MicroMarks photo etch kit

[RancheroSteve]

Here's a photo of my parts after just a small amount of clean-up. Not too bad for a first effort, IMHO. But as you can see, some of the bolt holes near the edges have blown out a little. Hard to tell here, but these parts are pretty tiny - 1/24 scale block plate, trans faces and rear block surface.

I'm not sure if this amount of detail is pushing the capabilties of the system, but I'm going to take another stab at it in the next few days and see if I can get it a little better.

[Jdurg]

One thing that I have read about is that the "fineness" of the detail is limited by the thickness of the metal you are using. If your metal sheet is only 0.10 mm thick, then the thinnest "detail" you can have on the photo-etched product is 0.10 mm thick. This is especially true around edges because of where the resist rests, the etchant will still eat a little bit underneath it. So if you have a fine detail too close to the edge, when the etchant eats underneath the resist it will likely go right through the detail.

I have already got my images setup in Illustrator, both front and back sides. This should help me do a lot of "half-etching" like on the gas cap and nose emblems where I need to etch out part of the top, but not all the way through the piece. Where I need to make cuts all the way through, I'll just leave the back side open.

I'm REALLY looking forward to getting the kit. Per the shipping instructions, I should have it tomorrow and get to use it this weekend. Amazingly, while digging around in my basement I found a red photograph developers lightbulb which is used for photographic work. I'll use that when I need to see, but don't want to exposed the film.

[The Creative Explorer]

The pictures for sure don't look bad for a first attempt. I think more detail would've been there if you kept the etching time a bit shorter (like you mentioned).

Other than that, I think it is nothing but trial and error to get somewhere where Joseph is.

[Len Woodruff]

Very interesting stuff guys! Thanks.

[Chief Joseph]

Those parts look really good, Steve! As Justin commented, the thickness of the metal dictates some of the details you are able to achieve. Regarding some of your holes being over-etched, a rule of thumb to remember is "Holes get bigger, parts get smaller." That is, a hole over-etches slightly from the way it was originally drawn and printed, and the overall part over-etches around its perimeter, making it slightly smaller that it was originally drawn. A hole that's placed very close to the edge of the piece will cause both of these properties to come into play, and the result will be a blown-out hole. Now, the amount of over-etching that occurs is directly related to the thickness of the metal. The general "fudge factor" to account for this over-etching is 15% of the metal thickness. Therefore, if you are working with 0.010" thick brass and you want a hole exactly 0.022", you will want to decrease the diameter of the hole by .003" (15% of 0.022") and draw your hole at 0.019". I usually round everything to the nearest .001" for sanity. Keep up the good work, Steve, and I hope you other guys get your stuff from MicroMark soon and join in the fun!

[RancheroSteve]

"Holes get bigger, parts get smaller."

Thanks, Joseph. This is a great piece of info (seems obvious once you know) that should almost be in the manual!

Edited March 24, 2012 by RancheroSteve

[Jdurg]

Got my kit today. I'm still working on getting my artwork finalized, so I likely won't give it a go until next weekend. I may try some trial pieces with the insanely thin sheets that came with the kit, but probably will want something slightly thicker for the end product.

[The Creative Explorer]

with 0.010" thick brass and you want a hole exactly 0.022", you will want to decrease the diameter of the hole by .003" (15% of 0.022") and draw your hole at 0.019". I usually round everything to the nearest .001" for sanity.

No bashing here, but boy, am I glad I work with the metric system hahaha,

@Joseph, thanks for the tip, that is usefull information making the artwork. Do you also make the part itself 15% thicker of the metal thickness? Since those holes were eaten away from the outside as well.

[Chief Joseph]

No bashing here, but boy, am I glad I work with the metric system hahaha,

@Joseph, thanks for the tip, that is usefull information making the artwork. Do you also make the part itself 15% thicker of the metal thickness? Since those holes were eaten away from the outside as well.

Yes, the outside perimeter of the parts get smaller because of the sideways etching action, so you have to compensate by increasing the size just slightly. A vector drawing program allows you to easily do this by adding a stroke around the object. Parts get smaller, holes get bigger.

[The Creative Explorer]

well, I finally made the decision and ordered the set. Now I have to wait a couple of weeks for it to come.

