If you want to buy a tub or shower seat that will stand for years without modification, DO NOT BUY THE DRIVE™ TRANSFER TUB BENCH (item# 12011KD-1) FROM MEDICAL DEPOT, INC. Over all, it looks like Direct Medical planned to deliver a quality product made from materials that were suited to the application; however, dissimilar metals, water collection points, and internal steel parts are significant flaws in that plan. Dissimilar metals in contact guarantees corrosion. Dissimilar metals and steel parts in direct contact with water guarantees rusty water a few days or weeks after the first use. If you are willing to spend a bit of time and money on modifications, however, the Drive™ Transfer Tub Bench (Item# 12011KD-1) from Medical Depot, Inc, can be improved so that it will serve you for many years. DETAILS ---------- On Friday, February 12, 2016, I order a Drive™ Transfer Tub Bench (item# 12011KD-1) from Amazon as a Valentine present for my wife. I received the bench on Sunday, quickly put it together, and put it into the shower. The bench looked great and worked the way my wife wanted. In a review I read before buying the bench, the customer complained of rusty water draining from the bench after it was used, stored, and then reused. Remembering this review, I examined the bench for water collection points and for parts that could corrode and/or rust. Examination -------------- There are three (3) areas of the bench where water can collect: • the inverted “U” tube under one end of the seat, • the leg braces under each end of the seat, and • the leg extensions. In particular, the leg extensions connected to the large suction cups (i.e., short legs) that are supposed to be immersed in a bath tub. When installed, the large suction cup seals the bottom of the leg extension. The bottom portion of each leg extension holds about one (1) teacup of water. Overall, I am impressed with most of the materials used in this product. The bench seat and backrest are made from plastic. The bench frame, legs, backrest supports, and arm rest are non-magnetic and look to be made from anodized aluminum tubing with plastic end guards and plugs. The screws, washers, and cap nuts are non-magnetic and look to be made from chrome-plated brass. The threaded stud attached to each large suction cup is slightly attracted to a magnet suggesting it is made from stainless steel. These are all excellent materials for a product designed to be used in a wet location like a bathtub or shower. The push pins are non-magnetic and look to be made of brass. Normally, brass is an excellent material to use in a wet environment; however, aluminum in contact with brass in a wet environment corrodes to form a fine white powder. Some parts are strongly attracted to a magnet. All of these parts look to be made from zinc-plated steel. These parts are: • Push pin springs located behind each push pin, • Washers inside of the small rubber tips attached to the long legs, and • Tube connector inserts located at the bottom of each short leg and at each end of the leg braces. A leg brace is located at each end of the bench, about 4” below the seat. A “tube connector insert” is a device similar to a nut that is pressed into the end of a tube or pipe to provide on-center screw threads. The device is also called a “Spring Threaded Tube Connector”. Steel parts used with aluminum in a wet environment eventually rust - even though the parts are zinc plated. Aluminum, zinc, brass, stainless steel, and even chrome are dissimilar metals that can react electrochemically; however, aluminum reacts less with stainless steel and chrome than with zinc and brass. Direct contact with water promotes the reaction between dissimilar metals. In the case of zinc plated steel parts, the zinc corrodes, washes away, and leaves the steel to rust. NOTE: I inspected all of the bench parts before use. All of the aluminum, zinc-plated steel, and brass parts were free from rust and/or corrosion. After two (2) weeks use in a shower, corrosion in the form of gray powder is present on ALL of the zinc-plated steel parts. White powder is present on the brass push pins where they pass through holes in the aluminum tubing. Rust is present on ALL of the tube connector inserts and some of the push pin springs. Because of direct contact with water, the push pins and push pin springs in ALL of the legs, the washers inside of the small rubber tips, and the tube connector inserts inside of the short legs show the most corrosion and/or rust. SUGGESTED IMPROVEMENTS --------------------------------- Push Pin Springs ----------------------- There are fourteen (14) brass push pins in the product - eight (8) in the bench legs, two (2) in the armrest, and four (4) in the backrest poles. A single zinc-plated steel spring holds each brass push pin in place. Because one end of each spring is in direct contact with aluminum, the other end is inserted into a hole in the back of a brass push pin, and the brass push pin is in contact with the aluminum, the contact points quickly corrode and the steel quickly rusts. Because of direct contact with water, the springs in the legs sustain the most damage. A solution to corroding/rusting push pin springs is to replace the zinc-plated steel springs with stainless steel springs. This solution seems to eliminate ALL of the corrosion between the aluminum tube, brass push pin, and zinc-plated steel push pin spring. Because I did not use the backrest, I did not replace the push pin springs in the backrest poles. Stainless steel wire that will work in the application is available from most welding supply stores as 1/16” stainless steel gas welding rod that is sold in 36” sticks. Each spring is made from about 5” of wire. Use bent long nosed pliers to form the welding rod into the correct shape for the push pin spring. Use the same long nosed pliers to remove/install the push pins and push pin springs. Water Collecting in the Inverted “U” tube and Leg Braces --------------------------------------------------------------- Each leg brace is an aluminum tube with a slight downward bend at the center. A tube connector insert made from zinc-plated steel is pressed into each end of each leg brace. At one end of the bench, the leg brace ends are connected with screws that go through leg receptacles and through the armrest receptacles. At the other end of the bench, the leg brace ends are connected with screws that go through the leg receptacles and through each end of an aluminum tube that is shaped like an inverted “U”. Both ends of the inverted “U” are sealed with a plastic plug. The screw connections are not sealed against water infiltration and there are no obvious drains. Water can collect at the center of each leg brace and inside of the inverted “U” shaped tube, above the plastic plugs. Because the tube connector inserts inside of the leg braces are made from zinc-plated steel, they will eventually corrode and rust; however, because there is no direct contact with water, deterioration is slow. The only solution for water collected inside of the inverted “U” shaped tube and the inside of the leg braces is to drill a 1/8” hole in each plastic plug and through the bottom of the bend in each leg brace. NOTE: After two weeks of use in a shower, the only corrosion or rust showing on the tube connector inserts inside of the leg braces is on the threads. Applying “Plumber’s Grease” to the screw threads delays further deterioration. NOTE: After two additional weeks of use in the shower, no additional corrosion or rust is present on the tube connector inserts inside of the leg braces. Water Collecting in the Leg Extensions ------------------------------------------- There are two (2) leg extensions attached to large suction cups (i.e., short legs) and two (2) leg extensions attached to small rubber tips (i.e., long legs). The short legs are about 1/2” shorter (i.e., one (1) push pin hole) than the long legs. A tube
