Tips for Beginners

February 24, 2023 In Safety, Stone, Tips for Beginners

Catching Dust

If using power tools we create dust. We are wearing our masks so we aren’t breathing it in. But the neighbors…

Wood dust collectors do not seem to work well. You can make a downdraft table but that is good for small projects only. There are excellent (expensive) professional systems that have a vacuum system behind a “waterfall.” In Italy, they often use a DIY system consisting of a water trough with a corrugated metal or plastic sheet in it. Water cascades from a pipe with holes along the top of the sheet. A small pump recirculates the water. Either a fan is placed behind the sculptor or holes in the sheet have a suction system behind it. (Excuse the crude sketch.)

February 24, 2023 In Stone, Techniques, Tips for Beginners, Tools

Pinning

Bases are the frames for sculptures. To mount stone to a base you must use a pin to connect them (just glue will break apart). This should be a stainless steel rod so it won’t rust or a brass turning pin.

To mount a turning pin drill the two holes: base and sculpture.

Grind a little of the hole in the sculpture so the “cap” is level with the bottom. Let the cap sit on top of the base. This provides some separation for turning. Test before gluing with epoxy. If the sculpture still rubs on the base when rotated, you can put a brass washer over the base hole to raise it up.

 

February 24, 2023 In Techniques, Tips for Beginners

Photographing Your Masterpiece

To create a professional portfolio or to impress friends, it is important to have a clear picture of your work.

  • Set up a backdrop appropriate to let the sculpture stand out. Black backgrounds avoid some shadow problems.
  • Double-check that the background totally covers the frame. Look carefully through the lens.
  • Use stands that allow the placement of lights at different heights (sticks in a can, tall tripod).
  • A powerful full spectrum (3500K to 5500K) bulb such as a 100 to 500 watt will maintain colors. (Sunlight is about 6000K).
  • Diffuse light with translucent screens such as a frame with white acetate or umbrellas. A plain white foam core board can be used to bounce light into a shadow.
  • Direct 60% of light in the front; 40% in the back.
  • For translucent sculptures try to backlight (without having the source in the frame).
  • Consider light boxes for smaller pieces.
  • If possible, set the camera on a higher f-stop (like f8) and a slower shutter speed. With point and shoot cameras use the telephoto extended.
  • Use a tripod or stabilize on the back of a chair.
  • Use the timer to prevent shake. Set cell phones on the highest reso- lution and shut the flash off: Flash bad!
  • Experiment with different camera angles: side, from above, below… You can buy lighting and background kits. Google these two videos for low cost ways of getting professional photos:
    • Smick Product Photography Tutorial (by Gavin Hoey)
    • DIY Studio Product Lighting PROPHOTOLIFE, Episode 2

February 24, 2023 In Safety, Stone, Techniques, Tips for Beginners

PPE for Stone Sculpting

All the stones sold from 2sculpt are safe to carve. That means no asbestos, arsenic, radioactivity, or trans-fats. Still, you should always wear personal protective equipment (PPE), namely a paper mask and safety glasses.

If you are using power tools and therefore creating a lot of dust you need ear protection and should have on a respirator.
Whereas a paper mask catches about 40% of the dust, a double respirator labeled as P100 will provide about 99% protection. Gel bicycle gloves without the fingers are my favorite for vibration.

February 24, 2023 In Tips for Beginners, Tools

Power Tools

The most important tools are the basic hand chisels, a 1.5# hammer and a rasp. The first power tool should be an angle grinder (7.5 amps or more) and a diamond blade (or a Dremel if working very small).

The next step is a big but wonderful one: an air compressor. This will open up a world of lighter but more powerful tools. A portable compressor should be rated for at least 4.6 cfm at 90 psi (30 gallons). This will run an air hammer. To drive an air grinder you need a larger stationary machine that preferably has at least 12 cfm at 90 psi. If you use the portable compressor, there is nothing wrong with getting an electric die grinder that uses 1/4” shaft tools.

