Materials and Accessories
Pizzi Glue Spreader
Flexible Plywood
Bagpress D3 PVA
West System Epoxy Resin
West System Pump Dispensers
We have always understood that there is no point selling vacuum presses if our customers then have difficulty in finding the specialist materials required to make the most of their investment. We have therefore continuously expanded out range of plywoods, flexible veneers, adhesive, tools, mould making foam and other accessories that are available for delivery by mail order.
Polystyrene Block
We stock two thicknesses of mould making foam, 118mm and 165mm. These come in block sizes of 810mm x 1940mm and 600mm x 2500mm respectively. You should not that we have to cut these blocks in half to send them out but if you can collect you can have them full size. This material is an extruded polystyrene and is not made up of the friable beads associated with expanded polystyrene. It can be cut and shaped with normal woodworking tools and sands very easily. It has a compression factor of about 1% at 35 tonnes per square metre and, as a vacuum press generates about 8.5 tonnes per square metre, there is no distortion of the mould in the press at all.
Thin and Flexible Plywoods
There are two main plywood materials that are used extensively in the manufacture of curved panels and components, namely thin birch plywood and flexible plywood (AKA Flexiply, Bendyply etc). The former is usually 0.8mm or 1.5mm thick and comes in a sheet size of 1200mm x 1200mm and 1525mm x 1525mm respectively. Flexible plywood is stocked in 3mm, 5mm and 8mm thicknesses in both cross and long grain sheets measuring 1220mm x 2440mm. Please note that only cross grain sheets can be sent out by mail order although if you are fairly local you can collect long grain material or we may be able to deliver it on our own vehicle. As a general guide we would recommend that you use the thin birch ply as an outer skin with the panel core being made up flexible plywood. This gives a smooth and hard surface to veneer on to whilst reducing the number of glue lines (and therefore moisture added) to a minimum.
Adhesives
PVA
99% of all the panels that we laminate and veneer at Bagpress are bonded using a high grade D3 (water resistant) PVA adhesive. This type of adhesive has improved significantly in the last 20 years and, with the introduction of specialist materials such as flexible plywood (see below), can now be considered as ideal for most veneering and laminating jobs. We tested more than 15 different types of PVA before choosing the one that we now use in our own manufacturing workshop and this is the same product that we sell. You should note that we buy direct from the manufacturer and so you are guaranteed that the product is exactly the same formulation every time - something that isn’t always the case if buying a generic PVA from a hardware store or mail order catalogue.
Epoxy and Resocinol
The only time that we would recommend an adhesive other than PVA would be if the client specifies it (eg for fire rating rating purposes) or when making a structural component that will be exposed to constant or regular significant stress, for example a chair leg or skateboard.
Epoxy - We now stock the well know West System epoxy resins in 600g and 1.2kg pack sizes. The 1.2kg packs are available with either a slow or fast (not that fast!) hardener. The other advantage of the 1.2kg pack is that a pair of push pumps are available that screw onto the cans. One press of the pump head on each delivers a measured volume of each to give the correct mixing ratio giving 24g of mixed adhesive per dual pump dose. This can save a lot of time fiddling about with measuring jugs or weighing scales. It also makes it possible to mix several small batches when gluing up a job rather than a single large one (which results in a much shorter pot life due to the exothermic nature of the cure process). Once the adhesive is spread as a thin film the cure process is much slower than when it is a single mass in the mixing pot. West System epoxy cures almost clear and can be used as a heavy duty high gloss finish although it doesn’t offer a particularly high level of UV protection.
The faster of the two hardeners will give a cure time of around 16 hours (pot life of 15 minutes based on 100g mass @ 25°C) and the slower a cure time of around 24 hours (pot life of 20 minutes based on 100g mass @ 25°C) Pot life is extended at lower temperatures.
Resorcinol Resin - This is a two part phenolic adhesive which is commonly used in the manufacture of plywood and gives the distinctive dark coloured glue line especially associated with birch plywood construction. Resorcinol is an extremely effective bonding agent and is resistant to most environmental influences including salt water and strong sunlight and, as such, is popular with boat builders. The resorcinol compound itself is used in various medical treatments and the glue does have a strong smell reminiscent of hospitals or industrial cough sweets! If you are trying to replicate the appearance of a plywood glue line or if the colour doesn’t matter then this is a very good choice of adhesive for large or structural or stressed components. It isn’t, however, an adhesive you would use with figured sycamore! Resorcinol can be mixed in much bigger batches than epoxy and offers a pot life of at least 45 minutes - 1 hour at 25°C and a cure time of 16 - 24 hours depending on temperature.
If using either of these adhesives in an education environment please check your H&S guidelines.
User Guide and data sheet downloads
WestResinsPhysicalProperties.pdf
ResorcinolHardenerSafetyData.pdf
Flexible Veneers
Flexible veneer can be an easy way to veneer larger areas especially if you are unpracticed in the art of joining leaves of veneer together. This material is supplied in mainly long grained sheets measuring 1220mm x 2440mm and is made up of a joined veneer lay on that has been bond to a fibrous backing sheet, sanded and then passed through a roller system that imparts a high level of flexibility with the grain.
We stock a range of standard commercial species as well as some unusual specials such as fumed oak, red elm, tiger brown oak and European figured sappy walnut. We can also have custom manufactured to your specification so please ask if you are looking for something unusual.
Finishing Oil
If you are looking for an easy to apply finish to bring out the beauty of your veneer then an oil may be a good solution. We stock two Fiddes finishing oils (satin finish or matt) which are simply wiped on, wiped off and then left to dry for 24 hours. Two applications are usually all that are required to produce a beautiful finish. Fiddes oils does not become tacky anywhere near as quickly as Danish oil and so it is easier to achieve an even coating and without contamination with fibres from the application cloth.