Renovation of Laboratory Benches and Drain Troughs and carbon black. Wet glassware placed on these benches obtains an ohjeetional brown coating. This surface was appropriate 40 years ago, but modern chemistry laboratory technique places an emphasis an cleanliness. The drain troughs in the center of these benches leak a t the seams on the biology laboratories below despite yearly patching by the best sealing materials. The leaks open up because of thermal contraction and expansion. When we renovated our laboratory, we found that the plant department or local contracton could replace locks, plumbing, and electrical service for a fraction of the cost of new benches. These restored benches, except for bench tops and the drain troughs, are as functional as most new bench tops, in fact, many restored benches are superior t o new benches. However, we were left with the hench topltrough problem; we considered three approaches to solving the objectionable bench coating problem: covering the hench tops with stainless steel, grinding to % in. off the tops of the benches, and covering the benches with a chemical resistant coating. Covering the benches with stainless steel can he done by a local sheet metal company. The stainless steel is glued to the table with wateroroaf oanel adhesive. The disadvantaees of this surface are hieh cost. electrical conductivitv, and low for a few pitted areas, they are as good as the day they were installed. Grinding the tops in place did not work because the linseed oil-carbon black coating fouled the grinding paper. We did not try sand blasting. Untreated soapstone may be ground with ease. I have been in a laboratory where the old tops were removed and ground for less than $10 a section a t a local quarry. The inclusion of the cost of removal, transportation, and installation make this approach as expensive and more complex than covering the tops with stainless steel. Soapstone is one of the finest general purpose laboratory surfaces. It does stain and etch, hut the damage is cosmetic. Covering the benches with a chemical resistant coating is a simple and economical solution. We used two part epoxy paint purchased from a local catalog outlet of Sears and Roebuck. The paint was rolled on the bench tops after they were washed with a caustic solution. The paint was not worked in since this would lift the previous coating. Two coats were applied. The surface holds up well except for staining. The laboratory was used for quantitative analysis, biochemistry, and inorganic laboratories. The tops may be reeaated to cover the stains. The paint is available in colors. Color can be used to designate work areas and for appearance. We expected that a black paint would have a greater resistance to staining, but it was not availabl? Our solution to the leaking drain troughs was to mount 3-in. plastic drain pipe with tees for aspirators, drains, and faucets. An elbow was placed a t each end (one up for a drain and the other down into the sink). The plant department did this a t about twice the cost of the annual patching. The pipe was painted to match the table tops. No problems have been observed or are expected with the new drain system. Subsequently, I have observed this type of drain installation in new laboratory bench systems. J. W. Beatty Ripon College Ripon. Wi 54971
610
Journal
of Chemical Education
