This invention relates to the field of epoxy coating and more particularly to a system and method for epoxy coating cylindrical items.
Epoxy coatings are useful for both protective and decorative purposes. Epoxy creates a tough and chemical-resistant surface, while strengthening the underlying structure. In the hands of an artist, the coating can also be attractive with a mix of color and patterns.
But to create artistic coatings, the epoxy must be applied in a layer thicker than a film, creating the problem of movement. Epoxy is self-leveling, which is a benefit when applied to flat surfaces. But when applied to a sloped or rounded object, the epoxy runs off the surface. Thus, round articles cannot be coated in the protective and artistic way that flat surfaces can.
What is needed is a system and method for coating round objects with epoxy.
An epoxy coating can be applied to a round surface by keeping the round surface in constant motion, thus defeating the tendency of the epoxy to run off the outer surface of the round object.
The process is aided by mechanical equipment that rotates the cylindrical object or item about its center, along an axis, while also permitting adjustment of rotational speed.
An explanation of epoxy is helpful.
Epoxy is the result of a mix of resin and hardener in a specific ratio. The ration varies by manufacturer. For example, Uvpoxy by EcoPoxy uses a ratio of 1:1. Epoxy from Total Boat Resin uses a ratio of 2:1. Total Boat also has the option of Fast, Medium, and Slow hardeners which may cause a user to choose it as the preferred epoxy.
Once mixed, a chemical reaction begins and the mixture begins to stiffen. Thus, timing and order of operations are each important.
The process is summarized as:
When the mixture changes from a liquid to a gel, it can no longer be manipulated, thus working time ends.
Sample times are included in the following table. “TB” is an abbreviation for the manufacturer Total Boat:
Next, discussion turns to the mechanical components that allow a user to execute the method.
The primary component is a motor with optional gearbox that rotates an axle, the axle in turn rotating an internal support that interfaces with the cylindrical object. The motor optionally includes variable speed and reversible direction. As a further option, the motor may use a controller to automatically reverse the direction of rotation following a certain number of rotations. For example, five rotations clockwise, then five rotations counter-clockwise, then five rotations clockwise, and so forth.
The motor and gearbox must generate sufficient torque to rotate an out-of-balance object because during application of the epoxy mixture sections of the cylindrical object will have excess epoxy. This excess epoxy will weigh down the associated section, thus resisting rotation. The motor and gearbox must overcome this opposing torque to maintain rotational speed. Insufficient torque will result in surging, or inconsistent rotational speed.
The axle is supported on each end by bearings or blocks. The axle defines the axis of rotation.
Optionally, additional axles are used to rotate additional objects. This allows the user to coat multiple objects in a similar manner, thus creating matching items.
The internal support, bridging the space between the axle and the cylindrical object, can take multiple forms.
A first form is an inflatable bladder. The inflatable bladder is inflated using air passed through a hollow axle, exiting the axle into the center of the bladder.
Inflation of the bladder presses the outer surface of the bladder against the inner surface of the cylindrical article, creating a mechanical connection.
A second form of internal support is expanding arms. The arms are rotationally fixed with respect to the axle, with feet that can move outward to press against the interior surface of the cylindrical article.
A third form of internal support is a spoked wheel, or other type of disk. This support is most useful for objects that have a narrow band of internal surface, and thus are difficult to hold with the methods described above. For example, a ring of material.
A fourth form of support is an external support, used for solid objects such as drumsticks. The drumstick is inserted into a chuck, which grips a section of its outer surface using a foam or other deformable material.
A fifth form of support is similar to that used for a wood-working lathe, with an adjustable chuck at one end and pointed axle/tail-stock at the opposing end.
Using the above mechanism, the process is as follows:
First, the cylindrical object is mounted in place using a support affixed to the axle.
Next, the cylindrical object is optionally coated with a tinted quick-dry resin to prepare the surface. The use of a quick-dry resin is most critical for porous surfaces.
The quick-dry resin is preferably an epoxy with a fast-set time to reduce the opportunity for the introduction of air bubbles. Application may be by brush or spray.
Once dry, the quick-dry resin is sanded to even out any raised grain that may have been created by absorption of the quick-dry resin.
Next, an optional background coat is applied. Note that this is the first layer of material, and thus the lowest layer of the final product. The background may include the addition of particulates, such as glitter.
Next, epoxy application then begins.
For each layer, the user chooses between a fast or slow setting epoxy.
Fast-setting epoxies are preferred for elements of the image that are smaller or defined by a single color. For example, a beach or a sky. The faster set is preferred to minimize mixing with subsequent layers and reduce the wait time for application of subsequent layers.
