# All About Plywood (aka Multiplex)



## NightKnight

This purpose of this thread is to list info found from a variety of sites about plywood. At times on this site you will find refrences to Plywood as "Multiplex", which is not the proper technical term for layered wood.



> http://en.wikipedia.org/wiki/Plywood
> *TYPES*
> 
> *Softwood plywood*
> Softwood panel is usually made either of cedar, Douglas fir or spruce, pine, and fir (collectively known as spruce-pine-fir or SPF) or redwood and is typically used for construction and industrial purposes.[1]
> The most common dimension is 1.2 m × 2.4 m or the slightly larger imperial dimension of 4 feet × 8 feet. Plies vary in thickness from 1.4mm to 4.3mm. The amount of plies depends on the thickness and grade of the sheet but at least 3. Roofing can use the thinner 5/8" (15mm) plywood. Subfloors are at least 3/4" (18mm) thick, the thickness depending on the distance between floor joists. Plywood for flooring applications is often tongue and groove; This prevents one board from moving up or down relative to its neighbor, so providing a solid feeling floor when the joints do not lie over joists. T&G plywood is usually found in the 1/2" to 1" (12-21mm) range
> 
> *Hardwood plywood*
> Used for demanding end uses. Birch plywood is characterized by its excellent strength, stiffness 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. Birch plywood has excellent surface hardness, and damage- and wear-resistance.[2]
> 
> *Tropical plywood*
> Tropical plywood is always made of mixed species of tropical wood in the Asian region. 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 the UK, Japan, Taiwan, Korea, Dubai, and other countries worldwide. It is the most preferred choice for construction purposes in many regions.
> 
> *Aircraft plywood*
> High-strength plywood, known as aircraft plywood, is made from mahogany and/or birch, and uses adhesives with increased resistance to heat and humidity. It was used for several World War II fighter aircraft, including the British-built Mosquito bomber, which was nicknamed "The Wooden Wonder".
> Structural aircraft-grade plywood is more commonly manufactured from African mahogany or American birch veneers that are bonded together in a hot press over hardwood cores of basswood or poplar. Basswood is another type of aviation-grade plywood that is lighter and more flexible than mahogany and birch plywood but has slightly less[citation needed] structural strength. All aviation-grade plywood is manufactured to specifications outlined in MIL-P-607, which calls for shear testing after immersion in boiling water for three hours to verify the adhesive qualities between the plies and meets specifications.
> 
> *Decorative plywood (overlaid plywood)*
> Usually faced with hardwood, including ash, oak, red oak, birch, maple, mahogany, Philippine mahogany(often called lauan), rose wood, teak and a large number of other hardwoods. However, Formica, metal and resin-impregnated paper or fabric bonded are also added on top of plywood at both side as a kind of ready for use in the decoration field.
> 
> *Flexible plywood*
> Flexible plywood is very flexible and is designed for making curved parts. In the UK this is sometimes known as "Hatters Ply" as it was used to make stovepipe hats in Victorian times[citation needed]. It is also often referred to as "Bendy Ply" due to its flexibility. However these may not be termed plywood in some countries because the basic description of plywood is layers of veneered wood laid on top of each other with the grain of each layer perpendicular to the grain of the next. In the US, the terms "Bender Board" and "Wiggle Board" are commonly used.
> 
> *Marine plywood*
> Marine plywood is manufactured from durable face and core veneers, with few defects so it performs longer in 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 durable tropical hardwoods, have negligible core gap, limiting the chance of trapping water in the plywood and hence providing a solid and stable glue bond. It uses an exterior Water 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. There are few international standards for grading marine plywood and most of 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 Okoume or Meranti
> Marine plywood is frequently used in the construction of docks and boats. It is much more expensive than standard plywood: the cost for a typical 4-foot by 8-foot 1/2-inch thick board is roughly $75 to $100 US or around $2.5 per square foot, which is about three times as expensive as standard plywood.
> 
> *GRADES*
> Grading rules differ according to the country of origin. Most popular standard is the British Standard (BS) and American Standard (ASTM). Joyce (1970), however, list some general indication of grading rules:
> Grade----Description
> A----Face and back veneers practically free from all defects.
> A/B----Face veneers practically free from all defects. Reverse veneers with only a few small knots or discolorations.
> A/BB----Face as A but reverse side permitting jointed veneers, large knots, plugs, etc.
> B----Both side as reverse of A/B
> B/BB----Face as reverse of A/B. Reverse side as reverse of A/BB
> BB----Both sides as reverse of B/BB
> WG----Guaranteed well glued only. All broken knots plugged.
> X----Knots, knot-holes, cracks, and all other defects permitted.





