Outing for a Duck

QUOTE (chief32s @ 11 Mar 2009, 12:57) <{POST_SNAPBACK}>(Note: I'm very unhappy with how the paint job turned out. I hope Jarius is averting his eyes, or at least watching from behind the sofa! lol.)

Over the next few days/weeks I hope to fill in the missing 4 months between these two photographs and detail the highs and lows of my first ever chassis build. Where I can I will repeat the advice I got on the way from people on this forum, and list the retailers from whom I sourced the materials, just in case any other rookies might be reading.

Comments, advice and criticism are welcome throughout.

As for your paint job, just remember: "burnish, burnish, burnish!"

It's a GREAT looking car! TERRIFIC theme! (Did you know that the real Platypus has "spurs" in it's hind legs "which produce a cocktail of venom?" I wouldn't have guessed by looking at 'em.)

And, about the "Over the next few days/weeks...." thing, you DO realize that's like three years in Slot Car Time? We need to see details!!

Hey Al,


great name

You have and excellent design there
Will be looking forward to your next creation

i-ray

SPLENDID* project, Chief! Just SPLENDID!

QUOTE (bres3000)...about the "Over the next few days/weeks...." thing, you DO realize that's like three years in Slot Car Time? We need to see details!!
Holy words Bres, holy words!
Hurry up Chief, we ain't got time to loose!
E

* Save for a few pink details

Fantastic Al,

Excellent job.
It would be nice to see a bit more what's hiding under it's skirt.

And it would also be interesting to see how you build the vacformer,
when i am back in Switzerland (home) i will make one too, i have a old spare vacumer i can use for it.

Cheers,
Jaak

Bres3000, John, Ray, Edo, Lou E, Jaak, many thanks for the kind words guys.

QUOTE (bres3000 @ 11 Mar 2009, 21:25) <{POST_SNAPBACK}>As for your paint job, just remember: "burnish, burnish, burnish!"

Did you know that the real Platypus has "spurs" in it's hind legs "which produce a cocktail of venom?" I wouldn't have guessed by looking at 'em.

And, about the "Over the next few days/weeks...." thing, you DO realize that's like three years in Slot Car Time? We need to see details!!

bres3000: maybe I missed out that last burnish. Unfortunately every step in the painting process suffered from an attack of Murphy's Law, and with the deadline looming ever closer, I had to accept a finish that I know I could have improved on, given time.

I had no idea about the platypus' venomous rear. From the Low's first round reports it sounds like my car also has a dangerous rear that needs handling with care, .

As regards the "Over the next few days/weeks...." thing, I don't want to tread on Steve's toes with his Sunchaser thread, where I think he will be showcasing each car in turn, and I only have a few photos of the finished car anyway, but I promise to keep things moving along nicely, and let's face it, as this build is complete, this thread has a definite time line.

Jaak: Vacformer pictures coming soon.

QUOTE (Edo @ 12 Mar 2009, 07:53) <{POST_SNAPBACK}>Hurry up Chief, we ain't got time to loose!
E

At your command, sire.

Next post coming up presently.

Al.

Although I had the shape of the body in mind, I couldn't begin to build it until I had a chassis design to size it from. At this point I didn't even know the dimensions of a 1/24 Thingie motor. And so, November and December were spent researching, planning, designing and ordering materials.

For any newbies (like me) that want to learn about chassis design and development, then the independent scratch builder is a must.

Never having bought brass rod or piano wire before, I asked the good folks on Slot Forum to point me in the direction of a retailer, and amongst others I was recommended Chas Keeling at scd. The service Chas provides is excellent and I placed an email order with him for 1/16 brass rod, piano wire, rear bracket and some Parma equipment (motor, crown, bearings, wheels etc (Sorry E)). He sent me an invoice by return and after paying through PayPal I had the stuff a few days later.

Now I could design a chassis that would fit under the body that I had in mind. Pretty soon I had this:



An iso chassis with 4 1/2" wheel base, 5 1/16" guide lead and I was aiming at a width of between 3 and 3 1/4" across the real wheels.

With the chassis design drawn up, I couldn't resist having a go at bending some brass.



Using regular pliers (from Halfords) to bend the brass for outriggers (is this the correct terminology?)



I used the drawing to help me measure where to bend the brass, and to ensure that my angles were accurate, it was invaluable.



Checking finished bends against the drawing for fit and accuracy.



Putting it all together, to see how it was looking.

Note: None of these rods made it into the finished car. I was just practising, and as I went along, the chassis design evolved which meant I needed more brass.

