50% developed  as of April 22, 2006

Do-It-Yourself/Wooden boat – Wikibooks, open books for an open world

By David Moss
50% developed  as of April 22, 2006 (April 22, 2006)

Deciding on a design[edit]

The design (structure) concerned for this challenge would possibly simply be essentially the most troublesome a part of the entire course of.

Your first boatbuilding challenge ought to be easy and cheap, but the boat must be helpful when it’s completed. The stability between these standards is a person resolution. The Web is a good place to start out when searching for a design. A web site I discovered helpful without cost design info was http://dwelling.clara.web/gmatkin/design.htm.

In my case I selected the “Dug”, designed by Hannu Vartiala. Free plans can be found on the internet at Hannu’s Boatyard: http://koti.kapsi.fi/hvartial.

Dug canoe.JPG

I selected the Dug as a result of I wished one thing easy and cheap as my first boatbuilding challenge. It’s created from a single sheet of plywood so it doesn’t get any cheaper, and the design on the web site regarded straightforward to observe.

I modified the design to make use of 3mm plywood slightly than 6mm. Not solely was the thinner ply cheaper, nevertheless it was a lot lighter. It additionally gave me the chance to experiment with becoming gunwales.
The completed product was a one individual canoe. I can choose up and carry this boat simply on my own and it virtually floats on moist grass. It’s excellent for fishing within the shallow rivers across the headwaters of the Murray Darling system in Queensland, Australia.

The Dug was my selection, although. Your personal selection of design on your first boatbuilding challenge could be completely different.

Plywood[edit]

Plywood is a person made development materials. It normally consists of an odd variety of layers of skinny timber veneer glued along with the grain of alternate layers working at 90° to one another. The outermost layers are termed the faces. Since these are the one seen layers, the looks of every face is topic to plain specification. In Australia every face of a plywood sheet is described by a code letter:

  • A — a top quality look grade veneer appropriate for clear ending.
  • S — an look grade veneer which allows pure traits akin to knots as an ornamental characteristic topic to settlement.
  • B — an look grade appropriate for top of the range paint ending.
  • C — a non-appearance grade with a stable floor. All open defects akin to knot holes or splits are stuffed.
  • D — a non-appearance grade with permitted open imperfections. Restricted numbers of knots and knot holes as much as 75 mm broad are permitted.

Marine plywood that meets the AS/NZS 2272 commonplace has two A grade faces and an A or B grade core.

Within the USA some producers use a letter code for the “entrance” face and a corresponding quantity for the “again” face, i.e. a code of AB in Australia could also be specified as A3 within the USA.

Typical functions utilizing this grading commonplace are AA for marine plywood, AD for a wall cladding the place solely the entrance face of the plywood is seen, CD for structural plywood flooring and DD for structural bracing.

The adhesive used to bond collectively the laminations within the ply is of paramount significance to boatbuilders. There are 4 commonplace glue rankings:

  • Sort A bond is produced from a phenol-formaldehyde resin [PF] which units completely underneath managed warmth and stress. It kinds a everlasting bond that won’t deteriorate underneath moist circumstances, warmth or chilly. It’s readily recognisable by its black color. Sort A bond is laid out in AS/NZS 2272 for marine plywood.
  • Sort B bond is produced from melamine fortified urea-formaldehyde resin [MF] which units underneath managed warmth and stress.
  • Sort C and Sort D bonds are inside use bonds produced from urea-formaldehyde resin [UF] and shouldn’t be utilized in boatbuilding.

Plywood for boatbuilding is historically bought in eight foot x Four foot sheets. In metric this rounds out to 2400mm x 1200mm.

It’s obvious from these dimensions that it’s mandatory to affix plywood sheets collectively to construct even the best of boats.

Exterior grade ply[edit]

Exterior ply is manufactured in accordance with AS/NZS2271 from a wide range of supplies together with hardwoods and ornamental veneer facings akin to Sapele, White Ash, Teak, or inlaid Teak and Beech.

It’s not manufactured to the identical engineering requirements as marine ply however is commonly fairly appropriate for a primary boatbuilding challenge. The glues used between the layers are the identical as these utilized in marine ply so delamination shouldn’t be an issue

Exterior grade ply could have one “good” face and the opposite of lesser grade, for instance AB.
The “Dug”, my first boat, was constructed utilizing exterior grade ply in pacific maple.

Marine ply[edit]

Marine ply is an engineering product that should adjust to revealed requirements. In Australia the related commonplace is AS/NZS2272. Within the USA, the UK and different components of the world the BS1088 commonplace could also be used to specify marine ply. These requirements element virtually each side of the composition and efficiency of marine ply. If you’ll construct a seaworthy boat, or a ship that should meet survey requirements, use of an authorized marine ply is important.

