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Scratchbuilding pt.8: Basic Body Construction

Last time we covered research & planning - and if you're following along at home you'll already have a card mockup of a Volvo Laplander body, scaled for a short wheelbase Tamiya CC-01 chassis.

This instalment covers building the basic body structure, with a bit of an appendix on modifying CC-01 kit wheels. I also realised that jumping from the card mockup to a description of how to put pieces cut from the new plans together would be missing out something important - all the time I spent thinking about how to translate card into styrene, what parts would have to change, and so on. The resulting section may be a bit of a dry read, but I would recommend it to anyone that's asked a "how do you ...?" type question about any of the scale stuff I've built.

You will need:

  • 1.5mm styrene sheet - at least three A3/A3+ sized, plus one A4/A4+*;
  • 1mm styrene sheet: at least one A4/A4+ sheet*; 
  • 0.5mm styrene sheet (less than one A4 sheet)*;
  • 3mm styrene sheet (just a small strip)*;
  • Printer, A4 paper + Pritt stick or equivalent (or self adhesive label sheet), thin card (optional);
  • A3 or bigger cutting mat, 300mm & 600mm steel rules;
  • Scalpel, craft knife;
  • Glue for styrene (preferably EMA plastic weld or bulk Dichloromethane), brush(es);
  • Masking tape (for clamping);
  • 2.5mm square styrene strip (e.g. Evergreen # 175);
  • Files, wet & dry paper of various grades, possibly even a Dremel;
  • Time ... I'd estimate the time needed for just this part of the build would be on the close order of 24 hours, spread out over at least a week or two to allow adequate setting/drying time. Add around another 1/3rd again if you want to do the wheels as described here too.

Note: I anticipate the next two instalments will need three more A4/A4+ sheets of 1mm, ditto for 1.5mm, probably one 2mm sheet too, plus one A3/A3+ sheet of 3mm - in case you want to buy ahead.

The Small Print

If you want to build one of these at home but have no prior experience I really would recommend reading all the preceding parts & making the example projects: I think you do need to work up to a big project - that's why I wrote them :)

Some of the tools & materials described here have the potential to cause injury if used in an unsafe manner. Read & follow all tool manuals + MSDS for materials/solvents, use appropriate PPE, take instruction and/or work under supervision if necessary.

The plans are provided for guidance only - make sure you check dimensions before cutting. Careful fitting/fettling will be required. The plans are provided in good faith, but are for personal use only & may not be reproduced or published elsewhere.

 

More Thinking/Planning

Note: a lot of this applies to details that won't be dealt with until future instalments. Also note that the drawings for this part have had all the necessary changes already made.

jr scratch 8 001 jr scratch 8 002

 

Material Thickness

I would have like to used 1mm sheet styrene for the broad areas of the body for the sake of lightness, but as a lot of edges really ought to have some curve put on them it makes more sense to use 1.5mm thick sheet instead. The heavier material will also be a benefit when it comes to making the window apertures in the rear section convincing (looking at 1:1 photos, the windows have a deep bevelled recess around them).

1.5mm sheet is also stiffer, and although an internal panel at the back of the driver compartment will help, the rear section is quite a large area to have unbraced: using the thinner material could result in a lot of unwanted shimmying.

 

Doors

Looking at the front door/driving compartment "cheeks", it's evident that I made an error at the bottom of the section rearwards of the doors. That needed correcting - and while I was at it I moved the door apertures back a few millimetres to make the windscreen (or "A") pillars a lot beefier for ease of cutting out, strength, and to allow space to make the edges curved.

The outside face of the "cheeks" should be flat - but the card mockup has a crease running through them. That crease is essential for the front end to be the correct shape, so the cheeks will probably have to be made from a number of carefully shaped parts (and filler) rather than the simple bevelled slabs I'd hoped.

I don't plan to make any of the doors openable (it's not a feature usually found on RC vehicles anyway) - but I will make sure the apertures are visible by cutting the opening in the relevant panels and fitting the doors back in the gaps against suitably cut "jamb" forms.