[Chief Joseph]

Erik, have fun and above all, be patient while you work through your first few attempts. Make notes on what you do so that you can go back and see what works well and what doesn't.

[Jdurg]

Funny that this post got brought up, as I just started working on my first photo-etching attempt. I went to Home Depot today to get a yellow bug light as I was told that wouldn't expose the photosensitive material, and it doesn't. The biggest problem I had with my first attempt was getting the danged sheet to laminate to the metal. I think I cleaned the metal too well as water doesn't "sheet" on it. It immediately rolls off. Still, the laminate itself seems to pick up dust like it's nothing and that left some, well bad spots on the laminate.

With the sun having set long ago, I figured that the UV light from the CFL bulbs in my house would be able to expose the material. It really doesn't do that. I only got a very faint ghost image of the artwork on the metal, but with great resolution. When I went to wash the unexposed areas off with NaOH, the entire laminate came off. So it's pretty obvious to me that the UV light from the bulbs isn't strong enough. I've got my alarm clock set and will be outside at noon tomorrow to get some good UV rays from the sun to take care of the laminate.

Any flaws in the lamination will be taken care of with a very fine sharpie marker to cover up exposed areas that shouldn't be. After a mother's day lunch with my mother, I'll head back home and get the etching started. Already have the tank built and tested using distilled water to ensure no leakage. This will hopefully work out great and once completed, allow me to finally finish that '88 Corvette 1/16 scale kit I've been working on.

Will update my workbench thread with photos once this comes out alright.

[RancheroSteve]

I'm not sure that it's possible to over-clean the metal. The MicroMark kit has a 3200 grit pad and it's also important to not get any grease from your fingers on the metal. I try to handle the peeled photo-resist as little as possible once peeled and get it laminated onto the metal as quickly as I can, but even then a few dust spots are probably unavoidable. In most cases they won't affect your finished product.

I've been exposing in the noon (or near noon) day sun and generally letting the laminate expose longer than suggested. Also, when developing, it's easy to over-develop and remove all the laminate if you're not carefull - 30 seconds per side is usually plenty long enough, but better to err on the side of under-developing at first.

Finally, given that this is a "home version" of a fairly meticulous industrial process, perfection is certainly something to shoot for, but you won't get 100% of your parts turning out - even GSL winner Randy Derr has told me as much.

[Jdurg]

Yeah, I'm aware of the inability to have it be perfectly, laser-cut accurate. The metal I'm using is definitely not greasy. Once I have put it through the scuffing with the 3200 grit pad and rinsed in distilled water, I never touch it by the face areas. I only handle it with nitrile gloves that aren't powdered so that nothing is left on there.

For the first run, it was certainly just a lack of bonding or very, very underexposed material as I have looked online and seen images from others who have done it, and while their "imprint" looked a nice dark blue, mine was very, very faintly blue. The sun should be out and shining nicely tomorrow, so I'll be able to ensure proper exposure and hopefully get a nice result. Any spots on the metal where the laminate didn't seem to apply perfectly, I ensured those areas were in the covered up spots so that they'll just be wiped away by the NaOH anyway. The exposed areas of the artwork all look good.

Time for bed though. All this photo-etch excitement has got me wide awake. Hehe.

[Chief Joseph]

Justin, several posts ago I stated that photoetching is sort of like an algebra problem with a lot of steps to solve. If you have an error in any step, no matter how well the other steps are performed, will result in a wrong answer. You're seeing this action now! Each step-- from cleaning the metal, to applying the resist, to exposing the resist, to stripping the resist, to etching the metal, and finally to removing the resist-- has its own set of issues that have to be overcome to get a quality part in the end. And that's all assuming you have good artwork, which is another procedure all to itself. And it IS possible to get laser-cut accuracy!

You are probably getting your metal cleaned well enough with the scuff pad and as long as you don't touch it with greasy fingers you should be okay. You are getting dust in the film because you are applying it dry, and that will attract dust out of the air. I recommend you apply the resist wet, which reduces the chance of dust and air bubbles trapped under the film. It's easy to wet-laminate: spritz some distilled water from a spray bottle onto the metal, lay the piece of resist over the metal and use a squeegee (an old credit card works fine) to press the film to the metal and push the water from beneath the film. After you apply the film this way, it is very important to let the film/metal sandwich dry thoroughly before you try to laminate it. I wipe the pieces with a paper towel to remove any excess water and then let them sit overnight to completely dry out.

