The Mandalorian Detonator (Chapter 10) - an adventure in conversion

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Sr Member
Hi folks!

I feel it's been wholy to long since I last made a post here, I've still been working hard on props but mainly in the Facebook space! this project, however, felt like one that needed some extra documentation for future makers Since it's a conversion of a Found part and one that seems to be particularly popular at the moment I thought i'd share my adventure so you can prepare for your own Build

Credit to the Reddit Community as i understand for Correctly Identifying the M42G Alarm Unit this is a now-discontinued (70/80's era) Honeywell-ELAC Military Sounding unit.


Here is how it ends up on the show:


There are several key areas I'd ID'd changed from the original:


1: I belive theese guard rails are not found items although they are common they have several tells that lead me to belive these were created by the prop team
The exposed surface nuts mean the ends of the rod are threaded, this is a very easily done thing in a limited workshop but for a mass produced item this would add needless cost to the product when drilling and tapping a hole in the rod would provide a cleaner and cheaper part, further more there are some tell marks of a non industrial bender being used to form the guards:


these indentations are marks from forming, similarly on a mass produced item these would be die formed and would not feature such "defects", I believe from the shade of metal these are Mild/carbon steel with stock Imperial 10-24 Nuts based on the sizes available & Shim washers

2: After searching for countless hours and likely no less than 5000 switches I'd found the right Switch, this is an NKK Switches "TL22DCAW015C"

3: Included on the original are two D-rings where as in the show we have a formed Top hat loop

4:There are two surface plates on the detonator I believe these are cut from Sheet metal and Epoxy bonded to the surface the damage and weathering lead me to belive they are Mild/Carbon Steel

5:The Side Rails at first i thought were rubber or some cut down plastic part but i belive them to be some model of Picatinny Rail, this may be a red herring as i couldnt find anything to be a dead match based on my modeling of the scaled parts:

Aluminium showing through Weathering:

I believe they are aluminium mainly because for such a small prop i dont belive they would have spent the time to so expertly topically weather the parts in this way

6: The The Bottom edge has been groved out i suspect by a Mill and holes are added, i suspect this is somthing to do with the electronics or perhaps an additional idea the team had for the prop that just didnt work out, i suspect it's somthing to do with power however as they are aligned with the binding posts:


7/8: The BUND Logo and the Sounder Switch have been removed and filled in I also believe the rear model plate was removed, but i'll get to the evidence for that later on!

My first step after reciving was to remove the Electronics inside so i could evaluate where I was at I;ve stored all the componants and unused part lest they be some other found part down the line!


The ground point was unscrewed and posts were desoldered from the board, they are mechanically wrapped around the posts so you must use tools to manipulate the parts to remove them if you wish to take them off with care, otherwise, you could snip them off (but you might have issues removing the posts if you do so


at this stage the IP Gasket was also removed and stored, it was only held in by friction and removes with ease.

the Toggle switch was now removed, to remove it requires a Metric Number 14 Wrench, next I desoldered the Peizo Sound unit leaving only the Cluster LED in the center


The Cluster LED was then desoldered and removed with a metric Number 17 Wrench, everything was bagged for safe keeping for the next steps to remove the Peizo unit


after closely inspecting the Peizo unit I discovered the entire unit is Threaded into the Housing, using Card to protect & and a pipe wrench I removed the part with relative ease (I applied some WD 40 to the front threads to ease it along but it was likely ok without this)

There a conformal coating applied to the inside of the casing which would also create issues for moulding as is likely sulfur-based which can be a Cure inhibiting agent. This was cleaned up with wooden tools a Chip brush and some acetone.



be sure to work in a well-ventilated space and wear gloves when working with Acetone.