 

Door Handles

The driver/passenger/side door handles all need correction - an extra rectangle seemed to appear around them.

Note: I had to amend the door handles again as the one on the side doors interfered with the "waist" line - so I shrunk both down a little & raised them. This means they are wrong on the "rework" pic (above), but "correct" in the plans. Also note that I cut handle holes in the driver/passenger doors in error (and filled them back in later), so some of the photos will not correspond to the text and plans in that regard.

 

Mirrors

Scaling the 1:1 mirrors back - especially their single point attachment - is likely to result in breakage and loss even before the vehicle gets run, at the moment I'm thinking along the lines of adding bracing points and having the mirrors fit on a long U shaped brass rod.

 

Windscreen

The windows need some thought too: starting with the easiest one (the front windscreen) an aperture for the "glass" (Lexan sheet) needs to be cut halfway between the two "rubber" lines, and a separate piece cut using both lines made to replicate the rubber seal. After painting, the glass (cut to a size to fit closely within the original gap) will be held in against the faux rubber seal by a self adhesive vinyl "seal" (cut to same shape as the outer) stuck on the inside.

Wipers got lost somewhere between my initial drawings and the part 7 plans, but they will be included at the detailing stage.

 

Front Door Windows

The driver and passenger windows on the 1:1 vehicle are a fixed forward panel and a sliding rear one* - this can be approximated by cutting a full size aperture in the doors, adding a outline piece to the inside (so the top & front match but the rear and base show a little), and adding interior pieces to control the position of a slightly oversized front pane, which can be held in with another piece of vinyl.

For the "sliding" pane, we can take advantage of the trim piece and two obvious fasteners on the full sized version to screw an outer trim piece through the bottom of the pane. By making the top of the sliding pane taller and leaving a slot in the underside of the roof gutter, it'll be supported at both ends. It won't slide, but there is always the possibility of fitting it in an open position.

* Note: this later turned out to be wrong - it's the front pane that slides open, not the rear. When it comes to making & fitting these windows the details will have to change, but not necessarily the concepts.

Further Note: having fitted the windows much further down the line it's apparent that a full step all the way round (not just bottom & rear) would have been better ... It's too late for me to go back & redo this fully, so I've amended the plans & will have to fake it a little on my build...

 

Rear Section Windows

Considering the windows in the rear section - specifically the four subdivided ones - some changes will need to be made. Whereas the 1:1 vehicle has a chrome trim detail and small rubber seals, cutting parts that narrow from sheet styrene will be problematic - so I'll amend it to larger fake rubber seals.

Looking at a typical upright section as an example and starting at the outside & working inwards, I'll delete the 3rd line. Bevelling will start at the 2nd line & taper back to the full thickness of the panel at the first line.

A fake rubber seal will be made up using the 2nd and new 3rd (previously 4th) lines as a guide, and this will be glued in, backed by a 3rd piece cut from styrene sheet, dimensions will be line 1 and halfway between lines 2 and new 3. The lexan "glass" dimensions will be dictated by that latter dimension. Interior vinyl "seal" will be the same as the outer styrene one - just swapped side to side.

The "plain" side windows leave a bit to be desired on the mockup plans, so I'll rework a copy of the subdivided windows. Dimensions & creation will be very much like those then - as will that of the rear window.

 

Body Sides

I'd like to cut the wheelarch edges from 3mm sheet so they can be sculpted a little. Other detail strips on sides and roof are all additions, so they can be worried about later too. Angles in the panel are best achieved by heavy scoring on the inside (2-3 passes of a Tamiya Scriber II).

The rectangular apertures for the side door step should be cut out before basic assembly, as should the exhaust holes. The curve near the bottom of the low front where it meets the bottom of the grille panel should be made an angle instead of a curve.

Side door handles need apertures cutting earlier rather than later - the innermost full rectangle will make a good cutting guide.

