GMade BOM - Yet Another Scale Rig

[Mad Ax 9310]

I printed off my new decals on white vinyl.  As I've mentioned in other threads, my later printer isn't compatible with vinyl so the toner doesn't adhere very well and scratches off easily.  I thought it was worth trying the old inkjet trick and giving it a few coats of spray lacquer.  This is Halfords brand and has been under my workbench for best part of a decade.

Then it was time to break out the laughing liquid and start scrubbing off all the residue left by the decals.  One side came off really clean, the other left pretty much all of it on the door.  And no amount of stick stuff removement would get rid of it, so it was still there when I went crawling on Sunday...

[Mad Ax 9310]

This GMade brand roof rack and light bar arrived on Saturday, so I sat and assembled it while I was watching TV with my daughter, and after bedtime I took it to the workshop to test it out on the BOM and the J45C.

It's a really good fit on the BOM.

No LEDs yet - I'll have to find time to work on those.

[Mad Ax 9310]

I had a bit of time off this week, so I decided to crack on with something I have been putting off for ages: painting the fuel tank.  I used Halfords white plastic primer, Halfords Hyundai electric red, a really old can of Halfords spray lacquer and some generic satin black that I've been using on just about everything recently.

I didn't go crazy with prep, just a quick sand off around where it had been cut from the tree and then a wash in soapy water.  A couple of coats of plastic primer and then a few coats of red.  I did this under a pair of halogen lamps so I didn't have to wait for the coats to dry.

A few hours after the lacquer was added, I masked up for the satin black straps.  I probably should have waited a couple of days for the lacquer to fully cure, as the tape left marks when I pulled it off, that I had to get out as best I could using Halfords polishing compound and an old pair of boxers.

I added the filler cap detail by hand using Tamiya chrome silver.  I'm not much good at hand painting, but the detail is raised enough that I could brush on fairly liberally without getting it on the main tank body.

[Mad Ax 9310]

I could have done a far better job if I'd assembled the tank first, then filled around the join.  A day of fill, prime, sand, repeat would have got rid of that annoying join line.  Except this is another area where GMade don't make it easy: the tank  bolts to the cage from inside, then the lid screws on.  So to assemble, fill and paint first, I'd have to glue some nuts in place inside the tank, then drill out the mount holes in the cage to pass an M3 thread through.  And I couldn't be bothered.

Also I figured that large, empty space might be useful for adding weight or hiding my Arduino controller unit further down the line, so I want to be able to take the lid off later.

All-in, I think the fuel tank is a really good way to add some detail to the truck and I'm glad GMade included it as part of the kit (notably they don't provide a spare wheel or tyre, although the cage looks a bit daft without it).

[Mad Ax 9310]

There are just three weeks to go until the UK Scaler Nationals.  In fact, in 3 weeks time I will probably (hopefully) be on my way home with the windows down and the heaters up, riding a high from two solid days of tough course trials around one of the best spots in the UK, and very much looking forward to my chicken kebab, which is a bit of a ritual after a long road trip.  However, those of you who followed my Southern Scale Trail thread will note that the BOM didn't exactly behave itself on the trails.  Although the stock tyres are surprisingly good and the front-heavy bias makes it an excellent climber, the BOM is absolutely awful in descents and side-hills.  So bad on descents that the normal way to get down an obstacle is to front-flip all the way to the bottom, and so bad on side-hills that it will sometimes just flop over on its side for absolutely no clear reason.

First port of call to address this somewhat distressing problem is the battery location.  Mounted up high and out front makes the rig top-heavy, so putting it across the middle is probably a better option.

Here's the standard layout for the BOM:

With the ESC relocated and radio box slotted into the battery tray, the embarrassingly big 3S softie fits nicely across the middle.

Stock battery tray is perfectly sized for the radio box.

[Mad Ax 9310]

The transmission output sits just above the floor pan, so I can't just flop the battery down on the pan and call it done.  Instead, out came a trusty slice of 2mm GR4 in black, which got marked up with a scribe tool.

A bit of L-section makes nice caps.

The final battery tray.  Toggle switches added for the lights (head/tail and roof lights) which I'll be adding later.

These spacers came from my Shocks Spares Tray.  I think they're extension limiters from Tamiya CVAs.  They're the perfect size and also black, which is the proper colour for black plastic.

Nicely bolted into place.

[Mad Ax 9310]

The standard battery strap is repurposed as, well, a battery strap:

I then added some tidy to the wiring:

BOM body is wide enough that the new battery tray doesn't interfere with it

After that I took it out for a quick run.  It seems to go well enough on my 1:10 scale mountain, although it's hard to climb on now that it's covered with herb robert, morning glory and dandelions.  It clomb up the tricky ascent well enough once I'd found the right angle to get the tyres to bite, and I did a couple of descents without flipping over.  The trails will be the real test for this one.