Slow-setting epoxies are preferred for broad scenes that may use multiple epoxies that are mixed during and after application. The slower setting time allows the user greater flexibility to manipulate the epoxy. Slow-setting epoxy is also preferred if a thinning color additive is used because some additives will thin the epoxy mixture and increase the set time, but others will thicken and decrease the set time. A slow-setting epoxy is more tolerant of these changes because the slower set time allows heat to leave the epoxy mixture gradually, no matter how the tint affects the behavior of the epoxy.
Having chosen the desired epoxy, the user mixes the resin and hardener. The user optionally mixes in solids, such as glitter, golf leaf, pearl, or powders. The user may also optionally mix in liquids, such as alcohol-based tints, or paint.
Next, rotation is started of the cylindrical object.
The user then begins to apply the epoxy mixture. The epoxy mixture is poured onto the rotation surface of the cylindrical object, where it is then manipulated.
Manipulation can take the form of direct contact from a finger, brush, or stick, or indirect contact using hot air—which thins the epoxy—or air from a compressor or blown through a straw.
Manipulation can continue until the epoxy sets, at which time it is too thick to be readily manipulated.
The user can then begin preparation of the next layer, repeating the steps of choosing an epoxy, mixing, and applying while the underlying layer continues to harden until fully cured.
When the user has completed application of epoxy, the cylindrical object is allowed to continue to rotate until fully set, although not yet dry. This step is estimated to require between six and eight hours.
After the underlying epoxy is dry, a protective coating of clear epoxy is applied. The protective coating is applied using a notched trowel to ensure the correct thickness. If too little is applied, crater or depressions will form. If too much is applied, ridges and bulges will form.
This protective layer is then allowed to dry.
Epoxy creates heat during the chemical process of curing. To take advantage of this property, a temperature sensor is optionally used to monitor the temperature of the curing epoxy. When a low temperature is detected, rotation is stopped.
The benefit of epoxy application is not only artistic, but also mechanical. For example, when drums, such as those used for music, receive an epoxy coating the result is a drum with increased resonance and a decreased delay between a hit and the drum reaching its final pitch.
Coated drum sticks are softer and more-comfortable to grip than uncoated sticks. Additionally, as a user holds the drum sticks, the body heat of the user warms the epoxy coating, making it tacky and more easily gripped by the user.
Discussion now turns to a detailed description of an embodiment.
The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:
Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures.
Referring to
The epoxy coating apparatus 1 is shown before any epoxy has been added.
The rotation apparatus 10 includes axle 12, the free end of which rotates on, or within, a block 14.
The opposite end of the axle 12 connects to the motor 18 with optional rotational speed and direction controls 20.
A cylindrical item 30 is held using an internal support 36 that bridges the distance between the axle 12 and the cylindrical item 30.
Referring to
User one 130 is applying epoxy mixture 100 by pouring from an epoxy container 102. User two 132 is using a notched trowel 104 to spread the epoxy mixture 100 while maintaining a constant thickness.
On a flat, horizontal surface, the epoxy resin can be allowed to sit and self-level, creating an even thickness. But on the rotating surface of the cylindrical object 32, a notched trowel helps to ensure even application.
Referring to
User one 130 and user two 132 are removing any lines left by the notched trowel 104 (See
Referring to
A new section of epoxy mixture 100 is being applied in a different section of the cylindrical item 30.
Referring to
User one 130 is using a brush 106 to add on isolated items, such as images of clouds. User two 132 is using a notched trowel 104 to even out the section of epoxy mixture 100 applied in the previous step.
Referring to
User one 130 is using a straw 108 to blow across the epoxy mixture 100, spreading and creating effects.
Referring to
User one 130 and user two 132 are each applying epoxy mixture 100 using an epoxy container 102
Referring to
User one 130 is blending the two epoxy resins 100 applied in the previous step, using gloves 110.
Referring to
User one 130 and user two 132 are applying small amounts of epoxy mixture 100 using sticks 112.
Referring to
User one 130 is applying final touches using a brush 106.
The cylindrical item 30 is then allowed to rotate until the epoxy resin has fully set.
Referring to
Application of layers of epoxy resin is a progressive process, in particular for layer that the user does not want to mix. For example, a lower layer of dark epoxy and an upper layer of lighter epoxy resin that, if mixed, would lose their contrast.
The application of layer 1, the first and lowest layer, starts with the layer 1 epoxy mixing interval 160.
Then begins the layer 1 epoxy setting interval 162, during which the epoxy resin is in liquid form and ready to apply and be manipulated. This interval ends when the epoxy has cured to stage where the epoxy is too thick to manipulate.