> http://alliedveneer....ltic-birch.html
> *Q: What is Baltic Birch?*
> Baltic Birch, aka 'Russian Birch', is a popular panel best known for its light color, strength, multi-ply construction, and affordable cost.
> 
> *Q: What sizes does it come in?*
> The most common Baltic Birch size is 5'x5'. However, we are seeing much more 4'x8' available in the marketplace.
> 
> *Q: What are these grades? They don't look familiar.*
> They are indeed different from the domestic grades many of us are used to seeing. Baltic Birch is manufactured in accordance with the Russian export GOST 3916.1-96 standards. We have simplified the extensive list to what you see below. The baltic birch full grading standard is available online.
> 
> B----Selected one-piece face, generally light and even in color. Occasional small pin knots and some brown streaks may be allowed, but generally no patches, voids or mineral streaks. Sanded surface intended for natural finish.
> 
> BB-One-piece face generally light and even in color. Pin knots and mineral streaking or discoloration is allowed with occasional sound tight knots permitted. Open knots and defects in BB face veneers have been cut out and replaced with small oval or round veneer "football" patches before gluing. The veneer selected for the patches is of the same general color as the face veneer. Sanded surface.
> 
> CP-One-piece face very close to grade BB. Rejected from BB for small defects with more streaking. Occasional hairline splits of less than .5mm are allowed. The oval or round patches may or may not be matched for color with the base face veneer. There will normally be more patches per face than the BB grade. Sanded surface.
> 
> C---Patches, open knots and veneer splits allowed. Not sanded.
> 
> *Q: What is this shop grade that I see all of the time?*
> 
> Baltic Birch "shop grade" is an evolved grade brought on by the demand of the customers. When the Russian mills first began manufacturing birch plywood, occasionally some cracks in the veneer would form on the edges during the drying process. The plywood mills would then cut off the 2"-10" that were damaged and send only the good part of the panel (60"x 58" or 60"x 50") to us at a discount rate.
> 
> Well, the manufacturers here got smart and asked that the mills just send the full sheet at a discount price. They figured that they were cutting the material anyway and would be happy to cut around any splits for a discount on the material.
> 
> So the loose interpretation of shop grade is defined as allowing splits on one edge of the panel, 2-10" long, and splits of no more than 1/4" wide.
> 
> *Q: What type of glue do they use? Can this be used outside?*
> Baltic Birch comes in Type I and Type II glues. Type I is a phenolic, exterior glue. This does not mean that an exterior glue is a substitute for a true marine plywood. (Link to marine plywood page) This simply means that the panel will perform slightly better in outdoor applications. Type II glue is an interior glue, and by far the most prevalent in today's marketplace.