This is where the learning comes in for folks attempting you require the top half of the Peizio speaker to fit the NKK switch unfortunately for me i have to do this somewhat destructively, the back half of a sharpie was cut down to fit in the hole and use as a hammer punch (with quite some force required)

the plastics and the piece were entirely destroyed however it revealed to me there was a recessed lip on this part which i may have been able to pry with a wedge, but since this part has to be cut it's no big deal

as you can see the switch doesn't quite fit due to the wide back on the part

using a hacksaw I cut the aluminium threaded section in half which allowed me to excitedly do my first dirt fit of the switch!, take care to clean up the ends of the thread

next up i clamped down the part and begun to go to town on the raised markings using 400 grit with a solid block (to ensure minimal low spots



the Bund logo was braided and scratched up for the next step

to get the lower details flat it was quite tricky i had to resort to a diamond bit dremel to carefully grind of the raised details


any mess here would be dealt with filler later

more wet sanding to smooth things out
and more ....... next up was filling of the hole & void as I was spanning a wide hole I opted for Metal epoxy


to minimise cleanup i taped the face of the hole and applied from the rear using a stick & toothpick to deair the mix checking the underside periodically, i also masked around the BUND logo to raise the filler and also to clean the edge a little



after 1.5 hours (4-5 hour full cure time) I used a blade to cut the excess (and remove the tape around the BUND to minimise how much i was cutting




after the part was fully cured i wet sanded the area and cleaned with Acetone to remove any dust & residue


I then used £M Spot filler in a couple passes to get the pin holes & Low spots levelled out

followed by some filler primer to highlight any areas that need further attention

more to follow in the next post!!


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Sr Member
Will this form the basis for a kit by any chance? Learning that the body of the real thing is metal kind of dampens my enthusiasm for converting a real one – too much work to accurize it without proper tools.

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Sr Member
and so ... the adventure continues!

after an incredibly fruitful weekend last week, we cracked on this weekend to the next stage! now that the master was pretty much prepped we spent some time mid week finalizing our CAD data to match the original so we can design the accessories accurately and send them for production (we've ordered around 100 conversion kits .. more on that later!) we'll also release the CAD files on our site so folks can print their own if entire screen accuracy is not the end goal!


excuse the messy desk!!

after this step we checked our overlays against the onscreen prop with careful attention to match the perspectives perfectly to nail those parts!
Side Overlay.png

Side Overlay2.png

now we are happy with the CAD we've ordered up our Conversion kits featuring Alu side rails and steel top plates, Switch Guards and top loops (shown below)

Conversion Kit2.png

Back to the build! we spent some time working out our Circuit and testing & probing the LED to work out the internals

For future hunters the Wiring is as follows:

Red 12V+ (6 Red LEDs in Series (2V 20mA Per LED -> 12v 120mA Total Feed)
Black 12- (6 Red LEDs)
The Grey and Green Wires are 2V 20ma for the center Amber light it is not used in this prop, however)

Using a Small DC-DC Converter I created a small circuit that would feed the 2V LED in the Switch and also feed the 12V LED Array these DC-DC converters are widely available for a low price and come with small trim pots, once your voltage is set you can add a dot of glue to secure the pot

my small circuit was done and dusted! (I'll share the full diagram schematic later)

next up before moulding the case i wanted to take the time to mark where the switch guards would be fitted so when the time comes it's an easy job to drill them without having to measure having the cad data on hand i transcribed the dimensions and made center marks.

These small center punch marks will be more than enough to do the job after moulding my next job was to seal the main thread up before molding so it wouldn't stick and also to seal from silicone getting into the thread using our new Cricut I cut some of our logos and hole masks

next i filled the screw holes that were to be unused

the first halves were mounted up to MDF and 3D printed PETG Walls applied around (the edges were sealed with Polymer Clay) and given a lovely silicone bath ...

they were then put into the Pressure pot and left to cure for 3 hours


the first mold halves were now cleaned up and prepped for the second side

enter a sea of Mold Vents ... probably the most I've ever had on a part!

this too was given the Silicone bath treatment (and so was the rear side)

the moulds came out beautifully and I'm really happy with the results!!

the first test castings were made just a few hours ago and I'm really thrilled with how they came out! i really wanted to ensure i caught everything in the mold without a sea of air bubbles!

after they cured up i removed all the vents and demoulded
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The castings for the most part are flawless!



one thing i forgot to photograph earlier was that i used threaded inserts inside of the mold when casting so the parts have a real metal thread


the white residue is some remnant of the clay

and the final casting assembled (sans the accessories)


although this is fairly work-intensive making castings will be much more economical than just doing conversions as the filling and sanding all take much longer than casting going forward!

I'll have the kits & electronics sets in various forms up in the Cargo hold soon!

the next update here will come after the metal stock arrives! (or when i make the Schematic whatever comes first!)


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Sr Member
For those folks interested! we've launched a range of Conversion kits and a few slots for originally converted kits!


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