SJSoane

Hi everyone,

Well, I am going to have to admit defeat at the hands of photo-etching. Third attempt today, and the entire resist washed off in the developer. Not even a trace of the resist.

I may not have the right mind-set or aptitude for this kind of work. There are dozens of steps, each of which requires judgment as to how clean, how much water, how much exposure, how much brushing, etc. At any point, the process can fail, and then you start all over again from scratch. I had thought that the third time through to the development stage, I would have learned from most of my mis-judgments, so it was a surprise when this was the worst example of losing the resist altogether.

I somehow managed to get through my entire education with only physics and no chemistry. Either I was not suited to something like chemistry, or the lack of this education put me at a big disadvantage when it comes to the mysteries of chemical actions in photo-etching!

Maybe I will come back to this another time, but for now I will explore a couple of other ways to get these xxx$?x& cyphers onto my cannon masters. I only need 4...

I tip my hat to those of you who have mastered photo-etching!

Best wishes,

Mark

Hi Peter,

Exceptionally clever! I never would have thought to do it that way. I will try it myself and see how it works. Fusion has just the right tool for everything, it seems, if just you can find it.

Mark

druxey, what are the wooden structures immediately behind the gunports?

Mark

John, thanks, that sounds very helpful. A bit frustrating to have it all wash off.

Mark

Hi Mike,

Fair enough! Purism should never win out over maintaining high quality of craftsmanship if a choice has to be made, as far as I am concerned. I wonder how good a job the sailors did out at sea, cutting paint to that outer edge. It might have looked like smeared lipstick!

My wife the retired architect, never, ever, specified paint to change color at an outer edge because it is impossible to get a clean line.

Mark

Hi MIke,

Beautiful work!

I somehow got the idea in my head that the red paint at the gunports would extend out along the revealed edges of the planking, to meet the face of the planking at the outer edge, not the inner edge. Do you have another understanding, or are you planning to paint those edges later?

I have been fretting over how to do this myself, assuming I did not misunderstand this detail!

Best wishes,

Mark

Hi Alan,

I might still be trying that. I learned more about photo etching today, getting as far as exposing and then developing the resist. I discovered (after talking to the great tech support at Micro Mark) that I had probably not cleaned the metal enough and/or run it through the laminator enough times. The resist had not stuck properly to the metal, and washed off completely in big areas.

So, the artwork is good, now I need to start again with the metal prep, exposure and development of the resist.

My wife is very patient about me taking over the guest bathroom for my developer studio...

Mark

Hi John,

It has taken a little mental adjustment to think about everything as a negative. It makes intellectual sense as I read it, but it doesn't stick intuitively that the black is what will be eaten away, especially since it is exposure to light that makes the mask.

I am intrigued by your circuit board experiments. How did it go?

I hope to see soon just how well this resolves. Interestingly, I had access to two printers for making the artwork; a relatively high end large format Canon printer that my wife used in her architecture practice, and our cheap home scanner/printer also by Canon. I was pretty amazed to see that the cheaper printer had finer resolution. It is a few years newer, but I didn't think the print resolution on inkjets had improved that much, and lower down the price range.

Hard to keep up with everything!

Mark

I learned a lot today about photo etching. First, the instructions and I came to a misunderstanding about the required length of the artwork film on front and back. They have to be taped together back to back while registering exactly. One side has to be longer so the other side can be taped to it, to form a hinge at the top. The metal then slips in between. I did it wrong, leaving too short a distance at the hinge to allow the artwork to slip down to be centered on the metal. So as long as I had to do the film again, I reworked the art so that I could get all of the hinges on. I also placed registration marks at the corners to help with aligning these to each other.

I also talked to tech support at Micro Mark. They were very helpful. They said that the exposure to a 60 watt bulb will do the job well. 100 watts tends to deform the plexiglass that the metal and artwork is temporarily sandwiched within, and fluorescent takes all day. 60 watts takes about 10 minutes per side. Time does not seem to be critical; the film will turn a darker blue when properly exposed, and there is no danger of too much exposure. Basically, the resist under the exposed areas (white) is being hardened by the UV light, so the unexposed areas (black) can be washed away to reveal the metal for etching. It apparently cannot be over-hardened with too much exposure.

