We investigated ordinary Marine Ply, and Skatelite ™, and Phenolic Resin coated board. We used 18mm wirefaced Phenolic ply on all flat surfaces, including flatbanks and funbox ramps, and 6mm on curved surfaces, over two thicknesses of 6mm marine ply. All side panels are 18mm Marine Ply, painted.
Marine Ply, however good, will always “fray” under use, with thousands of tiny splinters making a “furry” surface. These splinters aren’t dangerous, but they harbour moisture long enough for algae to grow, and that makes the surface slippery.
Skatelite ™ is an exceptional surface, but can be dangerous when damp, and unfortunately this ain’t California. It is also extremely expensive, even if purchased in bulk direct from the UK importers. Most manufacturers fix Skatelite ™ with pot rivets, but these snap in their hundreds in use because of electrolytic corrosion at the junction between steel frame and ally pot rivet..
Wire Faced Phenolic Coated Ply is marketed in the UK under the trade names of “WisaWire” or “Buffalo”, and is predominantly used for Truck and Trailer Floors. It is designed to sustain industrial loads and impacts, forklift trucks, and 1-1.5 tonne pallets being dropped and slid about. It is Tough! It can be purchased in 18mm and 6mm thicknesses, and whilst dearer than Marine Ply, is about a third the cost of Skatelite ™. It is also waterproof. Ours has been supplied by EE OLLEY & SONS at Dartford, http://www.eeolley.co.uk/ It also has the virtue of being waterproof.
We have now used this material on two skateparks, both for about 4 years, and apart from some gouges where people have stacked, there has been NO WEAR! Be careful when handling new sheets, the fresh surface is extremely rough, and the edges of the coating are sharp, but this quickly smoothes off. Be careful handling it, the underside is VERY slippery, and a sheet can very quickly get out of control.
All fixing to frames was achieved by using 50mm x 14g self tapping posidrive screws obtained from local Truck parts Factors, again used for trailer and truck floors. These will need predrilling.
We did experiment with roofing screws that have their own drill bit cut on the end of each screw, but we found that the threads were very thin, and quickly rotted and came loose. We have since used #14 x 50mm self tapping screws, sold by truck motor factors. We have found that over 3/4 years the screw and the threads in the hole rust, and screws can snap or bounce out. We tried Stainless Steel, but these are very delicate. Our latest experiment is to put a squirt of silicone sealer down the hole before the screw. This should keep the rust at bay.
FLAT SURFACESThe surfaces of decks and funboxes, and flatbanks are the simplest, just a question of screwing the 18mm sheets to the frame.
CURVED SURFACES sound a bit tricky, but they are quite simple using 6mm layers. Lay the first layer (marine ply) top to bottom of the ramp, securing mainly at the top edge first, with a couple of extra screws to hold the curve. Lay the next layer (marine ply) across those, from left to right, and again just a few screws to hold them in place. The top sheets are wirefaced, and lay them top to bottom. Get each sheet butted to the top and butted together at the centre, and put a row of screws along the top. Use a length of box steel and two clamps to pull the sheet inwards as you progress downwards, stitching the sheets down with self tapping screws down the centres first, and then the outer edges. Screws should be spaced at about 300mm gaps, but note where the under braces are before you drill, you don’t want to be drilling through 2 or 3 layers of steel.
TRANSFER EDGES from decks to ramps, and ramps to ground, we have used 150mm wide 2mm thick Zintec plates.
Zintec is a galvanised steel plate, and we were lucky enough to have it donated cut to size, drilled and countersunk, by a local engineering company.
PAS 35 Regulations suggest 3mm, but as the same regs also say no lip more than 3mm, a bit of dirt under the plate can make a trip hazard. 2mm is also more flexible, easier to work and drill.
Where we secured these plates to the ground we used a wonderful invention, available from Screwfix, called Multi-Monti. You drill a 5.5mm hole straight into the concrete, and screw the plate down using a torx bit : Magic. Watch your wrists though, when they want to stop, they will, and if you use too much power, you will snap the head off. Where the plate is direct on the concrete, use a 25mm MM, but on the ramp side, drill straight through the ply as well and a 50mm MM will also hold down that front edge.
50mm x 50mm box 3mm walls
50mm x 50mm angle 3mm
50mm x 5mm flat bar
Frames 50mm x 25mm box 3mm walls
Bars 30mm round bar
Mounting brackets 60mm x 60mm box 3mm walls
Ground Fixings M10 x 100mm thru-bolts Use these because you position the ramp, and then drill straight through the hole in the steel into the concrete, rather than precision drilling beforehand with ragbolts or anchors, and then having trouble aligning the ramp onto the bolts.