Experimental Plug Track: continued

[Phil G]

Hi Martin,
its interesting you should say all this, it is something I have been a bit concerned about myself, I have been doing quite a bit of research on the resin (I thought I better had given I am in the chemical engineering industry) There is no doubt the temp of the resin in the vat is critical to constant replication, This is because even though the reaction is between the chemicals and the UV light, the reaction profile is still directly temperature related. The ideal temp looks to be 25 to 26 degrees, but of more importance is you hold it consistently print after print. Ideally to within 1 degree. So its more critical to find your optimum temp, and then set the Templot adjustments to suit.
This mean accurate temp control is required. The attached link is what looks to me a very good way of doing it on the Mars 2. I have also found and started to make an equivalent for my Mars 3, using exactly the same electrical components.

https://www.elegoo.com/blogs/3d-printer-user-guide/elegoo-mars-2-pro-how-to-make-a-heater.

Just a foot note as Martin has pointed out its very likely a change of resin will result in a change of the reaction profile, especially if is its a different manufacturing batch. meaning if your planning to do quite a large amount of trackwork your be advised to purchase more then one bottle and check there from the same batch, failing that each new bottle will need a bit of fine tuning of the setting.
As to the FDM same issue but the temp is already about as good as you can get. my personal preference is to go with laser cut timbers.
that said I am a long way from proving that, due to the fume issue which has to be resolved. So to use Martins preferred explanation, "that is still very much experiment in progress "
I don't think laser will work without glue but given superglue is often used in the woodwork game, it does lend itself to this holding application.
Phil

 

[Martin Wynne]

Hi Martin,
its interesting you should say all this, it is something I have been a bit concerned about myself, I have been doing quite a bit of research on the resin (I thought I better had given I am in the chemical engineering industry) There is no doubt the temp of the resin in the vat is critical to constant replication, This is because even though the reaction is between the chemicals and the UV light, the reaction profile is still directly temperature related. The ideal temp looks to be 25 to 26 degrees, but of more importance is you hold it consistently print after print. Ideally to within 1 degree. So its more critical to find your optimum temp, and then set the Templot adjustments to suit.
This mean accurate temp control is required. The attached link is what looks to me a very good way of doing it on the Mars 2. I have also found and started to make an equivalent for my Mars 3, using exactly the same electrical components.

https://www.elegoo.com/blogs/3d-printer-user-guide/elegoo-mars-2-pro-how-to-make-a-heater.

Just a foot note as Martin has pointed out its very likely a change of resin will result in a change of the reaction profile, especially if is its a different manufacturing batch. meaning if your planning to do quite a large amount of trackwork your be advised to purchase more then one bottle and check there from the same batch, failing that each new bottle will need a bit of fine tuning of the setting.
As to the FDM same issue but the temp is already about as good as you can get. my personal preference is to go with laser cut timbers.
that said I am a long way from proving that, due to the fume issue which has to be resolved. So to use Martins preferred explanation, "that is still very much experiment in progress "
I don't think laser will work without glue but given superglue is often used in the woodwork game, it does lend itself to this holding application.
Phil

@Phil G

Hi Phil,

Thanks for the link and resin info.

I'm very pleased with my improvised heater for the Mars using a brewing heater belt and bungee cord:

https://85a.uk/templot/club/index.php?threads/3d-printers-messin-with-resin.103/post-7161

Linked to the Inkbird controller with its probe inside the printer cover, it is maintaining the temperature at exactly 25 degsC +/- 0.2 degs.

I'm so pleased with it that I've ordered a second heater belt to fit below the first one. That will take it to 50W total, which should be enough to lift the printer to working temperature even on the coldest winter days.

But not at present -- one warm day recently the printer's own generated heat took it to 26 degsC. At that point the Inkbird's cooling output came on, and I plugged in a desk fan pointing at the printer to prevent it going any higher. Which seemed to work -- but obviously wouldn't do if the ambient temperature was higher. That would make the 3D printing den unbearable, so I'm not likely to be doing any 3D printing on such days. But I must remember to put the bottles of resin in the fridge.

cheers,

Martin.

