Introduction to Shona Sculpture -

How to Repair Stone

The stone can suffer two common injuries:  scratches and crush marks.  The following is a step by step guide with tips on how to repair these two conditions.  We have been importing stone from Zimbabwe for the last 5 years and have repaired hundreds of sculptures.  The technique we use was taught to us by the artists with whom we work.  While this process appears simple to follow we cannot guarantee success.  Working with stone is an acquired skill not unlike baking.  The more you do it the fewer burnt batches you will get.  We do not take any responsibility for any loss or damage that may result from using the above described technique.

Identifying the Problem 

Scratches are usually a line and result from something sharp such as nails or rings being run across the stone.  Crush marks are usually circular and result from impact to the stone.  Both scratches and crush marks appear whitish. 


If the scratch is not too large it is better to try to “spot” repair it.  Minor scratches often only affect the finish rather than the stone itself.  To avoid having to refinish the entire piece you will want to work on the smallest space possible.

For deeper scratches and crush marks the process is a little more involved.  Ideally you want to have to alter the stone as little as possible so try the steps outlined for minor scratches first and resort only to this if necessary.

Warning:  Sadly, hasty artists sometimes hide the beautiful natural color with black or other dark colored shoe polish.  While we take special care to ask the artists only to polish the stone in such a way that the natural grain is revealed with the volume that we buy some pieces get missed.  Alternately, some artists prefer the uniformity and we respect this artistic decision.  If you are repairing one of these pieces you may find it necessary to take special care to match the color to the original and ensure you blend the edges of the area you are working on very well.

Getting Prepared

Before you begin, you will want to collect everything you will need.  Many of the items are things that are commonly found in your home, though some you may also need to buy.  Depending on the severity of the damage these are some tools you might need: 
:
•    Heat source that can be directed eg/ hair blower , fan with heat setting, hot air gun
•    Kettle
•    Spray bottle with water. 
•    Plastic bucket large enough to submerse the entire sculpture.  Metal busckets can also be used but they can cause further damage of the sculpture is dropped or bumps against the bucket.  You might try a plastic ice cream container that you would otherwise discard. 
•    Mask
•    Old toothbrush or paintbrush
•    Heavy weight rubber gloves
•    Waterproof sandpaper -  220 grit , 400 grit and 600 grit .  Most hardware store sell packages with multiple grits.  Regular sandpaper may also be used but will loose it’s finish in the water so you might have to use more.
•    Metal Files
•    Shoe polish close to the colour of the sculpture.  Light brown tends to be the most versatile, though black, burgundy or dark brown may be appropriate in some circumstances.  Paste wax used for floors can also be used.

•    Lint free rag.  Keep your old bed sheets or t-shirt.  When they are threadbare they are often also less likely to leave lint.

How to Repair Minor Scratches

Tools needed:

•    Heat source that can be directed eg/ hair blower, fan with heat setting, hot air gun
•    Waterproof sandpaper -  400 grit and 600 grit. 
•    Spray bottle with water.  
•    Mask
•    Old toothbrush or paintbrush
•    Shoe polish close to the colour of the sculpture.

Repairing the Finish

Step 1:  With your heat source heat up the scratched part of the stone.  This will help to melt the wax and facilitate adhesion to the stone.

Step 2:  Once it is warm to the touch take the toothbrush and apply a small amount of shoe polish.  Be sure to blend with the unscratched areas.

Step 3:  Let the stone cool.

Step 4: Buff the stone using the lint free cloth.

Step 5:  If the scratch is gone you’re done.  If not you’ll have to do a little sanding.  

Sanding the Scratch

Inhaling stone dust is not recommended so we suggest taking two precautions:  first wear a mask and second use water to “trap” the dust.    

Step 1:  Spritz the stone with your spray bottle and gently sand the scratch using the 400 waterproof sandpaper.  Gentle circular strokes work best.  Try not to stray too much from the size of the scratch.  

Tip:  By keeping the stone wet you will also be better able to see once the scratch is gone.  

Step 2:  Once you can no longer see the whiteness of the scratch on the wet stone change to the 600 grit.  This will give you a very smooth finish.  If the original finish is not very smooth you may skip this step.

Step 3:  Go back and repeat the steps given above in “Repairing the Finish”

How to Repair Deep/Large scratches and Crush Marks

Tools needed:

•    Bucket large enough to submerse the entire sculpture.
•    Kettle
•    Waterproof sandpaper 220 grit , 400 grit, 600 grit. 
•    Metal files
•    Mask
•    Heavy weight rubber gloves
•    Old toothbrush
•    Shoe polish close to the colour of the sculpture. 
•    Lint free rag. 

Sanding the Scratch or Crush mark

Inhaling stone dust is not recommended so we suggest taking two precautions:  first wear a mask and second use water to “trap” the dust.    

Step 1:  Immerse the sculpture in water that is a temperature comfortable to work in.  Gently sand the scratch using the 220 grit waterproof sandpaper.  Gentle circular strokes work best.  Try not to stray too much from the size of the scratch.  If this is a very deep mark, you might want  to use a metal file and follow up with the 200 grit sandpaper. 

Tip:  By keeping the stone wet you will also be better able to see once the scratch is gone.  If the stone dries out it will appear white as in the picture on the right. 


Step 2:  Once you can no longer see the whiteness of the scratch on the wet stone change to the 400 grit.  Be sure to

Step 3:  For a very smooth finish use the 600 grit.  If the original finish is not very smooth you may skip this step.  Once the stone is smooth you are ready to refinish it.

Repairing the Finish.

Step 1:  Empty the water in the plastic buck and fill it with boiling water.

Step 2:  Immerse the entire sculpture in the bucket.  Metal buckets may also be used but since plastic is less likely to cause new scratches extra care should be taken.  No need to make more work for yourself.  

Step 3:  The stone will get quite hot so we recommend using a thick pair of rubber gloves which will insulate your hands from the heat.  Remove the stone once it is hot and gently pat dry.  

Step 4.  Take the toothbrush and apply shoe polish to the entire sculpture.  You will need to apply extra to the spot that was sanded down.  Be sure to blend well.  

Step 5:  For added sheen we like to apply a layer of clear paste wax with a paintbrush.  Depending on the piece of stone used you may or may not be able to get a high gloss.  We recommend trying to match the original finish.  

Step 6:  Let the stone cool.

Step 7:  If you notice some patches that are uneven repeat steps 2 through 6.

Step 8:  Buff the stone using the lint free cloth.

Disclaimer:  While these steps appear simple to follow we cannot guarantee success.  Working with stone is an acquired skill not unlike baking.  The more you do it the fewer burnt batches you will get.  We do not take any responsibility for any loss or damage that may result from using the above described technique.



If you are interested in seeing a good cross section of stone and sculpture from Zimbabwe please check out our store Wanderlust Imports .

Wanderlust Imports has been operating as a fair trade importer since 1999.  Please see our About Me page for more details.  We thank you for your support.