Post by Andrew Rowland on Sept 29, 2014 2:15:16 GMT -5
Having tested the car on George Turner's track and found it works well i've decided to build the plastic crown gear element in bronze to ensure it can deal with the rigours of a long proxy series. The gear shown above is still a plastic prototype designed to push the Policar Lotus which only weighs 55g. This heavier scratchbuild will need something beefier! So i'm combining a Wizzard 25t crown with a 1.5mm bore with a Policar straight cut gear with 3/32 bore. In the absence of any real machinery I bolted through the centre of the crown and held that in my dremel. Then filed away the hub to 3/32 and pushed the gear on. The gear similarly had a shelf filed off.
Post by David Mitcham on Oct 28, 2014 2:42:00 GMT -5
The Brabham looks terrific. The suspension detail is a work of art and the exhausts look just right to me. If it goes as well as it looks - which I have no doubt it will - I'm sure it will set the benchmark for the rest of us live up to. It would be good to see the progress on some of the other builds apart from yours and Mark's.
Hi Andi, lovely work on the construction of both the body and chassis of the Brabham. Would you be able to describe how you bend, hold and solder the parts with out disturbing other soldered joints on the pieces please? Thanks Nigel
Post by Andrew Rowland on Nov 1, 2014 12:22:50 GMT -5
Hi Nigel, thanks. Unfortunately I didn't take any build shots so i'll only be able to describe in words.
First I always start with a very clear drawing, at least in one direction. With the dimensions in the other. Then I start to sketch out roughly which parts might be bent out of a single piece. The idea is to have as few soldered joints as possible and to make as strong a structure as possible.
So I had a side view drawn out and simply bent a piece of 0.8mm dia. Brass bar round to make one of the main frames, in this case I did the bottom one then the top. For brass i use smooth teeth pliers or, if I want curves a pair of round teeth pliers.
The first frame I superglued to the paper drawing standing up vertical. Then I glued the second one similarly so they just touched at the long 'top' joint. No glue anywhere near the part to be soldered.
With that I soldered the two together. For this size of work I use a 25W soldering iron which is about 60 years old..... My dad's in fact.
Next came the 'c' shaped piece that fixes the four main bars together. Here I made the piece just over width so it was a push fit and held itself in. No other means to hold. Hold the soldering iron on the part glued down to the paper and the heat transfers to the other part and then offer up the solder to the joint. Touch the solder against the iron to get it melting and running into the joint. Before soldering clip a crocodile clip onto the already soldered joint (the closest one) as a heat sink so that it won't un solder.
Then the rest of the bits get added up to the point when the whole thing has to be cut off the paper. From there you need to find ways to keep the pieces steady as you solder them and use crocodile clips to keep already soldered joints from desoldering. This can get complex but is usually no real big deal.
Eventually you get the thing built up as required.
Don't worry if too much solder goes on, just file and sand it down after.... Of course the less you use is better but really don't worry it can always be taken off later.....