Friday, June 26, 2009

Hardware Info

Interstate Screw Corp has an interesting page about myths and misconceptions regarding fasteners. They also have a variety of technical information that is available, such as the recommended tek screws for different material thicknesses.

Friday, June 19, 2009

History of Plastics

The PPC website has some interesting information (quoted below) about the history of plastics. They have a variety of materials on their website along with qualities attributed to each type. The website seems a little out of date, but the information seems valid for an introduction to the many types of plastics.

Plastic materials trace their origin in this country back to 1868, when a young printer named John Wesley Hyatt came up with Celluloid, the first American plastic. He mixed pyroxylin, made from cotton (one of nature's polymerics), and nitric acid, with camphor to create an entirely different and new product. Celluloid quickly moved into many markets, including the first photographic film used by George Eastman to produce the first motion picture film in 1882. The material is still in use today under its chemical name, cellulose nitrate.

In 1909, Dr. Lee Hendrik Baekeland introduced phenoformaldehyde plastics (or "phenolics", as they are more popularly known), the first plastic to achieve worldwide acceptance. More importantly, Baekeland also evolved techniques for controlling and modifying the phenolformaldehyde reaction so that products could be formed under heat and pressure from the material. This characteristic of liquefying the material so that it can be formed into various shapes under heat and pressure is still common to most plastics.

The third major thrust in the development of plastics took place in the 1920s with the introduction of cellulose acetate (which is similar in structure to cellulose nitrate, but safer to process and use), ureaformaldehyde (which can be processed like the phenolics, but can also be molded into light colored articles that are more attractive than the blacks and browns in which phenolics are available), and polyvinyl chloride (PVC, or vinyl, as it is commonly called). Nylon was also developed in the late 1920s through the classic research of W.T. Carothers.

Each decade saw the introduction of new and more versatile plastics. In the 1930's, there were acrylic resins for signs and glazing and the commercialization of polystyrene, which became the third largest-selling plastic, literally revolutionizing segments of the house wares, toys, and packaging industries. Melamine resins were also introduced; these later became a critical element (in the form of a binder) in the development of decorative laminate tops, vertical surfacing, and the like.

Polyethylene -- today's most widely used plastic -- evolved out of the need for a superior insulating material that could be used for such applications as radar cable during World War II. The thermoset polyester resins that only a decade or so later were to radically change the boat-building business in the United States were also a wartime development introduced for military use. And acrylonitrile-butadiene-styrene plastics, or ABS, (the plastic most often used today in appliance housings, refrigerator linens, safety helmets, pipe, telephone headsets, and luggage) owes its origins to research work emanating from the crash wartime program aimed at producing large quantities of synthetic rubber.

The decade of the 1950s saw the introduction of polypropylene and the development of acetal and polycarbonate, two plastics that, along with nylon, came to form the nucleus of a sub-group in the plastics family known as the "engineering thermoplastics." Their outstanding impact strength and thermal and dimensional stability enabled them to compete directly and favorably with metal in many applications.

The 1960s and 1970s also saw their share of new plastic introductions, most notably thermoplastic polyesters with the kind of outstanding resistance to gas permeation that made them applicable for use in packaging. During this period, another sub-group of the plastics family also started to emerge, the so-called "high temperature plastics," which includes the polyimides, polyamide-imides, aromatic polyesters, polyphenylene sulfide, polyether sulfone, and the like. These materials were designed to meet the demanding thermal needs of aerospace and aircraft applications. Today, however, they have moved into the commercial areas that require their ability to operate at continuous temperatures of 400 degrees F, or more.

Thursday, June 18, 2009

Hardware Source

Wild West Hardware offers "Unusual Hand-Forged & Hard-to-Find Rustic Hardware". You can find a variety of economical barn hinges, decorative nails (good for rivets/upholstery, and specific design needs)dummy hinges, and a variety of other pieces. It is definitely worth a look.