> http://www.mcilvain....-grade-plywood/
> *Marine Grade Plywood*
> Unfortunately, the term "marine grade" gets thrown around a lot and has created many misconceptions about what it is and how it should be used. These days when someone specifies they need marine grade plywood they could be searching for a waterproof product to be used for exterior work on boats that will coming into direct contact with water and possibly submerged completely, or they could be seeking an exterior grade plywood that have some water resistance to be used for something like a house in a wet climate. These are only two examples of the many applications for which marine grade plywood is used.
> Water resistance, weight, strength, and ease of bending are all important factors to consider before deciding which type of marine plywood to buy. The most common species available in marine plywood are Okoume, Meranti, and Douglas Fir. As with all our products, J. Gibson McIlvain strives to provide a higher quality.
> 
> *Douglas Fir Marine Plywood*
> Douglas Fir marine plywood is very strong, bends well, and is of medium weight. It is the cheapest of options for marine plywood, and the faces may have up to five patches or repairs but no voids. Although the grading term is no longer in use, a BS 6566 grade could be applied to our Douglas Fir plywood. It excels in all things except appearance. The lower BS 6566 grade means that the appearance is not as good as BS 1088 and knots and patches may be apparent, but it still meets the high standards for weather and boil proof (WBP) glue that is key to keep the plies from de-laminating. The early and late growth common with a softwood can leave an uneven surface that will telegraph its inconsistencies through a fiberglass or epoxied surface. This is the plywood to use in the many areas where it will not be seen. The natural weather resistance that is inherent with Douglas Fir makes this an outstanding plywood for marine use.
> 
> *Okoume Marine Grade Plywood*
> Okoume plywood is rated as BS 1088 and is a top rating product to be used when appearance is key. The Okoume tree is not naturally weather resistant, but it has a very consistent appearance with a tight grain and is very light. When used as a plywood that is treated with WBP phenolic glue and laminated with a Fir core, it is very durable, weighs little, and finishes like glass. This is the product to choose for decking and exterior surfaces that need to be veneered with an attractive wood, painted, fiberglassed, or epoxied. Our Okoume plywood is of a very high quality and is sought after by the best boat builders in the world.
> Both species are available in a variety of thicknesses with rotary cut faces and zero voids. The veneer ply count may vary depending on whether the product is domestic or imported. We do this on purpose to offer options for those looking to bend the plywood in boat building applications who may require more or fewer veneers.