 

[Martin Wynne]

Martin all my work so far including the 80cm point i build have been with solid jaws. It was tricky holding the whole lot together why I slid in the rails and then dropped into the sleepers but it worked.

@Michael Woods

Hi Michael,

Thanks for your thoughts.

I'm now firmly convinced that the loose jaws option is an easier way of building track. It avoids all the hassle of preparing the rail ends, sliding chairs onto the rail in the correct order, spacing them out, locating them all over their sockets in one go, and holding multiple rails in place.

Take one chair at a time from the raft. Fix it in its socket. Simple. Drop the rails into position when you are ready, one at a time. Insert the loose jaws to clip them into place, again one at a time. There is a very satisfying click as each one locates into position below the rail head.

It sounds too fiddly for words -- but it isn't. With some magnifying specs and some fine point tweezers it's quite easy to do and you soon get into the hang of it. It takes a bit of time, but no more than you have already saved by not having to slide chairs onto the rails.

The trickiest part is keeping track of which loose jaw goes where. I found a useful container is an ice-cube tray. One row for the stock jaws -- S1, L1, P, SC. One row for the special jaws, in order, labelled, as you remove them from the raft.

Admittedly you can't build loose-jawed track while riding a galloping horse. It needs a quiet relaxed setting with some calming music, and a nice bunch of flowers in a vase on your bench. Just don't knock it over.

Despite wittering on about correcting fluid, I'm still pondering how to improve the press-fit option. It might be possible to run an angled barb along the side of the plug to retain it in the socket, rather than relying entirely on the interference fit at the ends of the plug. It can't be too fierce a fit on the socket sides, because in places the walls are quite thin and would bulge the timber sides. But it might be enough to prevent the plug coming loose. It could instead be an actual groove in the side of FDM sockets -- but that won't work for plywood.

So that's another experiment to be conducted, and another tick-box to control it, and another settings button for the barb dimensions. And on it goes.

cheers,

Martin.

 

[Martin Wynne]

'
A few days ago I obtained one of these:

https://www.amazon.co.uk/dp/B0080R1CLG

I was interested to see what quality could be expected for just £3. I thought probably not much.

But I was pleasantly surprised. It is actually a nicely made G-clamp. The frame is cast iron and substantial. The 1/2" dia. screw is a good close fit with very little play and a smooth action along its full length. The tommy bar is nicely finished with no sharp edges. The screw is actually chemically blackened rather than plated in the picture -- but blacking generally allows a better screw fit and retains lubrication better. The shoe is painted and swivels freely without excessive play.

Although labelled 50mm / 2" the actual maximum opening is 61mm / 2.3/8"

And the relevance to plug track is?

I've been thinking about the rail bending tools. They will have 2mm dia. dowel pins in FDM slides. I wondered if I could design them to fit onto a G-clamp frame, so that the screw could apply the bending force in a smooth controlled manner. This G-clamp looks very promising for that, and is inexpensive. Any thoughts? Is this worth a try, or another of my daft ideas?

p.s. yes I know they should correctly be called cramps when used to apply force.

cheers,

Martin.

 

[Steve_Cornford]

Adhesives,
I have found that Gorilla wood glue bonds resin bases to card, cork and plywood quite adequately.
it contains: acetic acid ethenyl ester, polymer with ethanol; 1-phenoxypropan-2-ol;
2-methyl-2H-isothiazol-3-one
Whatever that means but it does seem to work.
Also when testing some L1 loose jaw chairs with increased socket size, I glued some loose ones into resin base with a dab of Glue'n Glaze from underneath(as I had it to hand). So this was resin to resin, and that also seemed to hold.

 Paint
Before, during, or after ballasting some form of painting will be required, both from applying the required colouring/weathering, and for UV protection . This will also help bond everything in place.

let's face it the previous method of using solvent to attach ABS chairs to plywood timbers was not fool proof, too much solvent and the detail of the chair disappeared, same with pressure, and gauge distortion with angled rail seats.

