I can see how I’ve manged to damage the template on my previous attempt at cutting my own scratchplate. Same way I managed to write off the original Telecaster plates. Unless I can keep the router exactly level – then the bit can run offline, and dig-in at the top or bottom of the template. If the router is kept absolutely level – then the cut should be straight and perpendicular. If the router is level, and the bit still digs in at the sides anywhere – then the sides of the template can’t be perpendicular, to begin with.
I’ve checked the template over, and found a couple of areas which need looking at and fixing. The main one is at the tiny lug, which sits just below the neck pocket. As I’ve worked away at the plate – the flat area, on which the router rests, can get pretty small. I’ve obviously gone off line as I’ve gone around this little lug, and have eaten away a little bit too much from the inside of the pocket. This has led to the template, itself, getting damaged and running slightly off-line. I take some two-part wood filler, and gradually build up enough replacement material to re-work the curve – cutting and sanding it back, whilst matching the template against the neck pocket opening on the body. It’s looking better now, and it finally appears to run roughly parallel, with the top side of the neck pocket opening. It’s likely it will still require some fine adjustment – but that might, eventually be a question of tailoring the actual, finished plate in-situ. Reaming or scraping away some of the edge of the plastic with a blade.
At a few other points along the edge of the template – the router bit has obviously gone off line slightly, and bitten into the sides of the MDF. This is where the template sides probably weren’t quite perpendicular to begin with – but these areas are easy to identify, and remedy. Once again – they’re filled with two-part filler, and then sanded flat and perpendicular. On curved sides, the repairs are refined and feathered-in to the overall, outside curve. With the template now repaired, and checked against the body for fit – it’s time to have another attempt at cutting a plate from scratch.
I trim a little polycarbonate from my stock sheet, (not too much wastage this time). I try to use a fraction of the double-sided adhesive tape as well. Hoping that small tabs of the tape – well spread – over the face of the template will suffice. Once again, this is reclaimed polycarbonate sheet, from a framing job – so there’s no protective film to stick to, or to protect the plate. If there had been, I’d have probably used more tape. Removing the protective sheet would have made removing the plate from the template much easier, and less messy.
To try and stop the acrylic sheet from splitting, when drilling any screwholes – (especially the two close to the pickup opening) – I decide to test driling the holes first. I place the work, template side up, and drill the holes through with a sharp HSS drill bit. I use a fairly high speed on a drill press, and drill through into a solid piece of oak – hoping that the extra support from the wood below might prevent the plastic sheet from distorting and cracking. Most of the holes go through quite cleanly – although a couple show signs of the plastic melting a little. They clean up well however, with a small, hand held countersink burr. It’s essential, in all cases, to clean off any melted plastic from the drill bit. I used a scalpel blade to pick and cut it away – so that the drill bit cutting edges could do their job properly.
I also drill a pilot hole in the pickup rout, so that the router can drop straight into position. I start with a 3mm HSS bit, work my way up to a 6mm bit, and then finish the cut with a 13mm, spade ended, cutting bit. The result seems to be much more accurate and controllable this way.
I manage to drill the plate with only one of the screwholes showing any sign of cracking – and that’s just one tiny split on one face of the plate – right next to one of the screw holes. However, I think it might be smoothed out when I countersink the holes. I fit a countersink bit into the drill press, and drill countersinks for all but the two holes adjacent to the pickup. The split isn’t visible any more and the plate hasn’t cracked. I think the countersinking has alleviated the potential problem.
The locations of my countersinks are “eyeballed”. Not all of them are dead centre on each screw hole, and I can’t guarantee they’ll all measure the same. (They look pretty close though). I need to come up with some way of measuring the end result, and a technique to keep all the holes equal and consistent. Instead – for this attempt – I go slowly, and check often – using one of the scratchplate screws I’ll be using, as a guide.
With the work clamped to a work horse bench – polycarbonate side down – I use the same top-following, straight edge trim router bit, to cut the new plate to match the template. I set the router depth so that the following bead sits mid way on the sides of the template. When it comes to the cuts – I try to work in much slower, more considered and controlled passes – rotating the work and reclamping often, so that the largest possible flat area of template is left exposed for me to ride the router plate on. I also manage to find a better way to hold the router – one which helps keep the machine flat, and also gives me a chance to keep a closer eye on the cut.
I think it takes five or six operations to cut the whole plate – but it feels much more positive this time, and the result seems to follow the template well. There is a slight flat spot on one of the longer curves, but I should be able to sand that out manually. The only real problem seems to be that some of the frass from the cut has found it’s way under the plate. Presumably – there’s not quite enough adhesive tape this time. Fortunately however, there doesn’t seem to be any damage to the face of the plate. A softer acrylic may have scratched up – but this seems to hold up well. I’ll have to try more tape next time. If the work flaps around under the router – the plastic might conceivably stress and crack – especially near those screw holes. Too much debris might also push the router away from level.
For a second attempt – the result isn’t too bad at all. Using less tape definitely helps release the plate from the template, and the adhesive residue cleans off much more easily with naptha. The slight flat-spot at the leading edge is smoothed away, and feathered-in with some 320 grit paper over a sanding block. A more noticeable error might have required the use of a drum sander, to keep the edge perfectly perpendicular – but this was a very slight imperfection, and a light rub with a hand-held block was enough.
I’m also pleased to discover that a little proprietary vinyl record cleaner – loaded with isopropyl alcohol – is just the thing to clean the plate over. I use a similar product when framing with acrylic sheet, and it’s formulated to provide an anti-static effect. Stopping dust being attracted to the newly cleaned surface of the plate is vita,l for what I want to try next.