February 24, 2023 In Stone, Tips for Beginners

Enlightenment of Carving Stone

Enlightenment of Carving Stone (by a sculptor, not a geologist)

There are thousands of possible stones to carve. Each has its own characteristics. They can be classified by hardness, workability, “bedding” plane, and chemical composition. There is a hardness chart, the MOH scale, from 1 (soapstone) to 10 (diamonds). The latter is more than a thousand times harder than the former meaning it is a geometric (non-linear) scale.

Soapstone (1) is talc and can be scratched by a fingernail. It is easy to work and is weather durable. However, it obviously scratches easily and sometimes contains asbestos.

Alabaster (1.5) is calcium sulfate or gypsum AND 3
parts water. It carves well and finishes beautifully but
must be stored indoors (or you’ll get drywall dust). It comes in a wide variety of colors and translucencies and mostly as smaller boulders.

Steatite (2) is talc with some magnesium mixed in, which gives it a little more hardness. Like its cousin, it carves nicely with a rare soft spot and can be kept outside. Common colors are green, black, and gray.

Limestone (2-3.2) is a sedimentary stone of crushed shells. It carves nicely, the softer ones may not take an edge or achieve a high polish. It is opaque and is generally tan, light yellow, or gray.

Travertine (3-3.4) is calcium that formed from hot bubbling water and therefore has holes. Still, it can carve as well as marble and take a polish. Reds, yellows, creams, and whites are most common.

Marble (3-4.2) is compressed limestone or calcium carbonate. It might contain slight amounts of other minerals that give it veins or color (eg. copper for blue or green, iron for red, magnesium for orange or yellow, etc.) It can almost always take a fine edge and a high polish. Crystal size and layering (called bedding plane) vary greatly.

Onyx and Calcite (4) are, again, calcium carbonates formed by flowing water or dripping water (stalagmites/stalactites), respectively. They are usually translucent and finish beautifully. These are mostly cutting and grinding stones as they are too brittle for chisels

For the not faint of heart are the igneous stones of basalt and granite (6) which produce fine work and may contain minerals requiring good masks.

March 5, 2019 In Techniques, Tips for Beginners

Heads Up

Useful diagrams for sculpting the human head

Head Proportions (very generalized):
1. Distance between eyes is an eye width
2. The width of the nose is about one eye.
3. The eyes are at the vertical center.
4. The ears go from nose to eyebrows.
5. The neck slants back and has muscles.
6. The mouth is barrel-shaped– rounded.
7. The mouth is 1/3 from nose to chin.
8. The neck is about half the head width.
9. Since the head is “V” shaped from the nose to the ears, the corner of a stone

 

 

March 5, 2019 In Tips for Beginners, Tools

Flying Hammer Heads

Petro warns against flying hammerheads. Dry weather makes wood handles shrink. Soak the head and handle end in a solution of antifreeze (Propylene Glycol specifically) and linseed oil (50/50%). The solution gets into the wood cells and they remain “swelled”.

 

March 5, 2019 In Stone, Tips for Beginners

Crap––It Broke!

I have been told by a sage that there are two legitimate ways of dealing with flaws: 1) glue it before it breaks, and 2) accentuate rather than hide the break.

I was unenthused about this sculpture. I left it in a bad spot and it got kicked and broke in three. Ah, I was now excited about creative “accentuation”. I glued the pieces back together, routed out the seams, and then filled them back in with crushed red travertine and black-dyed epoxy. While at it, I added a necklace.

Always use stainless pins for gluing. Even 1/8” ones will prevent another break along the next row of crystals above the glue.

 

March 5, 2019 In Stone, Techniques, Tips for Beginners, Tools

Sanding Tips Pt. 2

I use the first two or three grits of sandpaper dry and the rest wet.

I wash off the stone between grits and allow it to dry for inspection before continuing. Use an old sheet of 1000-grit sandpaper for a few minutes between grits to bring out missed scratches.

