RESIN WINDOWS

Since the beginning of this Eaglemoss 1:900 scale U.S.S. Enterprise NCC-1701-D partwork build, I have been sanding down all of the plastic windows to keep them from sticking out of the hull deck panels. However, I have also been thinking about other solutions that could possibly be even better. One of those ideas was to try some kind of clear resin to fill in the window openings. I had never worked with resins before, so I thought I would give it a go, see what happens, and perhaps even learn a thing or two along the way that I could share with everyone.

Choosing A Resin Type


There are many different types of clear resins available. However, I was looking for something that would create thin, non-yellowing, hard curing windows that were fairly simple to make. I decided to try a product from the fly fishing world that I have seen a few other modelers use. Thankfully, Amazon carries a great starter option for it – this Solarez UV-Cure Fly-Tie Resin – Pro Roadie Kit:

Solarez Fly-Tie Resin is a durable aliphatic urethane resin that does not yellow with age like other resins. ‘Aliphatic’ means it is an open-chain organic compound that is non-aromatic – in other words, it hardly has any odor.

And, as an UV (ultraviolet) cure resin, it will not cure until it is exposed to the light from a UV flashlight (or sunlight). We can work with it indoors (or in the shade) for as long as we want without worrying about it starting to harden on us. Because of this, we will not have deal with measuring or mixing any messy, smelly catalysts. UV Resin does not need to be mixed, it is ready to use out of the container.

Safety


Disclaimer: I am not a medical professional. This section contains some suggestions, but you are ultimately responsible for your own health. We do not want anyone getting hurt, so you assume all risk by following these procedures. Always be safe!

The 385nm (UV-A) wavelength of light produced by the curing flashlight or sunlight is not good for your eyes/skin. Just like we shouldn’t sit in the sun too long or ever look at it without protection, avoid pointing the UV source at your skin and use a pair of UV glasses to protect your eyes. I picked up an inexpensive pair of Shatterproof UV Safety Googles to use when curing our resins – and you should too:

As for handling the uncured resin, wear protective gloves and avoid getting it on your skin or clothes. If you do, it should be rinsed off with water and isopropyl alcohol. If any skin irritation develops, seek medical assistance. Cured resin should be able to be handled without gloves, but I still wash my hands after doing so. Finally, I hope it goes without saying, but do not ingest the resin or breath in any vapors while curing!

Trying the Resins


The first thing I wanted to figure out was which of the three kinds of resin included in our Solarez UV-Cure Fly-Tie Resin – Pro Roadie Kit would work the best: Thin-Hard, Thick-Hard, or F-L-E-X. The main differences between them is how viscous (thick) the uncured resin is and how hard it be after UV curing.

  • Thin-Hard has a similar viscosity as 30 wt. motor oil and cures very hard
  • Thick-Hard has a similar viscosity to 10 wt. motor oil and cures very hard
  • F-L-E-X seems to have a little thicker viscosity than Thick-Hard, but this version remains somewhat flexible when cured

I wanted hard windows, so quickly I ruled out the F-L-E-X version. However, when I tested removing the cured resin windows later on, I did give the F-L-E-X version a try. You can find those details at the end of this page. For now, we will stick to the two Hard resins:

Before we can begin pouring any resin, we need to seal the outer surface of the windows flush with our Deck Panels. I did not want anything that could damage the surface of our Enterprise and/or leave any residue behind. While doing some research into using UV resins, I discovered that we can actually buy UV Resin Tape. This tape is specifically designed not to stick to UV resin and is very smooth – both things we want!

Amazon carries a bunch of different kinds of UV Resin Tape. I just picked a quick and cheap option and bought a couple of rolls:

I had the completed parts of an extra Stage 4 laying around, so I figured I would try these two resins in a few of the window openings. I cut a piece of UV Resin Tape off the roll and pressed it firmly over the window openings of a Deck Panel. This step is important to prevent the resin from leaking out around the windows and onto the panel surface. Also, avoid touching the sticky side of the tape, especially where it will cover windows. Any fingerprints on the adhesive can show up in your cured resin:

Starting with the Thick-Hard version of the Solarez resin, I removed the outer and inner caps from the bottle, installed the syringe type nozzle, snipped off the tip, and poured a drop of resin into the back of two of the window openings. I immediately noticed the uncured Thick-Hard resin has a slight tinge of yellow to it. It also created and trapped bubbles quite easily:

Next, I put a drop of the Thin-Hard resin into each of the three nearby windows. Since this resin is thinner, it flowed much better into the corners of the windows, reducing the creation and trapping of bubbles quite a bit. It also appeared to be less ‘yellow’ out of the bottle:

Next, I cured both resins with the included UV flashlight. This flashlight can run on either a rechargeable Li-Ion 16850 battery or a couple of standard CR123 lithium batteries (which is what I used). Unfortunately for me, I failed to read the instructions well enough and gave the windows about 30 seconds of UV light coverage right from the start:

It turns out that blasting the resin with a bunch of UV light is NOT the right way to go. It causes any little bubbles to get bigger or even make more bubbles. This is because the resin heats up when exposed to the UV light making any existing air bubbles expand.