> http://www.chemical-...ywood-c144.html
> 
> *Marine Grade Okoume Plywood:*
> Never has a construction material been at the center of more confusion about its name, its qualities and its sources. There are three key areas of confusion; the manufacturers and methods; the materials used; and the British Standard specifications & Lloyds of London certifications.
> 
> *The History of Okoume Marine Grade Plywood:*
> True marine grade plywood actually dates back to the thirties when Bruynzeel, a door manufacturer in Zaandam, Netherlands, developed a superior form of plywood.
> 
> Cornelius (Kees) Bruynzeel was a Dutch businessman, timber merchant and yachtsman. In 1920 he became manager of the family's new door factory in Zaandam. By 1939, their production had expanded to include floors and kitchens, but the threat of World War II was depressing the building industry. Kees began to consider alternative markets and pioneered the development of new timber materials for the production of the Bruynzeel kitchen and for boat construction. Using a newly-developed water-resistant synthetic resin glue, Bruynzeel developed a durable three-ply laminated panel similar to plywood and intended for the fabrication of external doors.
> 
> The naval architect Ricus van de Stadt, known to Bruynzeel through the sailing fraternity, received the order to design a daysailer suitable for series production. Bruynzeel suggested that his new "Hechthout" laminated panel, as he called it, was superbly suited as a building material for such a sailing yacht. In 1939 the Valk came into being, still a popular open sailing boat in the Netherlands today. The special marine grade plywood from Bruynzeel was a perfect construction material for the project.
> 
> While this established Van de Stadt as an innovative yacht designer, Okoume marine grade plywood from Bruynzeel was also established as the new standard of the industry. Today Bruynzeel Multipanel Int. B.V., as it was later renamed, is a leading timber company that specializes in marine and construction timber.
> 
> Bruynzeel now has more than 40 years of experience in the production of marine plywood. Ships built from Bruynzeel that were built over forty years ago are still under sail. This experience enables Bruynzeel to be one of the few plywood manufacturers in the world to offer a 10-year guarantee on its marine plywood.
> 
> Bruynzeel used to "own" the US market but as their prices continued to rise, other sources developed. Now this material is largely provided from facilities in Western and Northern Africa (Gabon and Morocco, for example).
> 
> *The Material-Okoume (Gaboon) Veneers:*
> The more formal name for this timber is Gaboon, scientific name "Aucoumea klaineana." You might also see it called "Gabon", but more commonly, it is simply called "Okoume," (pronounced, "Oh-koo-mee"). It is also sometimes called "Gaboon Mahogany" or "African Mahogany" though it is not a true mahogany. The trees from which it is derived grow naturally in the West African provinces of Congo and Gabon to heights of over 200 feet.
> 
> As woods go, it is not considered a particularly strong wood, nor is it rated good for bending, stiffness or crush strength. But, due to its light weight (average density = 27 lb/ft3, specific gravity = .43) it has an extremely high strength-to-weight ratio.
> 
> When rotary cut into veneers and laminated into plywood, it has the appearance of a light-colored mahogany with a very tight, close grain. (see "The Encyclopedia of Wood," Walker, 2005)
> 
> *The Plywood:*
> If you are in the United States, unless you have been directly involved in the construction of racing boats or wood aircraft, you more than likely have never heard of this plywood. You may have come across the Douglas fir variety of marine plywood, maybe even some mahogany marine grade plywood but Okoume Marine Grade plywood is something totally different.
> 
> Imagine a plywood that has the same core veneers as the faces, and instead of 3 or 5 plies, it has as many 1.5 millimeter plies as it takes to make the desired thickness. Additionally, all the core plies are of the same quality as the face plies-no plugs, no voids. It is also important that any plywood used for boat or aircraft construction be "balanced". A balanced laminate is one in which there is a center ply with an equal number of veneers on either side of it. Additionally, the opposite corresponding veneers must be of the same thicknesses thus making a symmetrical layup.
> 
> Okoume Marine Plywood is used for Formula 1 race boats, hydroplanes, canoes, racing dinghies, shells, cabin cruisers, motoryachts, cold-molded boats, lapstrake or clinker-built designs, mine-sweepers or commercial craft. Because of its light weight and high strength to weight ratio, Okoume Marine Plywood is even used in aircraft construction.
> 
> *The Standards:*
> Okoume marine grade plywood is made according to a specification. The primary specification is British in its origin and simply called British Standard 1088 or "BS-1088."
> 
> The plies are bonded with WBP (water and boil proof) phenolic glue (often called resorcinol). The BS-1088 plywood must use an adhesive proven to be very resistant to weather, micro-organisms, cold and boiling water, steam and dry heat. The product's adhesive bond must pass a series of British Standard tests.
> 
> The face veneers must present a solid surface that is free from open defects. Face veneers must be free of knots other than "sound pin" knots, and there can be no more than an average of two such knots per square foot over the entire surface of the plywood sheet. The veneers must be reasonably free from irregular grain. The use of edge joints is limited, and end joints are not allowed.
> 
> The core veneers have the same basic requirements as face veneers, except that small splits are allowed, and there is no limit on the number of pin knots or edge joints. However, end joints are still not permitted.
> 
> Defective bonds, pleats and overlaps, and gaps in faces are not permitted. Occasional gaps may be repaired using veneer inserts bonded with the proper adhesive.
> 
> Moisture Content -- BS 1088 plywood must have a moisture content between 6% and 14% when it leaves the factory.
> 
> It is important to note that there is a sister specification, BS-6566, for a lesser grade panel with thinner face veneers of lower quality, and fewer laminations.
> 
> *The Certification:*
> The big difference here is between a plywood panel being manufactured to comply with the BS-1088 specification and one that is actually certified that it complies.
> 
> Lloyds of London, the famous insurance company, provides a certification for these plywoods for use in yachts. Okoume lumber, as a species is rated as a non-durable wood. In order to obtain a rating by Lloyds as equivalent to a minimum of moderately durable, Okoume plywood must be treated with a preservative. Because of this treatment Lloyds Register provides an approval for applications in pleasure craft and small craft construction. There are several manufacturers of Okoume plywood but not all have this rating.
> 
> *Today's Supply Chain:*
> As with many manufacturers, reputation supports a brand name along with rising prices. Such is the case with Bruynzeel. In the last few years, their prices have risen so sharply that a market void was created, encouraging competition to new players.
> 
> Since most of the Okoume timber comes from Western Africa, it was only logical that a manufacturing plant would develop there.
> 
> *The Joubert Group:*
> One of the most recent players in the production of this certified plywood is the Joubert Group, based in France. In 2000, Joubert completed their veneer peeling and drying plant in the equatorial Western African seacoast town of Port Gentil, Gabon. Joubert produces two marine grades; their "Joubert Marine Ply" and their "Super Marine Ply" okoume plywoods to meet the BS-1088 standards with the main difference between the two being the number of plies.
> 
> *CEMA:*
> The company, CEMA, Bois De L'Atlas, located in the city of Casablanca, Morocco, in the northwestern portion of Africa has been making BS-1088 certified Okoume plywood for several years now.


