Traction Engine Tyres?

[Bo’sunParticipant @bosun58570]

Good afternoon,

I’m about to make some tyres for my model Traction Engine.  One each for the front wheels, and two each for the rear wheels. The material is Black “general purpose” solid Neoprene Rubber, 2mm x 10mm.

Before I start, some guidance would be appreciated.  Firstly, how to ensure a neat perpendicular cut (scarf or butt joint)?  Secondly, what adhesive?  I had planned to use a “superglue”.  And thirdly, any tips on lining up the joints prior to bonding?

To secure the tyres (they will have a little stretch in them), I intend to use hair lacquer just like I’ve used in the past to secure the handlebar grips on my mountain bike.

[Robert Atkinson 2Participant @robertatkinson2]

Superglue is pretty rigid when set and may crack. A rubber based “contact” adhesive e.g. Evo-Stik “IMPACT” is a better choice with a scarf joint.
Professionally I would use a similar adhesive like 3M Scotch-Weld 1300L that is qualified to MIL-A-1154.

You might also consider using it to glue the tyre to the wheel as a strip rather tha a closed band. A scarf joint can still be used and will allow for a little variation in length.

Robert.

[Bo’sunParticipant @bosun58570]

Thanks Robert, I had considered an Impact Adhesive, but thought the tyres cross section at 20 sq mm a little small for it to be effective.

[Robert Atkinson 2Participant @robertatkinson2]

A scarfed joint, through the thickness of the rubber will increase the surface area and reduce the peeling forces on the joint. You are correct that  a simple 2mmx10mm butt joint exposed to bending is unlikely to hold with contact adhesive. Super glue wil hold it statically under tension but I’d be concernd about the compression if the joint rolls over on a hard surface.
What diameter are the wheels and how much does ithe model weigh?

Robert.

[JasonBModerator @jasonb]

The larger engines use a good quality superglue, 3M do “black magic” which has some rubber particles in it to join the ends and then a flexible rubber adhesive to bond them to the rims such as Marineflex. These are probably a harder rubber than your flat strip may be but by the size of it I doubt you will be doing many road miles.

Fitting instructions

[Bo’sunParticipant @bosun58570]

Robert,

The rear wheels are 115mm dia and the fronts are 70mm dia.  I’m guessing, because the model’s in pieces at present, but the weight is around two kilos.

Jason,

Thanks for that, I’ll have a look at it tomorrow.  Certainly not many road miles.

[bernard towersParticipant @bernardtowers37738]

I used Double B designs tyres for my DNY 2″ engine, now supplied bt MJ engineering there is some info on their site . Mine are butt joined with their supplied superglue ( be careful) it actually smokes when the two pieces are put together. I think from memory that the tyre is 1 inch shorter per foot of wheel dia. I fitted mine on the wheel with no adhesive and a 1/2 inch rod under the tyre and put the adhesive in the gap and rolled the bar around the rim adding adhesive as I went. Still there after 20 years but not used much.Beware its a messy job!!!!

[Nigel Graham 2Participant @nigelgraham2]

To answer the accompanying query, perhaps a simple jig made to guide a sharp knife or a junior hacksaw will ensure a true cut. Cutting rubber with a knife is easier with a little lubrication by soapy water.

[Alan CharlestonParticipant @alancharleston78882]

Hi,

Rather than gluing a rubber strip to the wheels, it might be interesting to coat the rims with silicone sealant which will cure to silicone rubber. If the wheel were slowly turned during curing it should maintain a uniform thickness rather than sagging. When cured, I believe it could be cut with a sharp tangential cutter to produce a perfectly round tyre.

Regards,

Alan C.

[JasonBModerator @jasonb]

Silicon sealant is likely to be far too soft. I don’t know the exact shore hardness of the tyre “strips” but just like the vulcanised rubber or PU resins it is much firmer than tube silicon sealant but a firmer RTV one may work .

Though having said that it now turns out to be a rather small traction engine since my earlier reply so unlikely to suffer creep on a road run.

[Bo’sunParticipant @bosun58570]

Thanks for the suggestions.

An update for those interested:  Hairspray worked quite well to secure the tyres to the wheels, and as Jason suggested, tyre creep is unlikely to be an issue.  Actually, the tyres remained in place OK without any adhesive, except the front tyres tended to slip sideways when turning.  The tricky task was jointing the rubber strips.  I favoured a scarf joint to get a large gluing surface, but the diagonal cut just caused the joint to slide sideways as soon as pressure was applied.  A simple but joint, and some additional magnification won through in the end.

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