When you expose the resist to UV, consistency is very important. The Micro-Mark kit suggests using a 100-watt light bulb or the sun; of those two, the light bulb is more consistent, but it's a rubbish UV source. The sun is a really good UV source, but it hard to get consistent exposures from one day to the next, and sometimes you need to work at night! I use a 500-watt halogen work light as my UV source. It works better if the tempered glass protective cover is removed (tempered glass filters UV).

By the way, I do not use NaOH (lye!) because it is far too harsh. I use Soda Ash, sodium carbonate Na2CO3, because it is much safer and works just as well. A 1% solution works as the developer (that is, 5mg of soda ash mixed with 500ml of distilled water) and a 2% solution as the stripper. Another benefit of soda ash is its price and availability. I got a container at Wal-Mart years ago (pool supplies) for about 6 bucks and I still have half of it.

See, I need to write all this into a book...

[Jdurg]

Yeah, I've learned quite a bit from my first experience. I certainly didn't expect to get perfect results, however, what I did end up getting looks like it will work out just fine after I paint the pieces that need it. The tougher parts, the interior speaker grills I tried to make, are the most difficult due to the very fine lines I tried to get in there.

The UV rays of the sun are perfect. Today, I went outside and could see the laminate turn a very deep shade of blue right before my eyes. Still, the developer and the lamination itself is the toughest part. I got the vast bulk of my sheet adhered properly, but it looks like some fingerprints did wind up in parts of it that I didn't thoroughly clean off. I have no issues using NaOH. Having a degree in forensic chemistry and having spent many, many hours of my life working with the stuff, I have no worries. I actually have a tub of NaOH pellets as it is the best stuff at degreasing things that need it, and having vast experience using it and being fully aware of its dangers, I don't worry.

I don't have a photo of the end result, since with the design I have and the lighting conditions I have, it doesn't really show up properly. (A good deal of shadows on the piece itself due to the number of half-etches I have). I think the main Corvette emblems I made, the TPI logo on the engine, and the alternator bracket will work out fine. The seatbelt pieces and the speaker grills will likely be tossed. I'm thinking of trying to re-do this next weekend and do more preparatory work on the metal before laminating. I think a bath of NaOH prior to rinsing it off then leaving it in distilled water will provide a proper result.

To be honest, the etching part itself wasn't tough at all. I heated up the ferric chloride and then dumped it into the tank with the aerator going, and it etched quite well. I also didn't even spill a droplet of the etchant so that was nice not having any messes to clean up. I was very happy that the registration of the front and back artwork came out perfect which is incredibly sweet. I already see where I need to spend more time on my next one, and there will be a next one. This kit is amazing and the things one can do with it, if you have enough time and patience, is limitless.

[Chief Joseph]

Fantastic Justin! Keep it up and post some pics when you can. What metal did you use from the Micro-Mark set? The brass or the stainless? Stainless is really, really difficult to etch with Ferric Chloride alone.

[Jdurg]

I've been using the Stainless since I figure, if you're going to master something, start out on the harder difficulties. This, and the fact that I have some parts that I really want to have a steel/silvery look to them and if I use brass, I'll need to paint the part after it's where I need it to go, and I'd rather not do that. I'd rather the part be able to be handled without fear of the paint just rubbing off. So as of right now, It's been stainless.

I went and decided to re-print my artwork and make some small corrections so that the parts aren't so close together, and thicken up the lines in the parts that seemed to need it. I went and applied some laminate to a sheet of stainless, and had the same issues with spots and bubbles when doing it "wet". It seemed that the edges would dry up first and seal shut, so no matter what I did with the squeegee process, it would leave massive bubbles. So I had to strip off some poorly applied laminate and try again. This time, I decided that instead of putting the laminate on wet, I would try it dry again. Did it dry and this time applied the laminate like I would if I was putting wallpaper on. I only exposed the top 2mm or so of the laminate and then applied that, burnishing it on strongly as I slowly went down. This left me with a GREAT laminate job that only resulted in a few bubbles and marks showing up once it went through the laminator. After printing out artwork and registering the artwork, I was able to see that the flaws aren't near my parts.