More to come soon, I promise.



Just to whet your appetite

Regards,
Al

Excellent post! I love drawings and usually do one for each chassis I build. Watching with great interest...

Many thanks Jairus, more drawings coming up shortly.

With most of the brass bent into shape I began to practise soldering, and soon found that my ancient 25W iron didn't have enough power for the job. So the chassis was put on hold and it was back to the body.

As I was using my own designed body I knew that I would have to build a vacformer !! I checked out the various threads on SlotForum for DIY vacformers such as Howmet's here and put a lot of thought into how I'd build my own machine, then it was off to B&Q.

I bought some Conti board (cheap as chipboard lol) that seemed to aspire to other things. Little did it know


The first thing I did was to make the vacuum table. Using a mitre saw I cut some lengths of conti board, which I screwed and glued together to form a box open at both ends. I secured this firmly to a base of 18mm MDF (this was an offcut from another project) Note the hole I drilled with a hole saw, to accept the vacuum cleaner nozzle.


I then glued in some supports (to hold the vac bed) made from 3mm MDF and notched together in the middle.


Finally I made the bed of the vacformer. This is where the mould sits.
Using some 3mm MDF cut to size, I marked out the centres of some 200 plus holes using isometric grid paper and set about drilling each of them with a (unfortunately blunt) 6mm drill bit. This was very laborious and I'm sure some sort of grill material would make the job easier, but nonetheless, it works perfectly.
Here it is fastened in place. (It is pinned, but I taped it to ensure better suction).


Next I needed to make a mechanism to bring the vacuum forming plastic into contact with the mould when it is "plastic" enough. So using the conti board again, I made a second open box, larger than the first which could slide over the first like a close fitting sleeve (The outside/overall dimensions of the sleeve are the same as an A4 sheet of paper).
Note the blocks at each side, which hold the sleeve at the correct height whilst the plastic is being heated. Also note the mouse-hole shaped hole that allows this sleeve to clear the vacuum cleaner nozzle, when the plastic is drawn down onto the mould.


To make the frame that holds the vacforming plastic securely in place, I cut two rectangles of 3mm MDF, these are 10mm larger than the sleeve on all sides and overhang (so that they can be clipped together when in use). I then routed out the centre of the two rectangles so that the hole was a tad larger than the vacforming bed. I pinned and glued one of the frames to the top of the sleeve (ensuring that the sleeve still slid up and down the centre box smoothly and the frame didn't impinge on the vacforming bed). The other frame remains loose and is used to sandwich the vacforming plastic.
I applied draught stopper (the rubberised type) to the face of each frame that comes into contact with the vacforming plastic, to ensure a good seal. I was concerned that 3mm MDF might deform in use, but it seems fine. I could add some bracing to the loose frame in future.


The vacuum former was now ready to use, I bought a pack of bulldog clips to fasten every thing in place when in use. Here it is in its first real operation. The machine worked perfectly, unfortunately the mould let me down and I needed some releasing agent. So it was a bit of trial and error to begin with.
I use the heat gun at the side to warm the vacforming plastic sufficiently (just until it begins to get a uniform sag) then I pull out the blocks and turn the vacuum on in one swift and smooth motion. The vacuum helps pull the sleeve down the inner box/vac table, ensuring that the plastic is in good contact with the mould.



I asked Howmet which plastic he used for his creations and he told me that PETG was the best and he recommended a few retailers. I bought my PETG online from 4D modelshop it is clear PETG 0.5 x 500 x 800mm and can be found here (about half way down the list). I can cut each large sheet up into 6 smaller 294x207mm sheets to fit in the machine.

When I had finished building the vacformer, I had some conti board left over, which i turned into a very useful sanding board.


Next installment...Body Building.

OK, I said I'd rattle this off as quickly as I could, so here is the next instalment.

I took the chassis drawing (shown in a post above) and laid a clean sheet over the top of it, and began sketching various plan views of the car. It took a while for me to get a body shape I was happy with, one that would sit comfortably over the chassis I was going to build and which had enough room for the guide to move about. But eventually I came up with this.


I then traced the body's centre line, and the outer and inner curve of one half of the body, and scanned these lines into some photo editing software. This allowed me to mirror the curves thereby ensuring perfect symmetry of the left and right hand sides of the body. It also allowed me to adjust the width of the rear, which otherwise would have been a little narrow.


