APPARATUS FOR ABRASIVE SURFACE TREATMENT

Abstract

An apparatus for treatment of a surface has a holding tank configured to mix pressurized gas from the source with an abrasive glass powder, wherein the powder has a mean particulate size of 210 microns or less. A regulator in fluid communication with the holding tank is configured to reduce output pressure from the holding tank to 20 psi or lower. A nozzle is in fluid connection with the holding tank output, the nozzle having a shutoff valve, a feeder tube fitted to the valve and formed of a polymer material, and a hardened metal insert fitted into an end of the feeder tube and having an orifice that is configured to direct the compressed gas and abrasive glass powder to the surface.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional application Ser. No. 63/324,786, provisionally filed on Mar. 29, 2022 entitled “APPARATUS FOR ABRASIVE SURFACE TREATMENT” in the name of David Ogle, incorporated herein in its entirety.

FIELD OF THE INVENTION

This disclosure generally relates to apparatus for abrasive removal of surface finishes and more particularly relates to apparatus and methods for surface treatment using low pressure abrasion with a dry, chemically inert abrasive.

BACKGROUND OF THE INVENTION

Stripping of finishes from the surface of wood and other materials is a familiar task to those who refinish and refurbish furniture and household items. Conventional solutions to this problem have included the use of toxic solvents and other chemicals, applied to the coated item by painting or spraying or, in some cases, by immersion, followed by painstaking scraping and probing with various types of hand tools.

More recently, the surface stripping problem has been addressed using caustic abrasives such as soda, mixed with water and blasted against the surface at high pressures. While this method has proved successful for removing finishes on metal, its use for wooden surfaces is highly unsatisfactory. Following blasting, for example, the caustic chemical must be fully removed from the wood surface, or at least neutralized, to prevent ongoing damage. The application of water causes the wood to expand and can easily damage the surface, so that subsequent refinishing is compromised and subject to undesirable chemical reactions, even where the surface has been thoroughly cleaned.

The high pressures used, as well as use of chemical agents, and related side-effects of high pressure blasting with caustic substances, can make conventional solutions unacceptable for renovation of delicate wood veneers having highly intricate carvings, typical of many antique furniture and structures. Moreover, abrasive blasting must be done under carefully controlled conditions, due to dust and other hazards of high-pressure abrasive delivery and complicated by environmental measures needed to dispose of the spent abrasive chemicals. Antique surfaces such as those that can be found in built-in fireplaces and mantles, kitchen cabinetry, and other structures, must often be physically removed and treated outdoors or processed in a separate facility, risking damage to antique woodwork that can be irreplaceable and, in some cases, is considered priceless.

Thus, there is a need for surface treatment apparatus and methods that can remove surface finishes without damage, even allowing in situ stripping and refinishing for delicate antique woodwork.

SUMMARY OF THE INVENTION

It is an object of the present disclosure to advance the art of surface treatment, particularly for surfaces of wood and other delicate materials.

It is a feature of the present disclosure that it provides a solution to the surface removal problem that is nontoxic, works at relatively low pressures, and leaves no chemical or caustic residue that would obstruct subsequent refinishing processes. In particular, the nozzle that is used for application of the surface removal apparatus has simple construction and can be readily formed using additive or “3D printing” fabrication techniques.

These and other aspects, objects, features and advantages of the present disclosure will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and any appended claims, and by reference to the accompanying drawings.

According to an aspect of the present disclosure, there is provided an apparatus for treatment of a surface comprising:

• • (a) a source of gas pressure;
  • (b) a holding tank configured to mix pressurized gas from the source with an abrasive glass powder, wherein the powder has a mean particulate size of 210 microns or less;
  • (c) a regulator in fluid communication with the holding tank and configured to reduce output pressure from the holding tank to 20 psi or lower; and
  • (d) a nozzle that is in fluid connection with the holding tank output, the nozzle having:
    • (i) a shutoff valve;
    • (ii) a feeder tube fitted to the valve and formed of a polymer material;
    • (iii) a hardened metal insert fitted into an end of the feeder tube and having an orifice that is configured to direct the compressed gas and abrasive glass powder to the surface.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter of the present disclosure, it is believed that the invention will be better understood from the following description when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of a surface treatment apparatus according to an embodiment.