Is the key to a good bond between rail and slide chair a thorough decrease of the rail just before assembly and application of glue?

Steve

 

[Steve_Cornford]

Your c*amp idea is definitely worth a try, especially if it was somehow held in place by some sort of slot on bfc the jig so that one could concentrate on rotating the lever rather than holding the c*amp in the right place as that is one of the difficulties of using these small ones.
How about some sort if lever?

 

[Martin Wynne]

Your c*amp idea is definitely worth a try, especially if it was somehow held in place by some sort of slot on bfc the jig so that one could concentrate on rotating the lever rather than holding the c*amp in the right place as that is one of the difficulties of using these small ones.
How about some sort if lever?

@Steve_Cornford

Hi Steve,

My thought is that the bending jig will grip/clamp/clip into place on the cramp frame, possibly using clamping screws and wing nuts. Then the G-cramp assembly is held vertically in the bench vice. That leaves one hand free to hold the rail in place on the jig, and one to turn the screw. But it's all got no further than thoughts so far.

How does everyone feel about having to buy a £3 G-cramp from Amazon if they want to use the bending jigs? Is that a reasonable thing to ask, especially for users around the world?

re The gluing of L1 chairs -- my fear is that pressing a chair into sticky glue will cause some glue to get into the pin slot from below. Preventing the loose jaw from subsequently fitting fully down. Did you find any problem with that? It would be possible but fiddly to trim a little from the bottom of the pin if it did happen.

Is the key to a good bond between rail and slide chair a thorough decrease of the rail just before assembly and application of glue?

I seem to remember @Paul Boyd is the man to ask about this. There is a specific Loctite number adhesive which sticks rail to injection-moulded chairs and may work equally well with resin chairs. Searching the old forum archive should find the number. 406 comes to mind, but my memory is not to be relied on.

cheers,

Martin.

 

[Steve_Cornford]

Sorry Marti , it was more a suggestion that Glue'n glaze might be worth trying as a glue between resin chairs and FDM timbers.
Steve

 

[Steve_Cornford]

If you are worried about the G clamp, how about an FDM printed version?
Would just need a nut & bolt to be supplied by the user, with the nut captured by the 3D print, then wind the bolt in with a spanner to press the dowel against the rail?
Steve

 

[Paul Boyd]

@Steve_Cornford

Hi Steve,

My thought is that the bending jig will grip/clamp/clip into place on the cramp frame, possibly using clamping screws and wing nuts. Then the G-cramp assembly is held vertically in the bench vice. That leaves one hand free to hold the rail in place on the jig, and one to turn the screw. But it's all got no further than thoughts so far.

How does everyone feel about having to buy a £3 G-cramp from Amazon if they want to use the bending jigs? Is that a reasonable thing to ask, especially for users around the world?

re The gluing of L1 chairs -- my fear is that pressing a chair into sticky glue will cause some glue to get into the pin slot from below. Preventing the loose jaw from subsequently fitting fully down. Did you find any problem with that? It would be possible but fiddly to trim a little from the bottom of the pin if it did happen.



I seem to remember @Paul Boyd is the man to ask about this. There is a specific Loctite number adhesive which sticks rail to injection-moulded chairs and may work equally well with resin chairs. Searching the old forum archive should find the number. 406 comes to mind, but my memory is not to be relied on.

cheers,

Martin.

Hi Martin,

My memory is struggling a bit as well! Loctite 406 is formulated for plastics and rubber but does stick cleaned metal, and I can’t remember if that’s what I used in that application. Loctite 435 might be better for sticking rails to chairs. Both are flipping expensive though, and have a relatively short shelf life at room temperature. I haven’t tried either with resin, but I feel that if it’s thoroughly clean there should be no problem - I use cheap Expo cyano on resin aftermarket model aircraft bits with no problems and suspect that’ll be equally sufficient for sticking rails to chairs, not to mention easier to get hold of for most people. If I understand correctly this would be just to hold the rail in place whilst fiddling the pin into place?