I printed off several copies of this drawing, and stuck them down onto 3mm MDF, which I then cut out with a piercing saw (more accurate than a coping saw). At this stage I also cut out the recesses that would form the duck's bill shape, cockpit and engine bay. Finally I glued each piece of MDF together, trimming some to take account of the drop of the nose, before sanding the nose to the correct slope.






Next I used Milliput to form the contours of the Duck's bill, and the fluting of its sides/skirts. My Milliput was about 6 years old, and rock hard, so I stuck it in a plastic bag and immersed it in very warm water for a few minutes. This softened it up like a dream.




The next step was to fine sand the body down until it was smooth and then to spray on several coats of primer. Between each coat of primer I was able to sand out any minor imperfections, and at this stage I was very happy with the product.


After reading many of the body building threads here on SlotForum, I thought the next step was to spray a few final coats of gloss, to give the mould a perfect finish. Here is a photo I've shown before. It really did look good.


And here it is again on the vacformer, after forming. Note the lack of contours in the bill. I had forgotten to drill an air hole for the vacuum. Doh! (Pilot was fashioned out of Milliput too).


Unfortunately the gloss proved to be a problem in the vacformer, sticking to the plastic and being near impossible to release (you can see this in the photo above, if you look at the nose). I realised that I should have used some kind of releasing agent, but it was too late. When I prised the plastic off the mould, it took several layers of paint with it. I had wanted to pop a few bodies in case there were any problems later in the paint shop (Hmmm!!), but instead of doing a production run, I found that I had to repair the mould after the first pop.

This time I stopped at the primer stage. I raised the mould on a plinth, to make sure that any webbing was taken away from the body. And I remembered to drill the air hole in the bill.


And here is the first (relatively trouble free) body.


Chassis building next.

Al.

And for heat you just use a heat-gun?
Wow...

My former is not nearly as nice. But I built it back in High School and have never seen fit to change it. Just a box and a few frames where I heat it over the stove top and drop it over the master with the household vacuum hooked up. Very un-professional but I have used it for about 35 years!

Very nice work Al and great to meet and learn from a renaissance man!

Hey Al,

Nice work

I apreciate the fact that you took the time to make the photo's and the nice story that goes with them.
It is very inspiring to see how you did it.

And looking at the machine i see no reasons why i could not make one (accept for the fact that i am still in Holland )

It's also great to see how the first ever Al 'The Chief' Thingie body came to life
Will bug you for a body when i start finishing my other 'to do' projects.

Many thanks for the kind words guys.
Jairus, I would be very surprised if there is anything that you can learn from me, on the other hand I can only marvel at your skill as a chassis builder and body artist. You (along with a few others) set the bar.
Jaak, I wish I had more pictures, but you know how it is. You get so intent with the work that you can complete a whole stage and then realise that you haven't taken a single photo showing how you did it. Admittedly, some of the pictures here have been taken after the fact. Oh, BTW. You don't need to bug me, it'll be a privilege. Just let me know when.

So onto the chassis...

My attempts at soldering brass rod with my old 25W iron were dreadful. I had bought it for small electrical work and it obviously wasn't powerful enough for rod, resulting in cold joints and general untidiness, not the smooth flowing solder joints I had seen in other people's builds. I couldn't really see how people could get a nice smooth finish from an iron, whatever the power, and being more familiar with brazing and using a flame, I decided to buy a small soldering torch from B&Q instead of a new iron.



If something has to be done right first time, I usually get nervy and make a mess of it.
However, I found that if I messed up a joint when using the torch, I could heat the rod up again, remove any excess solder, clean it up with wire wool or sand paper, apply flux, flash it with heat and maybe add a little more solder and repeat the process until I was happy with the result.
My lack of soldering experience meant that I had been a little daunted by the idea of a scratch built chassis. But now I had found a method that worked for me and I could see the finished chassis in my minds eye. Here is the very first joint that allowed me to believe I could do this.



With all the brass rods bent into the correct shape and awaiting soldering, I began to think about the rear bracket which would be a visually important and essential part of the 'Duck'.
I initially tried to build the rear bracket out of one piece of 1/16 brass sheet, with disastrous results (no photos here). Most of this car has been built in my front room with limited tools, and I just wasn't set up to accurately build a bracket out of one piece of brass in the way Howmet does so excellently here . Although if Howmet's thread had been available earlier I might have made a better job of it. It was back to the drawing board. The whole "Duck" project was on hold and under threat.

I said there were highs and Lows (hi Steve)

More shortly, and I do mean shortly (got to nip to the shops).

Al

I have three Irons now of variety of wattages. Also have a nice butane Iron that I keep in my slot box for repairs at the track. Heats up faster than an electric iron... I just need to remember to put the flux into the slot box!

