Misplaced Pages

#879120

57-431: Päijät-Häme boasts a landscape shaped by two key features. Finland's second-largest, Lake Päijänne , dominates the region, offering a vast freshwater expanse and a vital transportation route. The Häme Ridge , a glacial remnant, adds a touch of elevation and scenic variation. Beyond these, Päijät-Häme features extensive coniferous forests . Rolling hills provide scenic views, while numerous smaller lakes and rivers create

114-476: A Pre-Finno-Ugric substrate language. Päijänne is a famous boating , canoeing and sailing attraction. The 119 kilometres (74 mi) long lake is connected by canals to Lake Keitele , Lake Vesijärvi and to Lake Ruotsalainen. Length of the open waterway for ships is 380 kilometres (240 mi). Construction of canals connecting Päijänne to the Baltic Sea has been discussed for decades. Nevertheless,

171-413: A composite material . The sheets of wood are stacked such that each layer has its grain set typically (see below) perpendicular to its adjacent layers. This alternation of the grain is called cross-graining and has several important benefits: it reduces the tendency of wood to split when nailed at the edges; it reduces thickness swelling and shrinkage, providing improved dimensional stability; and it makes

228-499: A Tourism and Environment award presented by the European Union Commission in 1995. Päijänne National Park ( Finnish : Päijänteen kansallispuisto ) is a national park in the southern parts of Lake Päijänne. It consists of 50 unbuilt islands and parts of inhabited islands. The national park has been established in 1993 and has an area of 14 square kilometres (5.4 sq mi). Leivonmäki National Park

285-428: A caveat along the lines of "not suitable for boat In India,marine ply is popularly called "Kitply" after the brand which popularised the concept of water proof marine plywood in the 1980"s. Other types of plywoods include fire-retardant, moisture-resistant, wire mesh, sign-grade, and pressure-treated. However, the plywood may be treated with various chemicals to improve the plywood's fireproofing. Each of these products

342-453: A crucial role in rural life until World War I, with some later being divided into new farms. Today, Päijät-Häme's settlement can be divided into three zones: the sparsely populated eastern area with smaller farms and estates, the more densely populated central region with a strong presence of independent farms, and the sparsely populated north with vast forests. As transportation networks evolved, settlement patterns shifted, with Lahti emerging as

399-642: A fuselage made of birch plywood sandwiching a balsa core, and using plywood extensively for the wings. Plywood was also used for the hulls in the hard-chine Motor Torpedo Boats (MTB) and Motor Gun Boats (MGB) built by the British Power Boat Company and Vosper 's, American PT boats , and the Higgins landing craft critical to the D-Day landings. The American designers Charles and Ray Eames are known for their plywood-based furniture, as

456-401: A good log, called a peeler, which is generally straighter and larger in diameter than one required for processing into dimensioned lumber by a sawmill . The log is laid horizontally and rotated about its long axis while a long blade is pressed into it, causing a thin layer of wood to peel off (much as a continuous sheet of paper from a roll). An adjustable nosebar, which may be solid or a roller,

513-714: A great island, nowadays it means a great forest area. The largest city on the shores of Päijänne is Jyväskylä in the North. The city of Lahti is connected to Päijänne through Lake Vesijärvi and Vääksy canal. An underground aqueduct , Päijänne Water Tunnel , connects the lake to Vantaa , providing the Greater Helsinki area with water. The deepest point in any lake in Finland is in Päijänne (95.3 m or 313 ft). The name of Lake Päijänne comes possibly from

570-402: A large number of other hardwoods. Flexible plywood is designed for making curved parts, a practice which dates back to the 1850s in furniture making. At 3 ⁄ 8 inch (9.5 mm) thick, mahogany three-ply "wiggle board" or "bendy board" come in 4 by 8 feet (1.2 m × 2.4 m) sheets with a very thin cross-grain central ply and two thicker exterior plies, either long grain on

627-406: A network of waterways . Päijät-Häme's landscape reflects the dramatic retreat of glaciers . The last Ice Age carved the land, leaving ridges ( Salpausselkä ) and large lakes ( Finnish Lakeland ). As the ice melted, the Baltic Sea went through various stages, dramatically changing shorelines. Land rose, creating islands and eventually dry land. Human settlement followed the receding water, with

SECTION 10

#1732771854880

684-431: A press at a temperature of at least 140 °C (284 °F), and at a pressure of up to 1.9 MPa (280 psi) (but more commonly 1.4 MPa [200 psi]) to form the plywood panel. The panel can then be patched, have minor surface defects such as splits or small knot holes filled, re-sized, sanded or otherwise refinished, depending on the market for which it is intended. Plywood for indoor use generally uses

