How to Fix LiquiStone Castings
So there's something wrong with your LiquiStone casting? There are several types of problems and lots of ways to fix them.
The types of problems can be boiled down to these:
- "Outey" Bubbles
- Missing fingers
- Broken fingers
- Broken fingernails
- Flattened fingertips
- Rough surface on casting
These are bubbles IN the surface of the casting. These were caused by bubbles in the LiquiStone mix coming to the surface. Usually these are small and easy to fix.
- Mix a very small amount of LiquiStone.
- Thoroughly wet the area where the fix is to be made.
- Put some LiquiStone mix into the hole.
- Wipe it with your fingertip lightly until it is smoothly fixed.
- It might take a little sandpaper to smooth off once it has set.
Usually these are small.
- Sometimes just rubbing your hand across them causes them to roll off.
- Sometimes they can be "popped" off with gentle steady pressure from a knife.
- If they are large you will have to carve them off with a knife. This is where some of the tools in Accu-Cast's LifeCasting ToolKit come in handy.
We go over this very carefully in the literature about hand casting and in the hand casting DVD. The problem is that the fingers in question were bent more than 90° and the fingertips weren't touching anything else when in the molding bucket full of alginate. It is often easier to redo the casting, but if you can't here are some tricks.
- If you can find the part of the original alginate mold where those fingers were it is sometimes possible to carefully pour those fingers separately. They can then be attached to the sculpture using more LiquiStone (since it sticks to itself.
- Other times the defect is very small and in an inconspicuous place. A small amount of LiquiStone can be built up where that fingertip was and carved back to the shape of the fingertip after it sets. This takes some sculptural skills but it is often unnoticeable by anyone but yourself.
Broken fingers are a result of applying too much pressure to them during the unmolding process. This is VERY easy to do with baby and child hand casts. It is also easy to do if you try to rush the demolding of the casting and peel off the alginate before the stone has gotten hard enough.
Broken fingers can be reattached using LiquiStone as the glue.
- Wet both mating surfaces well.
- Mix up a very small amount of LiquiStone.
- Put a little on the broken area and reposition the broken finger.
- It will need to be kept in place while the fix is setting. Often it is possible to prop up the casting in such a way that the finger in question is pointing straight up. It will hold itself in place if you do this.
- Clean off any extra LiquiStone from the joint once it is completely set- about 2 hours.
To avoid broken fingernails it is always advisable to put some clay up under the nails before doing the hand casting. Sculpt the clay so it the nail is about 3x as thick as normal. Sculpt the clay so the nail comes to a proper point at the tip.
LiquiStone is just not strong enough for very thin cross sections like normal fingernails. You can take a nail file and file down the broken nails on the casting or redo it if the nails are really important to the model.
Flattened fingertips are ALWAYS cause by rushing the hand removal from the alginate mold. It is imperative that the suction be released from all fingers before pulling the hand out. There is no way to beat atmospheric pressure and if you struggle to get the hand out the fingertips in the mold will flatten as the hand is pulled out. They are often rough and distorted in other ways when this happens.
Solution? Probably best to redo the mold. If the effect is very small it might be possible to resculpt those fingers by adding LiquiStone as described above in Broken Fingers.
Rough Surface on Casting
A rough surface on the casting can be caused by several things.
- Insufficient mixing of the alginate or LiquiStone.
- Removing the hand from the alginate mold before it is completely set.
- Waiting too long before pouring the LiquiStone into the mold.
Most of the time, this is confined to a small area. Careful use of sandpaper can often solve this issue. If the roughness is extreme or large scale, it is best to redo the mold. Try to determine the cause and do a better job the second time.