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KS4V -GR+ Castable-Refractory (quicker set)

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KS-4V+ GR is a moderate-strength, medium-density, easy-to-use fireclay-based durable castable refractory  rated to 2600° F.  Its versatility and cost make it an excellent choice for many applications.

This GR is a FASTER SETTING version of the standard KS-4V+.   The GR also has a finer base with fewer and smaller aggregate stones.

Both KS-4V castables are Very popular for Ribbon Burners, as it fills molds easier than some castables like Mizzou, and it has a fine grain structure making it suitable for burners and where detail is needed. 

KS4V GR, like KS4V reg, can be used for hand packing, or form filling, and the character can be adjusted with slight variations in water content to suit.

KS4V is our most popular PIZZA oven shell refractory.   The faster GR variant is suited well for molds, like floor bases.  molds and similar, and though the fine texture is nice for brick work, it should be used only in tiny batches for this work because it sets up quickly.

but if used for brick work  It works very well stabilizing bricks instead of mortar on domes.  Most of the refractory is quite a fine powder, with occasional small aggregate particles to about 3mm.  It is versatile, allowing 'dome' stacking of bricks, with one brick edge held close, and a 'wedge' of KS4V+ filling in the 'gap' of the brick's outside dome edge.  It is also suitable for casting domes or a thick parging exterior coat.  We also have refractory pins & speed clips which can be embedded in the dome to secure wool, wire mesh, and casting layers.

KS4V 's strength and abrasion resistance make it popular whenever a medium density easy to use refractory is needed.  

Note:  KS4V is a good option for pizza oven floor backings (if needed), but it is not rated for direct food contact. 

Our Pre-Krete G8 is rated for food & potable water contact and is used for pizza ovens.  Tips are coming soon or contact us.

The lower iron content instills better flux resistance than castables higher in Fe (Iron).


  • Water mix ratios are 12-20% typically depending on consistency needed.
  • Be sure to dry out very gradually to avoid micro steam fractures while curing.

 Sizes Available:

  • 2.5 lbs (in wide-mouth-jar)
  • 12 lbs (in 1-gallon-pail) 
  • 25 lbs (in 2-gallon-pail)
  • 25 lbs (in 5-gallon-pail for mixing space)
  • 50 lbs (in 5-gallon-pail) 


50 lbs in a 5-gallon pail has enough room left to conveniently use the same pail for mixing the KS4V GR+ with water if you are going to mix near full bag batches. 

If you want to mix smaller batches, we also sell 25 lbs in a 5 gallon pail, for ease of mixing.  Of course you can keep adding 1 or 2 gallons to this 5 gallon pail for mixing.

KS4V shipped in plastic pails minimizes damage in freight, and offers great versatility.  Scooping, re-sealing, dry storage, and transport is all easier and cleaner than product in bags.

Once cured, fireside KS 4V can be coated with ITC 100 HT to optimize heat retention & efficiency.

KS4V GR+ can be mixed with Reinforcing (304 SS) needles,  which behave like mini-re- bar fibers in any castable.  1 lb per 50/55 lbs offers maximal strength reinforcing, but quantity can be used to suit.

Note 1:  

Kast-o-lite 30 Li + (3000°F hand or form), Kast-O-Lite 30 LiG+ (3000°F very fine, fast-set), and RescoCast 8 (2800°F hand or form) are castables ~50% lighter than KS-4V +. It's a popular option when optimizing insulation value and lowering weight is more important than strength. 

Note 2: 

VersaGun ABR+ (3000°F ),  GreenKleen 60+ (3000°F)and GreenCast 94+ (3100°F) are all denser (poorer insulators) but offer strengths of over 10,000 psi.  They all have different qualities, setting times, hand cast / mold-able vs pour-able/self-leveling characteristics.

Note 3:

KS4V GR+ is also available in a slower setting standard KS-4V+ mix which contains slightly more aggregate stones. 

Note:  Contact us about Retarder Additives that can slow the setting time and increase your working time.

Click here for the KS-4V SDS (Safety), and here for the KS-4V Technical Data Sheet.

These application instructions for KS-4V are the same as for Mizzou+ refractory.

More photos coming soon.


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