DIY photoetch?

[Jens Andrée]

After having used PE parts for the first time on a tank I wondered if any of you make your own PE?

I tinker with a lot of things and one of them is electronics design. I make my own PCB's (circuit boards) at home with great results at low cost, and I thought it wouldn't be that different to etch a thin sheet of brass than to etch FR4 (the most common type of circuit board substrate we use).
It's not hard to achieve high resolution just using a laser printer to create the mask.

Any of you doing this?

I've noticed that PE parts can be a bit expensive, but mostly they are hard to find, and that's when this question popped up in my head!

I'm going to see if I can find a suitable sheet of brass to test with. I've got sheets of thin copper but in this application brass would be a much better option.

 

[Airfix Modeller Freak]

it's one thing etching it, it's another if the effort and getting the fit correct, accuracy etc is more worth it than dishing out for an Eduard Zoom Set to their full etch sets to their BIG EDS, which by the way, are pretty reasonably priced, and from my experience, worth it and improve your model a lot. The easier and safer one to do, which can be cheaper, is resin casting. PE etching is more chemically volatile. I've been to a casting tutorial @ the Australian Model Expo and done it, and it gave a very positive impression. PE done by yourself is a different matter
Cheers, John

 

[Jens Andrée]

I couldn't let this idea fade away so I made some prototypes and you know what? It works really well!

I used some really thin brass sheets and instead of doing the usual toner transfer method (transferring the toner from a glossy paper printed in a laser printer with a laminator or iron) I just taped the brass sheet to a A4 paper and printed directly onto the brass.
Before this I obviously cleaned the brass sheet from any oxide and contamination.
After this I cut out the piece I'd printed on and applied plastic packing tape to the backside - otherwise it'd etch from both sides and all would be lost. Zero air bubbles is very important here!!!
This was just given the usual hot etch acid bath and agitated until it was done. The tape and toner was removed with acetone.

As a prototype this was a success! Sadly I didn't take any pictures since it's a somewhat messy process with corrosive acids that I don't want to end up on my camera, or phone, but I will set things up better for the next run so I can document each step for those who are interested.

I've ordered some 0.2 mm brass sheet for the next, more serious test, and I've made a design that I'm going to use on a Tamiya Tiger I as a prototyping platform, to work out exact scale etc. Should arrive sometimes next week according to the supplier.
Here's the simple design I've made for the next test: (it should be pretty obvious what it is... )

Don't worry that it looks like low resolution because the real data is in vector format so it can be scaled to find the correct measurements, this is just a jpg export, but it should be more or less correct as it is now and the paper version I printed seems to fit. (one benefit with toner transfer method is that you prototype on paper, i.e. very cheap )

I make rather complex circuit boards for surface mount components with my laser printer regularly so it should be more than enough resolution for 1/35 scale models.
0.2 mm brass might be too thin but thicker material quickly becomes more problematic to etch and I think 0.4 would be max with this method, but that's just me guessing...?

To be continued!

p.s. For those who wonder how I made the template? It's just a quick thing in Illustrator, but you can use pretty much anything you want to create your templates. Exact measurements are obviously important. I might use AutoCAD for the real work, or perhaps even Autodesk Inventor? That way you build your templates based on real measurements entered with the keyboard rather than drawing lines of a specific length.

 

[Stevekir]

I couldn't let this idea fade away so I made some prototypes and you know what? It works really well!

I used some really thin brass sheets and instead of doing the usual toner transfer method (transferring the toner from a glossy paper printed in a laser printer with a laminator or iron) I just taped...........

In case its of interest, many years ago I made etched seat ends in 1/72 scale for the cast iron benches on railway platforms. (They had a GWR design.)

I printed the design on to transparent paper (or some sort of transparent sheet). Then I coated the thin brass sheet with a liquid photosensitive resist. When dry and on exposure to UV light through the transparent sheet the resist was deactivated where the sheet had no image. The brass was placed in a bath of ferric chloride which ate right through it. This produced very well detailed and attractive parts.

 

[Jens Andrée]

In case its of interest, many years ago I made etched seat ends in 1/72 scale for the cast iron benches on railway platforms. (They had a GWR design.)

