casting rubber tires?

[Martin KyteParticipant @martinkyte99762]

[Martin KyteParticipant @martinkyte99762]

Hi chaps

Anyone know where I can obtain suitable liquid rubber for casting a set of tank tires. I have seen suitable material in the past but cannot think where. Something like a cold setting silicone (black). 

Thanks in anticipation

 

Martin K

[JasonBModerator @jasonb]

Tiranti do a lot of casting and mould making materials

 

http://www.tiranti.co.uk/

[Ian S CParticipant @iansc]

If the compound that you get is another colour ie clear, grey or white, or what ever, a bit of lamp black goes a long way to getting it black, thats what is used in full size tires. Ian S C

[Sub MandrelParticipant @submandrel]

I’ve hear of a compound called ‘Shoe Goo’ but have never actually seen it. You can hand mould it to make/repair trainer soles and it is supposed to be very hard wearing. A friend has and suggests it would be easy to press it into a mould by hand.

 

If I can get my hands on some I will use it to make tyres for an R/C Standard Beaverette.

 

Neil

[Sam StonesParticipant @samstones42903]

Martin,

 

I’ve used a fair quantity of silicone RTV (room temperature vulcanising), for moulding medical instruments and other components.

 

There are various levels of hardness, but I know nothing of their wear properties.

 

It’s great to use, produces a very faithful reproduction of the mould surface, but you need a good (high) vacuum pump to clear the trapped air after thoroughly mixing the two ingredients together.

 

However, it’s not cheap.

Sam

Edited By Sam Stones on 26/08/2010 02:08:06

[Sub MandrelParticipant @submandrel]

Looked up more on shoe goo. It’s a polyurethane adhesive that can act as a filler – so would be expensive in bulk.

 

I recall Ted Joliffe tested a wheel cast from silicone rubber by dragging around a wheel on his daily walk – he did a lot of miles with no heavy wear IIRC.

 

Neil

[John OlsenParticipant @johnolsen79199]

You can buy polyurethane filler in cartridges to fit standard caulking guns. It is not cheap, but not impossibly dear if you want a few tyres of moderate size. I seem to recall somewhere around NZ$30 per cartridge, say about 10 pounds or so.  I used some stuff called Sikaflex for the caulking of the deck of my steam launch. It sets to a rubbery compound that seems as if it would be quite suitable for a model tyre. But I have not tried making tyres. The one I used is a very good black. The deck is laid with narrow planks of Kauri  about 40mm wide with gaps about 4 to 5 mm wide between them, filled with the black filler and then sanded flat. All properly joggled into the waterway at the edges. Looks lovely, even if I do say so myself!

 

One caution, once you have started the cartridge, it will not be too long before it sets all the way through. So start it and then use the whole thing. I have got away with a few days, maybe up to a week if you do your best to seal the end well.

regards

John

[Ian S CParticipant @iansc]

Hi John, where’d yer get the Kauri,Its usually easyer to get hens teeth! When my brother inlaw built his first boat, he got Kauri flooring from an old warehouse that was being demolished in Chch about 20yrs ago. Sikaflex sound as though it would work OK.Ian S C

[John OlsenParticipant @johnolsen79199]

Hi Ian,

 

The Kauri turned up on the firewood pile for the boiler at MOTAT. I was there as a volunteer that night, helped to unload it and called my wife to bring the trailer. We sorted out all the best  bits and took them home. Most of it was match lining from a house that had been demolished. I also used some wider pieces that a well known retired Auckland boat builder gave me for the waterway pieces around the edge. They were about quarter inch thick, 6″ and 8 ” widths, so I was able to bandsaw out the curved shapes. The planking is laid on top of a foam core deck, so is really cosmetic. (The foam core has 3mm plywood top and bottom.)

 

The ASME club guys keep saying it is not really model engineering, but the engine is based on a design published in ME  in 1983. It is a 12 inch to the foot freelance model of a late Victorian or Edwardian steam launch. *<

 

I should have said, try boat suppliers for the cartridges, although I guess that was implied by the context. The actual stuff is Sikaflex®-290 DC, and going by the google hits is available practically everywhere.

 

http://www.flints.co.uk/pdffiles/sikaflex290dc_tds.pdf  (No connection, just a UK site with some data)

 

 regards

John

Edited By John Olsen on 28/08/2010 02:13:03

[Ian S CParticipant @iansc]

John, thats great, seems a lot of funny things happen at Motat(so I’v heard). what do the ASME guys know, it does’nt matter what the scale is, if you call it model engineering then its a model. Got a bit of interest in boat building, nephew works at Franklins yard in Christchurch, and his dad built 2 boats, the first glass over ply then a 52ft cat glass foam sandwich, so lots of filler, resin etc. Ian S C

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