 

Roof

The edges will be too much hassle for too little return to make fully curved, it makes much more sense to have them simply as angles, and curve the top edges by sanding after initial assembly. This means some revisions to the plans will be required.

 

Front End

The front windscreen we've already discussed, but looking at reference pictures of the real thing, it's evident that the panel it's fitted to is recessed. This means cutting the panel out as a separate piece, and using square strips to step it back & make the appropriate pillars.

I'd initially thought that the roof overhang/gutter should be deleted from the drawing & reinstated as a strip of thick styrene sheet, but two strips of square styrene form will make more sense.

The front bumper doesn't need to be part of the front panel at this point, so it can be removed from the plans. The front grille can be made separately & fixed on later, there's no need to make any sort of aperture initially. I'm planning to fit LEDs so a couple of holes will be needed at some point.

Details on the panel under the windscreen will all be additions; the change in angle can be made by scribing the inside (note: this changed later on). The cabin air intake got moved to a central position very early on: that was an error as it's supposed to be off-centre.

 

Rear Panel

The bumper (and gap above it) can be deleted from the drawing as they'll be better made as details later. Door & window apertures can be cut out as discussed above. Rear lights on the 1:1 body are a bit on the crude side, so using off the shelf LED fittings makes sense; hole size to be determined later by measuring appropriate holders. Panel angles - scribe on the inside (as above).

The window should have bevelled edges like the 3 rear most windows on each side.

 

Internal Bracing

Butting the edges of panels up against each other doesn't make for a strong joint, so I'll use square strip where possible to beef things up a bit - though on the shallow angles of the roof it's possible that thin strips of sheet material may be more appropriate.

 

Rear of the Driving Compartment (and Dependencies)

I've looked at a lot of photos, and if this was a pickup, it would either be a blank panel, or one with twin windows shaped like rear window (only smaller) and some reinforcement ribs. Versions with enclosed back ends mostly seem to have a low divider panel, and most of those have some sort of metal "dog guard" type grille fitted in the gap.

It makes sense to build in something there as reinforcement of the basic structure - but in order to work it needs to touch all the way round. Ideally it would be thick enough that no extra bracing would be needed to hold it in.

What this adds up to is a sandwich of styrene sheet & metal mesh, plus a spacer piece to constrain the mesh & hold it all together. Dimensions of the outer will be along the lines of the rear panel, with the top part given an opening let's say 10mm in from the edge. The "filler" section will have an aperture say 5mm wider, and of a thickness to match that of the mesh.

Looking for "model mesh" on a certain ubiquitous auction site would be a good start - "coarse" Aluminium mesh or a small steel mesh are the most likely candidates.

Exact dimensions/plans will have to wait on this aspect as there are a lot of things to work out - especially how deep / what shape the bottom of the panel needs to be to clear the top of the chassis. To answer that the body fittings need to be complete - and that needs a lot of the front and rear detailing news to be done first.

 

Body Fittings

I've fitted the standard CC-01 front body mount to the chassis & will make something to fit that & fit to the front end. Rear mount will be a swivel catch cut from GRP sheet* - this will fit to a structure yet to be determined inside the rear of the body, and to a screw or post fitted to the back of the chassis.

Note: In the next instalment you'll see it didn't work out like that ...

 

Interior/ Engine Cover

Once the body fittings are complete I'll be able to see the extent to which the height of the CC-01 chassis will compromise the floor. As the 1:1 version has a high floor under the seats (falling away to footwell depth forward of the wheelarches) I'm hoping to dodge the CC-01 front arches and get a reasonably faithful driving compartment.

The front interior should consist of a sculpted floor, seats, dash & steering column/wheel and engine cover (the Laplander really is mid engined - half of it is between the driver and passenger seats, half protrudes into the load area) - all built up & painted in sections & only permanently fitted at the end of the project. Separate door cards that fix to the inside of the side panels are a distinct possibility.

