The Ship Model Forum

[quote="cosbymai"]This has probably been asked before but I couldn't find a thread for it anywhere. Could someone advise me on the most suitable computer program to use if I want to design my own PE fret? I would also like to use relief etching... how does one do that?

As I'm based in the UK I could do with a suggestion from someone as to a good company I could use to actually produce the fret.

I am not keen to etch the brass at home so ideally I would design the fret on my PC and then send the design to a company to etch it for me.


Thanks for any help

Max[/quote]

Relief etching is done using what we CAD guys call layers. The drawing of the "bottom" layer is done first which includes all the lines, then the relief etched lines are drawn as "the top layer" on top of the bottom layer. You will then have two drawings (files) that you can submit to a photo etcher. Everyone does everything electronically now, so you can email the drawings to the photo etcher which is what I do.

I briefly explain the technique for producing drawing in my "how to" CD called, "Working With Photo Etched Parts". If you're interested in the CD, go to my web site and check it out. [url]http://www.flagshipmodels.com/zencart/[/url]

Contact White Ensign Models. They should be able to hook you up with a photo etcher in the UK.

To revive this thread... I just received the Micro-Mark PE system and am gearing up to try it. I have a formal, florescent UV bulb I'd like to use as a light source for exposure. Do I need to adjust the exposure time for this or do I simply use the 15 seconds they recommend for noon-day sun?

DrPR,
I'm in Forest Grove. So far I haven't had much luck with finding a PE shop. My wife works for a circuit board shop locally, but they don't do side projects, especially in very low quantities. I talked to one of the technicians there, he might be able to help me out and point me in the right direction as far as getting very limited runs done. I will post it here if he has a solution.
I looked at your build, very nice work. I like your solution to finding acrylic, I wish we had a place like that here. Finding 1/2 inch thickness here is impossible, unless I want to purchase a 4'x8' sheet.

Jim

[quote="DrPR"]Pretty slick! What is the thinnest trace that you have etched?[/quote]
I think the narrowest trace was about .010.
[quote]One suggestion is that you etch as little metal as possible. Create unconnected "islands" between the details you want to etch. This minimizes the amount of etch precipitate, speeds up the process and extends the life of the etchant solution.[/quote]
Will eventually try this method.
[quote]I have etched quite a few circuit boards and photoetch patterns. You need to agitate the board/metal almost continuously and drain the precipitate frequently. If you do this the etching process will take only a few minutes. Think of it this way - as soon as the surface is etched it is covered with precipitant that impedes further etching. The precipitant builds up like mud on the surface and blocks fresh etchant from getting to the underlying metal. You have to displace this precipitant to keep the process going.[/quote]
I don't have a good setup to agitate. I tried a 12v motor on\next to the tray but it did not vibrate very well. Some day maybe I'll fashion a vibrating board. I kept taking the PCB board out and washing it down to remove the residue. Maybe if the tray was more vertical and narrow, the residue would drop to the tray bottom.
[quote]For two sided etching you will need two masks, one for each side. The metal to be exposed to light will be sandwitched between the two patterns. Create your patterns so the ink/toner will be on the metal side when you are exposing the pattern (or ironing it on as Ken suggests). For this you will have to print one side as a mirror image. If your printer driver won't reverse the image you will have to do it in your drawing program. Create both sides at the same time, on different layers in the drawing program.

Put "targets" in all four corners of your image outside the etch pattern before reversing one side. These should be outside the metal area on the board/etch metal. The targets can be a simple "+" mark, but make it big with very thin lines. Then, after reversing one side, remove one target from corresponding corners of both sides. This way when you bring the two patterns together, with the metal in between, you can align the patterns accurately, and it is obvious how they should be positioned with respect to each other (think about it).[/quote]
With the mirrored images on the film, you can fold it in half lining up the images and targets as you suggest. You could also drill a small hole to use as a alignment point.

jjasboat,

I'm in Corvallis. I looked up photoetch shops in Oregon and Washington several years back. Unfortunately, I don't have that information any more. But there are several shops in the Portland to Seattle area.