[Mad Ax 9310]

After that, I pulled off the rear shocks to add some stiff.  The standard springs are unbelievably hard (the cantilever design puts them under much more load than a conventional layout) but the damping isn't increased to compensate.  I deleted the stock oil and added some Tamiya hard oil to try to tame it.  To be honest, given this is a scaler-style narrow body with no reservoir (i.e. it's pretty much impossible to build the shocks with no air because they hydrolock, so they run as an emulsion shock with air mixed in the oil) I doubt it will be possible to get these shocks as stiff as they need to be.  The solution there is probably to change the cantilever design to offer a bit less leverage at the cost of overall travel.  But that's a project for another day.

[Mad Ax 9310]

I was going to call it a day at that point, as I'd been working on scalers since 9:40am and it was nearly 4 in the afternoon, but then I remembered one other essential addition the rig will need for the nationals: a rear towing shackle.  Seriously, it's no fun on a major scale challenge if you've got all manner of winches and kinetic straps, and your buddy gets stuck but you can't tow him out because you don't have a towing point.  I know the BOM has a full cage which is easy to loop a tow rope around, but really it should have a proper shackle to make the job easier (after all, I have to pretend to be a lil 1:10 guy* crawling around in the mud hooking up tow lines, otherwise I'd incur a Hand Of God penalty, so I might as well make life easy for him.  Or me.  Or...  Whatever).

I started with a piece of 1mm aluminium sheet, which I turned into a smaller piece of 1mm aluminium sheet using a hacksaw.

The BOM cage already has some pointing points, which I guess are for some kind of light bucket option (or maybe, y'know, body panel set), and they worked perfectly for screwing on the panel.

I had a 1:10 scale tow shackle (or possibly a 1:100 scale battleship mooring shackle, I'm not sure) which fitted nicely in a non-symmetrical fashion (I don't know why, but I have an intense dislike for symmetry on motor vehicles).

 

*anyone who has met me in person will probably tell you I don't have to pretend

[Mad Ax 9310]

That's not a bad outcome for an hour's work.  Now I have something solid that I can mount some brake lights and indicators too, as well as a licence plate.  Possibly a rear winch later on, too, although I'll want to mount it on the chassis crossmember somewhere and just pass it through a fairlead in the rear panel, because the cage is only plastic and isn't actually bolted to the chassis at all, just held in place by the shape of the lexan, and it'll deform if I put too much weight on it.

I also had an idea about the livery, too.  I put a real quick design together Friday lunchtime, and I'll get it printed, lacquered and stuck in place before the Nats (although that does mean doing a mud delete on the truck).  Also hopefully have a driver figure in place as well, assuming WWE stock is in a the bargain store this week.

[Mad Ax 9310]

Sunday dawned dry, bright and surprisingly warm, which was just as well as I had a heap of work to do on the BOM to get it ready for the Scaler Nats.  Not only the BOM, I also need to put work into the CFX-W and put the driveshafts back on the SCX-10 - so, there was lots to keep me busy and limited time to get it done.

The first thing I wanted on the BOM was a winch.  Doing a hard course event with no winch is like starting a marathon in your office shoes.  Five minutes in and you feel woefully under-equipped for the task ahead.

For the BOM, I chose one of these:

https://www.overlandrc.co.uk/product-page/servo-winch

It's a modified TowerPro servo with unlimited rotation, and plugs directly into your receiver.  For £20, it's a steal.  I can modify a normal servo to give unlimited rotation, but modifying the circuit to make them operate direct off the transmitter is tricky, as normal servos always want to re-centre, and replacing the positioning pot with a voltage divider never really works properly - so I have to gut the servo electrics and fit an aftermarket winch controller instead.  Now those are OK, but hard to find in the UK, requiring yet another China order, and they're not quite small enough to fit into the servo casing, so they need to be mounted somewhere on the chassis.  And by that point, the whole affair has cost twice as much as one of these ready-made winch servos with the built-in controller and I end up with wires floating around all over the place.

Anyway, this one arrived earlier in the week:

Complete with winch drum, line in a colour of my choice, and a sort of lobster claw attachment for a hook.

Now, the GS-02 BOM is an unusual beast compared to other scalers on the market.  The motor isn't really front or centre mounted, but sort of front-ish and to the left.  The battery is front and to the right.  That leaves practically no room for a servo winch.

As determined earlier in this thread, the whole truck is overly front-heavy and wants to topple over all the time, so my battery isn't up front any more.  That gives me space to add a winch, if I can work out how to mount it...

I started by hacking into some plastic with the Dremel.  I have literally done one course in this rig before getting the power tools on it...

The winch drum needs to be in line with the crossmember, which means the servo needs to be way up high.  Again, this isn't great for weight balance, but everything is dictated by the design of the chassis and shape of the body.