Within the Australian/ New Zealand Requirements system for veneers and bonds marine plywood has a grading of AA – A bond and may have the ‘PAA Examined marine’ stamp utilized to the sheet. If it isn’t stamped then it’s more likely to be materials which has not handed closing inspection.

Some examples of marine ply obtainable in Australia are:

  • Hoop Pine: AS 2272 Commonplace, Australian made premium plywood.
  • Gaboon: BS1088 and BS3655 Requirements, mild weight plywood having Lloyds Register certification.
  • Mahogany: BS1088 Commonplace, premium plywood
  • Pacific Maple: BS1088 Commonplace, essentially the most economical however barely heavier plywood.
  • Cortech: Balsa-cored plywood, has a really excessive stiffness to weight and energy to weight ratio. To be used in boat hulls, decks and so forth.
  • Veneered Plywood: Waterproof plywood with teak, ash and sapele ornamental veneer. Additionally teak/ash striped plywood for boat soles and decks.

Becoming a member of Plywood sheets[edit]

Plywood for boatbuilding is historically bought in eight foot x Four foot sheets. In metric this rounds out to 2400mm x 1200mm. It’s obvious from these dimensions that it’s mandatory to affix plywood sheets collectively to construct even the best of boats.

Two strategies are generally used to affix plywood sheets collectively:

  • The butt joint
  • The headscarf joint

The butt joint is by far the simplest to make. It’s fashioned by making use of liquid epoxy to the sides of the sheets to be joined, pushing them collectively and gluing a strip of ply to 1 or each side of the seam.

Buttjoint.jpg

A variation is to make use of fibreglass tape as an alternative of the strip of ply. As soon as the epoxy has cured the be a part of is stronger than the plywood sheets themselves and the wooden will fail underneath stress earlier than the epoxy of the joint.

Trace: Epoxy doesn’t stick with polyethylene. Laying down a sheet of polyethylene movie, akin to a disposable painters drop sheet, can save the embarrassment of gluing your work to the ground when becoming a member of sheets.You can even use baking paper for this goal if polyethylene will not be obtainable.

Lofting[edit]

Lofting is the method of taking the scale from a plan and drawing full measurement parts on the development supplies.

Utilizing the lofting batten

Typically the designer gives the required measurements within the type of a desk, however generally it’s essential to take the measurements immediately from the drawing and scale them as much as life measurement.

First a centre line is marked, then sequence of station traces are drawn on the ply at common intervals 90° to the centre line utilizing a set sq.. Station traces could also be drawn each 10cm for instance. The distances both aspect of the centre line at every station line are decided from the plans and marked on the ply as reference marks. Lastly clean lofting traces are drawn by means of the reference marks. A straight edge akin to a metal ruler could also be used for straight traces and the lofting batten is used for clean curves. It’s useful to briefly drive panel pins into a number of the reference marks to make sure the lofting batten follows the proper curve.

As soon as the lofting course of is full the lofting traces are used as reducing guides when the parts are reduce from the sheet.

Epoxy is the fabric that makes wood boatbuilding attainable for the common individual. It’s used as an adhesive, a structural element, and to seal the wooden to cease it absorbing water.

Wikipedia has an article about epoxy at http://en.wikipedia.org/wiki/Epoxy.

The WEST System[edit]

The Wooden Epoxy Saturation Approach, or WEST system, is a method for sealing a wood boat in opposition to the ingress of moisture. A skinny layer of liquid epoxy is utilized to the wooden like paint. Among the epoxy is absorbed into the grain and the pore construction of the wooden whereas the epoxy is a liquid and when it hardens the wooden is successfully protected by a moisture proof barrier.

The WEST System is a generic boatbuilding approach, but additionally a registered commerce title for a model of epoxy merchandise manufactured underneath license from Gougeon Brothers, Inc. USA. The Gougeon Brothers developed the epoxy coating of the unique WEST system along side DOW Chemical substances within the late 1960s. Since that point epoxy methods, together with the WEST System model, have undergone vital improvement. At present there’s a variety of producers providing epoxy methods for wood boatbuilding. An internet search utilizing the time period boat constructing epoxy will return hundreds of references, tailoring the seek for your personal location ought to return greater than sufficient native epoxy producers to select from.