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## NightKnight

Because of its durability, I think that some of the vendors should offer Okoume Marine Plywood slingshots.


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## Sean

Good and comprehesive Aaron, this should be of help/assistance to quite a few here and in the future.
Probably should be pinned.


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## Hrawk

AaronC said:


> Because of its durability, I think that some of the vendors should offer Okoume Marine Plywood slingshots.


Okoume is fantastic. Looks great too.


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## e~shot

Agreed with Aaron. Multiplex (plywood) only in Germany


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## hawk2009

I use the term multiplex for much the same reason as others do to sell your slingshot, multiplex is a word much more attractive than (plywood), all woods have a basic name but like the plywood they jazz it up and make it sound like something really special when in fact it is just another sales pitch, at the end of the day catapults/ slingshots are just a piece of wood or a steel rod heated and bent some are moulded and come in various shapes and sizes, they are not to hard to make attatch a quality piece of tube or flatband and hey presto. Its' a growing hobby that's cheap and almost free and you can have alot of fun shooting them if you knock up a natural and shoot stones through it. More and more people are jumping on the band wagon as they also see it as an opportunity to make money. its' a growing business and will do anything to sell their stock, I am a straight forward no bull**** kind of guy so I am sorry if this offends anyone but . It's only a matter of time now before our governments spot catapults/ slingshots as a money spinner and they then will be jumping on the wagon by introducing their taxes.


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## CSA

This plywood is not marine grade, however it is meant for precision steelrule die making. I have worked for a die cutting company for over 25 years and have seen it used for alternative purposes. It is strong, very flat, durable and extremly well made. Just an FYI. I'm going to have our die-maker (artist) cut a few of the patterns on the sight for me out of this die board. http://www.mccauseylumber.com/ppsrdp.html


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## NightKnight

Looks like neat stuff CSA!


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## All Buns Glazing

I've started calling plywood "multiplex" on here, cos it's the accepted term, just like I call a "ging" a slingshot. I'm glad someone else feels the same way. VIVA LA PLYWOOD GINGS!


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## Incomudro

I like the term "Multiplex" when I'm shopping slingshots.
Plywood just conjures up images of a 4 x 8 sheet of wood from Home Depot.

BTW, skateboards are referred to as "laminated."


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## All Buns Glazing

Wait, you mean you don't use that to make ya slingshots? ;-)


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## Incomudro

All Buns Glazing said:


> Wait, you mean you don't use that to make ya slingshots? ;-)


You mean one of my Skateboards?
No - they're not for sacrifice - though they do use good wood!

What I meant was the terminology in advertising.
For Slingshots - the term Multiplex sounds better than plywood.
For Skateboards - Laminate or Laminated sounds better thab plywood.
Who wants to buy a_ plywood_ skateboard? Once again, that Home Depot connotation...


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## NightKnight

Hmmm. I think we should call it "HyperStrenthFiberStuff" because that sounds cooler that plywood.


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## All Buns Glazing

Well, I've never set foot in a home depot, but I think you know what you mean. You think wood, made of various plys should have different names, depending on the intended use of the purchaser. Laminate (what do you call the stuff on kitchen benches now?), multiplex, which has multiple different connotations ( http://en.m.wikipedia.org/wiki/Multiplex) or plywood.