[Mad Ax 9310]

I figured I'd start by making an all-new crossmember from alu bar stock, to give me something solid and flat to build mounting brackets off.  I had a few concerns about this idea but figured I had to at least start with it to see where it would take me.

It took me a couple of hours to get this cut, filed, and drilled to fit, before I realised my bar stock wasn't big enough to accommodate the front bumper mounting lugs.  Dangit - back to the drawing board!  At this point I considered parking the project, and ordering an aluminium front crossmember.  I've seen some on Chinese marketplaces that have channels for the winch line and mountings for servo winches built in.  These are for the SCX10, but the BOM is much the same, right?  Wrong.  The front end of the BOM chassis is very similar to the SCX10, and an SCX10 front crossmember will fit into the BOM chassis (I tried mine, it's a perfect fit).  But the BOM bumper lugs are spaced differently to the SCX10 lugs.  So I'd need a new front bumper.  At which point I got overwhelmed by choice and underwhelmed by appearance.  The BOM bumper isn't great but it at least fits the body well.  I wasn't prepared to chance it on an expensive order that might not arrive in time for the event.

So - I sat and thought it over for ten minutes before I started cutting, drilling and tapping more bits of bar stock.

Servo mount:

Hole drilled in stock crossmember:

Clearance edge filed into the servo mount:

Mount screwed into crossmember:

Servo added:

[Mad Ax 9310]

OK, that's one side mounted.  Now to mount the other side.

I made this bracket from bar stock:

And attached it to the servo:

Washers added between mount and servo, because the lugs on the servo are webbed on top for strength.

I cut a channel in the crossmember

And also in the bumper

then added a roller fairlead from an old 3Racing winch

[Mad Ax 9310]

Here is the whole thing mounted up, from beneath.  Somehow I don't have a photo from the top, but basically the alu bar is attached to the crossmember using the bumper mounting screw hole (see small nut where the bumper mount screw should be), and at the back my a 10mm spacer made from alu sleeve, and a long screw going through the battery tray, with a nut underneath (see other nut).

The eagle-eyed among you will notice this isn't the same spool, line or hook supplied with the servo winch.  This is from another order I made a few months back.  The winch line is wire, the hook looks more scale, and the spool is slightly smaller and fits nicer in the limited space.  Although I did have to put a shim under it because the servo winch doesn't have a very long spline, and when torqued all the way down, the spool would stall against the casing.

et, voila

[Mad Ax 9310]

Next thing I wanted to fit was the LEDs.  We might get some dark-weather crawling, and we are in England and it is mid-October, so chance of glum weather and rain are high.  Light under the trees is limited when the sun is hidden behind rainclouds.

I made the switch mount in the last update, this time I had to wire it up.  I had an idea that I might use prototyping board to make for a neater installation.

Here I mount a servo wire direct from the receiver's bind port.  I used all 3 wires so I can fit a bind plug on here if I need to.  That saves removing and opening up the waterproof radio tray if I have to re-bind the receiver.

All wired in and screwed up to the switch plate.  Two switches, for main lights and roof lights, plus another plug to take the current into the body.

Re-attached to the chassis.  I will go over the exposed contacts with hot glue before this truck hits the trails.

Final chassis shot - radio sealed in waterproof box and stowed in the battery tray, wires neatly routed

[Mad Ax 9310]

I was planning on having a late one and getting the body wiring done, but had some family stuff to take care off.  I just about started braiding some wires to hide along the chassis rails before I got called in to sort Sunday dinner.

So - still loads more work to do before the main event!  

[Mad Ax 9310]

Next thing to do was add the rear lights.  There are no rear buckets / lenses / whatever included with the BOM, so I had to come up with my own idea.  The rear plate was the first part of that idea.

I don't have any light lenses or buckets that would work on the back of the rig, so I decided I'd just use plain LEDs, subtly modified to look like dome lenses.  But nobody would use exposed lenses on a rig like this - they'd have to be protected.  So, after drilling the holes for the 5mm LEDs, I cut off a length of household mains wire.

then I ope'd id with a Stanley knife

I extracted the earth wire and got creative with a hammer

drilled some holes in the plate

then used regular wiring solder to secure everything in place.  This solder won't actually flow on the aluminium plate, that would probably need a better solder and higher temps, but it works to lock the wire in and stop it falling out

then I drilled some smaller holes, and added a smaller piece of wire from one the neutral core

again, soldered from the back to secure it

[Mad Ax 9310]

et voila

next trick was to dip some clear LEDs in Tamiya clear paint, because I don't have any color-topped LEDs.  These ones emit an orange light, I also used red LEDs dipped in red paint for the tail lights.  I guess being a US truck from that era, it might have had all red lights on the rear, not red and orange, but when I added all red lights it didn't quite look right, plus I didn't want to have to program my scaler controller to handle US-style direction indicators (if I ever get around to finishing it at all).