Wednesday, June 10, 2009

Building a Sandwich

Over on the blog at Taylor Studios there is a post comparing building a sandwich to the design process in a commercial environment. Its a concise and fun way to look at the process.
However, if you are hiring someone to do design, you should confirm what your expectations are for the design process. For instance where I work, the first phase is a creative design phase. This would end with parameters on which the schematic design would work with. The schematic design would take these parameters and do several options (we do usually do 3). The creative development is important so that the schematic design can start to narrow some options. Since we do WAG/Rom Budgets and rough sketches during this period, having a decent idea of direction is necessary.

The end of the final design phase is an important point - at this point the design should be able to be very specific. If you are doing the design and build, perhaps this isn't as much of an issue - except that you will undoubtedly have scope creep, and lose money. If you are sending the final design out to be bid, the design package has to be done in such a way that your bids will come back and provide you with an apples to apples comparison.

A colleague, Chris Wilson, a Project Manager for a local museum stalks about the RFPs & the Scope of work:
Scope of Work (or Scope of Service) – assume nothing.

This is where RFP’s live and die. 99 percent of your effort should be spent on this section. This is the place for any and all information that might be relevant to the fabricator. Assume nothing. Leave nothing to chance.

Stick with me for a minute:

Imagine that you want a cookie. You call 6 bakeries and tell them that you would like a price for a cookie. You get six prices that are wildly divergent. You realize that you should have been more specific. You stipulate chocolate chip. Still the prices are all over the map. In separate conversations you stipulate size, type of flour, etc… Eventually, you have told the (now annoyed) bakeries (in a very tortured, drawn out process which, by the way, is not documented anywhere) the following information:

I would like one (1) chocolate chip cookie between 5 and 5.5 inches in diameter, containing no less than one heaping tablespoon of semi-sweet chocolate morsels. The cookie shall have a slightly gooey texture, but shall have sufficient tensile strength to be self supporting if lifted from one end only. No trans fats shall be used as part of the ingredients of this cookie, and it shall not be processed on any machinery that comes in contact with peanuts, or any other kind of nut. The cookie shall be delivered within the next 24 hours, in packaging that does not require the use of any tools to open.

Now, of course you would never buy a cookie in this way, because it is a far more intuitive process than building an exhibit. And because there is a cultural understanding of what is in a typical cookie.

I simply use this as an example of how you will never get what you want unless you ask for it.

This is why the Scope of Work, and especially the TECHNICAL exhibit descriptions are so important in an RFP. Depending on the characteristics of the exhibit you are building, the descriptions can be as important as the drawings.

Bringing that back to the sandwhich, unless the size and number of bacon/tomato slices are noted as well as the type of bread and such are documented, you may still find differences. One shop might use a high sodium bacon, because it is more economical. Another might use a high quuaility one, but less of it. A third shop might want to use turkey bacon because they have some left from a different recipe. While a shop might be able to save you money (value engineer) or increase the value (value added) you want this information to be clear so that there are no surprises. "Oh you wanted extra mayo - thats extra $$...."

Wednesday, June 3, 2009

Hidden Doors

I came across this site, and thought it would be an interesting technique for theatre stagecraft. The article has a good amount of information and feedback about how to construct a pivoting bookcase. The pivot hinges are one of the reasons for the success of this design, but it is interesting to see the way they cut the molding and rear of the shelving unit to make it open propoerly.

Once your done, check out the rest of the articles.

Tuesday, June 2, 2009

Barn Wood

Every now and then a show comes along and they want the look of old barn wood. I have (and have heard stories of others) that managed to actually get lumber from an old barn, which only manages to work out in very ideal situations. It also works better in certain parts of the country. The same is true for rough sawn wood - it isn't available everywhere. And of course there are a variety of ways to distress wood - but it never quite looks just right.

So the next time you find yourself in this situation check out Appalachian Woods. They offer flooring and a variety of reclaimed beams.

Also check out:
Allegeny Woodworks

Monday, June 1, 2009

SA Baxter Hardware

For some very fashionable hardware check out SA Baxter. They offer high end hardware and the ability to custom make hardware.