Half your sanding time is on the first grit—getting out those deep scratches. Then the next grit might be 1/4 your time and so on. The last grit is a “breeze.”

 

March 5, 2019 In Tips for Beginners, Tools

Blade Safety

First, those black abrasive blades are dangerous – my commentary. Diamond blades are wonderfully fast, long lasting and safe if used wisely. Use no more than a 5” blade on a 4.5” angle grinder (<12,001rpm): a 7” blade on a <8001rpm grinder: a 9” blade on a body grinder (<6001rpm). The best blades have hubs/flanges so they screw onto the the grinder. Make sure the blade is firmly on the arbor of the grinder, connected by almost all the screw threads. Regularly check the tightness of the screws of the hub. Never twist the blade during the cutting process and avoid putting the blade all the way into the 12 stone; leave at least 1⁄4” space to the hub. Check for cracks regularly.

 

March 5, 2019 In Tips for Beginners, Tools

Blade Types

Use the right diamond blade for the stone and tool. Sintered blades are great for alabaster, limestone, and very hard marbles. They are the most durable but are not good for soft or medium marbles. Electroplated blades are for alabaster and marble and cut the fastest. Vacuum-brazed diamonds are the most versatile for alabaster, limestone, and marble. Since the diamonds are partially melted into the metal they have good longevity but are a little slower.

 

February 27, 2019 In Stone, Techniques, Tips for Beginners, Tools

Devilish Details

Wanna get the finest detail? Try small carbide burrs. These are double cut steel burrs in 1/32” to 1/8” sizes for Dremel machines. With a steady hand you can get the most minute hairs or textures. The three basic types are rounded, fishtail (“V” on the edge”) and flame. I found the Dremel 3000 was not that expensive and very steady. The cheaper ones wobble. (We have the burrs individually or in a kit.)

^Not actual size; much smaller

 

^Not actual size; much larger
by Al Brown, master of detail

June 19, 2018 In Techniques, Tips for Beginners

Enlarging

There are several ways to enlarge or “point up” from a model.  It is best to use an even increment of enlargement (2x, 3x, etc.) to make the math easier.

(1) Use calipers and a ruler to transfer dimensions.  

 

 

(2) Build a wire box around the model and use it to measure depths from the outside of the stone to the final surface. 

 

 

 

 

 

 


(3) “Superimpose” your model over the stone by holding it a distance away until it “appears” the same size. Then you can mark on the workpiece where different things should be. 

 

 

 

 

 

 

(4) Use a “pointing machine” which is an adjustable frame that can be moved back and forth between the model and the stone, drilling holes for approximate depths.  See this for an example of pointing:

 

June 18, 2018 In Stone, Techniques, Tips for Beginners

Make it Flat

To laminate properly the surfaces must be very flat to avoid gaps. For large stones, we used power equipment, in particular, a Blackcat which is a diamond grinding wheel on an angle grinder. It still required laying a steel flat edge over the surface repeatedly to find the high spots, mark them, and grind again.  Eventually, the surfaces matched and we were able to drill holes for stainless pins and epoxy them together. The pins are necessary as stones can separate, not on the epoxy line but on the next layer of crystals.  

On a smaller scale, you can use a concrete block with some sand on it and rub the stone on it. This goes fast with softer stones but does take patience with marble. All the high spots are ground down for a very flat surface before gluing.

Lastly, if the carving is substantially done you might consider slightly “hollowing out” the middle of the stone. Then you will only have to flatten the outside “rim” of the stone. For a base to be flat I might remove just ¼” of the center of the bottom.

June 18, 2018 In Stone, Techniques, Tips for Beginners, Tools

The Miracle Workers: Rouge, Tin and Magic Potion

“Rouge” literally means red. Not so in the polishing business: it means fine abrasive. After sanding up to 600 (higher on darker stones) you may still want that deeper color and shine. “Rouge” may be the answer.

