• SCREWS - Screws are also good for mounting hardware and trim, constructing cabinets, and joining furniture parts, like attaching a tabletop to a base. Because screws cause less vibration—and less potential damage—upon insertion, they're also preferable when working with more delicate materials like plaster and drywall.

Screws are preferred for such tasks as:

Hanging drywall.

Attaching ledger boards.

Installing cabinets.

Fastening wood decking.

Fabricating cabinets, wooden toys, bookcases, and other woodworking projects.

For any wood-to-wood connection that you may need to take apart.

• NAILS - Nails are often preferred for large projects, like house framing and installing hardwood floors, because they are typically stronger and less expensive than screws. Since most nails have smooth heads and shafts, they insert easily and speedily with a hammer or nail gun.

• NUTS / BOLTS- Electrical equipment, automobiles, and spare parts are just some of the things that use nuts and bolts for fasteners.  Nuts and bolts are dimension specific and are strong and durable to ensure long life of the product that they hold together. 

• HYNGES - Hinges play a vital role in the movement, or opening and closing of doors and gates. They facilitate easy movement. Hinges can be of different types, which are used for various types of doors and gates.

• CATCHES - Catches and latches are terms frequently interchangeable but importantly they are mechanical fasteners that allow the joining between two hardware surfaces that frequently are used for the enclosure of cabinets, cabinets and door furniture.

• SIZE OF SCREWS - Metric Bolt Sizes

• The letter 'M' indicates that this bolt uses a metric thread.

• The number '8' refers to the nominal diameter of the bolt shaft in millimeters.

• The number 1.0 is the thread pitch of the bolt, which is the distance between threads, in millimeters.

• And the final figure, 20, is the length in millimeters.

M8 -1.0 x 20mm

Adhesive, any substance that is capable of holding materials together in a functional manner by surface attachment that resists separation. “Adhesive” as a general term includes cement, mucilage, glue, and paste—terms that are often used interchangeably for any organic material that forms an adhesive bond.

• POLYVINYL - ACETATE ADHESIVE (PVA) - Polyvinyl-acetate glues encompass a range of products from Elmer’s white glue to Titebond III, a yellow glue designed to be used in extreme outdoor conditions. PVA glues are classified into three categories based on their water resistance.

Type-III (not water resistant) PVA glue consists of as much as 50% water and cures as the water evaporates. Glued surfaces must be clamped together until they reach 15% to 20% of their bond strength, generally in about an hour. It can take as long as 24 hours, however, to reach full strength.

Type-I (waterproof) and type-II (water resistant) PVA glues, such as Titebond II and III, contain water, but also strands of polymers that become entangled and chemically bonded to perform better in exterior conditions. These adhesives demand the same clamp time as type-III PVA glue, but generally have a longer open time and bond at colder temperatures.

Water resistance aside, there’s little difference in the strength of the joint made with any type of PVA glue. They all can resist forces around 3500 psi to 4000 psi. PVA glue can be cleaned up with water. Once it’s dry, you can scrape or sand away excess glue.

• POLYURETHANE ADHESIVE - Polyurethane glues like Gorilla Glue and PL Turbo outperform PVA glues in several applications, such as bonding foam, stone, concrete, and ceramics.

One benefit of polyurethane glues is that because they are not water-based, they are not drawn into wood pores as drastically as PVA glue. For this reason, wood joints glued up with polyurethane accept stains and clear finishes better than with other types of glue. Polyurethane glues also enable you to glue up pieces even after a finish has been applied.

Because polyurethane glues cure by a chemical reaction triggered by moisture, they work well on wood with high moisture content or on oily woods, where PVAs have a hard time bonding. Polyurethane glues generally take six to eight hours to reach full strength and require the workpiece to be clamped for a proper bond. The clamps usually can be removed after about four hours.

The cured strength of polyurethane glue is slightly less than that of PVA—generally around 3000 psi—but still plenty strong for most any home-building application.

Prior to drying, polyurethane glue can be removed using solvents such as mineral spirits or acetone. Once the glue has cured, you can scrape or sand away squeeze-out.

• CYANOACRYLATE ADHESIVE - Not all CA glues are created equal. Some are one-part systems (Krazy Glue), and others require an activator to set up properly (2P-10). You also can buy CA glues in a wide range of viscosities, from thin versions that bond in as little as 10 seconds and cure at 30 seconds to thicker gels that have about a 10-minute open time and require clamping.

Marketed as an all-purpose glue and recognized most often as Super Glue, CA glue bonds to most any surface. It’s more expensive than PVA or polyurethane glue, which means that it is seldom a smart choice for bonding large surface areas.

Many trim carpenters swear by CA glues for their strength, speed, and ease of use. If you’re working on a crown miter joint, for instance, you can apply the glue to one side, the activator to the other, then simply hold the joint in place for a few seconds until the glue bonds.

