Prefab houses could soon be taped together
An electrically-activated adhesive tape incorporating metal strips has been developed for constructing prefabricated homes
Prefabricated houses are made up of separate pre-assembled modules that are joined to one another on-site – those modules, in turn, are made up of various wooden components that are typically nailed (or sometimes stapled) together in a factory. The wood used in the frames of the modules must be reasonably thick, in order not to split when the nails are driven in. This places some limitations on design possibilities. Now, however, German scientists have developed an alternative to those nails: electrically-activated adhesive tape.
Created by scientists at the Fraunhofer Institute for Wood Research and the Technische Universität Braunschweig, the tape actually consists of a thin strip of metal with adhesive on either side. As long as no electrical current is applied to the metal, the adhesive remains “unsticky.” This allows workers an indefinite amount of time in which to optimally place the tape and components together.
Once everything is ready to go, however, the tape gets zapped. This causes the metal to heat up, which subsequently causes the adhesive to melt and flow into the pores of the wood. Once the electrical current ceases, the adhesive cools and sets. The whole process only takes about one minute, and reportedly creates a durable bond.
By contrast, regular liquid adhesives used by some home manufacturers either take several hours to set, or require the whole module to be heated.
The researchers have already selected an adhesive that they say bonds well with both wood and metal. They are now looking into the merits of different types of metal including stainless steel, aluminum, and one of their current favorites, brass. They’re additionally working on shortening the amount of time required for bonding, and hope to test the tape in practical applications within about six months.
About the Author
An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.
All articles by Ben Coxworth
Lightning strike = House of cards?
As an ex-firefighter I am wondering how long this bond stays strong in a fire? When building with wood, one must use long nails so if there is a fire the structure of the house stays together as long as possible. That is why i think thous staple/nail plates mainly used in US is too darn dangerous. They let go of the wood in a very short time. So how would this metal strip behave heated in a fire?
But I do love the idea it self, to glue the parts together makes for a much easier and faster way of construction.
If this uses hot glue it is a bad idea. If it uses an adhesive that the heat powers chemical reactions that produce a thermally stable bond it might be a good idea.
One advantage to fasteners is mechanical shear strength, which adhesives may not be able to match if the building frame is wood and butt joints are used. And this appears best suited to manufactured housing where jigs are common, so the advantage to fiddle may be small. An interesting developement nonetheless.
Bruce H. Anderson
If I were building today, stick & nail-built would be OUT. A Monolithic Dome, made of rebar imbedded in concrete with a high density poly foam coating is super strong, virtually hurricane, tornado and fire proof, way less expensive, and needs hardly any heating/cooling help due to the concrete and foam structure. Monolithic Dome all the way!
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