Help with 'Speedy' valve gear and other issues...

[Roger]

I've just done a little research to see what professional Graphics Designers use for their printing, and it would appear that you can get printers that go up to 2400dpi. The printer I've got only has a resolution of 600dpi, so it looks like it ought to be possible to get 4x the resolution. A couple of the dog walkers that I occasionally bump into are Graphics Designers, so I might tap one of them up to see if they can print me a sheet of them on some quality paper. I've got some Photographic paper somewhere, to I'll see if I can find that.

[chris vine]

Hi Roger,
I’ve printed stuff on photo paper in the past using an inkjet printer. After a year or so the inks start to blur or merge.
At least a laser printer would melt the plastic toner onto the paper or sheet, so should be more stable in the longer term.
Printing onto vinyl at a sign writer and then laminating over the top as if for an external sign might be best. Not sure of the resolution though. They could print a test in the margin of another job for you to try!!
Chris

[steamer5]

Hi Roger,
If you go down Chris's suggestion route of a sign guy, ask them to print on hi temp vinyl, its good for around 75C continuously, so for our use of a couple of hours a day a few days a month it should be good for years!

Cheers Kerrin

[Roger]

Mar 23, 2024 23:16:59 GMT chris vine said:

Hi Roger,
I’ve printed stuff on photo paper in the past using an inkjet printer. After a year or so the inks start to blur or merge.
At least a laser printer would melt the plastic toner onto the paper or sheet, so should be more stable in the longer term.
Printing onto vinyl at a sign writer and then laminating over the top as if for an external sign might be best. Not sure of the resolution though. They could print a test in the margin of another job for you to try!!
Chris

Hi Chris,
I would want to laminate or varnish the print, it's only ink after all. Looking at laser printers, they don't seem to be as high resolution, and aren't popular with Graphics Designers by all accounts.
I didn't know that you could print onto Vinyl. In all cases, I think there needs to be some kind of stabilising finish else it's not going to last.
I do have a laminator, so maybe high resolution Inkjet printing onto photographic paper and then laminating might work. Actually, I've got some of that Transfer Tape that I could use to protect it. I might give that a go if it's the right sort of finish. Sellotape is a bit shiny, and perhaps a bit thin.
There appear to be several commercial printers in our area, and also Ryman's Stationers who claim to have a printing service. I might have a ring round and see what resolution they offer.

[chris vine]

I have laminated inkjet onto photo paper, but the ink moves horizontally through the paper!

Vinyl might be much better I think, especially if there is a high temperature variety.

C

[Roger]

Mar 24, 2024 10:50:28 GMT chris vine said:

I have laminated inkjet onto photo paper, but the ink moves horizontally through the paper!

Vinyl might be much better I think, especially if there is a high temperature variety.

C

Hmmm... I would have thought that printing on Vinyl would be a challenge. Surely ink won't move through photographic paper, that's not really porous? I thin coat of sprayed varnish might fix it permanently, so long as the solvent doesn't disturb it while it cures. I think some experiments are in order.

[nick952]

How about printing them as waterslide transfers? Search for "printing waterslide transfers" to find the paper.
Apply to the white painted backplate and then if needed varnished.

[chris vine]

Hi Roger,

I think the photographic inkjet papers are coated with an absorbent layer. I guess it must be absorbent to take in sufficient ink to give the vibrant colours. Only the tiniest amount of moisture will probably allow the ink to travel sideways in this layer.

I found this article www.shutterbug.com/content/how-long-will-your-digital-prints-lastbryou-may-be-surprised-page-2

The part on humidity which I think would be a concern for you:

Humidity Fastness
Significant exposure to relative humidity higher than about 80 percent can cause colorants to migrate, thereby causing color changes or loss of sharpness. Long exposure to very high humidity can cause microbial growth and discoloration. Test labs can expose prints to elevated humidity for a period of weeks to qualitatively rank the relative humidity fastness of different products based on measured color changes. As with light fade, humidity fastness is typically improved by using the manufacturer's branded paper that is matched to that particular brand of ink.

For you, surely an engraved plate, easy for your machines, and then pad printing. You can buy the pads and I am sure a lash-up could be made with a pillar drill etc. Then you can print it with black paint onto metal painted white. Then it really will last a long time and be as crisp as a swiss watch face. You won't have to align the pad accurately with the job, because you can print onto a bigger piece and cut out to match to the design - especially if you printed the circle to cut to!!

I am only thinking that if it fades, you may have quite a lot of delicate dismantling to get to the part.

Incidentally, that reminds me: do you have an isolating valve so you can pressure test the boiler without damaging the gauge? I didn't do that on Bongo and so have to unscrew the nut from the gauge and fit a blank. All very tricky and fiddly!!!

Chris.

[stevep]

Mar 24, 2024 23:57:04 GMT chris vine said:

SNIP

Incidentally, that reminds me: do you have an isolating valve so you can pressure test the boiler without damaging the gauge? I didn't do that on Bongo and so have to unscrew the nut from the gauge and fit a blank. All very tricky and fiddly!!!

