Temperature/Dry/Cure

Fabrication of XS Backer should be inside a shop. Casting should take place when shop temperature and all materials are maintained between 50°F (10°C) and 90°F (32°C) throughout all fabrication and curing.

Product will dry and cure slower at cool temperatures and conversely, faster at warm temperatures. Full cure is reached at approximately 30 days, like concrete. Although rare, at high altitudes and dry climates, some pieces may require covering with plastic to slow the cure and avoid curling.

Mixing

Single Bag Batches

1. Utilize a handheld concrete mixer with a helical (spiral) mixer blade, such as an Collomix Xo-55 Dual Shaft Mixer or similar.
2. Thoroughly mix XS Precast Modifier.
3. Add 1 gal (3.8 L) XS Precast Modifier to a clean 5 gal (18.9 L) pail or similar mixing vessel.
4. Add Color Packs to XS Precast Modifier (if desired) and mix.
5. While mixing add approximately ¾ of the XS Backer Mix bag.
6. Continue mixing until all dry powder is incorporated.
7. Scrape sides of pail with margin trowel to prevent dry pockets from forming.
8. Add 16 oz (0.5 L) water, mix into a looser consistency.
9. Add remaining XS Backer and continue to mix for 2 – 3 minutes.
10. Up to an additional 24 oz (0.7 L) water may be added for a more fluid mix.

Application

XS Backer is designed to cover both vertical and horizontal surfaces via spraying for mass production and hand packing for smaller projects. To achieve ultimate bond, it is best to apply XS Backer when XS Face or XS Precast is still damp to the touch or within 6 hours of their placement. After placing XS Backer, the sample must be a minimum of ¾” total thickness. For pieces requiring excessive loading, further strength may be achieved through the addition of basalt rods and / or fiberglass scrim.

Demold

In warm weather 4-6 hours after placing XS Backer, it may be appropriate to de-mold. Cool temperature or pieces with extreme texture will require overnight drying. XS Backer should not be left in the mold past a 24 hour period, as curling of the piece is likely. A freshly de-molded sample should be handled similar to granite or natural stone, and should be well supported above the work surface to allow the free flow of air around the piece.

Cleaning

XS Backer is not a stand-alone product, and is always used in conjunction with XS Precast or XS Face.

For specific directions on SCR refer to its TDS.

Slurry

XS Backer is not a stand-alone product, and is always used in conjunction with XS Precast or XS Face. For addressing pinholes and voids refer to the TDS of XS Slurry.

Grind/Polish

XS Backer may be ground with 50 grit diamond pad. XS Backer is not a stand-alone product, and is always used in conjunction with XS Precast or XS Face.

For specific directions on polishing refer to the appropriate TDS.

Staining

XS Backer is not a stand-alone product, and is always used in conjunction with XS Precast or XS Face.

For specific directions on staining refer to the TDS of Eco-Stain.

Sealing

XS Backer is not a stand-alone product, and is always used in conjunction with XS Precast or XS Face.

For specific directions on sealing refer to the appropriate TDS.

Seaming/Adhesion

100% silicone caulk provides an excellent seaming and adhesive fastening material, as it allows for movement of the precast piece. XS Backer like any other concrete will undergo slight dimensional variations based upon its environment (e.g. shrinkage or expansion).

Do not use caulking or adhesive that could “bleed” through the finished surface, such as petroleum based products. Large pieces and under-mount sinks will require mechanical fastening.

Suitability Sample

Always prepare an adequate number of test samples for suitability for products’ intended use.

Clean Up

Before XS Backer dries; spills and tools can be cleaned up with water.

Disposal

Contact your local government household hazardous waste coordinator for information on disposal of unused product.