Marvin Pipkin

Marvin Pipkin (November 18, 1889 – January 7, 1977) was an American chemist. During his time in the United States Army he worked on gas masks. In his civilian life he invented a process for frosting the inside of incandescent light bulbs to cut down on the sharp glare and diffuse the light. He went on to make many other inventions and innovative improvements to the light bulb.

Family
The fourth of six children, Pipkin was born November 18, 1889, just south of Lakeland, Florida in a community called Christina. His parents were Daniel M. Pipkin and Sarah Catherine (Moore) Pipkin. Daniel, his father, owned a citrus grove and was a farmer. He married to Kathryn Patricia Enright (1896–1957) on July 21, 1919; they had three daughters. He spoke with a pronounced southern accent.

Education
He attended Lakeland elementary school and graduated from Bartow High School in Bartow, Florida. One of his classmates noted that his chemical knowledge was more than all the rest in his class put together.

Pipkin's first job was at a prospecting firm, where he worked for a year. Following that, he worked for about a year at International Mineral and Chemical Corporation of Bartow, where he was surrounded by college-educated people.

Having decided that he had to attend college in order to expand his chemical ideas, he went to Alabama Polytechnic Institute (API), graduating with a degree in Chemical Engineering in 1913. He worked for a year in a fertilizer laboratory then returned to API, where he gained his master's degree in 1915.

Mid life
Pipkin enlisted in the Army in Jacksonville, Florida, in November 5, 1917.

Gas masks
Because the Germans were using lethal gas as a weapon during World War I, gas mask research for protection of the soldiers and public had a high priority. With his chemical background, Pipkin was posted to the Army's Gas Defense Department at General Electric's Nela Park in Cleveland. The principles embodied in Pipkin's gas mask innovations remained in use throughout the twentieth century. He was promoted to the "senior grade rank of Master Engineer".

Nela Park
He remained at Nela Park after the war, and worked in General Electric’s bulb development department.

Light bulb innovations
The public felt that the glare from clear transparent incandescent lamps gave off a harshness that was unwanted by most people. Another side effect was that they made it hard to see objects in immediate vicinity of the lamp. They desired a lamp that had a softer light with no glare. In 1920, General Electric developed a 30 watt light bulb that had outside etching as a frosting effect for the electric lamp. It effectively diffused the light to make it softer; however, it decreased the light produced by 15–25 percent. Another problem with the lamp was that fluorides came off in the sealing of the lamp and attacked the tungsten filament. External etching of the globe bulb weakened it. The rough outside surface collected dust and dirt and was difficult to clean. The globes of the bulb were brittle and would often break with just ordinary handling.

When Pipkin went to work for General Electric he was assigned the "impossible" task of finding a way to frost electric light bulbs on the inside without weakening the strength of the glass. Not being aware his assignment was a type of joke, he went about the task as if it was something that could be done and had been done before. In 1925, Pipkin produced an innovative acid etching process for the inside of the globe of an electric lamp so that it did not deteriorate the lamp glass globe. His was a two step acid process that etched the interior of glass with tiny crevasses on the first process as was the normal procedure done by other science engineers, but he added a second acid step that caused soft, rounded dimples from the crevasses which gave the bulbs added strength. There was minimal loss of diffusion of light with his innovation. It left the outside of the globe of the glass lamp smooth that did not hold dust like a rough surface one did. The first electric light bulb frosted on the inside with sufficient strength for ordinary handling that could be sold to the public was invented by Pipkin in 1925.

This idea of having a second treatment to smooth out the fine-grained texture to dimples came about by an accident. Pipkin would often clean out the experimental bulbs with another solution of the acid, but in a weaker solution. If he let the filled bulb set for a while with this weaker solution it would clean out the etching previously done and return the glass globe to be transparent again. This saved the bulbs so they wouldn't be thrown away and could be experimented with again. One day, while he was pouring the weaker solution into a bulb, the phone rang. In the process of answering the phone, he accidentally tipped the bulb over before it had enough time to finish cleaning out the previous etching. When he returned to his work, he accidentally knocked the glass bulb off the workbench and onto the floor. To his surprise it did not shatter, as etched bulbs normally did, but bounced a few times and then rolled under the workbench. Pipkin was surprised to find that the bulb glass had somehow become much stronger. As it turned out, a short bath in the weaker cleaning solution, taken out before it had a chance to remove the etching, caused the etching of the first frosting treatment to form dimples in the etching, that strengthened the glass.