I skate. My board is plywood ;-)


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## ash

I'm glad to have found this thread, not so much for the excellent resource, but for the mutual eye-rolling at the term "multiplex" :lol:

Ever since I saw my first GK video I've been groaning with cynicism every time I've heard the term. Thiniking I might have been missing something, I Googled it only to find that most of the results were slingshot makers :lol:


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## Hrawk

ash said:


> I'm glad to have found this thread, not so much for the excellent resource, but for the mutual eye-rolling at the term "multiplex" :lol:
> 
> Ever since I saw my first GK video I've been groaning with cynicism every time I've heard the term. Thiniking I might have been missing something, I Googled it only to find that most of the results were slingshot makers :lol:


It was all started by some big bald German guy, comes down to a translation thing.

Everyone else just followed the leader leading to a lot of confusion when people go looking for 'multiplex' and mostly getting blank stares by shop employees.


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## Imperial

hey man, dont forget crosply. :neener:


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## ash

Hrawk said:


> It was all started by some big bald German guy, comes down to a translation thing.


Ah, I see.... Thanks and bye bye.


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## Viper010

im sorry for the confusion my american friends but multiplex has been called multiplex here in europe for as long as the stuff has been made and sold as far as i know. i remember my dad buying multiplex for a rabbit cage over 25 years ago. well before the interwebz were publicly available and certainly long before Joerg became a utube celebrity.

sorry for the rant but i just felt i needed to clear up this lil mystery 

its simple here really, 3layer plywood is called triplex here, anything with more layers is called multiplex.


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## ash

Makes perfect sense, Viper. My Google page operating in English probably doesn't go looking for Dutch and German webpages, but brings me slingshot results because it knows I like them.

In my part of the world a multiplex is a cinema building with multiple theatres.

A slight aside - I once had a customer ask me what a ply tree looks like :lol:


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## Hrawk

Viper010 said:


> im sorry for the confusion my american friends but multiplex has been called multiplex here in europe for as long as the stuff has been made and sold as far as i know. i remember my dad buying multiplex for a rabbit cage over 25 years ago. well before the interwebz were publicly available and certainly long before Joerg became a utube celebrity.
> 
> sorry for the rant but i just felt i needed to clear up this lil mystery 
> 
> its simple here really, 3layer plywood is called triplex here, anything with more layers is called multiplex.


Well I stand corrected!

Thanks for clearing this up


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## All Buns Glazing

Yeah, why didn't someone say so!


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## Imperial

this needs to be pinned and put in the newbs section.


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## Dr J

Je concur, interesting post. If you really think of it the European terminology is much more relevant to what the product is. Three layers is called triplex, more than three multiplex. Compare that to plywood, which could be either. Personally I think we are trying to split hairs which is difficult with a slingshot/catapult (lol)


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## TimR

Dr J said:


> If you really think of it the European terminology is much more relevant to what the product is. Three layers is called triplex, more than three multiplex.


One problem is that the word triplex is already taken in the US.

It refers to the standard way houses are fed with electricity here, with two hot wires and a neutral. If you go to a builder's supply or hardware store in the US and ask for triplex they'll sell you wire.


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## Dr J

Not surprising, we need go no further than spelling. The important thing is to know what the product is called in the area in which you live.


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## wombat

I wasn't going to weigh into this but.... even wikipedia didn't clarify the difference!!

When Jorg mentioned *'multiplex'* he was talking about *Russian Birch* ply or *Baltic Birch *ply if you prefer, there's also a Finish version.

If you go to your local lumber yard and ask for birch plywood, they'll sell you a plywood that is *faced* with birch but there will only be about *5* *filler layers *and they can be anything.
Whereas if ask for *Baltic Birch* ply chances are they won't have it as it's hard to get at a local store, but it will be *15 layers *of alternating pure birch veneers!!!

Don't get hung up on what differnt countries call plywood/multiplex/laminate. What you want is* Russian Birch*, *Baltic Birch*, or *Finnish Birch* anything else for a sling shot is a waste of time!!

This video explains the difference as well as anything I've seen.


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## ash

I agree with everything Wombat has stated except to say that there are plenty of useful alternative to those he has named. I have some outstanding beech ply, for example. The key is to know what you're getting and that the mysterious layers inside are something strong enough for the job.