FIG. 2 is a schematic diagram showing a holding tank used with the surface treatment apparatus.

FIG. 3 shows a perspective view of a valve and a nozzle assembly used with the surface treatment apparatus.

FIG. 4 shows views of a shutoff valve for the nozzle assembly.

FIG. 5 shows a cross-sectional view of a stepped nozzle assembly.

FIG. 6 shows different views of a nozzle insert.

FIG. 7 shows views of a nozzle insert according to an alternate embodiment.

FIG. 8 shows a cross-section view of a nozzle insert within the nozzle according to an alternate environment.

FIG. 9 is a schematic diagram that shows features of an insert for a nozzle in an in situ stripping apparatus.

FIG. 10 is a schematic diagram showing an insert for abrasive stripping according to an embodiment.

FIG. 11 is a schematic diagram that shows an insert in a nozzle for an alternate embodiment for a handheld abrasive stripping apparatus.

FIG. 12 is a schematic side view that shows the nozzle coupled with a transparent hood.

FIG. 13 is a schematic diagram that shows an abrasive surface treatment apparatus having a particulate recovery system.

FIG. 14 shows a hand-held abrasive surface treatment apparatus using a battery power source and external compressed gas source.

FIG. 15 shows a hand-held abrasive surface treatment apparatus using a battery power source and internal compressor.

FIG. 16 shows a hand-held abrasive surface treatment apparatus using a battery power source and internal compressor with a transparent hood.

DETAILED DESCRIPTION OF THE INVENTION

The present description is directed in particular to elements forming part of, or cooperating more directly with, apparatus in accordance with the invention. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art.

Where they are used, the terms “first”, “second”, and so on, do not necessarily denote any ordinal, sequential, or priority relation, but are simply used to more clearly distinguish one element or set of elements from another, unless specified otherwise.

As used herein, the term “energizable” relates to a device or set of components that perform an indicated function upon receiving power and, optionally, upon receiving an enabling signal.

The term “actuable” has its conventional meaning, relating to a device or component that is capable of effecting an action in response to a stimulus, such as in response to an electrical signal, for example.

The term “fluid” in the context of the present disclosure has its meaning in physics, relating to a substance that is capable of flow, and more particularly to an aggregate comprising air or other gas mixed with a particulate material, wherein the particulate is fine enough in size and weight to be suspended within a gaseous medium, to allow controlled flow from a source to a target surface that is being treated. Two components can be considered to be “in fluid communication” when such a fluid can be controllably conveyed, such as under pressure or due to gravity, from one component to the other with negligible loss of fluid content. The phrases “fluid flow” and “gas flow” can be considered equivalent for the purposes of the present disclosure.

Adhesive particles are graded according to particle size, under various industry standards, such as those established by the Federation of European Producers of Abrasives (Paris, France), for example. Grit sizes are expressed as numbers that generally represent number of particles that can be fitted or distributed over a given area, often without any specified measurement units designated (e.g. 80 grit, 100 grit, 1200 grit, etc.) As with conventional sand-paper grades, for example, mesh size value is inversely related to abrasive particulate size. Thus, the higher the mesh (sieve) size value, the smaller the maximum particle size that can be sifted through the mesh. Abrasive powder is typically graded by average size, such that a distribution of particulate has at least 50% of the powder at or near the rated or nominal size, such as within +/−10% of the nominal mean particulate size for a given grit grade.