I found some of them in the Oregon Business Directory and others with an online search. If you find a shop that has reasonable prices please post the information here.

I live in a smaller town west of Portland, Oregon. I have looked in the phone books, and scoured the internet as well, I'm just hoping to find a place somewhere close by that does small runs of photo-etching.

I went to Eurocircuits for my PCB :heh:

[img]http://blog.ontheslipway.com/wp-content/uploads/2008/09/asp_06.jpg[/img]

I also had my custom etch manufactured elsewhere as the etching is so fine I don't trust myself to reproduce the etching consistently.

Ken,

Pretty slick! What is the thinnest trace that you have etched?

One suggestion is that you etch as little metal as possible. Create unconnected "islands" between the details you want to etch. This minimizes the amount of etch precipitate, speeds up the process and extends the life of the etchant solution.

I have etched quite a few circuit boards and photoetch patterns. You need to agitate the board/metal almost continuously and drain the precipitate frequently. If you do this the etching process will take only a few minutes. Think of it this way - as soon as the surface is etched it is covered with precipitant that impedes further etching. The precipitant builds up like mud on the surface and blocks fresh etchant from getting to the underlying metal. You have to displace this precipitant to keep the process going.

For two sided etching you will need two masks, one for each side. The metal to be exposed to light will be sandwitched between the two patterns. Create your patterns so the ink/toner will be on the metal side when you are exposing the pattern (or ironing it on as Ken suggests). For this you will have to print one side as a mirror image. If your printer driver won't reverse the image you will have to do it in your drawing program. Create both sides at the same time, on different layers in the drawing program.

Put "targets" in all four corners of your image outside the etch pattern before reversing one side. These should be outside the metal area on the board/etch metal. The targets can be a simple "+" mark, but make it big with very thin lines. Then, after reversing one side, remove one target from corresponding corners of both sides. This way when you bring the two patterns together, with the metal in between, you can align the patterns accurately, and it is obvious how they should be positioned with respect to each other (think about it).

Thanks Ken,

I will pop over and have a look.

Andrew
:wave_1: :wave_1:

I have been etching circuit boards for projects for some time now. I wrote up instructions in a PDF on how to do this. I cannot attached the PDF file here, but if you go to this thread on RCGroups you can see what I have done. I'm sure this method can be modified somehow for PE. My thought is to print the top and bottom image on transparency in such a way that if you fold it in half, the top and bottom of the mask line up. Then use my method to adhere the toner mask to the metal to be etched. I would like to see someone try this and see how it goes. Someday I may try it myself.

http://www.rcgroups.com/forums/showthread.php?t=1360740

Does anyone know of any good references that describe well the process and techniques for creating photo etch? I guess there are really two parts to the problem:

1. creating the accurate drawings; and
2. actually doing the photo etch process?

My Varyag and Kirov class are very demanding with regard to radio antennas, radar antennas, railings etc., so having a crack at photo etch might be a good optrion.
(not too sure about my soldering skills :scratch: )

Secondly, off topic I know so please forgive, but are there any good references for moulding parts available?

Andrew :thumbs_up_1: :wave_1: :wave_1:

In my opinion the greatest problem in modeling is getting things too big - or too thick. For example, at the 1:96 scale I am working in, the common (in US Navy WWII ships) material thickness of 3/8" (9.5 mm) scales to 0.004" (0.1 mm) - this is a little over the thickness of a sheet of paper, or just a thin metal foil. Life rails were 0.75" (19 mm) to 1.25" (32 mm) diameter, and these scale to 0.008" (0.2 mm) and 0.13" (0.33 mm). Common 1/4" (6.4 mm) halyards scale to 0.0026" (0.066 mm). While it may be true scale, parts this thin would be very delicate. At much smaller scales it simply isn't possible to achieve true scale thickness of small details.