Pipkin then did a demonstration of the bulbs' integrity to his supervisor at General Electric. He presented to his supervisor six light bulbs that had been frosted on the inside. Some had just the one application of acid and others with his reinforced second treatment innovation, strengthening the glass globe. He placed the bulbs on his supervisor’s desk, standing up on their screw bottoms. He tipped the first three over, one at a time, to simulate a bulb being dropped from a small height. These were the bulbs treated with original single acid application, and as expected, all three bulbs shattered. He then tipped over the remaining three bulbs, which were tempered with his new two-step acid treatment. They remained unbroken, much to the surprise of his supervisor. Then, to further demonstrate the effectiveness of his tempering process, Pipkin took bulbs that had not shattered and dropped them again, this time allowing them to fall to the office floor. The bulbs bounced on the floor, and settled without breaking. This demonstrated Pipkin's innovation of a two-step acid etching process for frosting a glass light bulb interior, and creating a strong glass globe. Pipkin's new frosted bulb revolutionized the industry, allowing the manufacture of frosted bulbs, that diffused the light without losing much intensity, and were strong enough to be commercially viable. He went on to make many innovations to the light bulb and two decades later developed the soft white light bulb.

Pipkin in 1947 invented an improved version of the process with silica coating that replaced the internal acid etching process. The 1947 smoke-thin internal silica coating lasted for 30 years and had the trade name of Q coat. The 100-watt Deluxe Soft-White light bulb was made from this. Pipkin is also credited with perfecting the photo flash bulb with several patents. Besides the frosted light bulb, Pipkin invented or improved many other products during his career with General Electric, including the 100 watt Deluxe-White bulb of the soft light bulb series. These were noted in articles in Time magazine, Newsweek magazine, and the Saturday Evening Post magazine, as well in scientific journals.

U.S. patents

 * 1,520,437 Process of catalyzing gaseous reactions – filed on September 29, 1921 – patent granted December 23, 1924.
 * 1,687,510 Electric Lamp Bulb – filed on June 29, 1925 – patent granted on October 16, 1928.
 * 1,706,182 Colored or diffusing coating for incandescent lamps and similar articles – filed on September 20, 1926 – patent granted on March 19, 1929.
 * 1,900,463 Bulb and method of coloring the same – filed on November 7, 1927 – patent granted on March 7, 1933.
 * 2,053,164 Incandescent Lamp and method of manufacture – filed on December 31, 1931 – patent granted on September 1, 1936.
 * 2,142,372 Flash Lamp – filed on March 18, 1937 – patent granted on January 3, 1939.
 * 2,215,477 Method of manufacturing wire – filed on October 19, 1937 – patent granted on September 24, 1940.
 * 2,285,125 Flash Lamp – filed on March 16, 1939 – patent granted on June 2, 1942.
 * 2,291,983 Flash Lamp – filed on April 8, 1940 – patent granted on August 4, 1942.
 * 2,306,563 Flash Lamp – filed on February 26, 1940 – patent granted on December 29, 1942.
 * 2,361,495 Flash Lamp – filed on December 23, 1941 – patent granted on October 31, 1944.
 * 2,473,888 (Jointly with Paul B. Jordan) Lead-in wire for electric lamps and similar devices – filed on June 10. 1947 – patent granted on June 21, 1949.
 * 2,545,896 Electric Lamp, light diffusing coating therefor and method of manufacture – filed on January 7, 1948 – patent granted on March 20 1951.
 * 2,615,472 Glass tubulature for feeding mercury – filed on December 16, 1947 – patent granted on October 28, 1952.
 * 2,726,527 Flash Lamp – filed on October 30, 1951 – patent granted on December 13, 1955.

Later life and death
Pipkin retired from the General Electric Nela Park laboratory in November 1954. He settled at his home on Beacon Road in Lakeland, Florida. He had lived in the town most of his life. Pipkin died at the General Hospital in Lakeland on January 7, 1977, of cancer. He was 87 years old. He is buried at the Fitzgerald Cemetery in Lakeland. At the time of his death he had three daughters still living. He also had three brothers and three sisters.

Society memberships
Pipkin was a member of Tuscan Masonic Lodge, Knights of Pythias, and the American Chemical Society.

Awards
He was awarded the Charles A. Coffin award for his achievements in electric lamp improvements.