This is a block or stick in white, black, or green for light very dark, and green/gray stones. Use a muslin wheel on a drill or die grinder to pick up some of the rouges. Then rub it on the stone in a small area:  Pop – a colorful shiny finish. 
Tin Oxide powder is mixed with water to create a rubbing paste for a very high sheen (without toxic oxalic acid).

June 18, 2018 In Stone, Techniques, Tips for Beginners

Chemistry of Finishing

Sand, sand, sand. The more scratches removed the deeper the color and the more gloss. If you “finish” sanding and then wet the stone it might look much better. You can continue sanding to get more scratches out or apply a coat of color enhancer. The silicon in the enhancer seals those micro-scratches. Wax is a nice top coat for protection and a smooth feel. Buff the wax by hand or with a tool to heat the wax into the stone. Black wax enhances very dark stones. Outdoor sculptures can be left alone or protected with a breathable sealer like Limestone & Marble Protector. Water must be able to leave the surface.

 

Belgium Black Marble by Caro Pemberton

 

June 18, 2018 In Stone, Techniques, Tips for Beginners

Sanding and Finishing

There is no “magic wand” to finishing a stone sculpture.  It is just plain patience and work.  The critical work takes place in the beginning – getting the worst scratches out.  The steps are: flat chisel, rasps, sandpaper, rouge, or polishing powder or cream. Details:

1 – A sharp chisel starts getting out the chisel marks. Old school teachings are that the flat chisel, used gingerly, should provide almost the final surface.

2 – The larger the rasp the coarser the teeth. Pick the shapes that get in most of the spaces on your piece.  Most commonly we use point, spoon, and knife shapes but there are many options. Rasps need to be used in one direction; forward. Diamond rasps come in different grits and can be used in both directions. A good rasping job makes the next job much easier.

3 – Sandpaper must be made of silicon carbide (not aluminum oxide). It can be used wet or dry. Water increases speed and sandpaper longevity. You might start with 36 grit for marble or 60 grit for alabaster or limestone. A normal progression for sanding is something like 60, 80, 120, 220, 400, 600, 800, 1200, and 2000, if necessary.  Of course, not all stones need to be sanded this high. Colorado marble might only be sanded to 220 grit; limestone to 600 grit; black marble to 2000 grit.  Wash the piece between grits and then let it dry to see what you missed.

As a general practice, the first grit will take half the total sanding time. The next grit might take ¼ the total time.  So by the time we get to the higher grits the time required is minimal. Note the inevitable frustration: as you go up the grits you will find deeper scratches that you missed earlier. You will need to go back to some steps. Expect this.

(Advanced: Diamond sponges and sanding rotary tools speed up this process. I use all these to get the job done.)

4 – Higher abrasives are in the form of powders, bars or creams.  These are most commonly tin oxides. There are rouge bars that are used with a buffing wheel. (Make sure to use rouge for stone, not the metal stuff.) Powders are rubbed on the stone as are the creams.  These options are basically 5000 to 8000-grit abrasives 

5 – Chemicals are the last step – possibly.  I think I am done but test it by wetting it down. Did it make a big difference?  If yes maybe I should sand further with a higher grit. Another option would be to use a color enhancer. This is a diluted silicon solution that fills the microscopic scratches and keeps the surface looking wet.

6 – Wax protects the sculpture from fingerprints and other contaminants. I would not wax outdoor pieces as the wax will just burn off.  There are other outdoor sealants that allow the stone to breathe. 

June 18, 2018 In 2Sculpt, Stone, Tips for Beginners

What’s So Hard?

When choosing a stone for sculpting we must consider its consistency (how fragile it may be), it’s patterning (how busy it is), and its workability (its hardness). The MOH scale is a quickly accelerating rating of stone from “1” for soapstone to “10” for diamonds. Other factors such as molecular structure can also affect hardness. Here is a rough guide to our most commonly used stones:

1        Soapstone

1.5    Alabaster

2       Limestone and Steatite

3       Softer Marbles and Travertines

4       Harder Marbles, Calcites, Onyx

6       Granite and Basalt

 

Some of us like the harder stones. We get sharper lines, more exacting cuts, and beautiful finishes. With the right tools we can cut, chisel, and polish with reasonable effort.

