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3D Printing in 2mm Scale


TomE
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If you use lead balls, don’t set them with PVA glue. The acidity in the glue is reported to react with the metal, causing it to expand, with disastrous results.

John

I believe there are 3D resins specifically made to be used for as patterns that can be burned out for casting with metals such as brass. This will worth looking at.
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I believe there are 3D resins specifically made to be used for as patterns that can be burned out for casting with metals such as brass. This will worth looking at.

 

If you are making your own bodies, you can sort it that the cavities are designed to fit known weights, for example solid brass bar. Heavy weights from RTR locos are sometimes available as spares from the likes of DCC Supplies.

 

Chris

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The ideal place to print would be in a workshop/garage, the only thing to watch for is the temperature. Some resins don't print well at colder temperatures and I've seen some photon owners in colder climates devise heating systems for the printer, although in the UK you should be OK most of the time. 

 

 

Do you have any idea how cold "colder temperatures" actually are? I have a workshop in the house in a room which is part of an extension, and it's notably colder than the rest of the house - but it would be very handy for trying out something like this as it has a spray booth with built-in ducting to remove any fumes. I don't have a thermometer in there but I'd guess when the rest of the house is at 19C it's probably 17C. 

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Do you have any idea how cold "colder temperatures" actually are? I have a workshop in the house in a room which is part of an extension, and it's notably colder than the rest of the house - but it would be very handy for trying out something like this as it has a spray booth with built-in ducting to remove any fumes. I don't have a thermometer in there but I'd guess when the rest of the house is at 19C it's probably 17C. 

 

 

I think you'd be ok down to about 15C, below that seems to be when people start having issues. 

 

Tom.  

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Yup. My garage/workshop is generally about 17-18C when the rest of the house is 20-21ish. The coldest I've seen it in there (I have a very handy little cheap IKEA cube clock in there that is a thermometer, clock, timer etc depending which way up you put it) is about 15C - and that didn't pose any problems for printing. 

 

Like with the elaborate UV LED strip contraptions for curving, and custom duct adapters and extractors, the reptile heating pads and whatnot that you see on the "Anycubic Photon Owners Group" seem very much like overkill from people who seem to enjoy making things complicated, and 'preempting' problems that often seem to be purely theoretical! 

 

J

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post-14910-0-90189700-1546715729_thumb.jpeg

Version 2 of the GNR open wagon, this has big holes in the floor to see if it helps with some bulges that I was getting in the sides. Printing upside down it’s kinda like pushing an upside down mug into a washing up bowl, with hydraulic pressures building upon the down stroke, and suction pressures on the upstroke of the platform. The holes are there to help equalise the pressures. The next version will have a different floor design.

However this model is quite pleasing. The strapping is much finer than the Association kit ( not a criticism of the kit, just an observation), it is perhaps a bit too fine.

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I would say that strapping is spot on Richard. Much easier to paint & letter.

Tim

Thanks Tim, kind of you to say so. I will see what happens with the next print, which will be with a different resin. Just playing really to get a combination that suits me.
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A lot of people on the Facebook group seem to get very exercised about the smell, but I don't really find it that offensive. It's noticeable but not as unpleasant as some make out. I do have a garage workshop to run it in though.

 

Whilst my printer is in a home office my wife noticed a smell on my clothes (she doesn't miss anything!). So for domestic peace I change clothes when out in the man cave for any length of time.I also bought an air purifier fan which does appear to get rid of the smell, have it running when printing and in the shed.

 

More important than the smell is the potential irritant of contact with the resin and also other chemical bits and bobs we use. The resin is an issue I'd hope we all know about, wear gloves and the like, but something that's effected me is excessive contact with IPA, resulting in nasty skin rash and allergic reaction which hasn't fully cleared after three weeks. In hindsight I can see that when cleaning build plate and vat I'd ended up getting quite a bit of IPA onto my trousers - as I was doing all this sitting down. As there was no reaction at the time, and you'd think IPA would just evaporate, I thought no more of it and had gotten a bit blase about practises. So now, lab coat, apron, rubber gloves and safety goggles donned when working with the resin and cleaning stuff.

 

Better than just PPE, combatting risks at source (sorry getting all work related there) I am now exploring using either alternatives to IPA for cleaning, something detergent based or better still a water washable resin. First test of latter was positive but as I am printing 4mm models the sample bottle did not last long.

 

Hopefully others haven't had this bad experience, but do take care folks.