The apparatus and method of the Applicant address the need for an improved solution to the problem of surface treatment for removing finish treatments to various surfaces, particularly applicable to varnished wood surfaces such as those commonly found in antique furniture, built-in woodwork, and cabinetry. The Applicant's solution to the problem offers a number of advantages over previous attempts to address this problem, including:

• • (i) Non-toxic and chemically inert abrasive material;
  • (ii) Re-usable abrasive; and
  • (iii) Low-pressure delivery, relaxing requirements for nozzle design and safety of the overall delivery apparatus and permitting the use of materials and techniques that may not generally be considered suitable for high-pressure applications. The pressure supplied at the output of the Applicant's abrasive treatment system can lower than the air pressures commonly used in the conventional automobile tire, such as 20 psi or less, for example.

With appropriate nozzle and protective apparatus, the Applicant's solution can even allow in situ refinishing of varnished surfaces in some cases, obviating the need to disassemble highly ornate or old woodwork in order to provide re-surfacing treatment outside of a dwelling, for example.

System Description

The schematic diagram of FIG. 1 shows components of a surface treatment apparatus 10 according to an embodiment of the present disclosure. A compressor 12 or other source of compressed air or other inert gas provides the blasting energy for the system. A holding tank 20 that is in fluid communication with the compressed air source provides mixing of the compressed air with abrasive powder 24, a particulate that can be metered out to the holding tank 20 by a feeder 18.

Using the FIG. 1 arrangement, output pressure can be considerably reduced over the ranges used in conventional surface refinishing applications. In fact, the Applicant has found that, with the use of particular abrasives, lower pressures can be advantaged over conventional pressures used in the furniture-stripping arts for effective removal of surface finishes. A regulator 16 controls the air pressure level to constrain fluid pressure to the low levels used by the system. A hose 22 conveys the fluid mixture of abrasive powder 24 and regulated compressed air from holding tank 20 to a nozzle 30 for delivery onto the surface S being treated. An optional containment structure 40, shown in dashed lines, can provide a housing that constrains dust and airborne abrasive until it settles.

Abrasive Powder

The abrasive powder 24 used by apparatus 10 of FIG. 1 is a ground glass powder. Glass is chemically stable or inert, not reactive to most chemical substances under ordinary conditions of ambient light or heat. According to an embodiment of the present disclosure, an abrasive glass powder has a mesh size in the range from 70-100, alternately termed a sieve size, which can be expressed as an average powder size or “mean particulate size” of 210 microns or less, such as 160 or 100 microns or smaller.

The abrasive glass powder may be recycled glass; however, manufactured abrasive glass powder is typically not fabricated from recycled materials. One supplier of suitable abrasive is Strategic Materials, Inc., Houston, TX. A commercially available product of this supplier is 3-Mix-Processed Glass Abrasive, including a product named New Age Blast Media®.

Because the glass powder does not react with any known surface finishing material, it can be recycled easily for re-use. Spent abrasive powder can be swept or vacuumed from the floor and directly fed back into the holding tank, without requiring other treatment. Alternately, spent abrasive can be sifted through a sieve for cleaning before re-use.

Although it can present a dust hazard until the particulate settles, spent abrasive glass powder is chemically non-toxic and can be disposed of without requiring special treatment or handling.

Pressure Levels

The delivery pressure at nozzle 30 in the FIG. 1 apparatus is lower than conventional blasting pressures. Pressure can be as high as about 30 psi; however a pressure of 20 psi or less is preferred. At this low pressure, momentary exposure of skin to the abrasive blast mixture from the nozzle is unlikely to cause discomfort. However, gloves would typically be recommended, due to dust levels from the abrasive and residue from the particles of finish that have been removed.

Compressor 12 or other gas sources typically provide pressure in the 120-150 psi range. Regulator 16 then reduces this source pressure at the holding tank 20. The delivery pressure used at the output of the Applicant's surface treatment apparatus 10 is generally well below levels appropriate for trigger gun devices, which typically require a minimum of at least 70 or 80 psi.

