Bonstone Penetrating Epoxy RS (Rapid Set)

Product Overview

Bonstone Penetrating Epoxy RS is a two-component, very low viscosity, exterior grade, clear crack penetrating epoxy with rapid setting characteristics. It was developed for laminating and thin crack repair, where the shop needs the slab back in production the same day rather than the next.

Initial set is 1 to 2 hours at 75°F against 6 to 8 hours for standard Bonstone Penetrating Epoxy. It also cures harder and stronger: Shore D 88, 9,208 psi tensile, and 14,840 psi compressive. The tradeoff is a 12 minute pot life, so this is a mix small and work fast material.

Used on granite, marble, and quartzite for penetrating deep thin cracks, filling fissures, bonding stone to stone, and sealing and consolidating slabs. Per Bonstone product literature, the system provides a 40% increase in the strength of the stone.

This is the same product long sold as Touchstone Penetrating Epoxy RS. Bonstone is retiring the Touchstone name and moving the full line under Bonstone. There is no formulation change.

Key Product Details

Cured properties measured after seven days at 75°F.

Penetrating RS vs Standard Penetrating

Both are clear, exterior grade, very low viscosity penetrating epoxies that mix 2:1 by volume. Choose on set speed and how deep the resin needs to travel. RS turns the slab around in 1 to 2 hours and cures harder. Standard Penetrating is thinner at 250 cps and gives a 40 minute pot life, which helps on deep fissures and large slab work where you need travel time.

Use on Quartzite and Marble

Fissured quartzite and marble with soft veining often need to be stabilized before the slab can be cut, moved, and set. RS is the version to reach for when that has to happen inside a single shift. At 700 cps it still wicks into thin cracks, though standard Penetrating at 250 cps travels deeper if the fissure runs through the slab.

The stone has to be completely dry, dust free, and free of oil, grease, and coatings. That matters on quartzite in particular, since many slabs arrive resin treated from the quarry. Check the face before you commit to a repair, and call us if you are not sure what you are looking at.

Performance in Production

• 1 to 2 hour initial set at 75°F supports same day handling on laminations and thin crack repairs.
• 12 minute pot life at 75°F. Have the joint prepped, masked, and ready before you mix, and mix only the amount that can be used within 10 minutes.
• Cure speed roughly doubles for every 15°F increase. At 90°F set time is cut in half. At 60°F it doubles. Do not apply to a substrate below 55°F, and bring all material to 55°F or above before mixing.
• Higher cured hardness at Shore D 88 supports grinding and polishing back a lamination or repair.
• 4,128 psi shear on Academy Black granite gives a documented number on natural stone rather than adhesive-only test data.
• 0.21% water absorption over 24 hours supports the exterior grade rating and sealing use.
• Substrate must be completely dry and dust free, and free of oil, grease, and coatings.
• Do not stress the joint before the epoxy has fully cured.
• Uncured epoxy cleans from tools with toluene or xylene. Cured epoxy has to be removed mechanically.
• Can be tinted with Bonstone liquid tints when the repair needs to match the stone.

Common Applications

• Laminating stone edges and build-ups
• Thin crack repair in granite, marble, and quartzite
• Penetrating deep thin cracks in stone for high adhesive strength
• Filling fissures in stone
• Bonding stone to stone
• Sealing stone slabs
• Consolidating stone slabs
• Reinforcing slabs when used with scrim or fiberglass mesh
• Repair work where the slab has to move to the next station the same day

Kit Sizes and How to Choose

All kits ship Part A and Part B in the correct 2:1 volume proportion, so nothing has to be ordered separately. The 12 minute pot life is the thing to plan around on the larger kits. Draw what you need and mix at the bench, never at the pail, and keep batches to what can be used inside 10 minutes. Shelf life is approximately one year in unopened cans, so match the kit size to how fast the shop actually goes through it.

Special order item. Special order products cannot be canceled or returned. Call us for current lead time on your size.

Frequently Asked Questions

What is the difference between Bonstone Penetrating Epoxy and Penetrating RS?

RS is the rapid setting version. It sets in 1 to 2 hours at 75°F instead of 6 to 8, with a 12 minute pot life instead of 40, and it cures harder at Shore D 88 versus 78. Standard Penetrating is thinner at 250 cps versus 700 cps, so it travels deeper into a fissure and gives you more working time on a large slab. Pick RS when you need the slab back the same day. Pick standard when penetration depth matters more than speed.

How fast does Bonstone Penetrating Epoxy RS set?

Initial set is 1 to 2 hours at 75°F, with full cure within 24 hours. Set time is cut roughly in half at 90°F and roughly doubles at 60°F.

What is the pot life of Penetrating RS?

Twelve minutes at 75°F. Bonstone directs mixing only the amount that can be used within 10 minutes, so have the joint prepped and masked before you mix. A warmer shop shortens that window further.

Can Bonstone Penetrating Epoxy RS be used on quartzite?

Yes. Quartzite is a common use, since fissured quartzite often needs stabilizing before it can be cut and handled. The Bonstone data sheet describes use on stone generally, and the product is applied the same way on quartzite as on granite and marble. Confirm the slab is dry and free of any coating or quarry resin on the face before you start.

Is Bonstone Penetrating Epoxy RS the same as Touchstone Penetrating RS?

Yes, same product. Touchstone was the brand name Bonstone Materials used on this line since 1962 and it is being retired. There is no formulation change.

Why does my Part A say Bonstone and my Part B say Touchstone?

During the brand transition, Bonstone is using up existing Touchstone label stock rather than scrapping it. You may receive a kit with one component labeled Bonstone and the other labeled Touchstone, or both cans labeled Touchstone inside a box labeled Bonstone. Either way it is the same material at the same 2:1 ratio, and nothing about the formulation changed. If a kit looks mismatched and you want it confirmed before you mix, call us at (800) 220-1966.

What is the mix ratio for Penetrating RS?

Two parts Penetrating RS Part A to one part Penetrating RS Part B, by volume. Blend thoroughly and homogeneously for a proper cure.

Which kit size should I order?

The Quart Kit (3 qt total) fits thin crack repair and occasional laminating, and it matches a 12 minute pot life well. The Gallon Kit (3 gal total) fits shops laminating and repairing regularly. The Pail Kit (15 gal total) fits high volume shops. Shelf life is about one year unopened, so size to your actual usage rate.

Can Penetrating RS be tinted?

Yes. It can be tinted using Bonstone liquid tints.

Related Products

• Bonstone Penetrating Epoxy for deeper penetration and a 40 minute working window
• Bonstone Scrim Reinforcing Mesh, 3 ft x 150 ft Roll for slab and countertop reinforcement
• Bonstone liquid tints for color matching repairs

Questions on fit for a specific slab or repair, call (800) 220-1966 or email [email protected].