The epoxy is then allowed to partially cure during the layer 1 epoxy curing interval 164.
With layer 1 partially cured, a second layer can be mixed and applied. Thus, layer 2 passes through the layer 2 epoxy mixing interval 170, layer 2 epoxy setting interval 172, and layer 2 epoxy curing interval 174.
Then, with layer 2 partially cured, layer 3 passes through the layer 3 epoxy mixing interval 180, layer 3 epoxy setting interval 182, and layer 3 epoxy curing interval 184.
Referring to
The cylindrical item 30 rotates 140 during application of the epoxy mixture 100. An appropriate speed of rotation is important to ensure the epoxy mixture 100 dries evenly, but also is not ejected off the surface of the cylindrical item 30.
If the speed is an excessive rotation speed 148, a wet epoxy mixture 100 will be ejected off the outer surface 32 of the cylindrical item 30.
The working range rotation speed 146 of between two and four RPM (Revolutions Per Minute) is the ideal range for an epoxy mixture 100 during application. The speed is then increased to between five and ten RPM for between one and four minutes to allow the epoxy mixture 100 to level without falling off the cylindrical item 30.
When the epoxy mixture 100 has moved from the setting interval 162 to the curing interval 164 (see
Rotation 140 must be maintained at a high enough speed to ensure consistent thickness of the epoxy mixture 100. If the rotation speed drops to an insufficient rotation speed 142, a wet epoxy mixture 100 will fall off the surface, and a partially cured resin will cure in inconsistent thickness.
Referring to
The rotation apparatus 10 is shown with bladder 40. The bladder 40 includes an end surface 42, a perimeter surface 44, connected by a transition 46.
An air valve 48 is used to inflate the bladder 40. Air is preferably provided to the air valve 48 through a drive shaft with internal air passage 50.
A bladder coupler 52 connects the air valve 48 to the bladder 40.
Also shown is a location for secondary item rotation 80, shown with a drumstick 82 inserted into a chuck 84. By rotating two items together, epoxy mixture 100 may be mixed and applied to the items simultaneously, ensure that the items match each other.
The secondary item rotation 80 and drive axle 24 are connected by pulleys 26 and belts 28.
A motor 18 with optional gearbox 22 rotates the drive axle 24.
Referring to
A cylindrical item 30 is mounted on bladder 40. Again shown are air valve 48, drive shaft with internal air passage 50, and bladder coupler 52.
Referring to
The adjustable legs 60 include primary hinges 62 between the primary arms 64 and the primary sliding coupling 66 that moves along the drive axle 24.
Each primary arm 64 ends in a foot 68 connected by a foot hinge 67.
Secondary hinges 70 connect each secondary sliding coupling 72 with its connecting arm 74. Tertiary hinges 76 connect each connecting arm 74 with the fixed coupling 78, which is set in position on the drive axle 24.
The movement of primary sliding coupling 66 along the drive axle 24 moves the feet 68 toward and away from the drive axle 24, allowing the adjustable legs 60 to grip the inner surface 34 of cylindrical items 30 of differing sizes.
Referring to
The motor 18 and gearbox 22 are shown connected to the drive axle 24, which is in turn connected with pulleys 26 and belts 28 to locations of secondary item rotation 80, which are supported by bearings 16. Shown here as secondary items are drumsticks 82 inserted into chucks 84.
Referring to
When the cylindrical item 30 is shallow, it may be affixed to a support arms 90 held using spoked support 92.
Referring to
The uncoated drum 200 is a traditional vinyl-wrapped drum. Below the uncoated drum 200 is a decibel chart of the sound produced when the drum is struck. The drum is struck at moment 210, with the sound that follows being the drum head and shell resonating.
The coating drum 202 is the same drum, but with the vinyl wrap removed and the epoxy coating applied as described herein. The drum is struck at moment 210. The resonance shown in the chart indicates a truer and stronger note and tone. This effect occurs because the epoxy coating reduces the tendency of the plywood shell of the drum to vibrate, instead increasing the resonance between the upper and lower head of the drum. The result is a stronger, truer, deeper and longer-lasting note that is noticeable to the ear.
Referring to
Coating drums 202 and drumsticks 82 are shown.
Referring to
The artistry associated with the use of the disclosed method is evident.
While the beauty of the resulting item will vary depending on the skill of the user, the protective quality is consistent.
Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.
It is believed that the system and method as described and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.
This application is a continuation-in-part of U.S. Pat. App. Ser. No 62/715,880, filed Aug. 8, 2018, titled Method And Apparatus To Finish Cylindrical Articles.
Number | Date | Country | |
---|---|---|---|
62715880 | Aug 2018 | US |