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Fixing Aluminium Edging

Spring loaded cleco

I decided fitting Holden's extruded aluminium edge trim (which Holdens make for Morgan Car Co) made for better presentation of a Pembleton, than plastic "gripfast" push-on trim, despite the effort.

Tools: You must have a good dot punch, some very sharp 3.5mm drill bits, a good, sharp countersink, clecoes or skinpins ( I favour the manual ones rather than the spring-loaded ones you set with pliers; I found the manual ones will clamp firmer), gas torch with a wide flame, heat sink (I used some firebricks), thick welding gloves (you'll be handling very hot metal), a dense rubber hammer and a piece of hardwood (I used some oak heart-wood) to make a fork (which fits the trim closely). I found welders' mole grips with plain jaws useful to counter the sides gaping and a sawn-down table knife ideal for persuading the slot back, as it closed up. I bought used cleco fasteners on eBay - the aircraft industry renew theirs regularly for absolute precision - used ones are often for sale in batches of ten. You can never have too many!

Screw skin pin

The edge trim is flat-sided between rounded sides, roughly 12mm X 6mm in section, with a 9mm X 1.5mm slot cut in to one edge. The trim is "half hard" and is therefore difficult to bend, needing annealing frequently, especially when forming some of the more extreme curves. The slot fits either side of the aluminium panels; I fixed mine finally with 3.2mm countersunk head rivets. The holes for these need to be precisely drilled and it is important that they are not too close to the edge of the panel or else they will pull out, as you work the strip.

Plan where your butt-joins will fall on the car. In the centre of long straight runs is ideal, or where something else masks the join. Where something is very visible (like the bonnet), plan to have joins in the centre of the back and sides - apart from looking as though you've given it some thought, it means the strip can be well anchored before you form the curves for the corners. My edge strip came in 1.8metre lengths - all told I used 9 lengths to completely edge the car. Edging the cockpit greatly strengthened the front flare and rear top - as long as you've left enough height on the side panels, above the chassis side rails! You may find that there's not much panel edge showing (where the rear floor rises over the rear crossmember, for instance), sufficient to slot strip on. Where this occurred on my car ( and I didn't remake the panel, as I did with the rear sides and top, to make them longer creating space for a Monza fuel filler, at the same time slightly reshaping the cutaways), I cut the back half off the trim and fixed the outside remainder to the panel surface; a short "cut-back" section in between two whole strip sides is not a problem

Apart from some very sharp curves, I formed all my edge shaping of the annealed, hot metal strip, using the panels themselves. The first operation was to drill the first rivet hole about 1/4" from the end of the length. Put the strip, cold, on to the panel and drill the panel hole. This will allow you to use a cleco fastener to anchor the strip. If you have a fairly long straight run, before a curve, drill several holes (remembering what rivet centres you'd chosen!!) for clecoes. Where you need some really short sharp curves (e.g. bonnet front sides ) I cut some flat templates from scrap bits of aluminium sheet to the right contours, shaped the strip to those, flat, then drilled the anchor hole and reshaped the straight curves to follow the sloping sides of those on the bonnet panel. When making up another section to mate with a severely curved piece, cut the second bit long, then adjust the length for a close butt-join after both pieces are formed, then fix.

Heat and anneal your strip along the areas where your bends/curve will be. Slide the strip on to the panel and anchor with clecoes then gently but firmly press the strip on to the panel curve, using the wooden fork to prevent the strip twisting and "bumping"it along with the rubber hammer. It may be necessary to reheat the strip as you go, until the curve fits snugly over the panel, following the edge exactly.

Leave it to cool and then take the cleco 'anchors' out. The strip can now be drilled and countersunk both sides. This allows for the rivet head to be flush with the surface and for the rivet mandrel (the ball-ended bit) to sit below the inside face. Put the strip back on the panel - the cleco anchors will place it precisely - and drill the holes in the panel. Remove the strip, deburr the panel and remove any surface scars on the strip (you could do this after fitting), but I started out like this. Refit the strip using clecoes, at least one at each end, but sensibly one or two, spaced out along the length. Now you can rivet in place - the clecoes will stop the strip creeping. Once you've riveted the spaces, take out the cleco fixings and rivet those holes. Close up any side gaps (welders' mole grips or some carpentry G clamps with two flat strips of hardwood against the aluminium strip to prevent scarring). The strip is now ready for tidying up with fine wet-and-dry and final polishing.

Until you get the hang of it, I'd recommend doing several long, simple strips first and get those fixed. Once you've mastered the "knack" you'll feel more confident tackling the more demanding curves - try not to be too ambitious attempting to put several curves in to one single length. Use the "hidden behind something..." ploy and have a butt join.

The bonnet I did off the car, using a workmate with an old, rolled up duvet as a cushion. Apart from the self-inflicted problem of sculpting around and over the lamp bars, the other area of difficulty is deciding on the curvature of the bonnet corners (and getting both sides the same!). The cockpit edge was easier than anticipated, having decided to have the rear top sweep round in to the side panels, with a join either side of the cockpit. The strip "peeled on" in much the same way as a tyre on a rim. For the flare I chose to start in the middle of the strip either side of the flare panel join - you will probably need to gently trim the flare edges here, to ensure they are flat and equal. Again, a single length ran nicely both ways and on down to the sides. As I was going to fix coaming over the top when trimming the cockpit, having a short straight infil either side was acceptable

The real leveller was trimming the rear body under the spare wheel - the only true compound curve on the car. Chamfering the panel edges to ensure an even distance from the spare wheel AND present a continuous face for the trim was a really daunting task. Much annealing and persuading the edge trim with the oak fork was needed, to "turn the strip" as it was fed on, very hot, on to the panel edge.

Once all the edge strip is fixed permanently, scars and scuffs can be removed with varying degrees of abrasive, before actual polishing. Like the car panels, neat evenly spaced rivets will provide a very satisfactory appearance and significantly stiffen up panels. It's 3 years ago now, but it cost less than £45 for edge trim and countersunk rivets - but a lot of time and persistent effort.

Mike Meakin

I was talking to Barry at the weekend workshop and he has used the same edge trim as Mike but used a jig/former to bend the strip. I think he said he didn't anneal the strip. You can see the tight radius he can achieve using a jig/former.
The editor

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