By using the holding tank 20 and regulator 16 to control particulate delivery, the output pressure of the system can be well-controlled, kept to within levels well below those used for conventional refinishing. This can help to reduce waste and can offer benefits in reduced energy requirements.

Holding Tank

FIG. 2 shows a schematic of the holding tank 20 with associated components, according to an embodiment of the present disclosure. Holding tank 20 can have heavy duty construction and can typically be provided with heavy duty hoses for interconnection to compressor 12 and nozzle 30. A typical holding tank that can be used for a larger system is a Model SB10G 10 Gallon Abrasive Blaster from Buffalo Tools, Inc., capable of holding about 10 gallons of dry abrasive 24. A larger tank can be used, such as the Model SB20G 20 Gallon Abrasive Blaster or a 50-gallon tank from the same manufacturer. Input feeder mechanism 18 is provided, allowing funnel feeding of the abrasive 24 prior to application of pressure. Tank 20 can include a mixing valve 42. A pressure regulator 16 and pressure gauge 60 allow control of pressure within holding tank 20, constraining the pressure to within the low levels used in embodiments of the present disclosure. An additional in-line pressure reducer 64 can be used to reduce pressure of the compressed gas supply. A number of shutoff valves 66 can be provided for control of the supplied pressure. A water separator 68 can also be provided.

Hose

The delivery hose 22 can be plastic, nylon, or other type of material capable of handling the needed pressure levels.

Nozzle

Because the system controls and regulates internal air pressure, abrasive powder is ejected at relatively low pressures; there is no need for high-pressure trigger gun devices, such as those used for soda blasting and sand-blasting systems. Instead, the nozzle design for low-pressure delivery of inert abrasive glass powder can use mechanisms and materials that would be unsuitable for conventional surface-adhesive delivery equipment.

Referring to FIGS. 3-11, there are shown various views of the nozzle 30 according to an embodiment of the present disclosure. Nozzle 30 can have a rotary shutoff valve 32 and a feeder tube 36 with a metal insert 34. Because of the low pressures used, there is no requirement for so-called “deadman valves” to automatically shut off the flow if the user inadvertently loses grip on the handle. Valve 32 can be a quarter turn valve, for example. FIG. 3 shows the assembled nozzle 30 and shows valve 32 aligned with its seat in tubing key barrel, according to an embodiment of the present disclosure.

Nozzle 30 can be formed of plastic, nylon, or other type of synthetic material. According to an embodiment of the present disclosure, nozzle 30 is formed by additive manufacturing methods, using the type of fabrication commonly referred to as “3D printing”. Nozzle 30 can be formed from metal or from a variety of polymer materials, including nylon and other polyamides, plastic, and other synthetic materials.

FIGS. 4-7 show assembled and cutaway views of nozzle 30 with feeder tube 36 and its enclosed metal insert 34. As shown in FIG. 6, insert 34 has an orifice 38 that is sized with sufficient diameter to deliver the abrasive media in a continuous fluidic stream without clogging or jamming.

Insert 34 can be formed from a hardened metal component, of a metal material that is suited to handling abrasive flow without significant deterioration and wear to the orifice opening over time. Exemplary materials for insert 34 can include stainless steel, tungsten steel, and carbide steel, or other type of hardened steel for example. Orifice 38 size can be in the range from about 3/32 in. to 5/32 in. For example, a ⅛ in. orifice 38 can be suitable.

Hardened metal includes metals that are heat-treated following casting or initial forming to shape as a finished piece. Typical heat-treated steel can have a hardness in the range from 49-63 HRC (Rockwell scale), for example.

Insert 34 can be affixed within feeder tube 36 in a number of ways, including the use of adhesives or by press-fitting, heat-insertion, sonic welding, pressing, threading, and insert molding, for example.

