Use, Care, and Maintenance Guide

Unboxing

In your lap order you should receive a dressing stick and Lava Soap in addition to the lap purchased. The following guide will discuss general recommendations for use for those elements. Generally use of dressing sticks and lava soap on the laps are non-embedding, but keeping them separated per lap grit would be most conservative for preventing cross contamination.

Laps are shipped out freshly ground - and as such should be dressed with the included stick before first use. 

Dressing your laps

Dressing a sintered metal, hybrid, or resin bond lap uses a stick, typically loosely bonded aluminum oxide grains, to erode away the matrix supporting the embedded diamond until fresh, sharp grains are exposed. This will take a slow or dulled lap and bring it back to a fresh cutting condition.

 

 

With a high water flow, spin your lap in your preferred cutting direction approximately half your preferred cutting speed (half motor speed to start). Press the end of the dressing stick into the lap, sweeping from center out. Repeat until you feel the lap cutting the dressing stick freely, or approximately 3-6 times. 

Because the diamond in the laps, as it becomes exposed, will easily cut through the aluminum oxide, you will not damage you lap with a 'wrong grit' dressing stick, but the following is intended to be a rough recommendations for ideal pairings. Additional sticks are available for purchase on the site.

Dressing Stick (Grit)	Impulse Hybrid Lap Recommended Pairing (Grit)
Coarse (120)	150-250
Medium (260)	500
Fine (400)	1000+

 

Silicon carbide dressing sticks can be found through industrial suppliers and would be a more aggressive substitution for the recommended aluminum oxide dressing sticks. Cubic boron nitride or Norbide sticks are NOT recommended, and can quickly bring the surface out of true.

It's recommended to clean the lap after dressing, especially when cutting at higher grits or cutting materials softer than the dressing stick.

Cleaning your laps

Some materials like quartz are prone to fouling, and can clog up the exposed diamond preventing effective cutting before the working diamonds have dulled or pulled out.

Lava soap is recommended because the contained pumice acts to clear the lap. Simply turn on a flood of water and scrub the lap while spinning. 

During normal use, you will want to be cleaning your lap first upon signs of cutting action slowing down, before pulling out a dressing stick.

Cutting with your laps

These laps are intended to be used with a water drip. They should arrive flat and balanced and should have minimal flutter or vibrations even when at maximum speed for most faceting machines. Cutting at maximum vs minimum speed at a given grit may allow the laps to act slightly coarser or finer, so experiment with different cutting speeds and cutting pressure to find what works for you. A general recommended usage guide is as follows:

Impulse Hybrid Lap	Recommended Usage
150	Preforming, coarse cutting Ideal for ripping through large hard synthetics
250	Preforming, coarse cutting Ideal for slightly gentler but still cutting on larger natural rough where you want to trade speed for less subsurface damage
500	Primary cutting grit Fast and smooth cutting grit across a wide range of material harnesses. Sets up for a rapid pre-polish.
1000	Fine Cutting Transitionary grit, can cut softer stones fine enough to jump straight to polish, slower at moving material than the 500 grit. May cause orange peel on harder stones or stones with variable harness.
1500	Fine Cutting, Prepolish Fine grit, can act as prepolish on softer stones like quartzes and beryls.

 

Truing your laps

Throughout life all thick sintered (metal, hybrid and resin) laps will wear and need to be touched up to bring them back to perfect flatness. For Impulse Laps this can be anywhere from ~6 months to 2 years depending on use and wear pattern. This is called trueing a lap, removing material to bring the surface to a flat, minimal runout or flutter state. The laps are offered at significant initial thickness to allow for many repeated wear and truing cycles over time. Typically this removes a few thousands of an inch at a time and leaves the surface glazed or dulled, and dressing is recommended afterwards to open up the face and restore optimal cutting action.

The primary method for trueing sintered laps is flat lapping on a glass plate. This involves manually lapping with working surface on large flat glass sheet with loose ~80 grit silicon carbide power and water. Caution must be taken to lap evenly (consistently rotating under your hand pressure) as pushing the working surface out of parallel will introduce flutter into the cutting action. Impulse lapidary maintains the ability to factory recondition sintered (metal, hybrid, or resin) laps for a standard resurfacing fee if desired.