Chris.

Having an isolating valve to the gauge could be very dangerous - it could be left closed, and you could be left wondering why pressure is being raised, until the safeties lift.

I recommend accepting the inconvenience of fiddling with the union. It's safer.

[Roger]

Mar 24, 2024 21:57:38 GMT nick952 said:

How about printing them as waterslide transfers? Search for "printing waterslide transfers" to find the paper.
Apply to the white painted backplate and then if needed varnished.

Thanks for that. This YouTube video shows the procedure, and he's using Decal paper with a white background. I could use this on a thin piece of brass.
He uses three coats of Halfords spray varnish on his.

[Roger]

Mar 24, 2024 23:57:04 GMT chris vine said:

Hi Roger,

I think the photographic inkjet papers are coated with an absorbent layer. I guess it must be absorbent to take in sufficient ink to give the vibrant colours. Only the tiniest amount of moisture will probably allow the ink to travel sideways in this layer.

I found this article www.shutterbug.com/content/how-long-will-your-digital-prints-lastbryou-may-be-surprised-page-2

The part on humidity which I think would be a concern for you:

Humidity Fastness
Significant exposure to relative humidity higher than about 80 percent can cause colorants to migrate, thereby causing color changes or loss of sharpness. Long exposure to very high humidity can cause microbial growth and discoloration. Test labs can expose prints to elevated humidity for a period of weeks to qualitatively rank the relative humidity fastness of different products based on measured color changes. As with light fade, humidity fastness is typically improved by using the manufacturer's branded paper that is matched to that particular brand of ink.

For you, surely an engraved plate, easy for your machines, and then pad printing. You can buy the pads and I am sure a lash-up could be made with a pillar drill etc. Then you can print it with black paint onto metal painted white. Then it really will last a long time and be as crisp as a swiss watch face. You won't have to align the pad accurately with the job, because you can print onto a bigger piece and cut out to match to the design - especially if you printed the circle to cut to!!

I am only thinking that if it fades, you may have quite a lot of delicate dismantling to get to the part.

Incidentally, that reminds me: do you have an isolating valve so you can pressure test the boiler without damaging the gauge? I didn't do that on Bongo and so have to unscrew the nut from the gauge and fit a blank. All very tricky and fiddly!!!

Chris.

Hi Chris,
I'm not sure how porous Photographic paper is, it looks very shiny. I'll probably have to try it to find out. I can print something, spray with varnish and then soak it in water.

I looked at Pad Printing, but this is incredibly fine. I think I'd struggle to get an acceptable result. 

Yes, I do have an isolating valve, although I think it would be wise to crack open the union just to make sure it doesn't destroy the guage.

[Roger]

Mar 25, 2024 9:47:17 GMT stevep said:

Mar 24, 2024 23:57:04 GMT chris vine said:

SNIP

Incidentally, that reminds me: do you have an isolating valve so you can pressure test the boiler without damaging the gauge? I didn't do that on Bongo and so have to unscrew the nut from the gauge and fit a blank. All very tricky and fiddly!!!

Chris.

Having an isolating valve to the gauge could be very dangerous - it could be left closed, and you could be left wondering why pressure is being raised, until the safeties lift.

I recommend accepting the inconvenience of fiddling with the union. It's safer.

I hear what you're saying, but I don't see that as a huge risk. That's what they have in full size, where you could make the same argument.

[Roger]

I haven't had much time to work on this lately, but finally I have something that's going to work. I've remade the body, increasing the centre distance of the gears by 0.1mm because they were too deeply in mesh. The pivot holes have also been increased to 1.05mm to give more clearance on the 1mm shafts.

I've also added a clearance in the top plate and body so that the link wire can be fitted into the quadrant. I managed to break out one of the holes on the quadrant while manipulating it back and forth with tweezers, but I'll live with that. It's not going to get used anyway.

Anyway, here's a very wobbly video of the result. You can see how close the link wire is to the quadrant gear pivot, and that's given me plenty of travel, possibly a little too much. I need 100 degrees in total for 100psi.

I've also shortened the length of the pipe fitting thread because it's more like this on the fill sized item.


PXL_20240505_121919799.TS by Billy Roberts, on Flickr

Anyway, I finally feel like I can move on with this, it's been stalling the build for too long!

[chris vine]

Completely Magic, Roger.

It is these little sub-projects that make the whole hobby so intriguing...

Chris.

[JonL]

May 5, 2024 19:34:02 GMT chris vine said:

Completely Magic, Roger.

It is these little sub-projects that make the whole hobby so intriguing...

Chris.

I agree. Model engineering isn't learning one skill, its dabbling in a thousand...

[Neale]

...as Shakespeare well knew. After all, he summed up model engineering as "Dabble, dabble, toil and trouble!" At least, it is in my workshop...

I think that this topic veered off its original title subject a long time back, but is fascinating to follow anyway.

[Roger]

I've been laid up for a few days with my first bout of Covid, so I'm only just now getting back to this.

