
Some time ago someone posted a recommendation to use Kerr green wax
to repair pits etc. I never tried it. I use the same wax the model
is made with.
Be sure to cool the hot flask as described in one of the
anti-firescale papers added to the Orchid Bench tips. You will not
get firescale if you follow the very simple process.
Lee Epperson
Augest,
The problem is that the spot that was fixed now appears lighter
under the surface than the rest of the model
Filling a hole or pit should be rather quick. Here are a few I do
when adding wax to a wax pattern. First, always make sure the pen tip
is clean. Wax that has been burning will begin to loose its’ color
turn to clear and then start to burn. This puts a dark coating on the
tip. This blackish or brownish wax residue can and will transfer to
the wax pattern and appear like inclusions in diamonds. I clean my
tips by turning up the temperature to high allowing the tip burn off
the wax. (( Caution the fumes should be well ventilated)) Second,
the temperature of the wax pen if too high can cause all of the
above. Turn the wax pen down as low as you can while still allowing
you to effectively add wax to your patterns. Third the source or
supply of wax you draw from should whenever possible be the same wax
your pattern came from. Always use a block of wax. Bubbles: Make sure
you see no bubbles the wax you adding these will transfer to the wax
pattern. Bubbles in the pattren should be removed and then refill the
pattern. Or they can floated out by running a pen tip under and
around them. This will allow them to float to the top and break the
surface.
Hope this helps. Have a good day.
Michael Goin
Yes, you are seeing bubbles underneath the surface. The trick is to
hold the hot tip in the wax, wiggle and poke until the bubble rises.
You then might have to let it cool a little and add a bit to the
surface. All this is done with a gentle touch.
szs
The problem is that the spot that was fixed now appears lighter
under the surface than the rest of the model
Peck’s Purple is a good match for purple Karvex. I do not know that
it is still around… It is an inlay type wax, so the strength and
melting point are different. But it blends well and can be added
without further damage. Not sure how it makes a difference in the
final casting.
Good luck, Jon