Here's a video showing how plywood is made. Possibly informative for those who have no idea how it relates to tree. Someone once asked me where ply trees grow


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## wombat

I'll go along with Ash, in that there probably are some other plys out there, but the trick is to know what you're getting. I also forgot to stress that the grain of the veneer layers must alternate!! Spectraply, although usually made from birch the grain runs in the same direction for all layers. So don't be surprised when it breaks.


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## Gardengroove

Good point @wombat. I just found out it is the same with Dymondwood / Dymalux. All ply's are oriented with grain in the same direction.


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## Metropolicity

My fave so far is to laminate 3 sheets of 1/4" of baltic to make a 3/4", that way the layers are compounded and 1/4: it MUCH easier to cut with a band saw (I use lasers) or a coping saw than 3/4".

It's a total of 15 layers of material as a result and all cross grain. VERY strong. I've used this layer technique to include features like recessed counter sinks, hollow voids for ammo storage etc.


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## HarryBee

I.'ve bought and used plywood for over fifty years and never heard of multiplex until I read the forum. Ya learn something every day !


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## leon13

A slight aside - I once had a customer ask me what a ply tree looks like :lol:

ahhhhhhhhh hihihi thanks 4 that one

cheers


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## Mr.Teh

leon13 said:


> A slight aside - I once had a customer ask me what a ply tree looks like :lol:
> 
> ahhhhhhhhh hihihi thanks 4 that one
> 
> cheers


 :rofl: ....a ply tree hihi but better than the nerving customers, greetings mr.teh


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## Sharker

> *Q: What is Baltic Birch?*
> Baltic Birch, aka 'Russian Birch', is a popular panel best known for its light color, strength, multi-ply construction, and affordable cost..,.


This is common wood in our country (Estonia) and its very common building material to


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## JEFF BURG

pay me and i will teach you to say PLY WOOD PLYYYYY WOOOOD ALL TOGETHER PLYYYYY WOOOOD NOTICE HOW IT ROLLS OF THE TONGUE :rofl:


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## Individual

If anyone is looking to buy plywood, but is concerned about the prices, i reccomend going to you're local "diy" shop or B&Q for brits (not sure about what countries B&Q is in) And asking if they have "misscuts" Today i purchased 28.5x22 inches and 20mm thick for less than £3, and two other sheets around half the size for £1 each. one is slightly damaged but for £1 i dont mind!


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## coyote-1

I actually like the idea of a different word to represent the higher-grade stuff. Just like both 'hooch' and 'bourbon' are words that describe whiskey distilled from grain, but the latter would be higher quality.

So 'multiplex' would work for me.


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## Viper010

coyote-1 said:


> I actually like the idea of a different word to represent the higher-grade stuff. Just like both 'hooch' and 'bourbon' are words that describe whiskey distilled from grain, but the latter would be higher quality.
> 
> So 'multiplex' would work for me.


Multiplex does not indicate high quality per definition. It comes in grades, just like plywood. Because, ey waddayouknow, that's what it is...

Multiplex is just the term most often used in Europe to indicate plywood with more than three layers. Three layer plywood is called triplex here.

Best suited for slingshots is the Baltic birch, or waterproof meranti multiplex. What you want is many thin layers, well glued, and no voids.
That makes for the strongest plank.


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## Dr J

What the h**L happend to this thread? for a while I thought I had been sent to Mars or outer space!


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## inkspot

hawk2009 said:


> I use the term multiplex for much the same reason as others do to sell your slingshot, multiplex is a word much more attractive than (plywood), all woods have a basic name but like the plywood they jazz it up and make it sound like something really special when in fact it is just another sales pitch, at the end of the day catapults/ slingshots are just a piece of wood or a steel rod heated and bent some are moulded and come in various shapes and sizes, they are not to hard to make attatch a quality piece of tube or flatband and hey presto. Its' a growing hobby that's cheap and almost free and you can have alot of fun shooting them if you knock up a natural and shoot stones through it. More and more people are jumping on the band wagon as they also see it as an opportunity to make money. its' a growing business and will do anything to sell their stock, I am a straight forward no bull**** kind of guy so I am sorry if this offends anyone but . It's only a matter of time now before our governments spot catapults/ slingshots as a money spinner and they then will be jumping on the wagon by introducing their taxes.


agree


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