Cheers,
Paul

 

[Martin Wynne]

If I understand correctly this would be just to hold the rail in place whilst fiddling the pin into place?

@Paul Boyd

Thanks Paul.

No, this is for the P slide chairs where there is only the outside jaw (which can be loose) to hold the stock rail.

My usual solution for anything like this would be epoxy. If using loose jaws they can be finally fixed in place with a smear of epoxy after the rail is in place. Because the rail can flex, the loose jaws can be removed easily -- one at a time and returned with a smear of epoxy on the rail. Some blu-tack then holds the rail against them while the epoxy hardens.

But there is still a lot of learning to do on the tips and tricks for assembling loose-jaw plug track. For example if a dropper wire is soldered to the bottom of a rail in advance, it will be almost invisible and can be bent at 90 degrees to run between the timbers. It then forms a useful "handle" to hold the rail in place with a bit of blu-tack while the first couple of jaws are inserted. Plain TCW is fine for dropper connections. e.g.

https://uk.rs-online.com/web/p/copper-wire/0355085

A dab with the hot glue gun will attach it to the timber webs, clear of any contact with the other rails. Make connections to the layout wiring at the side of the track.

All lost under the ballast.

cheers,

Martin.

 

[Phil G]

Hi Martin,
If I understand you correctly, your turning the G-clamp with FDM printed base into a vertical press Jig. Thus allowing one hand for the rail position and the other to apply pressure via turning the tommy bar. Which is a great idea.

I can see what your saying, if the FDM jigs designed to fit a certain brand, it does at least imply the same brand is also likely required for ease of fit.

Personally speaking, I would have no issue in purchasing a 50 mm G-clamp from Amazon, although the post will be more than the cost of the G-clamp.

On a totally different topic the 1 in 10 fling jig works perfect, however I noticed after filing the rail, it was very hard to open the two jig half's. In fact I had to tap out the M6 coach bolts to get it a part. I did find I could use a flat blade screw driver to prize one side of the the jig open slightly that was created by the relief area data section, enough to get the screwdriver blade in, so I wounded if proving a similar relief slot on the other side would be enough to open the jig sufficient to slide the finished rail out? Just a thought
Phil,

 

[Martin Wynne]

On a totally different topic the 1 in 10 fling jig works perfect, however I noticed after filing the rail, it was very hard to open the two jig half's. In fact I had to tap out the M6 coach bolts to get it a part. I did find I could use a flat blade screw driver to prize one side of the the jig open slightly that was created by the relief area data section, enough to get the screwdriver blade in, so I wounded if proving a similar relief slot on the other side would be enough to open the jig sufficient to slide the finished rail out? Just a thought
Phil,

@Phil G

Hi Phil,

If it is that tight, your rail groove is too narrow. You need to adjust your settings somewhere. Either change the rail head width:

for a better match to your actual rail. Or deliberately set it a fraction wider than the rail.

More likely you need to change my Cura settings to suit your own extruder and filament. You are unlikely to need this much Horizontal Expansion -- reduce it a lot and do some test prints. Try maybe 0.03 mm:

To save time on test prints, reduce the part thickness a lot and only do one half:

The rail should fit closely in the groove without excessive play, either way up, but not require any force.

How did you get on importing my .curaprofile file?

There is masses of stuff to be written about the Cura settings before we are done.

cheers,

Martin.

 

[Paul Boyd]

@Paul Boyd

Thanks Paul.

No, this is for the P slide chairs where there is only the outside jaw (which can be loose) to hold the stock rail.

My usual solution for anything like this would be epoxy. If using loose jaws they can be finally fixed in place with a smear of epoxy after the rail is in place. Because the rail can flex, the loose jaws can be removed easily -- one at a time and returned with a smear of epoxy on the rail. Some blu-tack then holds the rail against them while the epoxy hardens.