Also, the ink side of the art work is placed directly against the resist film on the metal, which is why the artwork has to be reversed to read properly. So there is only the thickness of the ink to cast any shadows when being exposed, which appears to be negligible.

I had hoped to be further along today, but there was no rush because the sun never showed up here...

Mark

Beautiful!

Mark

Beautiful work, Ed. It is always hard to imagine, when looking at a finished model, just how much time and thinking went into it. Your posts tell that story exceptionally well.

Mark

Wow, Doris, those stands look fabulous! You built those so quickly, with such great craftsmanship and artistic vision. I am very impressed!

I am also inspired to do something like that when I eventually get to that stage with my project.

Mark

John, I once lived in Denver, Colorado, which also had something like 300 days of sunshine a year. I appreciate what you have got in Brisbane! I should have done these guns two years ago before I moved. The weather report for here tomorrow no longer shows sunshine, which was going to be the only sunshine for the next 15 days. Druxey, I am going to call Micro Mark tomorrow and see if they can shed any light (so to say) on how I can do this with a lamp. Moving the lamp around is an interesting idea.

As usual, nothing quite goes as one expects. I printed out the artwork on the film and got satisfyingly high resolution, higher than the printer does on regular paper. However, I did not read the fine print in the instructions that the maximum recommended size is 3" by 3" for the metal, not the artwork; the artwork needs to have a margin of  ½" within the metal all around. So my artwork was too big. A few failed attempts later, I finally got the film printed to the correct size. Used up the entire first sheet of film getting it right. And I don't have enough door hinges at this point. So there will be a round 2...

Best wishes,

Mark

Thanks, Ed, that was good advice. I have blocked out some of the wasted cutouts.

In case the sun does not cooperate with me in the next little while, did you have any experience and success with exposing the photoresist to an incandescent bulb?

Mark

Thanks, druxey and John, this makes sense. I will see which bulb I can find!

Mark

Hi druxey,

Quite true. They call my area the "banana belt" of Montana, ignoring the grey in the winter.

I just heard that I can drive to the top of a ski resort near here, where the lodge is at the top of the mountain. It often has sunshine when the rest of the valley is socked in due to a lake effect. That might be a way if the weather here does not cooperate. But then I will have to ski first!

By the way, do you think the Micro Mark instructions would be correct in saying that I can pull the photo resist material out of the black bag while using a yellow bug bulb, to avoid exposure to UV until everything is ready? I used to use a red light for old time photographic development, but this appears to be a different kind of exposure to a different aspect of the light. Wish I had paid more attention in those physics classes...

Mark

Thanks, Mark, I am happy to share what I learn, including mistakes and missteps.

Druxey, your comment about parallel light rays makes sense, particularly with the fine detail I am hoping to make.

I have a potential window for the sun on Monday, the only day for the next 15 days (see the weather forecast below; it reminds me of when I lived in London in the mid 70s to mid 80s). I will see if I can get everything ready by then. If not, or if the weather projection is wrong about Monday, then I am looking at a long delay...

Or maybe I can send my metal blank to one of you who sees the sunshine more often! It will only take 15 seconds of exposure on each side.😊

No, that won't work because it needs to be developed very soon afterwards...

Best wishes,

Mark

Hi druxey,

The exposure part has me nervous. The instructions from Micro Mark say it can be exposed either by sunlight (noon, on a bright, cloudless day for 15 seconds each side), or a 60 watt incandescent bulb for 10 minutes each side, with the bulb 4" from the surface. However, earlier in the paragraph it says a 100 watt bulb.

My part of the country hasn't seen a bright, cloudless day in some time (yesterday was completely fogged in). So I was reconciled to using the light bulb. But 100 watt or 60 watt? I think I will call Micro Mark on Monday to get further guidance. What happens when we can't buy incandescent bulbs for love or money? Does an LED bulb give off UV the same as an equivalent incandescent bulb?