A phrase of warning nonetheless. Not all epoxy formulations are appropriate for sealing a wood boat in opposition to moisture. Marine coating epoxies typically don’t embody natural solvents or thinners. They might be described as excessive solids epoxies. The reason being that natural molecules are a lot bigger than water molecules. When natural solvents evaporate from the liquid epoxy throughout curing the departing molecules could go away microscopic tunnels that enable a lot smaller water molecules to enter. This reduces their effectiveness as a moisture barrier and makes them unsuitable to be used as a marine coating.

When constructing my first wood boat I selected Bote Cote, a excessive solids epoxy produced by an organization in Brisbane, the closest main metropolis to my residence. My selection was largely influenced by comfort, status for high quality, and the need to assist a neighborhood enterprise. Your selection of an epoxy system could also be influenced by comparable concerns however as long as you select a top quality epoxy appropriate as a marine coating, the selection is yours.

Mixing Epoxy[edit]

Probably the most important a part of the epoxy course of is mixing the correct quantity of hardener with the epoxy resin.

Saved individually the hardener and the resin will keep in liquid type. When blended collectively the hardener acts as a catalyst and induces the resin to polymerise, or type cross linkages between its molecules. As these bonds between the molecules type the viscosity of the combination will increase and ultimately, after a couple of hours, it solidifies. The response continues for a number of days afterward so it is necessary to not apply extreme stress to the fabric for at the least 24 hours after utility.

The speed at which the polymer bonds type relies on the chemical properties of the hardener used and the ambient temperature. The response that kinds the bonds is exothermic which suggests warmth is generated every time a brand new bond is fashioned. The warmer it’s, the sooner the bonds type and the warmer it will get, so new bonds type even sooner. The warmth normally escapes to the encircling air by conduction so you will need to unfold the epoxy out in a tray slightly than hold it in a pot after mixing. The higher floor space of the tray permits extra warmth to flee and will increase the pot life, the time when the combination remains to be skinny sufficient to use successfully.

The pot lifetime of a batch of epoxy is mostly about 45 minutes. As soon as a batch has reached the tip of its pot life it’s not attainable to use it, so it have to be discarded. It is smart to combine up small portions of epoxy at a time. Solely combine up as a lot as you’ll be able to comfortably apply throughout the pot life or you’ll waste a variety of costly epoxy.

Polyethylene containers akin to these utilized by some takeaway meals retailers are glorious mixing pots for epoxy. Epoxy is not going to stick with polyethylene so it’s straightforward to peel out the skinny layer of hardened epoxy subsequent day and re-use the container.

You will need to observe the producers instructions about mixing ratios precisely. Including roughly hardener to the combination is not going to have an effect on curing time or pot life, however it’ll cut back the energy of the bond.

It is usually vital to make use of the kind of hardener the producer recommends for the ambient temperature of your workshop. Bote Cote advocate the next hardeners to be used with their epoxy system:

Quick Hardener: To be used in southern Australian climates and in winters, has a pot lifetime of 45 minutes and a skinny movie set time of 5-6 hours at 14-16 deg.C. Can be utilized at temperatures as little as eight deg.C.
Commonplace Hardener: Appropriate for hotter circumstances and southern summers, has a pot lifetime of 45 minutes and a skinny movie set time of 5-6 hours at 20-22 deg.C.
Tropical Hardener: For decent climates akin to northern Australia the place temperatures not often fall beneath 30 deg.C. and there’s persistently excessive humidity. Has a pot lifetime of 45 minutes and a skinny movie set time of 4-5 hours at 30 deg.C.

Metric conversion trace: go to google.com and sort “20C in F” within the search field.
This neat trick works in changing many different items too. (you’ll be able to check out the instance right here)

Some producers additionally provide a hardener accelerator. For Bote Cote the addition of two% accelerator doubles the reactivity (half the pot life) whereas 4% makes it react Four occasions as quick. The accelerator will not be a substitute for hardener, it simply speeds the method. This may be helpful when you’ve got a provide of tropical kind hardener however wish to use it with epoxy on a chilly day in winter.

No matter epoxy system you select you will need to observe the producers instructions precisely when mixing.

In my case the combo ratio was two components of epoxy resin to 1 half hardener. Whereas it’s attainable to combine epoxy to the proper ratio utilizing measuring cups, or by weight, I made a decision to buy measuring pumps once I purchased my epoxy.

Epoxy system and fibreglass tape

Two hand operated pumps have been required, one for the epoxy resin and one for the hardener. The pumps have been cheap (round AUD$10 every), match immediately on to the bottles, and I’ve by no means regretted the choice. Mixing was merely one squirt of hardener to each two squirts of epoxy resin. I extremely advocate measuring pumps to anybody intending to construct a wood boat.