At 1:128 scale I would do fine detail parts in 0.005" (0.125 mm) sheet, and larger parts in 0.010" (0.25 mm) sheet. Your rule of thumb - minimum part width = 1.2 times the sheet thickness (0.15 mm) should be a good starting point, although with practice you might be able to make parts only 0.125 mm wide in the 0.005" (0.125 mm) material. The trick is to etch quickly (warm etchant) and keep washing the surface to remove the precipitant. This is especially important in areas where a lot of material is being removed, such as with gratings and screens. Also, make a few extra pieces, just in case some don't etch correctly.

These are guides for do-it-yourself etching with hobby level equipment. If you plan to have a professional etching facility do the etching, ask them what rules they use for preparing the artwork. They will be able to achieve much finer details.

Another thing to try is etching from one side only to create small details and folding guides. This is a good way to make name plates with letters standing above the etched background. I recently saw a 1/8 scale locomotive builder's plate etched in 3/32" (2.38 mm) brass, with the letters at least 0.05" (1.25 mm) high. I have seen an N scale steam locomotive firebox side that was triple etched to create three levels of details (overlapping sheets, and rivets).

DPR, a question if I may. I don't have a handle AT ALL on 'thousandths' or imperial... just have never worked with them and it makes it really hard to buy sheet metal, mesh, etc, online. I'm learning now as we speak.

Your 0.010 thickness is 0.25mm? A quarter of a mm? [I've looked it up via a online conversion tool] And 0.1" is 2.54mm? I've got it now. 0.020 is half a mil!

I have another query: I need 1 sheet full of a ship-load of fittings. It can only be 1 thickness. I want to do items from funnel cages, inclined ladders, stanchions (and rails?), bridge cabin walls to small boat oars and maybe row-locks and fairleads and 'bottlescrews' and other rigging detail.

What is your advice on sheet-thickness for a general fittings fret for a 1:128 ship?? Is 0.25mm too thin?I have no frame of reference for sheet thickness.

[b]"The metal thickness must be less than the width of the finest detail you are etching - you can't etch 0.005" gaps in 0.010" thick metal"[/b]
Do you mean a full cut through of 0.005" etched from one side? Why? Is this because when you have finished, you will have have a 0.010 cut through?

I would think if etching from both side, it is possible? No? Though by the time it is finished, you would have an oversize cut

The general advice I am following is >minimum line width< and <minimum line gap> to be 'sheet thickness x1.2'. That would make the details on my 0.25mm sheet be 0.3mm. I think half mil details would suffice for me... be overkill in fact.

cheers

I tried the Micromark photoetch kit, with some good results. However, I have been unable to do fine detail with it (0.010" grids with 0.010" spacing, etc.). It uses a heat laminated photo emulsion - run it through a card laminator (supplied in the kit) to attach the photo resist to the metal. After exposure to UV light you develop it in a bath to remove the photo resist. I had trouble with this last part - a very thin invisible resist film remained over some parts of the plate after developing. This prevented etching, so some parts of the sheet would etch OK and others wouldn't etch at all. The kit has a small etching tank with a fish tank bubbler to keep the etchant circulating around the part, and this works pretty good. Here is a photo of some parts I made with this kit for a Cleveland class cruiser smoke pipe:

http://www.okieboat.com/Copyright%20images/Smoke%20pipes%203%201024%20C.jpg

I have ordered some spray-on photo resist, developing solution and a 300 watt UV lamp from Ocean State Electronics - parts of their Datak etching system. It is for printed circuit boards, but the etching is identical to metal foil photo etch. I haven't tried it yet.