 

Jon

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Whilst my printer is in a home office my wife noticed a smell on my clothes (she doesn't miss anything!). So for domestic peace I change clothes when out in the man cave for any length of time.I also bought an air purifier fan which does appear to get rid of the smell, have it running when printing and in the shed.

 

More important than the smell is the potential irritant of contact with the resin and also other chemical bits and bobs we use. The resin is an issue I'd hope we all know about, wear gloves and the like, but something that's effected me is excessive contact with IPA, resulting in nasty skin rash and allergic reaction which hasn't fully cleared after three weeks. In hindsight I can see that when cleaning build plate and vat I'd ended up getting quite a bit of IPA onto my trousers - as I was doing all this sitting down. As there was no reaction at the time, and you'd think IPA would just evaporate, I thought no more of it and had gotten a bit blase about practises. So now, lab coat, apron, rubber gloves and safety goggles donned when working with the resin and cleaning stuff.

 

Better than just PPE, combatting risks at source (sorry getting all work related there) I am now exploring using either alternatives to IPA for cleaning, something detergent based or better still a water washable resin. First test of latter was positive but as I am printing 4mm models the sample bottle did not last long.

 

Hopefully others haven't had this bad experience, but do take care folks.

 

Jon

 

I'll certainly second this. Years ago I did resin casting at home, the old fashioned way using rubber moulds and developed an intolerance to the resin. After that I let CMA do the casting bit. I stil detect that minor intolerance if I handle resin castings even now.

 

And I really would not expose myself to fumes from one of these printers. You have no idea what it might be doing to you and the results 20 years down the road. Get yourselves an extractor system.

 

Chris

Edited by Chris Higgs
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Going back a little to locos, it is possible to print bodies. Weighting them could be an issue but I suspect by using an etched chassis, this would be easier than with an adapted N gauge commercial chassis - my usual approach.

 

Some examples of my loco printing experiments using the photon.

 

post-943-0-66245200-1546763116_thumb.jpg

 

The K3 at the back uses the Farish N class chassis (as does the V3 at the front). As this has a traction tire, I've not bothered to add any weight and the previous two I've built (both different from this one) have been fine. Having a six foot diameter boiler, I suspect there is sufficient room for weight if using an etched or scratch built chassis. The problem locomotive is the Stanier 2P which uses the Dapol M7 chassis. The Dapol M7 isn't renown for its haulage abilities and there isn't a huge amount of room to add weight. I've put an open cavity at the front of the boiler for some lead shot and the original test loco's haulage was about on a parr with an unaltered M7.

 

The J3s have also been painted.

 

post-943-0-14263400-1546763163.jpg

 

These both have a lump of rolled lead flashing inserted into the boilers, held in place using superglue. Despite having only filled around 3/4s of the available space, these are far heavier than one of the earlier J3 prints which was completed filled with lead shot. The chassis are free running for use with a (to be designed) tender drive and run in Markits 1.5mm 'gearbox' bushes that are held captive in the frames.

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I'll certainly second this. Years ago I did resin casting at home, the old fashioned way using rubber moulds and developed an intolerance to the resin. After that I let CMA do the casting bit. I stil detect that minor intolerance if I handle resin castings even now.

 

And I really would not expose myself to fumes from one of these printers. You have no idea what it might be doing to you and the results 20 years down the road. Get yourselves an extractor system.

 

Chris

As someone who’s suffered from dermatitis from contact with various modelling products this makes me apprehensive about using one of these in the home. Do we have any suitably qualified members to give informed advice, or direct us the any authoritative material on the possible health issues?

 

Edit: And yes Chris, I do take your point that exposure to whatever unknown compounds are involved could lead to something a lot worse than dermatitis and it could take many years to surface. 

Edited by chrisveitch
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Next iteration for the GNR wagon. I have increased the ironwork depth a small amount, and added vent holes in each corner of the floor to mitigate hydraulic pumping issues with the resin. the mini supports of the wagon face can hopefully be removed without witness marks, after careful clean up. I'll go back to green resin as suggested by Julia for this print,

While its printing I'll re-assemble the 4F with the replaced steel axles on the driven wheels.

 

post-14910-0-14344900-1546773056_thumb.jpgpost-14910-0-71517100-1546773069.jpg

 

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I read several different brand's Material Data Sheets when I first started experimenting with the Photon. There are risks from inhalation - but they appear to require very great concentrations.

 

Whereas the risks from oral consumption, and contact with the eyes seem very significant, and skin contact seems to generally attract more attention in these documents.