The rear wheelarches on the CC-01 chassis are so high and so far inboard (not to mention the steering servo saver height) it's not going to be possible to have a realistic floor height for the rear interior without extensive modification of the chassis.

Instead, the floor will have to be around the "waist" line height. The rear section in a standard Laplander is pretty sparse - usually just 6 folding seat bases. I'll make & fit those, but they will have to be artificially close to the high floor.

Note: not all of this was apparent before I printed out the set of plans that I cut the styrene from. The plans as published and the text here should be considered definitive (bearing in mind what I've said about measuring up yourself and fettling) - some of the photos show an earlier stage in my thinking.

 

Building the Body

Print out all the plans on paper, as before all the plans should be printed at 100% page size on A4 sheets - use the scale to check. Overlap the two halves of each body side, roughly cut out each part & then bond to the appropriate thickness styrene sheet with a Pritt stick or similar, wasting as little space as possible (image 04). I've been using up a box of printer labels that never had much tack to start with & have lost even more as time has gone by, which is why some of the photos look as they do - but I can't recommend the average label - it'll probably stick far too well & be very frustrating to remove.

Download plans:

Right click and "Save target" / "Save link" or similar.

  1. Front end
  2. Rear end
  3. Roof
  4. Left front
  5. Right front
  6. Right rear
  7. Door jambs

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Note on Scrap/Waste Styrene

Cutting odd shaped parts/panels out of regular sized is bound to lead to unwanted oddments. Sending them for landfill is a waste, and recycling isn't an option as offcuts don't have a Kringloop & material code.

Keep all your leftovers as an awful lot of them can be reused in the future - I used to use takeaway trays to keep them organised but have recently upgraded to medium sized gardening gravel trays.

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Sides - Cutting Out

I'd suggest the cutting out starts with the sides, initially just the top & bottom edges (just along on the sill rather than all the wheelarches etc) to make the piece you're working on a little more manageable.

Moving on to the windows, score the inside of the inner line lightly several times with a scalpel, then go corner to corner with a craft knife, once you've gone all the way through you should be able to start snapping the pieces out to the scalpel line. Tidy up the corners with a small sanding drum in a Dremel and/or wet & dry paper.

The next step is to bevel the edges of the windows with rounded corners. Cutting just enough to pass through the paper (or label), I trimmed back the guide paper label layer to the second line - then shaped the edges with very light passes with a Dremel small sanding drum at a very shallow angle, followed by sanding with wet & dry paper (see image 06).

Cut the front & back edges of the side to shape, then mark the other side using the green lines as a guide. Score/scribe to allow them to fold to the correct angles later.

I cut out the small apertures next (door handles, exhaust, step) by marking the edges with a scalpel & Dremelling out the voids with a straight burr, finishing with various files.

Note: the door handle holes on the front door were made in error & don't need to be cut at this point.

Wheelarches came next, then I tackled the door apertures (cutting to the inner edge of the outside lines) with a combination of scalpel & craft knife work.

The doors followed, cutting to the inner edge of the outer line to keep the shutlines small.

The remaining paper/labels came off next, and any lips causes by the knifework were sanded off.

I moved on to the door jamb parts for a bit of light relief before starting on the other side.

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Sides - Assembly

Before putting the sides together (installing the jamb sections & doors) I made an extra copy of the back panel & used that as guide to make three temporary inner brace panels. I had a large piece of 4mm fluted plastic "Correx" board, but any reasonably stiff cardboard/corrugated cardboard would do.

Having made sure the sides would bend to the correct angles (the "waist" line needs scoring about 2/3rds of the way through, the roofline almost all the way through, and the edges bevelling with a combination of scalpel, file & wet 'n' dry paper work), the sides were taped down firmly to the temporary formers. I placed one of the temporary braces between the door apertures, one about an inch (25mm) behind the side door aperture, and one about the same distance forward of the back end (see image 08).

jr scratch 8 008

 

As the relationship between the cab doors & the jamb/inner window support is important (also see note & further note under More Thinking/Planning - Front Door Windows, above, and the amended plans) I glued the two together over the top half, making sure the lower half was still free (image 09). Line up the door in the aperture & glue the jamb panel/surround & door in a bit at a time.