June 18, 2018 In Safety, Stone, Techniques, Tips for Beginners, Tools

Lifting: Back Preservation

Yeah, stone is heavy. Alabaster weighs 160 pounds per cubic foot and marble 170 pounds.  Brute strength lifting is not wise: thought and cleverness rules here.  Think of the ingenuity of the Egyptians or Mayans of erecting tall stone monuments.

1. Never lose gravity.  If your stone is already off the ground, work vertically. That is use a board and rollers to get it to its destination. Do not lower it to the ground and have to pick it up again.

2. A stone can be walked on its corners. A 200 pounder can effectively become 60 pounds. Three steel pipes of 1.5” diameter can roll a very large block: two under and the third to replace the one coming off the back as it rolls. A pebble placed under a stone makes it easy to rotate.

3. An engine hoist is a relatively inexpensive lifting and moving devise. Wood planks might have to be placed under the small wheels to move it.

 

 

 

 

 

 

 

See this fun video where a guy moves giant stones via primitive methods:

 

June 18, 2018 In Safety, Stone, Techniques, Tips for Beginners

The Mounting Process – Summarized

  •  Get a flat and level surface to work upon
  •  Determine sculpture position; secure and hold it
  •  Mark bottom level line
  •  Cut bottom; check for flatness (might use a tile)
  •  On larger bases, cut out the center of the bottom to make flattening easier
  •  Determine the hole location in the sculpture bottom (find the center with a pebble)
  •  Drill hole with a hammer or core drill (consider the bedding plane)
  •  Determine hole in base: mark the sculpture footprint on the base or cut out a template (cardboard or masonite); mark “up”
  •  Drill base
  •  Decide on pins: stainless steel or turning pin:  gluing one or both sides or using threaded connectors. Consider the ultimate weight of the piece.
  •  Put non-scratch feet base or adjustable feet on a larger pedestal
  •  Proudly display sculpture

 

 

 

 

 

 

 

 

 

by Ken Miduch

June 18, 2018 In Safety, Tips for Beginners, Tools

Drilling Basics

All the stones sold from 2sculpt are safe: no asbestos, arsenic, radioactivity, or trans-fats. Stones of which to be cautious are sandstone and granite (silica), soapstone (asbestos), and jade and copper (heavy metals). This is not to say that they cannot be sculpted; just be thoughtful of the dust. 

You should always wear at least a paper mask (to minimize lung congestion) and safety glasses. If you are using power tools and therefore creating a lot of dust you need ear protection and should have on a respirator. Whereas a paper mask catches about 40% of the dust, a double respirator labeled as P100 will provide about 99% protection (less than $20 for a 3M half respirator).  Gel bicycle gloves without the fingers are my favorite for vibration. There are more elaborate anti-vibration gloves that secure the wrist to minimize carpel tunnel damage.

June 18, 2018 In 2Sculpt, Tips for Beginners, Tools

Chisels

There are hand and air hammer chisels – and rarely should the two meet.  That is an air hammer chisel should never be struck by a hand-held hammer. That distorts the shank of the chisel which, in turn, distorts the piston of the air hammer (very serious). There is a striking cap that can be placed over the air hammer chisel to protect it, though.

Stone carving chisels can have steel or carbide tips.  Steel ones are sharper but need to be sharpened more often.  The carbide ones are much stronger but because of the carbide insert they are “fatter.” On softer stones, the steel chisels produce cleaner lines. On harder stones, the carbide ones make more chips. Note that carbide is a brittle metal so protect these valuable tools from dropping on concrete or smacking against each other.

When using chisels stone must be coming off. If the chisel is held too steeply into the stone (like 90° )the chisel may break. If the chisel is held too acutely (like 15° ) it will just glide over the stone.  Experiment with angles until you are actually carving.  Never, ever use a chisel as a pry bar or try to knock off too big a chunk.