The metal thickness must be less than the width of the finest detail you are etching - you can't etch 0.005" gaps in 0.010" thick metal. The etchant doesn't just cut straight through the metal like a saw. Inside the etch channel it cuts in ALL directions, vertical through the sheet and horizontal outward from the etch channel. The result is parts with a " ( " shaped edge cross section, but this is usually barely noticable. The etchant will undercut the photo resist pattern, taking away metal leaving an etch channel through the metal with a " ( ) " shaped cross section where the cut is widest in the middle of the thickness of the metal. If the detail is too fine the etchant will cut through from both edges of the thin part before it cuts through the thickness of the sheet. To avoid this use thinner metal.

To speed up the process and avoid "V" shaped cuts, etch from both sides of the sheet. This will require precise alignment of the photo resist patterns on both sides of the sheet. This isn't as difficult as it sounds - just put alignment targets ("+" marks) on the patterns for both sides and align them carefully with the metal sheet between them.

A friend with experience advised me to make the parts oversized because the etchant will undercut the photo resist. For very thin material (0.002" to 0.003" foil) you won't need to make parts oversize. For 0.005" sheet maybe 0.001" oversized on all edges will do, but for 0.010" you need to make parts oversize by about 0.002". So, if you want a 0.010" wide part using 0.010" thick metal, make the photo resist pattern 0.013" to 0.014" wide to allow 0.002" undercut on both sides.

You can heat the etchant to speed the process, but don't get it much more than 96F/37C (body temperature). Just don't use refrigerated etchant. DO NOT use hot etchant - the reaction may boil over and splatter or you might cook off the photo resist.

You MUST keep the etchant flowing over the work piece. The chemical process produces an inert precipitant that will pool on the sheet and block further etching. You can move the metal by hand, occasionally lifting it out of the bath to drain off the precipitant. It is best to have a vertical etch tank so gravity will pull the precipitant to the bottom of the tank. Still, you need to keep the etchant moving to dislodge the precipitant from the etch channels. Spraying the etchant onto a vertical sheet of metal is the best method, but you will need a non-metallic pump with a fairly high volume flow rate and a confining tank to recover the etchant.

Etch as little metal as possible - cover unused areas between parts with photoresist to reduce the actual etch area. This will prevent rapid depletion of the etchant and minimize precipitant buildup.

Some printers have darkness settings to control the amount of ink/toner that is applied. They normally default to a "medium" setting. In the printer control dialog change this to the darkest setting. This will produce the best photo resist patterns.

Expose the emulsion with the brightest light you can find - direct sunlight is good (if you live where it isn't cloudy all the time).

Be CERTAIN that the ink/toner side of your photo master is against the emulsion before exposure. If it is on the outside of the pattern film sheet the edges of the resist pattern will be "fuzzy" and the actual width of the etch part will be unpredictable.

You're not the only one - it appears that he decided to remove them for whatever reason.

Why is it that I am unable to see ingura's posts?

Hi
I don't know where you're from but there's a good shop in France

http://www.letrainmagique.com/Tarif_promos_news.htm

I bought their equipment for photoetching and I'm really satisfied
They sell metal sheets too, and all the chemicals you may need

I make my masks with Corel draw

Hi
I need help to source materials or a kit to try this. Is there a basic kit of chemicals available? Maplins seems just to stock certain chemicals while I need 'a kit' with maybe a few sheets of metal and a sheet or 2 of the inkjet film or whatever?

We have a [un-used] box of overhead projector film here [anyone want it?] Actually, it is called 'Ink Jet Transparency'. It is white or near translucent but it doesn't take ink well... all the minute ink drops pool into larger, very noticable versions... and it won't dry. [I don't know if it is the film, or that our printer [canon 'bubblejet'] uses dye-based inks? The basic principal behind our Canon printer was designed to work with absorbent material... the sheet of paper MUST draw the ink into the surface! It is fast as well... it'll do an A3+ photo is highest quality in 2-3 minutes.]

I have a handle on the process now for 'photo' etching... as opposed to 'etching'. It is the making of a mask (negative) that gives the 'photo' bit of the name. Is there's 3 stages?