741-498: A result, many manufacturers are turning to low formaldehyde-emitting glue systems, denoted by an "E" rating. Plywood produced to "E0" has effectively zero formaldehyde emissions. In addition to the glues being brought to the forefront, the wood resources themselves are becoming the focus of manufacturers, due in part to energy conservation, as well as concern for natural resources. There are several certifications available to manufacturers who participate in these programs. Programme for

798-519: A single thick layer of wood. Understanding the industrial potential of laminated wood, he invented the rotary lathe . There is little record of the early implementation of the rotary lathe and the subsequent commercialization of plywood as we know it today, but in its 1870 edition, the French dictionary Robert describes the process of rotary lathe veneer manufacturing in its entry Déroulage . One can thus presume that rotary lathe plywood manufacturing

855-409: Is Finnish Architect Alvar Aalto and his firm Artek , while Phil Bolger has designed a wide range of boats built primarily of plywood. Jack Köper of Cape Town designed the plywood Dabchick sailing dinghy , which as of 2015 is still sailed by large numbers of teenagers. Plywood is often used to create curved surfaces because it can easily bend with the grain. Skateboard ramps often utilize plywood as

912-399: Is also a common European size for Baltic birch ply, and aircraft ply. Sizes on specialised plywood for concrete-forming can range from 15 ⁄ 64 to 13 ⁄ 16  in (6 to 21 mm), and a multitude of formats exist, though 15 × 750 × 1,500 mm (.59in × 30 × 59 in) (19/32in × 2 ft-6in × 4 ft-11in)

969-492: Is between the cities of Lahti and Jyväskylä . There are 16,000 cottages on the shores of Päijänne. Most of the cottages are private owned and have a separate sauna cottage. In addition to cottage tourism Päijänne attracts fishing, sailing, canoeing, rowing, paddling, trekking, ice-skating, snow mobile and nature tourists. The National Parks of Päijänne and Leivonmäki alone has tens of thousands of visitors every year. The Clear and Drinkable Lake Päijänne South Association won

1026-533: Is designed to fill a need in industry. Baltic Birch plywood is a product of an area around the Baltic Sea. Originally manufactured for European cabinet makers but now popular in the United States as well. It is very stable composed of an inner void-free core of cross-banded birch plys with an exterior grade adhesive. The face veneers are thicker than traditional cabinet grade Plywood production requires

1083-702: Is extremely strong and light. Howard Hughes' H-4 Hercules was constructed of plywood. The plane was built by the Hughes Aircraft Company employing a plywood-and-resin Duramold process. The specialized wood veneer was made by Roddis Manufacturing in Marshfield, Wisconsin . Usually faced with hardwood , including ash , oak , red oak , birch , maple , mahogany , shorea (often called lauan, meranti, or Philippine mahogany, though having no relation to true mahogany), rosewood , teak and

1140-509: Is from 1 ⁄ 8  to 3 inches (3.2–76.2 mm). The sizes of the most commonly used plywood sheets are 4 by 8 feet (1,220 mm × 2,440 mm) which was first used by the Portland Manufacturing Company, who developed modern veneer core plywood for the 1905 Portland World Fair. A common metric size for a sheet of plywood is 1200 × 2400 mm. 5 × 5 feet (1,500 × 1,500 mm)

1197-573: Is higher in the center of the panel, and at the outer fibres. Within Europe basic plywood can be divided into three main categories: birch plywood (density approx. 680 kg/m ), mixed plywood (density approx. 620 kg/m ) and conifer plywoods (density 460– 520 kg/m ). Different varieties of plywood exist for different applications: Softwood plywood is usually made either of cedar , Douglas fir or spruce , pine , and fir (collectively known as spruce-pine-fir or SPF) or redwood and

SECTION 20

#1732771854880

1254-506: Is made of mixed hardwood species of tropical timber . Originally from the Asian region, it is now also manufactured in African and South American countries. Tropical plywood is superior to softwood plywood due to its density, strength, evenness of layers, and high quality. It is usually sold at a premium in many markets if manufactured with high standards. Tropical plywood is widely used in

1311-508: Is made out of wood from dicot trees (oak, beech and mahogany) and used for demanding end uses. Hardwood plywood is characterized by its excellent strength, stiffness, durability and resistance to creep. It has a high planar shear strength and impact resistance, which make it especially suitable for heavy-duty floor and wall structures. Oriented plywood construction has a high wheel-carrying capacity. Hardwood plywood has excellent surface hardness, and damage- and wear-resistance. Tropical plywood