June 18, 2018 In Tips for Beginners, Tools

Air Hammer Usage

Air hammers are a major investment. However, they increase speed to about 6 to 7,000 blows/minute. Still, you stay in touch with the stone meaning that you do not lose control; stay “spiritually” connected.  Too often with a saw or grinder, we lose sight of our design – off goes a nose or paw. (Been there!)  The air hammer retains that feeling of hand chisels where we still feel the stone and stay “in control.”

Air hammers are classified by two variables: piston diameter and travel distance.  The larger the piston the more “punch”. So, the small air hammers might have a 5/16” or ½” diameter piston whereas the larger ones might have a ¾” or 1” diameter piston. This has no connection to the size of the chisel. They almost always have ¼” or ½” shanks to fit in the air hammers. 

The travel distance or “stroke” refers to how far the piston goes up and down.  A far distance is called a long stroke and a shorter one is a short stroke.  Again, the longer the stroke the more power. Long-stroke air hammers might be required for hard stone and larger projects. It does take a toll on your wrist but gets the job done. We prefer these air hammers (Cuturi and Trow and Holden) as they have very few parts and are therefore very reliable.  The major difference between these two brands is that the Trow and Holden has long and short-stroke hammers while the Cuturis split the difference and have only medium-stroke air hammers.

One last note: air hammers are controlled by a valve on a short, attached hose. This is called a “whip.” Never run an air hammer full throttle or without the valve.  That is too much air and usually, the valve is opened no more than halfway.

March 16, 2017 In Stone, Techniques, Tips for Beginners, Tools

Splitting/cutting stone

Ravinder from India once drilled a series of small holes in a 6’ deep block of marble. He inserted feathers and wedges in each hole and hammered a little on them each hour for a couple of days. Sure enough, the stone developed a crack through the 6’ resulting in 2 blocks.

In marble, determine the bedding plane or grain direction.

Drill the holes, insert the feathers and wedges, and hit them sequentially. Most times the stone will split quickly. If not, wait a few hours or overnight before proceeding to allow the crystals to line up.

 

July 1, 2015 In 2Sculpt, Stone, Tips for Beginners, Tools

Sandbags

For smaller or uneven stones a sandbag will stabilize the art-to-be. You can cut the legs off an old pair of jeans, fill it 2/3rds with play sand, and seal the ends with plastic ties. I like using old truck tire tubes from my car repair place (sometimes a little hard to get, but free). I then cut them in half or thirds and similarly secure them with ties after filling them partially with sand. This way if I hit the rubber “bag” with my grinder it just bounces off rather than cutting it open.

June 17, 2015 In Safety, Stone, Techniques, Tips for Beginners

Heavy Lifting

Don’t. One wrong twist or extension can have long-term implications. I got impatient and reached over the edge of my trailer to lift the edge of a heavy stone just a little. Cantilevered at a 90-degree angle I did the worst thing and pulled my lower back. That took over a year to heal. (If this should happen, get on a flat surface and start stretching immediately to minimize the damage.)

Of course, always lift with your back straight and have your legs take most of the weight. But machines, even simple ones, make much sense. To move horizontally I pry the stone up a little with a pry bar and then insert two short 1-1.5” pipes so that I can roll the stone forward. I may have to lay a few boards on the floor or grass so the pipes will roll but I will slowly get to my destination.

You can lift a stone with a portable engine hoist (around $200). You can also tilt a stone forward and put a 2×4” block under it. Then lift the other side and put a block under that side. Now lift the opposite side and insert a second block of wood. Keep repeating this process until you reach the desired height. See this interesting Youtube of a guy building his own Stonehenge with any power tools: https://www.youtube.com/watch?v=-K7q20VzwVs

Remember never lose height. If a stone is already up in the air, like on a pickup bed or car trunk, do not throw it on the ground to be lifted anew onto a stand. Do everything you can to avoid having to lift it a second time.