Feeder tube 36 itself can be formed from a polymer. The Applicants have found that polymers such as ABS and various other types of plastics, nylon, and reinforced composite materials that include plastics and other polymers, such as fiberglass, are advantaged over metal components due to low thermal conductivity. The ability of polymer materials to absorb heat levels from the propelled abrasive materials under pressure allows the operator to operate the nozzle equipment without concern for heat protection. This permits the operator to wear light nylon gloves, nitrile or neoprene gloves, vinyl gloves, or protective gloves of other light, plastic material during blasting.

Conventional fittings, such as hose clamps, worm-gear clamps, and other low-pressure-compatible fittings can be used for fastening hose 22 to nozzle 30.

FIGS. 7 and 8 show different views of a nozzle insert 34 according to an alternate embodiment of the present disclosure. FIG. 11 shows a cross-sectional view of an alternate embodiment of a blasting nozzle. This shows a view of the tip of a feeder tube 36 that is tapered or otherwise formed to seat insert 34 in position for directing airborne abrasive under pressure. As shown at the right in FIG. 11, force exerted by gas pressure from the compressor or other source can be used to urge and seat insert 34 securely in place for providing the output gas/abrasive mixture to the surface.

Fixture for In Situ Stripping of Surface Finish

A variety of fixtures and attachments can be added to the basic surface treatment apparatus 10 shown in FIG. 1, including devices that allow the use of surface treatment apparatus 10 for in situ stripping applications. Typical applications of this type include stripping older varnished finish from a fireplace mantle or from ornately carved wood trim or built-in cabinetry. This application would require methods for suppressing dust and spent airborne abrasive particles resulting from the surface treatment.

The schematic diagram of FIG. 12 shows a transparent nozzle hood 50 that can be attached to surface treatment apparatus 10 for deflecting and removing at least some portion of dust caused by the abrasion in treatment of surface S. Hood 50 is apertured to allow insertion of nozzle 30 at either fixed or variable positions. Hood 50 can encircle orifice 38 or may only partially cover the area being treated. Making hood 50 transparent allows the user to view the abrasive treatment process and to make some adjustments to technique, based on progress. Hood 50 can be formed from a flexible polymer material, allowing the user some measure of adjustment of the incidence angle of the abrasive stream. According to an embodiment of the present disclosure, hood 50 is dimensioned to position orifice 38 at a suitable distance d from the surface S that is being treated; thus, hood 50 can define a working distance d between the orifice 38 and surface S. The user can have the option of adjusting the position of hood 50, thus manually adjusting distance d and the angle of the pressurized flow, so that nozzle 30 can be positioned at an appropriate distance d and at an appropriate incidence angle or tilt relative to surface S, such as is shown in FIG. 13. Adjusted positioning, set by adjusting the relative position of the hood 50 along nozzle 30 and the relative angle of the nozzle relative to a front lip 51 of hood 50, can be based on surface features or on the relative difficulty of treating a particular surface, for example. Hood 50 can be detachable, such as for replacement or cleaning, for example.

FIG. 13 is a schematic diagram that shows an abrasive surface treatment apparatus having a particulate recovery system. For the exemplary in situ surface treatment apparatus 80 shown schematically in FIGS. 12 and 13, vacuum port 52 provides connection to a vacuum hose 54 that provides a vacuum to direct dust and other particulate to a recovery tank 70 or filter apparatus, such as a Dust Deputy from Oneida Air Systems, for re-use or disposal.

FIGS. 14 and 15 show embodiments that provide a hand-held abrasive surface treatment apparatus using a battery power source and external compressed gas source. As the schematic diagram of FIG. 14 shows, a portable surface treatment apparatus 100 can provide more compact packaging for a handheld abrasive blaster according to an embodiment of the present disclosure. A compressed gas source 90 can be a tank of compressed air or other suitable gas or can be a separate compressor 12 as shown in the FIG. 14 embodiment. Compressed gas source 90 can be carried by the user, or can be highly portable, such as embodied by a compressor on wheels. Source 90 provides the compressed gas to holding tank 20, which can be built into the body of surface treatment apparatus 100, along with its regulator 16. A trigger 94 or other type of switch can be used to actuate pressure delivery through tank 20 and regulator 16 and to nozzle 30. A control logic circuit 96 can control various valves for providing the abrasive under pressure controlled from trigger 94. Control can be hard-wired or can be programmable, as needed. A power source 92 can be a portable power source, such as a removable or built-in rechargeable battery, or can use standard batteries or wired AC power.