The Pressure and Steam Heating Gauges are mounted on a plate that's canted at an angle and offset from the Backhead Cladding.


Backhead8 by Billy Roberts, on Flickr

It's a bit clearer in this view, where you can also see that there are two ribs that support it. Obviously you won't be able to see much of this when the dummy pipe is finally fitted.

Since I don't have any drawings or better photos than this, I've guessed the angle and position of the bracket.

Backhead30 by Billy Roberts, on Flickr

It's all being made from 0.6mm thick Steel Sheet so it can be thin but still strong. Here I'm machining the 0.6mm wide slots for the tags on the two brackets to engage with. I'm using a 0.5mm PCB burr which is very cheap but not appropriate for the job. However, using 3mm/min feedrate and 0.025mm cuts, it cut these in a couple of hours, using lube of course.

PXL_20240512_174215132 by Billy Roberts, on Flickr

The whole set of parts looks like this, a bit messy with burrs, but good enough.

PXL_20240513_104742656 by Billy Roberts, on Flickr



PXL_20240513_110318579 by Billy Roberts, on Flickr

That took quite a bit of finishing with needle files, but eventually it all went together as planned. I've just twisted the corners of the tags to hold it together. They're 1mm long, so there's theoretically 0.4mm sticking out.

PXL_20240513_132401571 by Billy Roberts, on Flickr



PXL_20240513_132437623 by Billy Roberts, on Flickr

Once again I'm using Nail Varnish to mask for Silver Soldering and protecting the rest with more flux.

You can't see from this view, but there are pieces of Silver Solder wrapped around the other joints too.

The Silver Solder on the back here will wick through to the front easily enough.

PXL_20240513_134905631 by Billy Roberts, on Flickr

Ok, the top was going to get too hot if I carried on with this, so I've stopped before the bottom has melted. I'd protected the thin section on the left with the piece of Steel to stop that from getting even hotter.

PXL_20240513_135513910 by Billy Roberts, on Flickr


Anyway, I put another piece of Steel to protect the top joint and finished it off.

PXL_20240513_181929847 by Billy Roberts, on Flickr



PXL_20240513_181935648 by Billy Roberts, on Flickr

Yet more work with needle files and this is the result.

PXL_20240513_190531992 by Billy Roberts, on Flickr



PXL_20240513_190547471 by Billy Roberts, on Flickr

I need to drill and tap two M1.4 holes in the Backhead Cladding, so here's a drill jig that picks up two holes that hold the Cladding to the Boiler.

PXL_20240513_180631855 by Billy Roberts, on Flickr


I just need to make a spacer for the Dremel to make sure the tapping size is flexible and to provide a stop. We can't have it drilling into the Boiler!

PXL_20240513_202012837 by Billy Roberts, on Flickr

[Roger]

I made a spacer bush and set the drill to protrude 7.5mm clear of the face. The 5mm thick plate helps to keep the drill square to the face. The backhead is made from 1.6mm Brass, so it's plenty thick enough to take a thread for this. The holes were drilled slowly, clearing the flutes regularly. The last thing I wanted was to break off the drill.

PXL_20240514_073304850 by Billy Roberts, on Flickr

The drill jig was then removed and opened out to become a tapping jig.

PXL_20240514_080438844 by Billy Roberts, on Flickr

Simple enough, but worth taking a bit of effort to make sure that they're in the right place and nothing is damaged.

PXL_20240514_082530826 by Billy Roberts, on Flickr



PXL_20240514_090901935 by Billy Roberts, on Flickr



PXL_20240514_090910908 by Billy Roberts, on Flickr

[Neale]

Where do you get the PCB burrs from, Roger? Cheapies from eBay? I haven't used tab-and-slot for anything below 2.5mm so far, but would like to at least go down to 1.6mm for some fabrications, which implies expensive but fragile milling cutters. However, sounds like the machining time would be rather high using burrs instead. Be interested to hear your thoughts.
- Brian

[Roger]

May 14, 2024 16:53:33 GMT Neale said:

Where do you get the PCB burrs from, Roger? Cheapies from eBay? I haven't used tab-and-slot for anything below 2.5mm so far, but would like to at least go down to 1.6mm for some fabrications, which implies expensive but fragile milling cutters. However, sounds like the machining time would be rather high using burrs instead. Be interested to hear your thoughts.
- Brian

Hi Brian,
Yes, I get all my cutters from eBay, including the PCB burrs. To be honest, they're too fragile to use on a manual machine. The problem is that PCB cutters tend to be long and slender. Even 1mm ones are going to have very long flute lengths, making them very prone to breakage.

This is a company I've bought a lot from over the years, and they are as good as any. However, even though these are much more robust than PCB cutters, you'll have to be very gentle if you're using them on a manual mill.

If you look at the price of these PCB burrs, you can see they're less than £1 for 1mm or 2mm sizes, whereas the proper CNC metal cutting ones are between £6-£7 each. If you're running CNC then it makes no sense to spend a lot of money unless you're in a hurry.