I recently got a really helpful post from a commenter, (thanks Brian), – letting me know that Jimmy’s original guitar was on display in New York. Looking into it, I found some new pictures on ledzepnews.com which show the newly restored Tele. These are the best photos I’ve ever seen of the original, and they really help direct my thoughts on what material I might be able to use, to back my scratchplate with. The original seems to be a kind of holographic foil, although I think it might also possibly be a diffraction grating plastic sheet. I’ve searched around and have found a few candidates which might just give me the same effect. The tricky bit is going to be finding how to stick the foil to the plate – (unless it just sits there, pinned in place by the screws?)
I’d eventually like my plate to be backed with copper foil – so I can shield the circuit wires. I don’t know for sure – but I suspect the result will look better if I can get all the various layers, and different materials to stick to each other. Otherwise, I suspect that they’ll be misaligned here and there. That plate of Jimmy’s sure looks neat around the edges.
I’ve long been intrigued by optically clear adhesive films. These are produced to allow photographs and artworks to be “face mounted” onto acrylic sheet, for display. These adhesives usually require a special roller system to apply properly. They’re also expensive, and usually come in long rolls of 30 meters or more. I really only need a few A4 sheets at most. There are a few double-sided, “clear” adhesive sheets available for the scrapbooking and greetings card craft markets. I’m not convinced they’ll be as useful as the “optically clear”, expensive options. But then again – for a pound a sheet, I just have to give it a try. I’ve sourced some holographic vinyl from a signwriters suppliers – again, available in handy, A4 sheets. It’s not quite a match to the NY photographs – but it’s close. Cost-wise – it’s highly acceptable. I might as well try out the cheap and convenient option.
The trick is going to be to get a bubble and dust free sandwich of plate, adhesive and vinyl. Fortunately, I’ve had some experience of this type of thing before.
The adhesive sheet comes with peel-off paper on both sides. The scratchplate has been thoroughly cleaned with anti-static cleaner, and is laid to one side on a clean and dust-free bit of acid-free board. I take a sheet of the holographic foil, and lay it flat on another clean bit of mountboard. I use an anti-static brush to make sure the surface of the vinyl is also free from dust. Then, taking a sheet of the double-sided, adhesive sheet, I peel back – just along the very edge of one of the short sides, and fold the backing sheet back on itself. This leaves a small strip of clear adhesive sheet exposed. That is laid directly onto the top edge of sheet of the holographic vinyl, and smoothed down edge to edge. You can see – I’m not quite straight – but it’s just about close enough. The plate will just fit on an A4 sheet – with a little to spare on each long side. I’ll have to be super accurate when I drop the scratchplate into position.
Using the stuck sheets as a hinge, I can then lift the adhesive sheet, like opening the page of a book, and quickly reach underneath to pull back the rest of the pull-away sheet – smoothing the adhesive sheet down onto the holographic sheet, with a rubber roller, in one, easy movement. If you do it right – you keep out any dust, and also prevent any bubbles from forming between the adhesive and the holographic vinyl. If you do get any bubbles or contamination – you might still just be lucky enough to be able to use the sheet, and keep the bubbles in the waste area. Then again – if it goes horribly wrong, you just have to start again.
It’s now easy to pull back the other peel-away sheet from the clear adhesive film. The weight and stiffness of the vinyl helps a great deal. Then, while the scratchplate is still nice and dust free, and the face of the adhesive remains uncontaminated – position the plate over the adhesive sheet and place it flat, into position. You only get one shot at this – so make sure you do it right, and make sure you stick the underside of the pickguard down. Double check this orientation several times before you do it. Even when I’d checked twice – I was still convinced it was upside down.
Press the plate into position – then run around the outside of the plate with a razor blade, to cut away any excess material. A razor seems to be the best for the longer curves. Tighter radiuses require a scalpel, or a very short blade. Even once the vinyl has been trimmed perpendicular, I find I still have to pare around the bottom edges of the plate with another blade – to stop any backing from peeking out from under the edges of the plate.
With the vinyl and adhesive film pared back, I then flip the plate over, and burnish the sandwich from the back with a flat, agate burnisher. The vinyl backing is quite thick – but this helps the burnisher slide. The end result certainly has a bit of the character of the original. Perhaps the effect is a little understated – but it’s definitely along the right lines. However, this cheap adhesive certainly isn’t “optically clear”. In fact, it’s a little “milky” in places, and it shows a slightly blotchy, patchy appearance. But I suppose it’s a candidate, if I can’t work out anything better. The thick vinyl backing from the holographic sheet can still be removed, and potentially bonded directly to a sheet of copper foil – even a thin, aluminium sheet. I need to see if I can find some A4 sheets of the real deal adhesive sheet, and see if that makes any difference. I’m also keen to try a scientific diffraction grating sheet, instead of the holographic vinyl. I remember these things from physycs lessons at school, and I think the visual effect will be much more pronounced. That said – for a couple of craft shop purchases amounting to a shade under £2.00, and an off-cut piece of secondhand polycarbonate – I’d say that’s nearly in the ball park. The holographic effect is more pronounced in certain lighting conditions, and I can’t discount the possibility that the NY exhibit might just be specially lit to exaggerate and bring out the colours on the scratchplate, as Jimmy originally intended.
Checking it against the guitar – it’s nearly there. Definitely a contender. Although I need to work on a couple more options. Hone my cutting skills a bit more, and then tackle the edge profiling. I’d really like to round over some of the edges – similar to the pickguard on my Gilmour Black Strat project. I still need to punch out the holes on the vinyl backing – but doing so might risk tearing out some of the holographic foil. I’ll leave it until I decide whether to test a copper backing on this prototype. It should be easy enough to push through with a bradawl, without risking any tearing.
I’m giving it a 6 out of 10.