As soon as the epoxy and hardener has been allotted within the appropriate ratio it’s important to ensure it’s totally blended. Stir the combination rigorously for a number of minutes with a flat, disposable stirrer. Some skinny plywood offcuts trimmed to measurement are preferrred.

When the epoxy is totally blended many individuals switch it to a different container earlier than utility, even when the amount is simply too small to fret about it exotherming within the mixing pot. The rationale for that is irrespective of how cautious you’re with mixing, there’ll all the time be some unmixed epoxy resin or hardener adhering to the perimeters of the pot, or proper down within the corners. If a single drop of this unmixed resin finds its means on to your work it’ll lead to a sticky spot that can by no means remedy correctly. Murphy’s legislation dictates the sticky spot will happen within the worst attainable a part of your floor. Pouring the combo right into a clear container and giving it a closing stir with a clear stirrer is affordable insurance coverage in opposition to undesirable sticky spots within the epoxy.

Thickening Epoxy[edit]

Correctly blended epoxy is a really runny liquid. It’s preferrred for portray on to wood surfaces, however generally its low viscosity can current an issue. Build up a fillet within the be a part of between a horizontal and a vertical floor is inconceivable with out the addition of a thickening agent.

Epoxy producers promote a wide range of thickening brokers. Bote Cote provides the next fillers that can be utilized to thicken epoxy in numerous conditions:

Excessive Power Filler: A excessive density glass fibre and particle filler for max energy gluing functions akin to catamaran beams, mast bulkheads, load carrying transoms, and so forth.
Glue Filler: A low price blended filler used for many gluing functions and in addition for making all fillets.
Fairing Filler: A low density, simply sanded microsphere based mostly filler, which spreads like cream to an ideal feather edge. Used for filling and fairing.

Most producers provide their very own variations of those filler merchandise.

Some producers additionally provide wooden flour for thickening epoxy. Hannu’s Boatyard, the location the place I sourced the plans for my first boat, advised plain previous wheat flour as an efficient epoxy thickener. That’s what I used when constructing the “Dug” and it labored simply nice.

As soon as the epoxy has been totally blended, merely add your chosen thickener a little bit at a time, stirring constantly, till the combination reaches the specified consistency. It is smart to make use of as little thickener as attainable in keeping with the appliance. Each particle of thickener within the combine is a particle that doesn’t type polymer bonds with the encircling epoxy. The much less thickener within the combine, the stronger the fabric will probably be when it hardens.

I added enough plain wheat flour to deliver the epoxy combination to the consistency of peanut butter in an effort to type the fillets wanted on the “Dug”.

Instruments helpful in developing the boat included

  • Energy drill
  • Energy jigsaw
  • Energy airplane
  • Random orbit sander
  • Handsaw
  • Hand airplane
  • Hand sanding block
  • Clamps (plenty of them)
  • Lofting batten (an extended, straight, versatile strip of wooden to assist in drawing even curves)
  • Set sq.
  • Metal ruler
  • Tape measure

Protecting gear[edit]

  • Particle masks
  • Security glasses
  • Disposable plastic gloves
  • Shut weave work clothes

A particle masks is important. There’s a variety of sanding in boatbuilding and the mud it generates will not be good on your well being. Wooden mud itself is dangerous sufficient, however if you add epoxy mud and fibreglass mud you’ll undoubtedly wish to hold it out of your lungs. You should purchase disposable paper particle masks fairly cheaply at {hardware} shops.

Security glasses are extremely really helpful. Personally I put on prescription glasses so I don’t have to fret about particular security glasses. Individuals lucky sufficient to not want spectacles ought to contemplate buying a pair of security glasses earlier than utilizing chemical substances like epoxy and hardener.

Disposable plastic gloves are additionally a good suggestion if you find yourself mixing or making use of epoxy resin. Some individuals quickly develop into sensitised to epoxy and develop dermatitis. Disposable plastic gloves forestall pores and skin contact from occurring within the first place and keep away from potential well being issues. Disposable plastic gloves can be found cheaply at main grocery store chains.

Shut weave work clothes with lengthy sleeves and lengthy trousers is extremely really helpful. If you’re contemplating greater than only one boatbuilding challenge it is perhaps sensible to put money into mild cotton overalls. I made the error of sanding fibreglass strengthened joints sporting solely a pair of shorts. This was very comfy on the time within the scorching Queensland summer season, however very uncomfortable for over every week afterwards when the glass fibres within the mud made their presence felt. Ever since I’ve worn cotton drill work garments with sleeves down whatever the temperature!