1, Drawing the mask

2, Transfering mask on to sheet metal

3, Immersion of sheet int etching chemical


I am also unsure of how thick a sheet I need for various pieces. How thick a sheet would you use for funnel cages above 1:128 funnels. Same question as to inclined ladders and general deck fittings, same regards bridge cabin walls.

I'm pretty serious about thiss now and the sooner the better as I'm making stuff now that could be very much better if it was etched.

Cheers

Try looking at this page of the Mare Island Build up of Jean and Bruno: http://www.shipmodels.info/mws_forum/viewtopic.php?f=59&t=33372&start=180

They explain the process of which they take, but their sheet supplier is in Europe.

If you do not already have a program you should consider DesignCAD 3D Max. It is a drafting program (2D and 3D) so you get the advantage of being able to dimension drawings very accurately (thousandths of a millimeter), and it is easy to produce accurately scaled drawings.

I have experimented with photoetch at home, using a photoresist film available from Micro-Mark. I have had mixed results with this method. For fairly large items 2 mm and wider it works fine. When I tried to etch parts finer than 0.5 mm results were less satisfactory. The exposed parts wash away in the developer, leaving a film over areas to be protected. I found that the film does not develop evenly across the sheet. It may look as if the areas to be etched are clear, but a thin film remains in places that prevents etching.

I have obtained some spray-on liquid resist to try another method, but haven't used it yet.

Photo etch is very similar to electronic circuit board etching, and some of the materials and processes are the same.

I printed my masks on clear plastic overhead projector sheets.

There are several things you need to know:

1. Your parts should be oversized by about 1/3 the thickness of the brass sheet. This will help correct the undercutting mentioned in ingura's post. If you want a 0.5 mm (0.020 inch) wide piece in 0.125 mm (0.005 inch) brass you need to design it to be 0.54 mm (0.0216 inch) wide. I got this tip from a fellow who runs a model ship company.

2. You must mask both sides as ingura said. You cannot control fine detail any other way. This means you must have very accurate registration of the masks on both sides. To my surprise I discovered this really isn't too hard to do! Put registration marks (+) on three corners of your masks (this way you won't accidentally reverse one of them). Leave a wide (1 cm or 1/2 inch) margin at the top of the reverse side mask, and a 5 mm (1/4 inch) margin on the top side mask. Line the registration marks on the top and bottom masks carefully, holding them up to a window or back lighted sheet of glass. Then tape the two masks together across the wide margin. Slip the sheet to be exposed between the masks, being careful not to twist along the taped edge, and the masks will be registered correctly.

3. Ink jet printers usually make darker masks than laser printers. Whatever you use, be sure to turn off the "economical" print settings if it has one, or turn on the high resolution or dark print mode. This will give a darker print, and this is important when printing on clear plastic.

4. Reverse print the top side mask (mirror the drawing before printing). You want the ink on the mask to be on the same side of the plastic mask sheet as the metal to be etched. Even very thin sheets of plastic are thick enough that light diffuses in them. If the ink is on the top (opposite side than where the metal is) light will diffuse through the plastic and cause a fuzzy edge to the mask. This will cause unpredictable part thicknesses.

5. When you get good enough at it to try something new, you can double etch to produce patterns in the metal. For this you etch only one side of the sheet at first, removing a thin layer of metal in appropriate places. Then you use a second mask, top and bottom to etch through a different pattern. This trick can be used to put a texture on one side, such as deck plate treads, or patterns of grooves for doors or hatches.

6. Whatever you are etching you must keep the etchant moving over the metal at all times. The etching process produces a residue that can build up on the surface and stop the etching process. This residue must be removed. A fish tank air bubbler can be used to bubble through the etchant to keep it stirred. The residue will settle to the bottom of the etch tank.

7. Last, but not least, don't make the mistake I made the first time I experimented with etching. Don't use an aluminum pan for your etch tank! I majored in chemistry, so I have no excuse! I understood the reactions, and aluminum etches very quickly! I was in a hurry and didn't think. It was a stupid mistake and it made a real mess!