While the LEDs were curing, I primed and painted the rear plate in UPol Wheel Silver.  This is a hardwearing generic automotive paint.  Here it's curing under the halogen lamps, although it really needs a few days to harden off properly, heat or no.

reattached to the rear cage part, partly for the photo, partly to protect the face on the workbench before the paint is fully hardened

[Mad Ax 9310]

Meanwhile, I cut some lengths of 5mm ID styrene tube to space out the LEDs.

the paint on the bottom was still a bit wet (I'd properly dipped it in the paint pot) so when I glued it on with hot glue it kind of smooshed about a bit

et voila

clearance is fairly tight behind the plate, but it fits

[Mad Ax 9310]

Next trick was to start the wiring.  Wiring up LEDs isn't something I get a lot of joy out of, it's a fiddly process and inevitably comes with a dissatisfactory result.  I wonder if the companies who make pre-wired LEDs are using special machines to get everything really tight, or are just using really skilled people.

Anyway, here's the rear plate.  I tend to add my resistor direct onto the LED positive terminal, then heatshrink the lot.

After testing, there was quite a lot of bleed through the hot glue, plus it looked real messy, so I tidied it up with some flat black paint.  I managed to drop a blob in the middle of the plate, but it won't show when fitted.

Then I started on the front lights, using hot glue to secure the wires against the body.  The black tape I added to the body is helpful here as it stops the glue burning the paint.

A rubber grommet gives a factory look and protects the wire

[Mad Ax 9310]

Then I made the roof lights.  There were really fiddly and awkward, next time I think I'll try to buy some pre-made.

but actually the final result looks alright.  I cut the terminals as short as I could get away with, but still the loops are really big.  If there was some way of adding insulation after soldering, I'd be able to get a tighter install - hot glue works but is really messy on an exposed part like this.

I went with all-black wiring because the roof rack is black, and the wires blend in better.  Once I've added some more colourful scale stuff, the wires should be less obvious and more hidden.

I routed the wires under the roof rack, down the cage to meet up with the front light loom at the bottom, then along to the back where they'll meet the tail lights and the plug.  More to follow, as the day got old before I was done.

[Mad Ax 9310]

Workshop Saturday Update!  I don't usually do workshop on a Saturday, but things are a bit non-standard this weekend, and that's just as well because there was loads to get finished before the Nationals next weekend.  First and most important being finishing off the lights, so I can see my truck in a gloomy Peak District forest in mid-October.

This is how my workbench looked at 10am today.  It's been a pretty crazy few weeks and I'm way behind for a decent tidy-up.  Not sure when I'll get time for that!

After shouting at some wires and burning myself on the soldering iron, I had this to show for my efforts:

and when it was all plugged in and switched on, it looked like this:

The bleed on the back of the roof lights is annoying - I'll have to do something about that

[Mad Ax 9310]

Next on the list was making an interior.  I think @whahooo wanted to take a look at this.

I started by trimming a single sheet of plasticard to go over the battery and electronics

then reinforced it from underneath with some box section, to stop it flexing.

check the floor fits:

then I added some side pieces to help locate the floor

these slot into the side rails to stop the floor slipping forward or back

 

[Mad Ax 9310]

After that I cut some seat backs - just plain plastic squares for now - and experimented with a few positions and angles to get something that looked right.  I pulled up some Google Images of old Ford Rangers to try to gauge how far back the seats should be compared to the B pillar.  It took a few attempts to get the right position.

All of this effort was undertaken so I had a good place to house this young lady, who I acquired in B&M Homestores earlier this week.  I'm not usually in the habit of bringing home underdressed young ladies from bargain stores, but I couldn't say no to this one.

I started out by adding some box section to gauge the seat height, but turns out the best height for the seat was the height of the plastic floor, so they came off.

I also had to do some surgery on poor Dakota's leg, which is a terrible shame, as it looks like she's spent the last 15 years getting to that level of definition, but it won't be visible once the dash is installed.

[Mad Ax 9310]

No self-respecting four-wheeler would hit the trails with a seat back like a death star cantina tray (even if it isn't wet), so I took my trusty scalpel to the plastic to get something a little more suitable

This is a little bit overexposed (not unlike Ms.Kai, I suppose) but basically this is some lengths of styrene circle section glued into the channels I scored in the back of the plastic, to help form a rigid seat design

This is my seat support.  It actually shifted while gluing and has a gangsta lean worse than the famous cheese-and-tomato flavoured tower, but that's OK, it'll be hidden when it's installed.  Angle is about 70 degrees - it just looked right that way.

No, it's not an early test-run for my Halloween project, it's my protective bucket seat.  I wasn't going to try to cut slotted holes in the top, they always come out terrible.