By then it was too late – this resin cures almost immediately under UV light and those bubbles were trapped in there forever. My mistake was even more visible when I removed the tape to check my work!

LESSON LEARNED: The Thin-Hard resin seems to be better for making the windows, but do not blast them with the UV light!

Still, our UV Resin Tape application worked perfectly. It left the exterior surfaces of the resin windows smooth, nearly flush with the hull, and did not leave one speck of residue behind on the windows or the panel surface. I say ‘nearly flush’ because these particular windows cured a bit concave (sunken down into the window openings). This was also because I blasted them with the UV light for too long which caused the resin to rapidly shrink while curing.

LESSON LEARNED: The UV Resin Tape is great! But again, do not blast the uncured resin with UV light.

Blacking Out the Resin Windows


With our very first resin windows now cured in place, they are almost perfectly clear. This is good for the windows that we want to be lit, but there are just as many dark windows on our Enterprise model. First, I tried painting the back of the ‘dark’ windows with a black acrylic paint pen. This option worked reasonably well:

We could also use a black Sharpie here, but I found that just using a paintbrush and some Tamiya XF-1 Flat Black acrylic paint actually worked best. Both of the other options tended to go on a bit thin and could let our bright LED light leak through the dark windows. The effect created by doing it this way gives the windows depth, even when they are ‘blacked out’.

LESSON LEARNED: Black out the back side of the appropriate windows with a layer of paint.

Trying to Improve the Process


1st Attempt

Taking everything we have learned so far, I grabbed another spare Deck Panel to try to improve the process even further. As before, I cut a piece of UV resin tape and pressed it firmly over the windows I planned to pour resin into:

Using our Thin-Hard resin, I filled a row of windows openings from behind:

However, this time I followed the curing instructions correctly. I flashed the UV light over the windows for only ONE second at first. I waited 15 seconds, then flashed them again for 1 second. Then, after 15 more seconds, I lit them up for about 30 seconds. The idea behind flashing the resin with the UV light at first is to start the curing process slowly. This reduces heat/bubble generation and resin shrinkage.

LESSON LEARNED: Flash the UV light over the uncured resin for 1 second, then wait, then 1 second, then wait, then 30+ seconds.

As before, I painted the backs of a few windows to black them out. Then, I removed the tape to see how we did:

Well, unfortunately, the bubbles are there again and they actually created holes in the windows! But, on a positive note, this time our windows are perfectly flush with the hull surface. While we seem to have fixed the shrinkage problem, we still need to work on the bubbles…

To see how these resin windows compare to the stock plastic windows, I randomly filled up the rest of the panel with the Eaglemoss parts:

From the front, there is a definite difference between the smooth resin windows and the plastic windows. Sadly, the bubbles look awful!

When lighting is applied to the back of the panel, the new resin windows let as much, if not more, light through. It is hard to see in this picture, but the resin windows are so clear you can actually make out the guts of the lighting LED and even the screw holes of the reflector behind the panel. I put a piece of white napkin between the panel and the reflector panel to diffuse the light and that worked really well:

2nd Attempt

For my second attempt, I was able to reduce the bubbles even further by picking them out with toothpicks before curing the resin. Unfortunately, I removed the tape too soon. The outer portion of the resin had not cured so it spilled out and left the windows sunken into the panel. Whoops!

LESSON LEARNED: Bubbles in the resin can be picked out with a toothpick, but do not remove the tape before the resin is cured!

3rd Attempt

For my next attempt, I tried using regular clear packing tape on the outside instead of UV Resin Tape. Packing tape is cheaper and more readily available, so I thought I would see how well it works as a possible substitute.

I also tried two new procedures this time around. First, I used a smaller drop of Thin-Hard resin in each window opening and gently nudged it into the corners with a toothpick. Second, I did the initial ‘flashes’ of UV light from the tape side (outside of the window).

Well, the result of using packing tape was a mess. It left adhesive residue all over the outside of the resin windows. The adhesive did eventually come off with a fingernail, but it took a long time to get it all removed.

BUT, there is good news! A thinner resin pour made for even better results – it cured quicker, shrunk less, and created less bubbles to pick out. And, doing the initial UV flashes from the exterior side of the windows resulted in no new bubble creation and ZERO shrinkage on the outside surface. These windows are so flush with the deck panel that you can barely feel them at all when you run your finger across them.