The eighteenth century model builders didn't have to worry about things like this!

Mark

Alan, too right about remembering to come back! I put off rebuilding the cannon for several years (admittedly, retiring and moving slowed down my ship production time).

At the risk of making too many boring postings, I thought others might find interesting my first explorations of photo etching as I proceed. I am using the Micro-Mark Pro-etch system from their catalog. The following is what I understand will happen:

The system will chemically etch metal wherever it is not protected by a photoresist mask. The mask has to be applied to both sides of the metal, otherwise it would just eat through the metal from the back irrespective of what mask was placed on the front.

Where the masks are the same on both sides, the metal will be etched all the way through. Where the masks are different, the etch will only go halfway through, leaving a depression on one side.

To create the photoresist mask, artwork is created for both sides of the metal, each the mirror image of the other so the two sides line up precisely. This involves making the artwork for one side, then creating a mirror image for the other. The artwork will then be used as a mask to expose the photoresist on the metal to UV light, white areas protecting the photoresist material and therefore protecting the metal underneath from etching, and the black areas eating away the resist and therefore allowing the metal in these locations to be etched.

Using Adobe Illustrator, I drew the artwork, then created a mirror image for the mask on the other side. Looking at the door hinges, I created black dots for bolt locations on the front side, and removed these on the back side so they will not etch all the way through. Similarly, I added white triangles on the back side to hold the pieces in place when the etch is completed; these thinner parts will be cut through just like cutting parts from sprues in plastic models.

I need to rig a dark interior room with a yellow light so I can work with the photo resist and not expose it to UV light until everything is ready to go. The exposure to develop the resist is done with a 60 watt incandescent bulb (fortunately, I still have one in my old drafting light). Many unknowns still to go!

Mark

Hi Doris,

I have long admired those dolphin supports in contemporary models, and have vaguely thought about making something like that for my own project. I look forward to seeing how you make these!

Mark

thanks, Greg and druxey, this is very helpful. I face the great unknown of photo-etching next week, once my replacement chemicals arrive. No two-day delivery where I now live!

Mark

Hi Bob, thank you very much for your comments. As you can see, I am very often learning as I go along. And many of the great builders on this website have taught me more than I would ever would have discovered for myself. Learning from a lot of mistakes has also helped! Sometimes when the mistakes are really bad, I put those aside for a while and go onto something else to get my confidence back, and then revisit the mistake to try another approach. I tried making the cannon several years ago, and was quite discouraged by the outcome. A few years later, I have renewed energy to do it better.

Mark

Oh, good to hear about epoxy, druxey,  I haven't really yet learned silver soldering. I used super glue on my previous failed effort, and it was almost a disaster when it quickly began to stick down in the wrong place. Epoxy sounds like just the right thing.

Mark

Hi Greg,

Yes, that is my plan. I have made several of each in case I screw up attaching to the master cannons, and also to see what happens with different thicknesses of lines. I am not yet sure just how much the Micro Mark etching kit will resolve down to these fine lines.

And as long as I have to use up a 3X3 sheet, I might as well fill it up!

Mark

Hi everyone,

I spent a little more time in Adobe Illustrator, trying to get cleaner drawings of the king's cyphers for photo etching. Once I got the hang of the pen tool, I was able to draw the forms rather than filling in the backgrounds (my previous attempt). And this allowed me to vary the thickness of the lines. Since I don't know how well the photo etch will deal with fine detail, I will try a couple with different thicknesses of line, hoping some good ones come out of the mix.

Thinking about other metal objects that would be 5/16" thick real size to fill up the sheet, I have drawn up the door hinges for all of the partitions. I also drew some vent fields for the cannon.

Can anyone think of other metal objects this thin, while I am at it? I thought about the compass. The etching process is supposed to etch from both sides, which means that there can be recessed parts not cut through all the way depending on how the art is arranged. Maybe cut the compass rose into one side? Not sure how I would color that to pick out the raised parts later.

Maybe the pump rhodings?

Mark