Direct or indirect method mosaics?
When you decide to make a mosaic, you first have to decide which mosaic techniques you are going to use – the direct method (for a simple ‘how to’ project using the direct method, follow this link: https://helenmilesmosaics.org/making-mosaics-2/how-to-make-mosaics/making-mosaic-trivet-photos/) or the indirect method.
The direct method involves putting the mosaic pieces, or tesserae, directly onto the base (which could be wood, stone, concrete, ceramic etc), grouting the completed piece and that, more or less, is that. Alternatively, you can apply the pieces onto fibre glass mesh as I did for the mosaic floor which means the finished work is light and transportable and also bendable so that it can be applied to rounded surfaces. The mosaic on mesh is fixed to its final substrate using tile adhesive (indoor or outdoor as appropriate) and grouted on site.
The indirect method is slightly more complicated. The tesserae are fixed upside down with water soluble glue onto brown paper. Once the mosaic is ready, there are two things you can do: 1. Put a frame around it, pour a concrete mixture into the mould and wrap the piece in plastic to make sure the concrete sets slowly, without cracking. When it is fully set and rock hard, you turn the mosaic over, dampen the brown paper, pull it off and, voila, the true face of the mosaic is revealed! OR 2. Pre-grout the back of the mosaic, and then it’s all ready to be placed wherever you like, much like a bathroom tile.
Why, one might ask, would you want to use the indirect method when the direct method seems infinitely easier and has the huge advantage of allowing you to see the mosaic as you work and it evolves?
The direct method
Think table tops, garden pots, kitchen trivets, mirrors – (almost) any surface can be mosaicked. Shop dummies, skulls, shoes…I’ve seen it all. Spain’s Antoni Gaudi was the king of the direct method:
But plenty of other people use it too:
And here’s a rather tame (or lame, as my children would say) flower pot by me:
The advantages of the direct method are:
- 1. You can see what’s going on as you make the piece.
- 2. You can correct mistakes as they occur because they will be apparent as you work, as long as you do it quickly before the glue has set.
- 3. You can go mad covering all sorts of surfaces and use an enormous range of materials from conventional tesserae such as glass and ceramic, to bottle tops, found objects, buttons and beads.
- 4. You can make direct method mosaics on mesh and transport them to whenever they are going to be installed which means they are lighter and easier to handle.
The indirect method.
The copy (above) of a detail from a Pompeii aquatic mosaic (in the Naples Museum) is made using the indirect method and so is this:
The disadvantages of this mosaic technique are hard to ignore:
- Placing the tesserae reverse side up means that you cant appraise your work as you progress. This shouldn’t, in theory, be a disadvantage but it’s hard, if you are working on a largish piece, to have a sense of how the mosaic is developing. There is nothing worse than spending days making a mosaic, casting it and then waiting several more days for it to cure, only to remove the backing material and find that there are things you’d like to change. However, this particular disadvantage only applies if you are using natural materials which have differently shaded sides.
- If you are using the mould method, the completed piece will be extremely heavy so transporting and hanging them is difficult.
- Faffing around making a mould to go around the mosaic to hold the concrete adds an extra layer of complication to the mosaic making process.
- Mixing concrete is not everyone’s cup of tea.
BUT there are a few very good reasons for choosing the indirect method which are:
- The completed mosaic will be entirely flat, so if you are using tesserae which are different depths and need a flat surface then this is the the method to use. Obviously, it’s perfect for floors.
- You can easily undo mistakes. The tesserae are stuck down using water soluble glue so all you have to do is wet the pieces and they will easily come off the backing material and can be reapplied once the backing has dried out.
- With the mould method, the completed work will be extremely solid and durable. You are essentially making a slab of concrete with a mosaic embedded in it, so as long as you make sure that you get the right mix of sand and concrete (not difficult) and that the cement dries slowly (be patient), it will set as hard as rock and be completely weatherproof.
- You can make mosaic ‘fragment’ pieces. This, in my view, is where the method really comes into its own.
Click here for a tutorial on how to make a mosaic fragment like the one above.