But there is still a lot of learning to do on the tips and tricks for assembling loose-jaw plug track. For example if a dropper wire is soldered to the bottom of a rail in advance, it will be almost invisible and can be bent at 90 degrees to run between the timbers. It then forms a useful "handle" to hold the rail in place with a bit of blu-tack while the first couple of jaws are inserted. Plain TCW is fine for dropper connections. e.g.

https://uk.rs-online.com/web/p/copper-wire/0355085

A dab with the hot glue gun will attach it to the timber webs, clear of any contact with the other rails. Make connections to the layout wiring at the side of the track.

All lost under the ballast.

cheers,

Martin.

Ah, ok! In that case, Loctite 435 would be better than 406 as it would be less likely to run everywhere - 406 is very thin and would be difficult to precisely place. Epoxy would be a cheaper and more readily available alternative though, if it can be prevented from stringing.

We have loads if different gauges of TCW at work, but I’ve never thought of using that as droppers, especially in the way you describe!

Cheers,
Pau

 

[Martin Wynne]

@Phil G

Sorry Phil. Serious brain failure there. You don't have 241b yet of course, so you can't change anything. I will post you the STL for a test print shortly.

cheers,

Martin.

 

[Martin Wynne]

@Phil G

Hi Phil,

Here is an STL you can use for test prints. It is just one half of the jig, and only 3mm thick:

Adjust the Horizontal Expansion in Cura until you get a nice fit on the rail.

cheers,

Martin.

 

[Phil G]

Hi Martin,
To be honest I could not get your Neptune setting to import. all I got was the attached. So I opened it in notebook and tried to manually set the values does not all as though a got it all right.
Any ideas who to get the imort to work?
Phil,

 

[Martin Wynne]

@Phil G

Hi Phil,

You are trying to import my Neptune profile settings into an Ender printer. Cura won't have that, no way! I've tried.

Did you not see my post about how to set up a custom printer that will accept my profile settings? See:

https://85a.uk/templot/club/index.php?threads/experimental-plug-track-continued.673/post-7361

cheers,

Martin.

 

[Steve_Cornford]

hi
Martin,
Are there any recommended spacing of rail and diameter of rod to go with your illustration of a knuckle bend jig?
Steve

 

[Martin Wynne]

hi
Martin,
Are there any recommended spacing of rail and diameter of rod to go with your illustration of a knuckle bend jig?
Steve

@Steve_Cornford

Hi Steve,

In a word -- no.

It depends on what you have to hand in your workshop. Also nickel-silver rail is harder than mild steel.

A starting point would be to have the rail oddments separated by the length of the knuckle bend, and the rod roughly about one quarter of the radius! (not diameter) of the knuckle bend, because the rail will spring back. That might require too much force, and separating the rail oddments a bit further might give you more control.

The length of the knuckle bend is shown on the templates (3 lines across between the rails at the knuckle). The radius of the bend is easily calculated as the crossing angle in feet. i.e. for a 1:7 crossing the knuckle bend radius is 7ft = 28mm radius in 4mm/ft scale. So your bar might be around 7mm radius ( so 14mm diameter ) or in practice what you have available. Guess what the diameter of an AA battery is?

You can use a much smaller bar, but the radius might be a bit sharper than the prototype.

It's much easier if you make the bend first, and cut the wing rail to length afterwards, measured from the bend.

Using double-stick tape, you might put the rail oddments vertically on one jaw of your bench vice, and the AA battery on the other. Then closing the vice on the wing rail gives you plenty of force and control.

cheers,

Martin.

 

[Phil G]

Hi Martin,
Thanks for the detailed info on setting up your profile. I have to be honest I somehow missed you post yesterday, having followed the instruction to the letter, I have now successfully loaded the Neptune profile,
I then printed the 3 mm STL unfortunately, the rail slot is now tighter then in previous attempts, and I just can't get the rail in the slot at all. what is much better at 0.15 layer height and 50% infill however this the file resistance of the PLA + Dont worry abou sending another STL I can wait for 241b
phil

 

[Phil G]

Guess what the diameter of an AA battery is?