After rethinking the design of the rear bracket/wing structure (strangely topical on the eve of the Australian GP) I worked up a solution that in the end would be thinner and lighter than the original idea. After a few rough sketches to ensure correct ground clearance and location of the iso pivot, I transferred the design to a basic CAD package, along with a pattern for the guide tongue, and printed this out.



I had some brass sheet (1.58mm and 0.45mm) set aside for another project, that came from P L Hill Ltd in Bradford. Having already hacked into the 1.58mm sheet for the abandoned one-piece bracket, there seemed no reason not to attack the other.

To ensure that the bracket sides were identical, I doubled up two pieces of .45mm brass sheet, securing them together with double sided sticky tape, then I spray mounted the bracket pattern to one face of the brass. I could now drill out the holes required in both pieces at the same time. To ensure greater accuracy I pre-drilled a piece of aluminium with holes of the correct diameter, and clamped this on top of the brass (hole by hole) to act as a drill guide. I know aluminium is soft, but it was up to the job for a one off.
When the 4 holes were drilled I was able to cut out both pieces with a piercing saw at the same time. Unfortunately, as I now felt under some time pressure, I forgot to photograph this stage.

Instead, Here is a picture of the bracket structure test fit.
Note: The .45mm brass sides are tied by a 9/32 OD bearing tube to a standard rear bracket (with its bearing holes reamed out a little) . The bracket then rests upon a 3/32 OD iso-hinge tube.



and again here, all soldered up, with some 1/16 rod ready and waiting for the rear wing.



The rest of the chassis coming soon...

Al

OK, last stretch and the finish line is in sight.

With the rear bracket all soldered up, and the guide tongue cut out of the 1.58mm brass sheet, I couldn't resist having a look at all the brass together for the first time.





Then I set about soldering up the rest of the chassis. This was one of the most enjoyable parts of the whole project. First off was the central section, including some small decorative/structural detail to add some forward weight (and not enough as it turns out).



followed by the outriggers (again, not sure of the correct terminology here).



Then it was simply a case of bringing it all together. OK, there wasn't anything simple here at all really.

I needed to use an iron to 'tin' the guide tongue but as I've mentioned, my old one wasn't up to the task. So I came up with the idea of preheating the tongue with the torch, then heating up the end of my old soldering iron with the torch also, before using the iron to spread a nice thin coating of solder on the underside of the tongue. Crazy, but it worked.

I found soldering piano wire to be almost impossible, but after putting out a call for help on SlotForum, I realised that my cleaning regime of using wire wool to prepare the piano wire was insufficient, and instead I needed to give it a thorough sanding with some wet and dry paper. It also helped to 'tin' the piano wire using the cobbled together method above.

Keeping everything square, particularly when it came to soldering the rear bracket to the central section, became increasingly difficult without a jig and I had to resort to increasingly complicated structures comprised of sacrificial brass rod, masking tape and other bits and pieces variously arranged.

Non-the-less I ended up with this. It was a bit rough and ready, but I'd be able to tidy this up in time. Note the piano wire that ties the outriggers together. From the start I had wanted to shape this into a roll-bar (look at the original picture in the first post), and I was pleased at how it turned out. Note also how the hinge assembly comes together to secure the two parts of the chassis. Also, if you look behind the rear wheels you can see the piece of holey aluminium I mentioned earlier.


I was on a high, and couldn't resist sitting the chassis under its body. Here it is under the first body (the one that stripped paint from the mould). I was relieved to see that the roll-bar was correctly located.


Final photos to come shortly.

Al

Well, that's about it for the build. I would show you how the paint job came together, but I have no pictures of it. This may be a blessing, as it was a complete mess from start to finish and this was to blame for the missed deadline and point drop. What I can say is that the Duck is currently running in The Sunchaser 2009 Proxy Thingie Race bedecked in her second fully painted body. This body is a slight improvement upon the first fully painted body (sat in front of me as I type), and is in fact the 4th moulding.

So here are the final pictures (some have been up already but I include them again for completeness)

Chassis first:

Top (Note: the little screws securing the hinge are motor mounting screws)


Underside:


Side View:


And the complete car:













Notes to self: Before building my next car I need to get hold of a higher powered soldering iron, a chassis jig, and I really need to read some paintwork threads.

Hope you've enjoyed it, and as said in the first post, comments, advice and criticism are welcome.

Many Thanks
ATB
Al

Great thread Al, thanks for posting!