Manufacturing new galvanised doors

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By Ed Evans

07 September 2020

SP_Panels_door_manufacture : credit: © Ed Evans

SP Panels are known for their galvanised door frames and bespoke door builds, but there is much more on offer from this Liverpool business, as Ed Evans learns

Series and Defender door panels are well known for their ability to corrode, both inside and out. Defender's steel internal door frame can rust away behind the door card, while similar rusting is openly visible on Series models. Externally, the aluminium door skins cor-rode along the lower edge and along the upper edge close to the window, producing unsightly white deposits as the aluminium slowly crumbles.

Repair sections are available for the steel door frames, but there’s little point in repairing those if the outer skin is corroding – a notoriously difficult problem to cure.

The only real option is to fit a complete new door assembly – either a standard replacement, or one with a galvanised frame which could potentially put an  end to the corrosion issue for many  years ahead. SP Panels manufacture both options, and are particularly known for their  long-life galvanised frame doors, but plenty of other interesting items are produced by this family-run business. Examples include Series and Defender galvanised frame half tail doors which are neatly capped along the top edge for soft tops; doors fully built up with glazing, locks, coated ready for paint; galvanised door tops for Series models, and SP will manufacture bespoke doors to suit your own needs or modifi cation ideas.

We’ll take a look at some of these options later, but right now we’re following through as SP Panels manufacture a brand new door from scratch. The whole process, when production is running at full tilt, takes around 40 minutes, and this is soon to be considerably reduced when a newly installed robotic welding machine is commissioned. Manager, James Staniford-Payne guides as through the job, with input from craftsman, Tommy Murphy.

 

Constructing a tail door

The process starts by cutting the shapes for the door’s frame from flat steel sheet. After drilling, this huge press forms them into the various shapes. 

Each section is formed in a steel die. Here a die is opened to reveal a newly formed top corner section of the tail door’s internal frame.

Various pressed plate sections are welded together between the electrodes of this spot welder to make the complex structural sections of the door frames.

 

Eventually, a stock of each of the various door frame sections has been fabricated, allowing SP’s craftsmen to begin building any of the many door types.

The components of the door’s internal frame are laid out on the flat steel workbase and clamped accurately into position, ready to be MIG welded.

Welds are completed around the central structure, which takes the weight of the spare wheel, before moving out to work on the peripheral frame joints.

The box-like structure that will support and house the latch, lock and handle of the tail door is ready in position here to be welded integrally with the frame.

After all the welding is completed, Tommy Murphy releases the jig and lifts out the completed frame, which is now ready to have the outer skins fitted.

This tail door lower outer skin is laser-cut from sheet aluminium, and the necessary flanges are formed in the press. Upper sections surrounding the window are also prepared.

The lower outer door skin is placed in the crimping jig, and the three individual panels which form the window surround are laid and interlinked into position.

The completed frame is now carefully laid over the door panel sections in the crimping jig, where the whole assembly is firmly held in in alignment.

The steel forming bars around the outside of the jig (operated by levers) will bend the door panel lips around the flanges of the frame, securing the assembly.

The steel die (right) presses down against the door panel’s lip to crimp it around the flange of the inner frame, forming a tightly-constructed joint all round.

The curvatures around the upper corners of the door’s top panel (around the window) are still to be folded, and will be shaped by hand on the bench.

The door assembly is now a solid one-piece, tightly joined component. James lifts it from the crimping jig for an inspection of the work so far (left).

Now, with the door inverted on the finishing work bench, the corner lips of the upper outer panels are carefully formed over the frame flanges.

With the outer panels securely crimped around the frame, the door is turned over and the outer surfaces are buffed to remove any impurities and high spots.

The door hinge bolt holes are reinforced by tubes welded in the frame. The tubes provide a guide to drill through the outer panels, which are then countersunk.

The final job is to drill through the aluminium door panel and internal latch handle box, and rivet two components together, creating a rigid structure.

James looks well happy with the finished product. So, we’ve seen how a standard-spec door is built, now we’ll take a look at other SP Panels products.

 

Bespoke door builds and other products

THE tail door that we’ve seen built, and other doors, can also be supplied with a long-lasting galvanised steel frame. Holes can be pre-drilled for a spare wheel carrier, wiper assembly, high-level brake lamp mount in the glass, and the glass itself can be supplied as plain, heated, tinted, or any combination. Doors can also be fully built up with all fi ttings including window winders, lock, latches and handles and new door cards, each of which are available to order from stock, along with a whole range of parts for Land Rovers. Here are a few examples of door-related products.

Because SP Panels can supply all the fittings for doors, new doors can be supplied fully built up with glass and winder, locks and handles, and door cards.

This aluminium skin is being fitted to a Defender push-button front side door with galvanised frame. Sealant aids adhesion while controlling panel vibration. Galvanised holes are drilled clear.

Galvanised frame second row side doors for Defender 110 are finished using hand tools to crimp the aluminium skin to the frame.

Series II and III front doors can also be built with a galvanised frame. Door tops, available separately, can be galvanised or plain, and glazed if required.
 

This half tail door for Series (alternative to drop-down tail gate) and for Defender soft tops, features a galvanised steel frame, zinc-coated steel skin and galvanised, riveted top capping.

This pair of aluminium skinned doors with galvanised steel frames are for a Series III military Lightweight model, as evidenced here by the tapered rear edge.

 

Future plans

IN addition to streamlining production with the use of a robotic welding machine for door frame manufacture, SP Panels is soon to produce two-piece second-row doors 
(glazed if required) for Series II and III long wheelbase station wagons. And, because so much of SP Panels’ work is hand made, the company will consider requests for other panels and specials.

Contact:
Website:  SP Panels
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