Sew and Glue[edit]

Sew and glue is a method for developing complicated three dimensional objects utilizing plywood and epoxy resin.

The sew and glue methodology was developed by the primary tv “do it your self” (DIY) professional, Barry Bucknell, in about 1964. Wikipedia has an article about sew and glue at http://en.wikipedia.org/wiki/Stitch_and_glue.

The sew and glue approach

First a row of small holes about 10cm aside is drilled near the sting of one of many mating items of plywood. An identical gap is drilled within the different piece adjoining to every of those holes as development proceeds and the 2 items are stitched collectively utilizing both copper wire or plastic cable ties.

As soon as the mating items have been stitched collectively a fillet of epoxy is utilized to the joint, gluing the items collectively. Within the photograph on the suitable a bit of waste plywood with a radius sanded on to 1 nook is getting used to unfold thickened epoxy into a good fillet.

Should you look intently on the {photograph} you’ll discover the sides of the mating plywood items are darkened. It is because the sides have been wetted out with a lightweight coat of liquid epoxy earlier than the thickened epoxy of the fillet was utilized. The unthickened epoxy wicks into the grain of the plywood permitting higher adhesion. Since each the thickened and unthickened epoxy remedy collectively they type a single polymerised construction of nice energy. In truth the joint fashioned is stronger than the plywood itself. As soon as cured the wooden will break earlier than the epoxy of the joint if enough pressure is utilized.

When the epoxy fillet has cured the stitches are eliminated. The holes stuffed and the addition of fibreglass tape and extra epoxy gives the required degree of structural energy to the joint.

Portray[edit]

Portray a wood boat is greater than only a beauty impact. The paint kinds a necessary a part of the boat’s construction.

If a wood boat will not be sealed in opposition to moisture it’ll take in water, the wooden will swell up and extreme harm can happen.

Most wood boats as we speak are sealed in opposition to water utilizing a skinny coat of epoxy. Epoxy does a terrific job sealing out moisture however is vulnerable to break from ultraviolet mild (UV). Unprotected epoxy will probably be broken by the UV rays in daylight and begin to deteriorate in a single season.

Fortuitously most exterior grade paints supply good safety in opposition to UV mild in addition to added safety in opposition to moisture ingress.

Deciding on a paint[edit]

Deciding on a floor end on your boat is a posh job. Should you go right down to your native ironmongery store and ask for a paint that’s good over epoxy you’ll most probably be greeted with a clean look. Only a few paints particularly state they are often utilized to epoxy. The excellent news is that almost all paints will stick nicely to epoxy regardless of the dearth of formal specification. Success is determined by floor preparation nonetheless.

Individuals usually change their minds about floor end throughout the development of the boat. They begin out with a imaginative and prescient of the boat painted in stable covers, however throughout the development course of the fantastic thing about the timber is revealed, particularly within the areas the place unthickened epoxy has been used. Epoxy kinds a clean, clear, shiny floor that enhances the grain of timber. Its too dangerous it might’t simply be left as-is however sadly it breaks down rapidly when uncovered to UV mild. Epoxy should be protected by a coat of UV stabilised paint or varnish if it will likely be uncovered to daylight.

Some floor finishes which were advised for marine use are:

  • standard-type marine enamels
  • silicon/alkyd varieties
  • epoxy paints
  • one or two-part urethanes
  • Linear polyurethane

Every of those floor finishes has its personal benefits and drawbacks. For my first challenge I chosen a latex kind exterior acrylic home paint. It was comparatively cheap, fashioned a clean medium gloss end and adhered nicely to the WEST handled plywood of the boat.

Some producers advocate the usage of etching primer earlier than the appliance of their product. This ignores the truth that cured epoxy is chemically inert. Etching primers, which depend on a chemical etching motion, haven’t any impact in any way on cured epoxy.

The one option to obtain good paint adhesion on cured epoxy is to flippantly sand the floor previous to utility, making thousands and thousands of microscopic scratches on the floor. This facilitates mechanical keying of the paint to the floor, decreasing the possibility of peeling.

Preparation[edit]

Earlier than doing any ending work or making use of finishes, enable the final coat of epoxy to remedy 5 to 7 days if the ambient temperature is above 20°C, even longer at colder temperatures. (There’s a variety of ready in all features of boatbuilding)

Some epoxy methods endure from amine blush, a greasy substance that kinds on the floor throughout curing. In case your chosen epoxy system suffers from this drawback, wipe down the work with a water/ammonia dampened rag or sponge previous to sanding. It will get rid of the greasy amine blush, make sanding simpler and decrease clogging of the abrasive paper.

Utility[edit]


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