Topic: Reproduction Indicators

[pso-buzz]

I would love to see some in progress pictures.

Are you making centre caps got the rear wheels?

That would be awesome'

[danny7147]

Yep, rear wheel centre caps, they're halfway through the moulding process but I can't see them being too much of a problem... That said, nothing's ever quite as straightforward as it seems 

Right, clear plastic lenses. Let me explain the task I'm facing and then I'm all up for ideas 

With the silicone I use for the moulds, it's not cheap, but it's great at replicating details. The main plastic it can be used with is polyurethane, like the hi viz masts.

Polyurethane comes in a couple of different types... some set very quickly, I can make a hi viz flag in under 5 minutes(!)... some set really slowly but are generally used for vacuum moulding or other types of casting rather than pouring into a mould which limits me to what I can use. With the one I use, it comes in white or 'clear'. The hi viz masts are actually white with a black pigment.

Following so far? Okay... the pigments cause more problems because they are extremely difficult to measure accurately. Pigments are used at a 0.5% ratio... for every 100ml, it takes 0.5ml to turn it that pigment colour! For that reason, the hi viz flags use 60ml of plastic, and 0.2ml of black pigment to obtain the right shade of grey and even then they're never identical!

With the indicator lenses, the problem gets even worse. 'Clear' polyurethane is actually amber. There IS a clear one, but it's a very slow setting one that can't be used with the moulds I have. The theory was to add a touch of red pigment so that red+amber=orange. The first attempt last night (100ml plastic, 0.2ml pigment) turned it a blood red. No good. So then it becomes silly. I think to get the right shade of orange will actually need approx 60ml plastic with about 0.05ml pigment, and as of yet I haven't found a way of measuring 1ml let alone 0.05ml! Which leaves me back at square one.

I've found a pigment online that is a 10% ratio, that might work, or I've found another which IS orange, but with the amber of the plastic this might turn it a murky orangy yellow instead!

Anyway, as for clear/frosted, I REALLY like the idea, but at the moment I can only do amber  I'm kind of an obsessive person, I won't stop until I've got it right, but it's back at the drawing board stage at the moment. I'll knock up a couple later to show you the moulding anyway, but if anyone does have an idea of how I can get orange then I'm definately open to suggestions!! 

[mhurt]

Have you considered weighing, rather than measuring, the pigment ?
As a general rule, 1ml = 1g, so 0.05ml is 0.05g and that's definitely possible, in fact I measure the same kinds of amounts for sausage making

You can get some cheap, accurate scales on Ebay (coincidentally, the same kind that druggies use...) that do 0.01g increments, just get one that can be calibrated if possible. I think mine cost about £10. you could just use a toothpick to add drops of pigment then.

Might be worth a try.

[pso-buzz]

I am very interested in the wheel centres if you can make them like the originals.

I have zero experience with moulding but if I was painting to get amber I would mix yellow and red.  I am sure this doesn't help but I thought I would mention it just in case.

[danny7147]

Ironically my wife had the toothpick idea too, but the problem is that I don't think it's accurate enough to produce the same colour every time. I like the scales idea, but how would I then transfer 0.05 grams of liquid? :-/

[danny7147]

Okay, first sneak peak... here's one I made earlier 




I didn't bother filing it down so it's a little rough, but it shows the shape I can mould at least. This colour is the 'basic' colour straight out of the bottles with no added pigment. I was taking in bad light so it doesn't show the "Magnalite England" on the bottom of the outside, but it's a crystal clear as the "FRONT" and "REAR" are on the hi viz sets.

[kamilb1998]

Looks very good. I'm sure you'll get the pigment correct soon.

[pso-buzz]

That looks pretty damn good to me.

[Lancealot]

Keep going that looking good as a 1st attempt.

Lance

[C5 ENTHUSIAST + RESTORER]

 Looking great well done ...Regarding the mixing what I use is a small plastic syringe and it works great 1 drop at a time ....
Chas

[Luke S]

look good

[mhurt]

Not sure if it would work, but if you weighed the pigment on clingfilm and then placed that over the resin to transfer it via contact ?
Just trying to think around the problem

[danny7147]

I think I might have hit on an idea... The supplier I use actually does an orange pigment, but it's quite a high intensity orange. Next time I place an order for silicone or plastic I'll get them to put some in!

Incidentally, I've just poured the second half of the centre cap mould so should have a prototype made up by about tuesday or wednesday when I have time!

My C5's got it's first show of the year in a week's time and ironically the only thing it's missing is the centre caps which is why it'll benefit ME if I can get them right  I really don't know a price for them yet, it depends on how they come out and how much work it takes to get them to fit etc  I'm aiming for about £6 each, so shouldn't be too bad, but obviously I won't know how good/bad they look until the first one comes out of the mould!

[alecjw]

Hi, any update on this? I'm very interested in some reproduction rear indicators