LESSONS LEARNED: Do not use clear packing tape to seal the window openings. Do use a thinner layer of resin and do start curing it from the exterior side.

4th Attempt

By this point, we have learned how to practically eliminate any bubbles in our resin windows and create a nice, smooth surface flush with the panel. However, the exterior surface of our resin windows does appear a bit shiny/reflective. Out of curiosity, I tried taped the outside of the window openings with common Scotch ‘Magic’ tape this time. This is the same tape you typically find in offices or when wrapping gifts. I thought the rougher adhesive surface of this tape would give our resin windows a ‘cloudy’ appearance, which might be desirable.

After pouring and curing the windows, I removed the tape. Well, Scotch tape does not leave residue on the resin, but it did discolor the surface of the panel for some reason. To me, this is unacceptable. It did create the ‘cloudy’ effect on the window exterior surface, but it is not worth possibly damaging the panel surface.

LESSONS LEARNED: Do not use Scotch tape to seal the windows for a resin pour.

5th Attempt

This final attempt was to be a compilation of all of the lessons we have learned so far:

  • First, I firmly pressed UV Resin Tape over the window openings on the outside of the panel.
  • Next, I poured a small drop of Thin-Hard resin into each window opening from the back and used a toothpick to gently guide the resin into the corners and pick out any tiny bubbles that may have appeared.
  • Then, I flashed the outside surface of the windows for one second with the UV light to quickly cure the outer surface, limiting the heat created and preventing any new bubbles from forming.
  • After waiting about 15 seconds, I gave the outside surface another one second flash of the UV light to cure it even further.
  • Finally, I waited another 15 seconds, then hit the inside surface of the windows with about 30 seconds of UV light to finish the curing.
  • On the inside of the windows, I used black paint to create dark windows. I even used my brush Sharpies to add a splash of color to a few.
  • I carefully removed the UV Resin Tape and was astonished at the results – these windows look AMAZING!

At a sharp angle to the panel, you can see how smooth and flush this final row of windows turned out:

Of course, I had to connect up the LEDs to see how everything looked lit up. I still have a piece of white napkin between the panel and the reflector to help diffuse the light, but the new windows are even brighter than before:

For comparison to the original plastic windows, I grabbed another panel with my sanded windows installed and placed it side-by-side with our resin window panel. What do you think of the difference? Better? Worse?

The final thing I wanted to touch on is something I mentioned before. This resin cures with a fairly shiny surface. That means it can be a bit reflective and you have to decide if that would be an issue for you. Using an LED flashlight from above, I tried to capture this shine in a picture:

Removing Resin Windows


I had a visitor ask about removing these windows once cured. I never tried to remove a cured windows, so I figured I would give it a try.

Solarez UV Resin is organically cross-linked to itself when it cures, so it does not chemically adhere to surfaces. This means we should be able to pop the cured resin windows out. At first, I tried to poke them out with a wooden toothpick, but they are just too hard for that. Next, I tried a screwdriver bit and a craft hammer and gave them a good tap. They actually shattered quite easily and fell out without damaging the panel:

As I further considered the removal process, I even tried making some windows with the F-L-E-X version of the resin. Since this is designed to be flexible when cured, I thought they might be more easily removed if we make a mistake. It is worth noting that this stuff is really thick, so it captured bubbles easier and I had to spend more time fishing the bubbles out with a toothpick:

This F-L-E-X resin requires more curing time. I still flashed the outside surfaces a few times to avoid bubble creation, but it still needs about 3 minutes of UV exposure to fully cure and avoid a ‘tacky’ surface. The good news is they came out looking just like the hard resins:

However, these F-L-E-X resin windows are not rock hard like the previous resins and have a little ‘give’ to them. When I tried to poke them out with my screwdriver bit, I did not even need the hammer – they pushed right through the panel by hand. The downside is they did not come out in solid pieces. The edges of the window opening had remnants of resin left behind which I had to remove with a hobby knife. This leaves us open to damaging the panels, which I do not recommend:

Thoughts


This was a great day in the modeling shop! We tried something new, we learned a ton, and I feel we ended up with a really nice result. The only thing keeping me from going back and replacing all of my plastic windows with resin is the idea of taking the model apart and building it all over again! I still have to decide if I want to attempt that.

As for the Solarez UV resin, I love using it! Of the three versions we tried, I like the Hard-Thin the most. It applied and removed easily, it produced the least amount of bubbles, it is practically clear as glass, and it cured in just a few seconds. It also worked on both the plastic and metal deck panels without any problems. If you have never considered using resin before, I hope this article gives you the confidence to give it a try. I had a blast and will definitely find uses for resin in the future!