Hi Guys,
just a word of caution your going to use AA Batteries as the rolling bars. Be carful not to damage the battery, as battery acid is nasty stuff.
Phil

 

[Martin Wynne]

Hi Martin,
Thanks for the detailed info on setting up your profile. I have to be honest I somehow missed you post yesterday, having followed the instruction to the letter, I have now successfully loaded the Neptune profile,
I then printed the 3 mm STL unfortunately, the rail slot is now tighter then in previous attempts, and I just can't get the rail in the slot at all. what is much better at 0.15 layer height and 50% infill however this the file resistance of the PLA + Dont worry abou sending another STL I can wait for 241b
phil

@Phil G

Hi Phil,

Sending another STL won't make much difference. What you need to change is this in Cura:

If the rail won't even look at the groove, reduce the above to zero, or even make it negative.

When you have got the rail fitting nicely, make another jig using the original STL.

Glad you got a custom printer set up.

cheers,

Martin.

 

[Phil G]

Thanks Martin OK will change Cura settings and give it another go
phil

 

[Martin Wynne]

We have loads if different gauges of TCW at work, but I’ve never thought of using that as droppers, especially in the way you describe!

@Paul Boyd

Hi Paul,

Are they still called "droppers" if they run horizontally? We need a new name -- "feeders" ?

At least that way they are prototypical. The prototype very rarely connects track-circuit cables by drilling a hole through the baseboard.

cheers,

Martin.

 

[Winander]

Hello Martin,

Would shellac (knotting fluid) be suitable as a glue? A useful property might be the ability to easily dissolve it with meths.

all the best,
Richard

 

[Martin Wynne]

.
• Advance warning -- design change

I was being a bit defeatist a few days ago. Having set my heart on dry assembly without messy, smelly adhesives I decided to go back to the beginning and have a rethink. I pulled out some sketches for snap-fit plugs from a couple of years ago.

At that time I rejected this idea as unworkable with the much thinner timbers I was trying to use to be compatible with existing flexi-track. And also because it obviously won't work with laser-cut plywood.

But as I think those wanting plywood have accepted the need for glued assembly, and the timbers are now much thicker to allow for the loose jaw pins, it seemed worth having another go at snap-fitting chairs for FDM (and maybe resin) timbers:

The plugs are redesigned with side tangs which clip into a recess in the side of the socket. Unlike the existing press-fit bash-fit plugs, with these snap-fit plugs once clipped in place there is no residual stress on the timber. The plug is an easy fit in the socket with much less need for very close tolerances. But not too easy of course, otherwise we won't maintain the track gauge with sufficient accuracy.

Having a recess in the side of the socket means that some socket walls are even thinner than before, but still just about acceptable I think. They need to be thin enough to flex anyway, as the plug is clipped down into place.

I've made some test prints, and so far they are working very well. The chairs snap into position with a satisfying click.

Be warned however, that once fitted there is no way to remove them without destroying them, so don't get them in the wrong socket or the wrong way round ! Some felt-tip marker lines along one end of the plugs while still on the raft will be very helpful when fitting them.

• If I decide to make this design the default it means these chairs and 3D-printed bases won't be compatible with any previous stock you have made. If you want to go on making the existing designs, for laser-cut bases maybe, you will need to change yet another option setting:

It's possible this design will push-fit into laser-cut ply ok, so not needing to swap designs for laser. But it's obviously not going to clip into plywood and will need some glue to retain it.

I'm going to make up a full turnout before finally deciding to switch the default design, but as of this evening it's looking very promising. Thanks all for the encouragement, it makes all the difference to me.

cheers,

Martin.

 

[Phil G]

Hi Martin,
Good on you for not giving up.
I can certainly why you want to find a solution for resin and FDM. Personally I think the issue is more with the FDM side and not the resin. Simply because there are no mechanical moving parts in the X,Y planes on resin machines. So it seems logical to me at least, that slot size variation its as much to do with machine tolerances as printed part tolerances.