The side doors can be done by gluing the surround in first, aligning the fold line with that of the door. Make another piece to fill in the gap at the top from a suitable bit of scrap. Fit the side door so the gap is even all the way round, then glue in the door.

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Front End

Cut out the windscreen surround, sand the edges and add short lengths of 2.5mm square strip to the sides & bottom of the front face before gluing in, so the windscreen panel is recessed.

Grille back: check the dimensions, cut out/sand & glue in so that the outer face meets the edges of the sides as neatly as possible.

For the badge/vent panel (the area between the windscreen and the grille), again check the dimensions before cutting out. Check the fit of the panel - it should meet the grille top and vehicle sides neatly, it should also meet the square strip at the bottom of the windscreen - you may have to sand a slight angle on the top & bottom before gluing in.

At the top of the windscreen, add two layers of 2.5mm square strip, one in front of the other.

Front roof panel: check & cut out, fettle (you'll need to sand an angle on the inside of the lower {wider} edge) & fit/glue.

Under grille panel: cut out & fit so the front edge is tucked under the back of the grille - sanding a slight angle on the leading edge of the panel will make the join neater.

Note that there is no panel to fill the final gap on the underside of the front - that may come later, but probably only after the front body mount & interior have been finalised.

Brace where possible, e.g. 2.5mm square on the sides and 15mm wide strips of 0.5mm sheet styrene on the long joints. The joint between the lower edge of the grille panel & the one underneath is more likely to take knocks in use so I made the bracing a lot heavier - an 8mm wide strip cut from 3mm sheet, with one edge bevelled to approx. 45 degrees (see image 12).

 

jr scratch 8 011 jr scratch 8 012

 

Back End

Cut out the panel, not forgetting the filling tube notch (just an oversize rectangular void at the moment). Transfer the score line points to the edges & back face (inside) before scoring heavily across the whole panel, including the door.

Cut out the door aperture, then cut the excess off the door panel. Cut out the window (the inner line), and bevel the window edge as for the side windows (above). Cut out & score the door jamb piece too.

Remove the rearmost temporary brace, and glue in the rear panel, starting from the bottom. Brace the edges use 2.5mm square strip. Glue in the jamb piece making sure the score lines match, then the door - making sure the gap is even all the way round on the outside. Brace the scored lines with thin strips of 0.5mm sheet.

 

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Roof

Remove the remaining two temporary bracing panels, making sure you don't handle the body roughly - if you let it "parallelogram" too much some of the joints will fail.

Ensure the body is sitting square by measuring across the diagonals - e.g. the distance from front left corner to rear right should be the same as front right to rear left. If not, tweak slightly & keep square as a much as possible.

Measure up for the roof carefully - after a lot of checking, I determined that my dimensions were 329mm long, and 159mm wide at the front - tapering slightly to 157mm at the back. Obviously it would have been better if it was 100% square, but it's more important that it fits ... I'd suggest going slightly oversize (no more than 1mm in any dimension) so you can sand slight angles on the edges to make them match better.

Test fit the roof panel, and with the whole thing upside down on the bench, tape the inside of the joints (image 16) - this should keep the roof panel level with all the edges so you can turn it right side up & glue the panel in (image 17). Allow a good long setting time before removing the tape & bracing the inside of the joints - I used 10mm wide strips of 0.5mm styrene sheet (image 18).

 

jr scratch 8 016 jr scratch 8 017 jr scratch 8 018

 

Shaping/Filling

Brace the inside of the scored lines on the inside of the side panels, leaving the doors free (see image 18). This means long strips of 5mm wide 0.5mm sheet near the roof line, a piece 180mm long (with angled ends to suit the gap) under the rearmost two windows on each side, and short bits between the doors.