I printed the design on to transparent paper (or some sort of transparent sheet). Then I coated the thin brass sheet with a liquid photosensitive resist. When dry and on exposure to UV light through the transparent sheet the resist was deactivated where the sheet had no image. The brass was placed in a bath of ferric chloride which ate right through it. This produced very well detailed and attractive parts.

Great Steve! This means that there is some sort of DIY photo etching scene going on already for scale modelling. I really haven't researched it at all since I just decided to do as I normally do - try and see what happens?

I used to etch with photosensitive film and UV lights in the beginning (i.e. many years ago) but it was just too slow when you were prototyping electronics in a hurry. You can't breadboard with surface mount components so you etch your own prototypes instead and then solder everything with solder paste and hot air, or a toaster oven.
It's much faster to reverse print on glossy paper and then just run the paper and FR4 PCB through a laminate machine (or just use a clothes iron) and then into the acid bath after removing the paper. That way you skip many steps in the process and it's also cheaper as long as you've got a laser printer. It doesn't work with a ink jet printer whereas your method will. It does require some skill when using my toner transfer method and there will be a few failures until you've dialled in all the steps.

Your method is also repeatable in a different way than the transfer method, but both methods are working well and as long as you end up with what you wanted, the method of getting there isn't so important. The toner transfer method is limited to whatever resolution your printer can muster and that's the downside of my method compared to yours with using transparent film if printed by a professional printer, but for home use they produce the same results.

By now printing directly onto the brass sheet I eliminated most steps, and fewer steps means less risk for errors, and that's what I liked about the way I did it this time!
Hopefully it can be easy enough for anyone to be successful on even the first attempt. I hope to write up such an instruction anyway...

Imagine if we one day could just download a pdf with the PE parts you needed and then just print, etch and done! Making the artwork for the PE is the big task though and I guess that's why we're paying for it. I do think the pricing is a bit on the silly side for a small piece of brass sheet - but I've got no clue of the setup costs for these companies so I'm going to leave it there and tinker on myself.

p.s. I like to tinker and prototype and not all of my ideas are great. In fact some of them turn out to be quite bad and silly, but I'm not going to let that stop me from trying!

 

[Gern]

Imagine if we one day could just download a pdf with the PE parts you needed and then just print, etch and done!

I think this idea was thrown about when 3D printing emerged onto the scene. Imagine going to your computer or into your local model shop and browsing through a catalogue of PDF files of sprues for whichever model you want. Then buying the file and printing out the sprues! Next thing you know, you'll be buying a PDF and printing out a completed model!

No thanks! I want to browse through the boxes on the shelves and hold the kits in my hands - and I have issues enough with assembling the ready-made bits without the hassle of making the bits myself!

Mind you, I could imagine my grandad saying something like:

"Who wants to buy a box of ready-made plastic bits you just have to glue together? Where's the fun and skill in that? I'd much rather start with a piece of wood and carve and shape it myself!"

 

[Jens Andrée]

Then buying the file and printing out the sprues!

I was referring to the "free" aspect of the thing, as in "open source" PE parts, for modellers - by modellers.

I've got a 3D printer that I built early on and I fully agree with you that there's no way I'd prefer to download the sprues rather than buying them in a box, like we do today!
But downloading small modifications that others might've done and printing them, or etching, I'm all in favour of.

Your granddad quote speaks volumes and I hope scale modelling never becomes obsolete due to pre-assembled things...

 

[tr1ckey66]

I have thought about making my own photo etch, but it does involve some nasty chemicals which do need to be disposed of responsibly and a certain amount of trial and error to get the etch times right. I guess what's holding me back is the need doesn't yet outweigh the messing about involved.

It is interesting though and if you do have a go I'll be interested to see the results.

Cheers
P

 

[Johnny1000]

I tried it, and will try again at some point.

I think the tricky things are designing the fret sensibly, which is harder than it looks if you have more than a few components, and controlling the etch.

My first go was a bunch of fiddly little bits for a 1/48 scale airplane, and I think I was a bit ambitious about trying to capture a lot of detail with tiny etched in details using registered front and back masks. The larger pieces were okay, but the smaller ones more or less disintegrated, and I cut through fold lines, etc.