However as you say this design is really only for Resin and FDM timbers, so its going to rule out both laser and CNC machined timbers.
I personally still favour the idea of Laser cut timbers, (although I have to be honest I am starting to come round with recent improvements to my Ender and you guidance on the correct Cura settings.)

That said it would be a great pity to lose all the great work you have done so far on the bash fit design. As such I do hope you decide to keep both options as live experimental ideas. I know that's more option buttons and its also likely to duplicate the outstanding chairs for the obtuse angle type crossings.
Phil,

 

[Martin Wynne]

@Phil G

Hi Phil,

I'm not removing anything -- I very rarely do. Both options will remain available for those who want them.

The big question as always is not "what options should be available?" -- it is "which option should be the default?"

There is no duplication of the chairs, there is no difference above the timber surface. It's just two different designs of plug and socket which can be generated for a chair, as required. I'm not planning any options to have different plugs for different chairs in the same file.

Have you now got the groove in the filing jigs sorted out?

cheers,

Martin.

 

[Phil G]

@Phil G

Hi Phil,

I'm not removing anything -- I very rarely do. Both options will remain available for those who want them.

The big question as always is not "what options should be available?" -- it is "which option should be the default?"

There is no duplication of the chairs, there is no difference above the timber surface. It's just two different designs of plug and socket which can be generated for a chair, as required. I'm not planning any options to have different plugs for different chairs in the same file.

Have you now got the groove in the filing jigs sorted out?

cheers,

Martin.

Hi martin,
I was suggesting you where going to remove anything, but I did not realize in your program you can split the visible chair from the hidden plug, thus I thought it would be a full chair rewrite, and thus 2 x for any future work on obtuse chairs. Glad to hear that's not the case.

Re filing Jigs, finished the 3 mm version I went +.1 (far too tight) then -.1(too lose) then the goldilocks value of Zero perfect.
Got the full STL file on the printer right now, I did note its a 5 hour 23 min opertion when slicing it though.
cheers
Phil

 

[Martin Wynne]

Hello Martin,

Would shellac (knotting fluid) be suitable as a glue? A useful property might be the ability to easily dissolve it with meths.

all the best,
Richard

@Winander @ralphrobertson

Thanks Richard. Welcome to Templot Club.

I tried some water-based sanding sealer on CNC-milled MDF timbers and it worked well to seal the chairs in place. So i would imagine shellac would work equally well, maybe better. Also probably on plywood. The great advantage is that it can be brushed around the chairs afterwards, in the same way as using a liquid solvent. If done after fitting loose jaws, there is no risk of clogging the pin slots.

Ralph is using shellac on card for laser-cut timbers, see:

https://85a.uk/templot/club/index.php?threads/building-3d-track.520/post-4727

However, if you have seen my previous post, I think I have now solved the problem of fixing the chairs in FDM-printed timbers without needing adhesive or sealant. At least I hope so.

cheers,

Martin.

 

[Martin Wynne]

Got the full STL file on the printer right now, I did note its a 5 hour 23 min operation when slicing it though.

@Phil G

Hi Phil,

When doing test pieces, the slowness of FDM printing does get very frustrating.

But once you get into actual production, it hardly matters. There is always something else to get on with on a model railway (or around the house) while the printer chunters away in a corner without needing any attention at all. Or making any mess. Or needing any clean-up afterwards.

If left running for hours in a room unattended, or left running overnight, you might want to fix a smoke alarm nearby.

cheers,

Martin.

 

[Steve_Cornford]

Barbie track?

 

[Martin Wynne]

.
With yet more settings for the snap-fit plugs, there was no choice but to do something about the DXF dialog.

I have shovelled all the buttons and bobs into a row of tabs for now:

In the process it's been possible to make the dialog window a little bit smaller.

Everything is still there, but you may need to hunt through the tabs to find it.

It needs a lot more work to make a proper tidy interface. It will all get done one day.

cheers,

Martin.

 

[Steve_Cornford]

A useful bit of housekeeping whilst waiting for your FDM recessed timbers bases to print perhaps?