The functions of holding tank 20 and compressed gas source 90 can be combined, such as by providing a pressurized holding tank, pressurized prior to use or fabricated and sold as a pressurized item.

According to an alternate embodiment, as shown in the schematic diagram of FIG. 15, compressed gas source 90 is a compressor 112 that is provided separately or within a housing 56 as an integral component of surface treatment apparatus 100, such as built into the handle or other part of the portable equipment housing 56. Compressor 112 can provide continuous air pressure when actuated or can provide a pulsed pressure, cyclically providing compressed gas at suitable levels within 10-30 psi. The output orifice of nozzle 30 can have a hardened insert 34 as described for the embodiment of FIG. 5.

A supply reservoir 114, within or coupled to housing 56, can be filled by the user prior to use of apparatus 100 and can be refilled as needed during the stripping process. Reservoir 114 is in fluid communication with compressor 112 and associated regulator 16 and other mixing components and tubing and can provide a gravity-fed abrasive treatment system. The regulator can be incorporated as part of compressor 112, if needed; alternately, compressor 112 may be rated to provide a suitable range of pressure levels without the need for a separate regulator component.

Portable surface treatment apparatus 100 can have an optional sensor 120 for sensing abrasive level in supply reservoir 114 and an optional indicator 122 that is energized to indicate a suitable supply level, above a predetermined threshold, or low supply level, below the threshold. For example, indicator 122 can flash on and off to indicate the need for replenishing the reservoir 114. An optional control 124 can be provided to allow adjustment of the output pressure, such as to adjust pressure for different materials being treated. Alternately, the effective nozzle 30 orifice opening can be adjusted, such as by rotating a control at the nozzle 30 output.

FIG. 16 shows a hand-held abrasive surface treatment apparatus using a battery power source and internal compressor with a transparent hood. Handheld embodiments such as those described with reference to FIGS. 14-16 allow the operator the advantages of low output pressures, relaxing requirements for protective gear, including high-performance gloves and ear protection, for example. When provided with integral power sources and self-contained compressors, a complete surface treatment apparatus 100 can be held in one hand, allowing ease of positioning for accessing and treating complex surface contours or for performing surface stripping treatment from a ladder, for example. A complete, handheld surface treatment apparatus 100 can weigh less than 12 pounds, for example.

Advantageously, the apparatus and method of the present disclosure can be used to remove surface finishes from highly ornate carved and veneer surfaces found on antique furniture, decorative trim and molding such as cornices, and household items. Because it operates using a dry abrasive that is chemically inert and nontoxic, the approach of the present disclosure is particularly suitable for treatment of wood as a preparatory step to subsequent refinishing. The method of the Applicants operates at low pressure levels, well below the air pressure needed within a standard automobile tire, alleviating concerns with use of compressed air equipment. The abrasive glass powder can be recycled numerous times and can be disposed of without concerns for environmental toxicity.

An apparatus for treatment of a surface has: a source of gas pressure; a holding tank configured to mix pressurized gas from the source with an abrasive glass powder, wherein the powder has a mean particulate size of 210 microns or less; a regulator in fluid communication with the holding tank and configured to reduce output pressure from the holding tank to 20 psi or lower; and a nozzle that is in fluid connection with the holding tank output. The nozzle has: (i) a shutoff valve or other valve type; (ii) a feeder tube fitted to the valve and formed of a polymer material; (iii) a hardened metal insert fitted into an end of the feeder tube and orificed to direct the compressed gas and abrasive glass powder to the surface. The apparatus can have a transparent hood with a vacuum attachment configured to remove spent abrasive powder from the surface. The output pressure can be further reduced, such as to no more than 17 psi.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention as described above, and as noted in the appended claims, by a person of ordinary skill in the art without departing from the scope of the invention.