Basically, get a feel for the materials before trying to do anything complicated. After spending several sessions over a few weeks (I have very little bench time) I decided to cut my losses and buy a commercially available product instead. A minor DIY setback, but I wanted to advance the progress on my build more than I wanted to master etching at that moment.

Jens, since you have a lot of experience with circuit boards, I bet you have a leg up just in terms of having a feel for materials and process. Open sourcing the files for the frets is a great idea, partly because it would be beneficial to be able to learn from others in creating successful fret designs, and partly because many builders are not no interested in design, but might want to get deeper into crafting parts.

Cheers
-J

 

[Gern]

I was referring to the "free" aspect of the thing, as in "open source" PE parts, for modellers - by modellers.

Now I'm confused young Jens! You want to copyright your pictures; which may or may not have some commercial value; and prevent people using them. At the same time you're prepared to allow folks to freely copy your PE designs; which surely take some skill and time to produce - and which definitely have a market value??

What am I not understanding?

 

[Jens Andrée]

Now I'm confused young Jens! You want to copyright your pictures; which may or may not have some commercial value; and prevent people using them. At the same time you're prepared to allow folks to freely copy your PE designs; which surely take some skill and time to produce - and which definitely have a market value??

What am I not understanding?

My pictures are my private property and not something I want to end up in advertisements for products I don't support, or for being (ab)used in other ways. That's just common sense!
Facebook tried to abuse this and got caught, but not before losing more than 10% of the users and their content - and a hefty fine.
I do post some pictures that I don't care about and they can be freely used or modified - I don't care, but some people think you can take whatever picture you find on the "internet" and do whatever you want with it and that's not ok in any way, and especially not in the legal sense. This is not a matter of commercial value - it's a matter of integrity and ownership.

Releasing other things as open source is a completely different matter and something I've been doing for 20 years with both hardware, software and digital media - but that's got nothing to do with my private photos that I choose to share for viewing. Big difference.
Open source releases also contain a license that stipulates how it can be used, modified, and re-released. This is so that open source products aren't abused and made commercial without releasing their changes back to the original release/product for free. Many big companies have tried to ignore this and they all were convicted in court.

TL;DR You can't compare your private photo album to a product you've decided to freely release - with a specific license agreement.

 

[Gern]

A faint light of understanding is beginning to glimmer in the distance!

It's the difference I suppose between someone using your work for themselves or abusing it for some sort of financial gain. So you'd be quite happy for me to use a PE design or perhaps a camouflage image to enhance one of my models, but not for me to sell or use them for gain - unless credit goes back to you as the original designer?

 

[Jens Andrée]

A faint light of understanding is beginning to glimmer in the distance!

It's the difference I suppose between someone using your work for themselves or abusing it for some sort of financial gain. So you'd be quite happy for me to use a PE design or perhaps a camouflage image to enhance one of my models, but not for me to sell or use them for gain - unless credit goes back to you as the original designer?

When you release something as Open Source with the usual GPL/LGPL license you can do whatever you want with it - even modify it and sell it if you want! The only rule is that if you change it you should post your changes for others to use under the same license because you can restrict Open Source projects. This is the difference between Copyright and Copyleft. There are many different Open Source license options depending on how strict you want to be but they all pretty much require that if you change something and release it commercially you must release back the files for others to download and use.

Another benefit of slapping an Open Source license on something you release for free is that it's some sort of warranty that every quality improvement is trackable and returned to the project.

Open Source is good and it is the future for many software, and hardware, products! You can still make money on Open Source but you can no longer call it proprietary and hide the technology for the end-users.

So in short terms; You can download an Open Source project, make alterations to it and sell for profit and you don't have to send a single coin to the author. This is an important part of Open Source in general! What you have to do is to release your version as Open Source as well, and often with the exact same license as before. There is no way around this. The purpose of this is to let things evolve and improve but always be freely available.

 

[Gern]

..... and I always thought ownership was simple! In a way, I'm glad I'm not clever enough to invent anything - 'cos I'm certainly not clever enough to get to keep it if I did!