The Workshop Progress thread 2018

Update... started painting... thought I'd use a different colour scheme than usual green & red... aluminium is bloody awkward to paint... even with etch primer, any suggestions please ( & I aint sticking it where the sun don't shine ) ... Aero blue with cream ​ ...



George.

Experiment with anodising? - if it comes out bad it might still provide a better surface for paint.

George

The key to getting even etch primer to stick to aluminium is slavish degreasing.

I would rough the surface of at least the easy bits (the uprights) with a Scotchbrite type abrasive pad first to provide a key, then degrease with something like cellulose thinners (evaporates well, and leaves no residue).

Don't handle with bare hands after degreasing, use gloves.

I have used industrial degreaser spray & used disposable examination gloves but probably still too smooth as was going to have a different finish... polished aluminium, but that oxidises fairly quickly so decided to paint. Ideally would liked to have blasted with fine crushed glass / sand but don't have the means or access to one ( or anodising equip' )hence the paint route so have left coating to harden up 24 /48 hrs, probably have to re-rub as suggested & try again.

George.

A quick soak with oven cleaner?
Don't leave it on ally too long.
(and don't ask how I know this)

Washing soda (sodium carbonate) does the same job and is much less aggressive. Gives off hydrogen, so ventilate well and avoid naked lights.

Thanks for the tips guys

Geo.

Hi All

Just completed the pillar and and base for a small Muncaster engine.

Many of you will know that the Muncaster engines were covered by E.T. Westbury in a series of M.E. articles back in 1957. This engine is the simple single oscillator which commenced the series.

Could I ask has anyone made this model to the Westbury/Muncaster sizes and if so what stroke did you use. Neither Westbury or Muncaster specify a stroke for the engine. Using the scale on the Westbury scale drawings it appears the crank has a throw of approximately 7/16" so the stroke I estimate would be 7/8".

Any feedback would be appreciated

Thanks Geoff

That seems to be about right scaling it off of the Muncaster book.

may be worth drawing it out to see how far the hole in the cylinder moves compared to the 3/16" spacing of the two air holes in the standard

EDIT just sketched it out and a 7/16" throw puts the holes a bit close together, 1/2" throw would be better. 0.486" throw would be spot on.

Edited By JasonB on 16/06/2018 15:27:35

Hi Thanks for that Jason,

I'm currently doing a CAD drawing for the whole model and from it I could see with a 7/16" stroke the hole centres were closer together. I made it 0.165" so with 2mm holes it would leave just over a 2mm space in between them.

I will look at 0.486 I think there is just enough room to accommodate a slightly longer stroke of around 15/16" to 31/32".

thanks again for your help

geoff

Started re-assembly of vertical cross now that paint has hardened off. I have now got a quandary; in the scheme of things I have not seen a colour like mine on actual machinery / models, so I decided to try another blue, 'Harbour blue' on the flywheel. Looking at it with the vision of it all in the darker blue, would it look too dark overall I ask my self, or do I stick with original blue?. the cladding would look more contrasting with the lighter blue but again would look reasonable with the darker colour.

​Decisions, decisions, have any other members been in the same situation over a flippin colour scheme, what sayest y'all ?, silly I know but opinions welcome... ... original colour...



... with new darker blue on the flywheel...



​...the more I compare the more I can't decide... Oh woe is me ! ... brain fade creeping in. Hmm, well at least I can use the excuse that I'm 70 in a couple of weeks ... , Yeah, I know, it's a personal choice thing...

​George.

Very difficult to choose, when the same 'original colour' looks so different in the two photos.

... Would I be right in guessing that the second photo is more accurate ?

MichaelG.

When in doubt use both, the two blues go well together, leave the frame and cylinder and fit the darker blue flywheel.

John

I'd go with the lighter blue all over, are you sure you have not seen it before

The light blue looks a bit pale for my taste George but plenty of engines were grey so it doesn't look out of place. The finish looks too good to remove and sometimes overthinking something makes the dilemma worse.

Keep it as is, mount the dark flywheel for a good contrast and call it done.

Jim

Edited By Jim Nic on 20/06/2018 20:19:36

... Would I be right in guessing that the second photo is more accurate ?

Correct MichaelG

Jim/Journey man... best of both options I guess, thanks for your opinions guys. Still a fair bit of titivation to do.

George.

.

Thanks for the confirmation ... I like that one.

Two-tone might indeed look good.

MichaelG.

Although my latest engine is fairly straightforward it seems to have been taking a long time to get it finished. However, I have now managed to turn this:

and a few other bits into this:

Plus of course a medium size pile of swarf and scrap parts.

It's an Oscillating Rotary Valve engine designed by Ray HasBrouck taken from his book "The Steam Engines of Ray HaSBrouck" and I've done it with a reduced bore and stroke of 15mm by 20mm . It's a lovely little runner as can be seen here: **LINK**

Jim

It runs very well Jim, a lovely model, excellent detail.

Just looking at the flywheel which I assume is cast iron, super outer rim finish, what's the secret?

What does a stroke of 15mm by 20mm mean?

Geoff

It means the cylinder is 15mm inside diameter (bore), and the piston has a travel of 20mm (stroke).