Acrylic Duck Calls

Acrylic Duck Calls

Above is an other good example of the results that can be obtained with dry barrel tumbling using Hardwood Media and the Finishing Creams. The part directly out of the milling is on the left and the final result is on the right.

There are a number of other pictures with brief descriptions of the process used located at these links:

Polishing Molded Acrylic
Polishing Machined Acrylic
Polishing Colorless Acrylic
Acrylic Button Polishing
Acrylic Knife Handles

Wood Parts Tumbling vs Hand Sanding

Hand sanding wood parts can be a tedious and labor intensive process. The ability to smooth the surface, remove cutting marks and round edges on a large quantity of parts can same time and money.

The part pictured above needed to be sanded down prior to the application of a stain and coating. The part on the right shows the sharp edges and some flashing after the initial cutting of the part. A two step barrel tumbling  process was used to achieve the end result on the left.

Step 1 involved using a Hardwood Peg Media and relatively coarse White Aluminum Oxide Grit. This produced the edge rounding and major 'sanding' of the part.

Step 2 used a similar Peg Media along with a much finer grade of White Aluminum Oxide Grit to result in a smoother, sanded finish. If necessary, subsequent steps with even finer grades of Grit or a quick hand sanding to the final required surface finish can be used. Barrel tumbling the parts in this dry process can eliminate most if not all of the hand sanding often done.

Wood Parts Tumbling to Remove Flashing

Common practice to remove flashing and sand wooden parts is by hand. Sandpaper or sanding wheels can be used to effectively clean up parts one at a time. A more efficient process (especially for large quantities of parts) is to use barrel tumbling.

This picture shows a before (left) and after (right) of a walnut wood part with heavy flashing, excess material on the edges and a rough cut surface finish. This is probably an extreme example; however, a simple barrel tumbling process created the surface finish on the right.

This part was tumbled with Hardwood Media and a small amount of 120 Mesh White Aluminum Oxide overnight. The result is a smooth surface finish with rounded edges and no excess material.

Acrylic Polishing

Here is another good example of the polished finish that can be obtained on acrylic plastic using a barrel tumbling process only. The part on the left had been cut and machined to the general shape and size. The machining marks and square edges can be seen rather clearly - along with the dull surface finish.

A two-step dry barrel tumbling process was used to achieve the polished results on the right. Both steps used a Hardwood Media. The first step using Shynolyte Pre-Polishing Cream provided the edge rounding and a smooth (but matte) surface finish. The second step using Microlyte Polishing Cream brought out the bright shine and gloss of the plastic. Each step was about 24 hours and the results certainly speak for themselves.

Fired Clay Parts Tumbling

Common sense would state that using a barrel tumbler for fragile fired clay parts would be inadvisable. The aggressive tumbling action would damage or crush the parts. This logic might follow for brittle parts such as ceramic tile and the like.

In fact, tumbling all types of fragile and brittle parts can be accomplished quite successfully in a barrel tumbler. The part in the picture above is a molded and fired clay pendant that is only about 1/8" thick. The project required that the excess material on the edges be removed and that the edges are heavily rounded.

In this case, a wet process would have involved undesirable absorption of water into the pendant. A dry tumbling process was used to achieve the stated goals. The parts were tumbled with Hardwood Media and White Aluminum Oxide for less than 2 hours to achieve the edge rounding as seen in the part on the right. As long as the proper ratio of media to parts (about 4:1 in this case) is maintained, damage the parts will be insignificant and batches as large the barrel will allow can be done.

Wood Deflashing

Before

This saw-cut wood part (before) has sharp edges and flashing that need to be removed prior to staining and sealing the wood. The traditional process would involve hand sanding with progressively finer sand paper. Given the round shape of the part and the requirement to sand the interior areas, a sanding wheel process is not feasible.

After

This finished part (after) has been barrel tumbled for 8 hours with Hardwood Media and Aluminum Oxide Grit. Since the part has some 'closed', internal areas that need to be sanded, the Hardwood Media is ideal to get into those areas and provide a much larger surface area for surface finishing. The grit acts as the sanding medium to quickly and efficiently removes sharp edges and result in a smooth surface.

If a very smooth surface is required, a couple of steps with finer and finer Grit will perform similarly to hand sanding with finer grades of sandpaper - without the hand work required.

Dry Tumbling Plastic

Tumbling nylon plastic parts to produce a polished finish can be difficult since the tumbling process itself often leads to small scratching, etching and inconsistencies on the surface.

Before

The picture above shows a part that was deflashed using a vibratory tumbling process. While the edges are clean and rounded, the surface finish shows the matte, tumbled finish typical of many abrasive tumbling media. The customer's desired result is a smooth, uniform surface finish.

After

This 'after' picture is the result after (dry process) vibratory tumbling for only two hours with Hardwood Media and Hi-Glos Final Cream. A dry tumbling process with a very mild abrasive cream will simulate a buffing wheel which is often impossible to use with many odd-shaped parts. While a wet process with a polishing media will also produce good results, on soft substrates a 'light' tumble can often generate a very high polish.

Finishing Aluminum Parts

Deburred
Deburring and polishing aluminum is almost always a multi-step process. The aluminum part pictured above was deburred using an aggressive Ceramic Media in order to achieve a heavily rounded edge. Using an aggressive media, of course, makes the polishing process much more difficult since the surface finish after deburring will be a rough, matte finish.

Polished

After tumbling with a Precision Ceramic Media (2nd picture above), the surface finish is much smoother and brighter. While this would certainly not be considered a mirror finish - which is extremely difficult to achieve on aluminum with a tumbling process alone - the part is ready to be painted or anodized to produce a beautiful result. In addition, the part can be further burnished using a dry tumbling process with a media such as Walnut Shell Grit, Corn Cob Grit or even a Hardwood Media and a polishing cream.

Fiberglass Deflashing - Alternative

Removing the flash off various types of molded parts (see last post) can be done in a wet or try process. Vibratory tumbling with a Plastic or Ceramic media in a wet process can be a quick and easy method to achieve the desired results. After the deflashing step, the parts will generally need to be rinsed and dried.

A traditional dry tumbling process involves the use of Hardwood media that have been treated with an appropriate cream compound. The selection of this compound depends on the needed aggressiveness and required surface finish. The challenge with these compounds isthat sometimes the cream can transfer from the media and become deposited in holes, slots or corners of the part. This then requires cleaning prior to further processing of the part.

An alternative to using creams is a similar previously described process for dry tumbling of wood parts. Depending on the type of part and the amount of flashing that needs to be removed, simply tumbling the parts with Hardwood media and an abrasive grit such as White Aluminum Oxide will provide excellent results with only a light dust on the parts. Because the abrasive material is not 'attached' to the media, a barrel tumbler is typically a much better process than vibratory tumbling.

Deflashing Fiberglass

Heavy flashing on edges

This molded fiberglass part has heavy flashing on the edges that needs to be removed more efficiently than a hand sanding or scraping operation. In addition, a dry process is preferred (in this situation) so the customer does not need to take the extra step of drying the part prior to further processing.

No flashing after vibratory tumbling

A dry tumbling process using Hardwood Peg Media and Dry Abrasive Cream successfully removed the flashing and produced a smooth, rounded edge. In this type of process, the compound is 'coated' to the Pegs and tumbles against the part to abrade away the flashing. If necessary (but not required in this situation), different dry tumbling compounds can be used to polish the part or even produce a high gloss finish.