1368-564: Is manufactured to a number of specifications including those outlined since 1931 in the Germanischer Lloyd Rules for Surveying and Testing of Plywood for Aircraft and MIL-P-607, the latter of which calls for shear testing after immersion in boiling water for three hours to verify the adhesive qualities between the plies meets specifications. Aircraft grade plywood is made from three or more plies of birch, as thin as 0.40 millimetres ( 1 ⁄ 64  in) thick in total, and

1425-539: Is pressed against the log during rotation, to create a "gap" for veneer to pass through between the knife and the nosebar. The nosebar partly compresses the wood as it is peeled; it controls vibration of the peeling knife; and assists in keeping the veneer being peeled to an accurate thickness. In this way the log is peeled into sheets of veneer, which are then cut to the desired oversize dimensions, to allow it to shrink (depending on wood species) when dried. The sheets are then patched, graded, glued together and then baked in

1482-662: Is situated few kilometres North East from the Northern part of Lake Päijänne. It is one of the youngest national parks in Finland. From North to South Plywood Plywood is a composite material manufactured from thin layers, or "plies", of wood veneer that have been stacked and glued together. It is an engineered wood from the family of manufactured boards, which include plywood, medium-density fibreboard (MDF), oriented strand board (OSB), and particle board (or chipboard). All plywoods bind resin and wood fibre sheets ( cellulose cells are long, strong and thin) to form

1539-589: Is the second largest lake in Finland (1,080 km (266,874 acres)). The lake drains into the Gulf of Finland via the Kymi River . The major islands are from north to south Vuoritsalo , Muuratsalo , Onkisalo , Judinsalo , Edessalo , Taivassalo , Haukkasalo , Vehkasalo , Mustassalo , Virmailansaari and Salonsaari . The largest island is Virmailansaari. The word saari means an island. Salo once meant

1596-530: Is typically used for construction and industrial purposes. The most common dimension is 1.2 by 2.4 metres (3 ft 11 in × 7 ft 10 in) or the slightly larger imperial dimension of 4 feet × 8 feet. Plies vary in thickness from 1.4 mm to 4.3 mm. The number of plies—which is always odd—depends on the thickness and grade of the sheet. Roofing can use the thinner 16-millimetre ( 5 ⁄ 8  in) plywood. Subfloors are at least 19 millimetres ( 3 ⁄ 4  in) thick,

1653-438: Is very commonly used. Aircraft plywood is available in thicknesses of 1 ⁄ 8 inch (3 mm) (3-ply construction) and upwards; typically aircraft plywood uses veneers of 0.5 mm (approx 1/64 in) thickness although much thinner veneers such as 0.1 mm are also used in construction of some of the thinner panels. Grading rules differ according to the country of origin. The most popular standards are

1710-684: The Battle Axe culture around 3200 BC brought new tools and pottery styles. During the Bronze Age (1900 BC), cremation burials and large stone cairns became common. In the Iron Age , settlements shifted to better farming areas near waterways. Viking raids and unrest marked the later Iron Age. Christianity arrived during the Crusades (1050-1300 AD). By the Middle Ages , villages dotted

1767-600: The Porvoo River valley being the oldest cultural landscape. Today, Päijät-Häme boasts a unique blend of lakes, ridges, and reminders of its glacial past. After glaciers retreated 11,000 years ago, the first settlers arrived in Päijät-Häme. Birch dominated the initially barren landscape. As the climate warmed, people lived near ancient lakes and bays. By 5100 BC, the Comb Ceramic culture thrived. The arrival of

Päijät-Häme - Misplaced Pages Continue

1824-512: The 19th century revolutionized transportation, and later road networks further influenced development. Heinola , for example, benefitted from its location near the Kymijoki River, which facilitated industrial growth once railways arrived. This pattern likely mirrored itself across Päijät-Häme during the 1800s and 1900s. Heinola, founded in 1776, became the region's first city in 1839. Industrial areas grew around its center, particularly on

1881-539: The British Standard (BS) and the American Standard (ASTM). Joyce (1970), however, list some general indication of grading rules: Plywood is used in many applications that need high-quality, high-strength sheet material. Quality in this context means resistance to cracking, breaking, shrinkage, twisting and warping. Exterior glued plywood is suitable for outdoor use, but because moisture affects

1938-538: The Endorsement of Forest Certification (PEFC) Forest Stewardship Council (FSC), Leadership in Energy and Environmental Design (LEED), Sustainable Forestry Initiative (SFI), and Greenguard are all certification programs that ensure that production and construction practices are sustainable. Many of these programs offer tax benefits to both the manufacturer and the end user. The most commonly used thickness range