Sand off any obvious discrepancies in panels on the outside, then fill any joined edges - e.g. the roof panel & roof corners, rear panel edges, windscreen pillars & front panel edges (images 19 & 20).

 

jr scratch 8 019 jr scratch 8 020

 

Sand back, being careful of the front overhang - especially the corners. Shape the four top edges of the roof, the four short angled joints on the corners, the rear sides, and pretty much all of the edges on the front end: I'd suggest starting with a very rough grade of paper (180 or lower?) and a small sanding block, and to do it wet with a little washing up detergent.

The amount to take off is a compromise between getting nicely rounded edges and not taking off so much the strength of the joints is compromised too much. I measured my results and on average the distance between where the flat of one panel ends and the curve ends as goes back to flat again is 6mm - so it might be helpful to use 6mm masking tape on each joint, mark the edges with more tape & remove the middle strip.

 

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Next Time...

The next instalment will cover adding layers of detail to the basic shape to make it look more like a scale model.

 

Appendix: Wheel Modification

If you want to stick with off the shelf Tamiya rims then the M1025 Hummer wheels (part # 9335205, also used on the CC-01 Unimog kits) look the most like the pressed steel items found on the 1:1 Laplander.

I didn't have any of those handy - and they're not as deeply dished as I would have liked. I did have the 5 spoke alloy looking wheels from the Pajero kit though, so modifying those was the obvious choice.

Now, this does involve using a lathe, and to be honest I don't see a way round that and still have the accuracy needed to reproduce four identical parts. I'd highly recommend the Unimat SL, although it what it can do in terms of size is quite limited. One of the generic 7x14" Chinese mini lathes would also be a good choice, although it will need permanent siting. I appreciate that not everyone has the inclination to buy or use one though - which is why this section is a little add-on at the end rather than a proper part of the build. One thing I will say is DO NOT buy a cheap copy of the Unimat 1 - I had one & spent a lot of time and money upgrading it to a useable state (proper power supply, new 3-jaw chuck to replace the off-centre original, variable speed control, etc etc) & it still wasn't a patch on a proper machine.

Anyway, the steps are:

  1. Skim off the unwanted detail on the face of each wheel, the final pass being just enough to take the plating off the centre where the wheelnut goes, so as not to reduce the strength of the 12mm hex area (image 25);
  2. Strip off the remaining plating - I used a very strong solution of Caustic Soda (wear goggles and gloves) in a Bain Marie arrangement in an ultrasonic tank (image 26)... a longer soak time in an unaugmented bath would have worked too;
  3. Make the inside of the wheels flat: cut four 50mm squares from 1.5mm sheets, find the centres & drill holes to hold them together with M4 fasteners. Turn them down to 43mm OD before drilling out the centres to 10.5mm & gluing to the wheels (Not pictured);
  4. For the "pressing" blanks, cut eight 45mm squares from 3mm sheet & bolt them together in fours before turning them down to 40mm OD (note the 3 jaw chuck clamping on protruding end of screw). Glue up in pairs, clamp up & leave to set (see images 27,28 & 29);
  5. Taper turn the outside (note the way the motor, drive & chuck assembly rotates on the Unimat SL - see image 30), and file/sand to a dome shape (image 31);
  6. Drilled/bore out the centres to 16mm, then taper turn (note used of 3 jaw chuck with jaws reversed & clamping down on outside edge in image 32). File & sand to a smooth curve (image 33): (The joints between the layers of styrene weren't as neat as I would have liked, so they were all filled (image 34) & sanded back).
  7. Locate the completed shapes on the wheels & glue on, with five 1mm long pieces of 2.5mm OD round rod spaced equally at 72 degrees (image 35). I plan to add some more scale looking bold heads, assuming I can find some suitable hexagon form strip.

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________________________

Written by TB member Jonny Retro