One downside of CA glues is that they are brittle, so they are more likely to fail under impact. But the strength of CA glue is not far behind PVA glues, with some capable of withstanding up to 4000 psi. Cleanup of CA glue requires a solvent, such as acetone, prior to curing. After curing, you can scrape or sand away squeeze-out.

• ADHESIVE PREPARATION - 

Removing intermediate surfaces

When considering surface preparation, first think about the materials you want to bond together. Do you want to bond paint to an oxide layer, or do you really want to bond the steel that is under the paint to the aluminium that is under that aluminium oxide layer? Do you want to bond that mold release agent to mold release agent or bond the pieces of polycarbonate under that mold release agent? In summary, use the surface treatment necessary to remove what is covering the material to be bonded.

Paint removal

Even when it appears easy to just apply adhesive epoxy directly on top of the paint, it is important to bear in mind that the strength of the joint is only going to be as good as the strength of the paint – i.e., if the paint peels off, then the bond will fail. For this reason, it is a very good idea to remove the paint and bond directly to the material underneath.

Rust/oxide layer removal

Removing rust mainly requires a good rust cleaner with oxalic acid. Try out a few brands and see what you like best. Make sure to use rubber gloves and goggles, as this stuff can be pretty abrasive.

Use a wire brush and the cleaner to scrub away the rust.

Depending on the extent of the damage caused by the rust and the adhesive you’re using, you may have to sand (or preferably abrade) the area down to a smooth surface before applying the adhesive.

It’s a good idea after all this sanding and brushing to give your metal surface a good clean off with a clean cloth and some acetone or isopropanol. These act as a good degreaser and evaporate to leave a clean, dry, contamination-free surface to bond to.

Many metals form an invisible oxide layer which can on occasion be quite weak. It is a good idea to abrade and degrease all metals before bonding, if possible. Use carborundum paper to abrade metal (similar to sand paper but more robust and less messy). If you have a lot to abrade, using a grit blaster is a good idea, so as not to end up with arms like an Olympic shot-putter.

Sanding

Okay, we all know how to sand, more or less, but there are a few tricks you can apply to improve your sanding kung fu…

Some general tips for sanding:

Use high-quality paper. It tends to last longer and be more effective.

Always start with the big, chunky, coarse papers, and work your way down to the finer grain papers. The coarser papers will even out the surface while the finer papers will smooth it down.

Tap the dust off of your sanding paper now and then to keep the grit from building up and scratching the surface or impeding the paper’s progress.

Some tips for abrading metal:

Before abrading, remove grease from metal surfaces with acetone or isopropanol. This prevents you from embedding the grime any further.

Use carborundum paper rather than sandpaper, starting with a rough grade to remove the bulk of the oxide layer and then a fine grade to get a good finish.

When dry abrading, don’t push down on the paper. Apply a light touch and let the paper do the work.

For a more consistent surface, don’t just sand in one direction, use an even, circular motion to give the adhesive a good surface to “key” into.

When wet abrading, apply a little bit of pressure and short strokes. Use plenty of water and don’t let the surface dry while sanding. It is important to dry the metal straightaway afterward to prevent rusting.

Cleaning

Of course, you need a clean surface. If you’ve got a layer of dirt on both surfaces, all you’re doing is sticking dirt to dirt.

The main task at hand is just removing any dust, grease or mould, so anything that gets the job done is fine. Know your surfaces and how to clean them. However, on some surfaces you may not be able to visibly see dirt or contamination – there may be traces of release agent if the component has been moulded or silicone-based cleaning agents which can be present on glass surfaces. Using an isopropanol wipe before bonding will set your mind at ease.

Increasing wetability

In order for an adhesive to effectively bond to a substrate, it must be able to “wet” the surface. Some surface treatments affect the surface energy. In non-technical terms it is the difference between water on a freshly waxed car which beads up and rolls off or water on an old unwaxed car that wets the entire car. Methods to increase wetability include plasma treatment, corona discharge and product-specific primers.

• ADHESIVE DRYING TIMES - In most situations, you can expect the adhesive to be fully cured in 24 hours or less. Some take less, like cyanoacrylate glues, also known as CA glues. Adhesive dry times also vary depending on humidity, temperature, and the material you're bonding. In extreme moisture situations, some adhesives may not cure at all.

• ADHESIVE HEALTH AND SAFETY - Use adhesives and sealants in well-ventilated areas, and avoid inhaling the vapours. Avoid build-up of solvent vapours in the work atmosphere (hot spots) by ensuring adequate ventilation and the use of flameproof exhaust fans where necessary.

The chemicals in adhesive and sealant systems can affect health when they come into contact with the skin, or if they evaporate and form a mist or vapor in the air. The main effects of overexposure are irritation of the eyes, nose, throat, and skin; skin allergies; and asthma.

If you do come into contact with adhesives, follow these guidelines: - Hands: Wash well with soap and water and use a skin moisturiser afterwards. - Eyes: Wash repeatedly with running water for at least 10 minutes. Cover the affected eye with a sterile bandage and consult an eye specialist.