1995-608: The UK, Japan, United States, Taiwan, Korea, Dubai, and other countries worldwide. It is used for construction purposes in many regions due to its low cost. However, many countries' forests have been over-harvested, including the Philippines, Malaysia and Indonesia, largely due to the demand for plywood production and export. High-strength plywood, also known as aircraft plywood, is made from mahogany, spruce and/or birch using adhesives with an increased resistance to heat and humidity. It

2052-526: The ancient Greek verb πλέκω . The ancient Egyptians and Greeks cut wood thinly and glued it together in layers with the grain in perpendicular directions as fine wood was in short supply. This is believed to have been done purely for cosmetic and economical purposes but it turned out to be a great alternative to pure wood as it reduced flex, making it a versatile building material. In 1797 Samuel Bentham applied for patents covering several machines to produce veneers. In his patent applications, he described

2109-447: The chance of trapping water in the plywood and hence providing a solid and stable glue bond. It uses an exterior Weather and Boil Proof (WBP) glue similar to most exterior plywoods. Marine plywood can be graded as being compliant with BS 1088 , which is a British Standard for marine plywood and IS:710 is Bureau of Indian Standards (BIS) for marine grade plywood. There are few international standards for grading marine plywood and most of

2166-574: The concept of laminating several layers of veneer with glue to form a thicker piece – the first description of what we now call plywood. Bentham was a British naval engineer with many shipbuilding inventions to his credit. Veneers at the time of Bentham were flat sawn , rift sawn or quarter sawn ; i.e. cut along or across the log manually in different angles to the grain and thus limited in width and length. About fifty years later Immanuel Nobel , father of Alfred Nobel , realized that several thinner layers of wood bonded together would be stronger than

2223-423: The dominant population center. Villages in Päijät-Häme have a long history intertwined with the landscape. Most likely arose around the 16th century, strategically placed near ridges and waterways for easy access to water and fertile land . Water remained the primary mode of transportation for centuries, with some villages even shifting their centers to be closer to navigable routes. The arrival of railways in

2280-797: The east and south sides. Lahti's story is tied to railways and lakeside industry. It gained market town rights in 1878 and city status in 1905. Factories like sawmills , a pulp mill , and match factories fueled Lahti's expansion. Village churches (kirkonkylät) also saw growth from the 1860s onward, spurred by relaxed land ownership laws. However, rapid expansion in some villages obscured their older features. Lahti housed sawmills, pulp mills, glass factories, and textile producers. Heinola developed sawmills, plywood , and fiberboard factories alongside metalworking. Notably, Hämeenkoski had Finland's first flax cleaning plant built in 1888. Worker housing districts accompanied industrial growth. The passage mentions both early examples and later, larger developments from

2337-412: The form of an alcoholic solution or powder, which, however, did not provide sufficient accuracy of application. Around 1930 a dry process of gluing veneers to plywood with phenolic resin in form of a film has begun to spread in the production of waterproof plywood. A typical plywood panel has face veneers of a higher grade than the core veneers. The principal function of the core layers is to increase

Päijät-Häme - Misplaced Pages Continue

2394-469: The less expensive urea-formaldehyde glue, which has limited water resistance, while outdoor and marine-grade plywood are designed to withstand moisture, and use a water-resistant resorcinol-formaldehyde or phenol-formaldehyde glue to prevent delamination and to retain strength in high humidity . The adhesives used in plywood have become a point of concern. Both urea formaldehyde and phenol formaldehyde are carcinogenic in very high concentrations. As

2451-461: The original material was not strictly plywood, but a single sheet of veneer. Marine plywood is manufactured from durable face and core veneers, with few defects so it performs longer in both humid and wet conditions and resists delaminating and fungal attack. Its construction is such that it can be used in environments where it is exposed to moisture for long periods. Each wood veneer will be from tropical hardwoods and have negligible core gap, limiting

2508-513: The plan is still to be materialized. Until the 1940s Lake Päijänne was a major transportation channel in the Central Finland . Numerous ships transported passengers and freight between the villages and cities on the shores of Päijänne. Nowadays, passenger transportation is rather a tourist attraction on the lakelands than the fastest way connecting the cities and villages. One of the most popular passenger transportation routes in summertime

2565-702: The post-war period and the 1960s and 70s. Blazon: Azure, a mermaid and in dexter chief a cuckoo close Or. In laymen's terms: The coat of arms sports a depiction of the ancient water goddess Vellamo as a mermaid, with a cuckoo. The region of Päijät-Häme consists of 10 municipalities , two of which have city status (marked in bold). Lahti sub-region Results of the 2019 Finnish parliamentary election in Päijät-Häme: 61°15′N 25°50′E  /  61.250°N 25.833°E  / 61.250; 25.833 Lake P%C3%A4ij%C3%A4nne Lake Päijänne ( Finnish pronunciation: [ˈpæi̯jænːe] )