As it is drizzle off and on down here I have been populating my test B8 timbers with more slotted chairs. Strangely satisfying.

I also tried your knuckle bend idea with the AA battery and it worked a treat, even though I am making a 1 in 8! No batteries were harmed in the process!

<heresy alert>
I have been having thoughts of "clipping" slotted chairs to laser-cut ply timbers then inserting the protruding plugs into sockets cut in the cork base layer. Assuming that is the "barb" can be 1.6mm below the bottom if the chair nameplate.
My therapist recomends that I sell my metal filing jigs and P4 gauges to fund the purchase of an FDM printer as a cure for these thoughts.
</heresy alert>

Steve

 

[Martin Wynne]

<heresy alert>
I have been having thoughts of "clipping" slotted chairs to laser-cut ply timbers then inserting the protruding plugs into sockets cut in the cork base layer. Assuming that is the "barb" can be 1.6mm below the bottom if the chair nameplate.
My therapist recomends that I sell my metal filing jigs and P4 gauges to fund the purchase of an FDM printer as a cure for these thoughts.
</heresy alert>

@Steve_Cornford

Hi Steve,

I didn't follow a word of that, so whether it is heresy or not I have no idea.

How about a quick sketch and taking a photo of it?

Drizzle stopped here. But maybe not for long.

cheers,

Martin.

 

[Steve_Cornford]

For nameplate read baseplate!
Perform a 2D DXF export.
Laser cut a 3mm cork tracked using the socket laye

Your new chairs have clips(barbs)
Clip them into a lasercut plywood timber.
The plugs of the chairs protrude below the timber.
The barbs keep the chairs in the timber.
Then using the protruding chair plugs as "locators" affix the sleeper/chair assembly to the track bed, using the sockets in the track bed for alignment.
Steve

 

[Martin Wynne]

@Steve_Cornford

Thanks Steve.

They are not really barbs in the sense of having sharp edges. I'm calling them tangs. I'm not sure that your idea will work -- surely the tangs will break the plywood as you push them through it? Plywood is not going to flex out of the way and spring back behind the tang as the plastic base does. Or maybe it will?

Would you like an STL with some tangs 1.6mm below the chair base to try? What is the width of the sockets you are now using?

p.s. If you are selling metal filing jigs you will need to be quick to get a good price. Within days of releasing 241b the world will be awash with FDM filing jigs.

cheers,

Martin.

 

[Steve_Cornford]

Thanks for the offer buut I think you are right about the ply not flexing, so might have to stick with the press fit option.
Socket size, cant remember, it was quite a while ago that I got them cut. I will have to measure them.
For now I will concentrate on disposing of the metal filing jigs!

Maybe there will be a "Fiddling with Filament" section soon to keep "Messin with Resin" company?

Sorry I kniew I should have had an egg for breakfast!

Cheers Steve

 

[Phil G]

Hi Steve, Martin,
Steve, I think your idea may not be quite dead just yet, I believe your basically saying make a sandwich of cork base layer then plywood timber and then the new type of resin chair. By making the cork slot slightly bigger then the timber you will create the stepped surface that Martin would be creating in an FDM timber brick. I fully understand the risk is the timber edge required will not hold and that maybe true. If only some fail it would revert to glue in. However there are two strong reasons not to give up just yet,

1,if you laser cut the timber and part laser etch the cork, your not limited to such a small brick shape, its quite feasible to print a full turnout in two halves or even a full turnout in one go if your laser print area is big enough. (I have a side project on the go, to make a laser X,Y frame using open build aluminium extrusions. This will have print area of 1000 mm by 500mm and basically will use all the drive mechanism from an ender type printer. But that another story)
2,If the timbers are only 1.6 deep with a cork layer below, it does mean Templot could still be intermixed with commercial type flex track.

Martin on this basis and I know I am going to contradict myself here, could you create a STL for S1 chairs made to suit 2mm thick ply wood? Only asking for that as I have quite a few pieces of 2mm plywood I got on the cheap. I will then have a play with a plywood and cork layer combo.
Phil,