Claims

1. An apparatus for treatment of a surface comprising:

(a) a source of gas pressure;

(b) a holding tank configured to mix pressurized gas from the source with an abrasive glass powder, wherein the powder has a mean particulate size of 210 microns or less;

(c) a regulator in fluid communication with the holding tank and configured to reduce output pressure from the holding tank to 20 psi or lower; and

(d) a nozzle that is in fluid connection with the holding tank output, the nozzle having: (i) a shutoff valve; (ii) a feeder tube fitted to the valve and formed of a polymer material; (iii) a hardened metal insert fitted into an end of the feeder tube and having an orifice that is configured to direct the compressed gas and abrasive glass powder to the surface.

2. The apparatus of claim 1 wherein the metal insert is maintained in position in the nozzle by output pressure.

3. The apparatus of claim 1 further comprising a transparent hood that fits over the end of the feeder tube, wherein the transparent hood defines a separation distance between the nozzle orifice and the treatment surface.

4. The apparatus of claim 3 wherein the transparent hood is further configured to adjust the separation distance and an incident angle of the compressed gas relative to the surface.

5. The apparatus of claim 3 wherein the transparent hood has a vacuum port for recovery of spent abrasive glass powder.

6. The apparatus of claim 1 wherein the abrasive glass powder has a mean particulate size of 100 microns or less.

7. The apparatus of claim 1 wherein the nozzle that seats the metal insert is formed from a polymer.

8. The apparatus of claim 1 wherein the nozzle is formed using additive manufacturing.

9. An apparatus for abrasive treatment of a surface comprising:

(a) a compressor that is energizable to generate and direct a pressurized gas flow through an output orifice at from 10 to 30 psi;

(b) a power source coupled to or provided within a housing, the power source configured to provide drive power to the compressor for actuating the gas flow, as controlled by an operator switch on the housing;

(c) a supply reservoir coupled to or provided within the housing, the reservoir in fluid communication with the gas flow and configured to supply an abrasive glass powder to the gas flow, wherein the powder has a mean particulate size of 210 microns or less;

and

(d) a transparent hood, formed of a flexible material and configured for coupling to the housing at a position that defines at least a working distance from the output orifice to the treatment surface.

10. The apparatus of claim 9 further comprising one or more indicators on the housing that indicate a low abrasive powder level.

11. The apparatus of claim 9 further comprising at least one operator-adjustable control for output pressure level, wherein the control is disposed on the housing.

12. The apparatus of claim 9 wherein the compressor is within the housing.

13. The apparatus of claim 9 wherein the powder has a mean particulate size of 100 microns or less.

14. The apparatus of claim 9 wherein the pressurized gas flow is pulsed.

15. The apparatus of claim 9 wherein the transparent hood position on the housing is adjustable by a user.

16. A handheld apparatus for abrasive treatment of a surface comprising:

(a) a housing that seats a refillable supply reservoir configured for storing and distributing an abrasive particulate, wherein the reservoir is in fluid communication with a nozzle on the housing, the nozzle having an output orifice that is treated for directing a pressurized fluid flow containing the particulate toward the surface, and wherein the housing further comprises a control switch for manual operation; and

(b) a compressor within the housing, wherein the compressor is energizable, according to the control switch position, to generate the pressurized fluid flow that exits through the output orifice at from 10 to 30 psi;

wherein the housing is configured to connect to a removable battery for providing drive power.

17. The apparatus of claim 16 wherein the nozzle is formed from a polymer.

18. The apparatus of claim 16 wherein the nozzle is formed using additive manufacturing.

19. The apparatus of claim 16 further comprising a transparent hood, formed of a flexible material and configured for coupling to the housing at a position that defines at least a working distance from the output orifice to the treatment surface.