 

So, I concluded it was probably fine to use the printer in the garage, which certainly has more air flow than the rest of the house. But I certainly don't linger in there when it is on - I set it and forget it until it's finished. Which is easy when it takes 5-6 hours to do most prints. I certainly wouldn't operate it in a bedroom or lounge without ventilation. I'd be pretty confident Tom's kitchen extractor etc would be fine, unless you're sat directly next to it.

 

There seems to be a strong consensus that the resin is no longer hazardous when cured. I certainly wear gloves whenever handling prints before this point. But then usually quickly blast them with primer, so you're no longer handling the material directly.

 

Brands do vary, and it looks like the own brand Anycubic resins are probably some of the worst. MDS here: https://fepfilm.eu/pobieranie/msds_anycubic_resin.pdf

 

Justin

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 I'd be pretty confident Tom's kitchen extractor etc would be fine, unless you're sat directly next to it.

 

 

The chances of that passing the scrutiny of the domestic authorities in these parts makes getting Theresa May's Brexit deal through the Commons look like a walk in the park.

 

Chris

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It’s never a good idea to handle unpolymerised resins because of the risks of contact dermatitis. However, do not assume that wearing gloves will give protection, as the small monomer molecules will transit any nitrile or latex gloves and concentrate next to your skin. So no-touch handling of the resins is a good idea. The surface of the polymerised resin will probably also have free monomer, but I presume that will be washed away with the IPA.

 

Tim

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It’s never a good idea to handle unpolymerised resins because of the risks of contact dermatitis. However, do not assume that wearing gloves will give protection, as the small monomer molecules will transit any nitrile or latex gloves and concentrate next to your skin. So no-touch handling of the resins is a good idea. The surface of the polymerised resin will probably also have free monomer, but I presume that will be washed away with the IPA.

 

Tim

 

Interestring, thanks. Whilst I am not going out of my way to get the stuff on me even when using gloves seems just as well that I am now making sure I am washing my hands and forearms thoroughly afterward. Would something like neoprene gloves, at some more cost, offer more protection?

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Interestring, thanks. Whilst I am not going out of my way to get the stuff on me even when using gloves seems just as well that I am now making sure I am washing my hands and forearms thoroughly afterward. Would something like neoprene gloves, at some more cost, offer more protection?

Butyl would be better.

 

Note that natural rubber has a short (c. 5 yr) shelf life and this is not helped by exposure e.g. UV light.

Edited by richbrummitt
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The chances of that passing the scrutiny of the domestic authorities in these parts makes getting Theresa May's Brexit deal through the Commons look like a walk in the park.

 

Chris

 

Thanks to a 'relexit' a few years back I am the sole domestic authority, removing the need for a second referendum on the issue. Any future relations may require a backstop however to ensure printing can continue seamlessly. 

 

Tom. 

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Pretty pleased with my first bash at 3D printing. Designed by me, but printed by Shapeways; I need to be pretty sure I can design this stuff before jumping in and buying kit. I got the holes for the buffers slightly wrong and the chassis is just a spare of the correct wheelbase but incorrect in brake detail etc.

 

Hull & Barnsley Covered Goods Van:

 

2zywjn8.jpg

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I can't drive a computer so I'm never going to design my own but the prospect of all these new, pre-group wagons is very exciting.

 

Jerry

 

Hi Jerry

 

I'm guessing you dictate your posts to your secretary then and she types them in?  :sungum:

 

I too thought I would struggle, but I tried Blender and made use of some of the threads on here. It's a bit like Lego on screen! As with anything, there's a learning curve but I'll be able to produce a dozen or so vans faster and to a higher quality using this method than trying to scratchbuild them all with plasticard. I'm still learning but I'm fairly pleased with the progress I've made to date.

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Hi Jerry

 

I'm guessing you dictate your posts to your secretary then and she types them in?  :sungum:

 

I too thought I would struggle, but I tried Blender and made use of some of the threads on here. It's a bit like Lego on screen! As with anything, there's a learning curve but I'll be able to produce a dozen or so vans faster and to a higher quality using this method than trying to scratchbuild them all with plasticard. I'm still learning but I'm fairly pleased with the progress I've made to date.

 

That's a fair point Tony although if you saw how I struggle with even the most basic of technology.....!

 

Jerry

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Will it print?

 

We'll find out on Friday......!

 

Tom.  

 

 

 

Much to my surprise, yes!

 

post-1467-0-99551800-1547239392_thumb.jpg

 

Some tweaking of the supports is needed on the left hand edge as it bulged out a little and one of the cross braces very nearly didn't make it, but it would probably pass muster once painted. I removed some supports for the photo. 

 

Tom.   

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