Sadly, the sun has set too far for the day so no UV exposure on this day. Perhaps later this week when I'm working from home I'll be able to step outside for a few seconds and expose it. At least the first difficult part is complete now.

[Jdurg]

Okay. For anyone who is thinking about getting this kit, the one key thing that from my own experience I can attest to is that you MUST have PATIENCE! I'm getting ready to etch my second attempt at this and what has been stopping me in the past has been rushing too quickly. Joseph had preached patience to me, and now I'm re-preaching it.

The first part is patience in ensuring the metal is completely clean. Once you've cut the sheet out and sanded it to give it a rough surface for the laminate to adhere to, DO NOT EVER TOUCH THE METAL WITHOUT WEARING GLOVES! I went and, with my gloves on, then submerged the sheet in a moderately strong lye solution in order to dissolve any grease that is on there. A dunk into a bath of distilled water to clean off the lye, and then I just shook it dry. If cleaned properly, there should be no beading on areas of the sheet. Beading indicates there is oils or particulates on the sheet and if those exist, the laminate won't adhere.

The second part of patience is applying the laminate. Make sure you have squeegeed out ANY air bubbles in there. I apply the laminate while dry as I had too many issues when trying it wet, but I must preach again to get every last bubble out. You are working under UV free light so take your time. I used an old credit card like Joseph recommended to get every last bubble out before putting it through the laminator. When done, and sadly I didn't take a photo, the sheet will look perfectly smooth. Artwork was applied on each side, after spending time to ensure proper registration, and then I went and exposed it the noon-day sun for about 25 seconds each side, and the semi-transparent light blue laminate quickly turned a deep, dark blue indicating it was exposed. Back into a UV free room and you could clearly see sharp, defined lines on the piece. Success! With a solution of 1/4 ounce concentrated lye solution to three full measuring cups of distilled water, I dunked the sheet into there for a few seconds for each side. The sheet was quickly dunked into another vat of distilled water, and with a spare paintbrush I lightly brushed over the unexposed areas. They quickly washed away and bare metal now shines through.

The sheet is etching as we speak, but before dunking I went and took this photo of the sheet. I had to take this at an angle in order for the metal to not reflect too much light and drown out the lines. The angle of the photo causes the dark blue exposed laminate to wash over the photo, but trust me, the metal is shining through very brightly. The lines, which admittedly look thin in the photo, are thicker than it appears so there are no worries there. For some reason, it's very difficult to accurately photograph the sheet, but hopefully in 20 minutes or so, you'll see an image of a finished piece.

[Jdurg]

And here we are. Took this photo just after letting the sheet soak in some lye to remove the exposed laminate. The picture is of poor quality as it's really difficult to photograph stainless steel. But you can see the gist of it. The parts are still a bit fuzzy in parts due to "gunk" left on the sheet, and once I briefly apply some polishing compound it will turn out okay. I think I could have left this in the etchant for a few more seconds to finish up some of the fuzzy areas, but I was starting to get worried that I was eating into the detail on the other parts so I took it out. I also see that my registration wasn't nearly as good as I thought it was, so my parts aren't super perfect. Still, I think they are good enough to go and once some paint is applied and some smoothing out is done, it will look just as I want it to.

I'll update this again, as well as my '88 Vette build in the Workbench area once I've cleaned up the fret and applied the paint.

[Chief Joseph]

Looking great, Justin!

[RancheroSteve]

Thought I'd share a little something I did that might be helpful for any of you guys using the Micro Mark kit. I found that after some use, the clamp that holds the piece in the tank started to lose its tension and wouldn't hold very reliably any more.

So I bought a 8/32 x 1" nylon bolt and wing nut from the hardware store, cut the old clamp off the rod and the head off the bolt, then epoxied the bolt onto the rod (with a plastic sleeve for additional strength).

Then it's simply a matter of punching or drilling a hole in the workpiece and putting the wing nut on to hold it.

No more worries about losing the part in the tank!