Finishing a model

[WolfieParticipant @wolfie]

[WolfieParticipant @wolfie]

I'm getting close to finishing my first engine. As I'm putting it all together I realise that I'm not quite done yet. Bits don't quite fit and it needs a little fettling.

It also needs gaskets. What do I use for gaskets? And also to put in the glands. (What are glands for anyway?)

[JasonBModerator @jasonb]

You can buy thin 1/64th gasket paper from the ME suppliers but brown wrapping paper lightly soaked in oil works fine. On small engines like this I tend to use a liquid gasket, the type sold in small tubes in Halfords etc which is a bit like silicon sealant.

For packing the glands again the ME suppliers will have either graphite impregnated yarn or the PTFE equivalent, but you could get by with making a "rope" from several strands of plumbers PTFE tape twisted together then wrap that 3-4 times round the rod before tightening the gland nut.

The packing acts as an adjustable seal to stop air/steam escaping around the valve rods.

J

[WolfieParticipant @wolfie]

PTFE tape… do you mean thread tape?

[jason udallParticipant @jasonudall57142]

ptfe yeah thread tape…white slippery stuff used on plumbing compression joints

[Eric CoxParticipant @ericcox50497]

Yes, what you call thread tape. If you're old school you'll probably try hemp and Boss White.

[TerrydParticipant @terryd72465]

Posted by Wolfie on 01/07/2012 20:22:50:

I'm getting close to finishing my first engine. As I'm putting it all together I realise that I'm not quite done yet. Bits don't quite fit and it needs a little fettling.

It also needs gaskets. What do I use for gaskets? And also to put in the glands. (What are glands for anyway?)

Hi Wolfie,

to answer your last question, glands, in this ciontext, are properly known as 'stuffing glands'. The idea is that a suitabkle material is wrapped in the hollow part around the tube. The 'gland nut' is then used to squeeze or compact teh matrial until a tight joint is made. If leaks occur at a later date then you merely tighten the gland down a little more. Hence it is adjustable.

You can use many materials for gaskets, sheet PTFE is popular at the moment, you can use gasket paper sold in various thicknesses in car part stores. howeveran old and successful method is to use oiled brown wrapping paper. Personally I have successfully used the covers of lod cheap exercise books, which as a techer, I used to have an ample supply of. All a gasket does is to fill surface imperfectionsand in a steam engine the temperatures are not excessive.

As for 'fettling', that is how we work as model engineers, we are not involved in volume production so parts are individually made to fit, rather than built to tight tolerances which is the case where interchangeability is essential. Many successful and accurate models are buitl using relatively primitive measuring equipment such as manual calipers as it is merely necessary to compare sizes rather than working to absolute standards.

Best regards

Terry.

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