2622-445: The separation between the outer layers where the bending stresses are highest, thus increasing the panel's resistance to bending . As a result, thicker panels can span greater distances under the same loads. In bending, the maximum stress occurs in the outermost layers, one in tension , the other in compression . Bending stress decreases from the maximum at the face layers to nearly zero at the central layer. Shear stress , by contrast,

2679-548: The sheet, or cross grain. Wiggle board is often glued together in two layers once it is formed into the desired curve, so that the final shape will be stiff and resist movement. Often, decorative wood veneers are added as a surface layer. In the United Kingdom single-ply sheets of veneer were used to make stove pipe hats in Victorian times, so flexible modern plywood is sometimes known there as "hatters ply", although

2736-415: The shores of waterways and lakes. The 16th century saw a solidification of village life, with the most prominent settlements around Hollola , Lahti , and Nastola . The 1800s brought a boom in agriculture, with cultivated land tripling and industries like flax farming and cattle raising flourishing. Forests were mostly owned by farms, and improved transportation facilitated timber sales. Manor houses played

2793-421: The standards are voluntary. Some marine plywood has a Lloyd's of London stamp that certifies it to be BS 1088 compliant. Some plywood is also labeled based on the wood used to manufacture it. Examples of this are Okoumé or Meranti . In the UK, one can find builders' merchants advertising a grade of ply as "marine ply" that does not conform to BS 1088 - generally online adverts for these products will include

2850-410: The strength of the panel consistent across all directions. There is usually an odd number of plies, so that the sheet is balanced, that is, the surface layers have their grains set parallel to one another. This balance reduces warping. Because plywood is bonded with grains running against one another and with an odd number of composite parts, it has high stiffness perpendicular to the grain direction of

2907-501: The strength of wood, optimal performance is achieved where the moisture content remains relatively low. Subzero conditions do not affect the dimensional or strength properties of plywood, making some special applications possible. Plywood is also used as an engineering material for stressed-skin applications. It has been used for marine and aviation applications since WWII. Most notable is the British de Havilland Mosquito bomber, with

SECTION 50

#1732771854880

2964-453: The surface ply. Smaller, thinner, and lower-quality plywoods may only have their plies (layers) arranged at right angles to each other. Some better-quality plywood products by design have five plies in steps of 45 degrees (0, 45, 90, 135, and 180 degrees), giving strength in multiple axes. The word ply derives from the French verb plier , "to fold", from the Latin verb plico , from

3021-404: The thickness depending on the distance between floor joists . Plywood for flooring applications is often tongue and groove (T&G); This prevents one board from moving up or down relative to its neighbor, providing a solid-feeling floor when the joints do not lie over joists. T&G plywood is usually found in the 13-to-25-millimetre ( 1 ⁄ 2 to 1 in) range. Hardwood plywood

3078-443: The top smooth surface over bent curves to create transition that can simulate the shapes of ocean waves. Typical end uses of spruce plywood are: There are coating solutions available that mask the prominent grain structure of spruce plywood. For these coated plywoods there are some end uses where reasonable strength is needed but the lightness of spruce is a benefit, e.g.: Phenolic resin film coated (Film Faced) hardwood plywood

3135-746: Was an established process in France in the 1860s. Plywood was introduced into the United States in 1865 and industrial production there started shortly after. In 1928, the first standard-sized 4 ft by 8 ft (1.22 m by 2.44 m) plywood sheets were introduced in the United States for use as a general building material. Artists use plywood as a support for easel paintings to replace traditional canvas or cardboard. Ready-made artist boards for oil painting in three-layered plywood (3-ply) were produced and sold in New York as early as 1880. There were experiments with gluing plywood with phenolic resins, mostly in

3192-490: Was formed in two separate mirror-image halves, using curved moulds. Structural aircraft-grade plywood is most commonly manufactured from African mahogany, spruce or birch veneers that are bonded together in a hot press over hardwood cores of basswood or poplar or from European Birch veneers throughout. Basswood is another type of aviation-grade plywood that is lighter and more flexible than mahogany and birch plywood but has slightly less structural strength. Aviation-grade plywood

3249-439: Was used in the construction of air assault gliders during World War II and also several fighter aircraft , most notably the multi-role British Mosquito . Nicknamed "The Wooden Wonder", plywood was used for the wing surfaces, and also flat sections such as bulkheads and the webs of the wing spars. The fuselage had exceptional rigidity from the bonded ply-balsa-ply 'sandwich' of its monocoque shell; elliptical in cross-section, it

#879120