Lost Wax Casting: Detailing A Wax Pattern

While detailing a wax pattern for a lost wax casting may seem like an ominous task, it doesn’t have to be. Here is some solid advice from Stuller’s master wax carvers to help you achieve success.  But, if you still run into challenges, don’t forget to contact us. We’re here to help. 


Before working on the mold, the most important thing you can do is to check the pattern is complete and undamaged.

  • Tip #1:  Hold the pattern up to a light and look for internal bubbles in the wax. These could break during the investing process and cause an inclusion in the cast piece. Small internal bubbles can be repaired in some areas.  But, if the pattern has large bubbles (or many smaller bubbles), it’s probably better to reject the wax pattern and replace it with a new one, rather than spending the time trying to fix it.
  • Tip #2:  Check carefully for missing prongs that would automatically lead to piece being cast over again. Remember: If it takes less time to inject a new pattern than to repair the existing one, inject a new pattern.
  • Tip #3:  Heavy mold seams and misaligned patterns should also be rejected. Wax patterns of varying quality can often be produced from the same mold. It is better to begin with a better quality pattern than to try to bring a poor one up to standard.


Being meticulous about the cleanup and repair process ensures the result you want.

  • Tip #1:   Remove the thin flashing along the mold seams with a sharp, pointed tool. If the surface of the tool is smoother, it will burnish the surface and smooth it more. Be cautious of the tool point so as not to scratch the pattern to the point that it can’t be fixed.
  • Tip #2:   For deep indentations, use a wax pen to melt and fill with wax. Build up the surface adding by a little wax at a time to avoid later having to remove excess wax.
  • Tip #3:  Once the surface filling is done, use your scraping tool to remove excess wax and smooth the surface.
  • Tip #4:  For small, internal bubbles in the pattern, use your pointed tool to break them open. Melt the wax surrounding the hole using a pax pen and add a small bit of wax to fill it. Should a small air bubble not come to the surface, move the point of the wax pen in small circles as you lift it from the hole to bring the bubble from the interior of the pattern to its surface.
    NOTE: Handling the wax pattern excessively, combined with using the wax pen, softens the wax pattern. This can be both an advantage and a disadvantage. It may be possible to reshape a distorted pattern slightly or misshape and distort the wax pattern while it is being worked on. Use care in handling the pattern when working on it to prevent accidentally distorting it.


Now that the wax build-up and scraping has been done, it's time to smooth the surface for casting.

  • Tip #1:  Once the surface filling is done, use your scraping tool to remove excess wax and smooth the surface.
  • Tip #2:  The tools you'll need;
    • Cotton swabs
    • Felt stick
    • Pointed tool
    • Wax polishing solution (Laboratory Solitine™) - Avoid using wax solvents not intended for this purpose (such as floor wax stripper). Most are overly aggressive  and will make the surface worse. Also, use the solution sparingly. Excess solvent left on the wax surface will continue to soften it and cause problems in investing, such as affecting integrity during casting and heavily texturing the casting surface.
  • Tip #3:  Smooth the interior surfaces of the pattern first, using a cotton swab treated with the wax polishing solution and applying light pressure. If the pattern is a ring, polish the inside first to avoid messing up the outer surfaces while holding them to polish the interior surfaces.
  • Tip #4:  Treat your felt stick with wax polishing solution and use it on the flat surfaces (i.e. the side of ring shanks) to smooth and blend any remaining mold seams. Using this method to remove minor mold seams often yields better results than scraping them smooth.
  • Tip #5:  Should small wax flakes form and stick to the surface while you're smoothing, use a dry cotton swab to remove them.  Move the swab in the direction the cotton is wrapped so the swab doesn't fray and leave fibers behind on the surface.
  • Tip #6:  If an area has many minor surface pits that resemble porosity, fix them by rubbing with a treated cotton swab in the same manner used to blend mold seams.

Process Complete

Before you mark your task complete, be sure to inspect your wax pattern again. Keep in mind that the entire detailing process should take less than three minutes. And, for each minute you spend detailing the wax pattern, you can save up to ten minutes working out the defects in the cast metal.

Discover more tips and techniques on wax carving and casting by reading our article on investing and burnout or melting and investment casting. And, as always, if you’re stuck with a problem, bring it to our community. We're always trying to have our customers hone their crafts together.