Transparent UV resin: Your feedback.

[Gilles]

Hi guys,
I hear a lot about these transparent resins to be used with a small UV lamp and which are often used in nail polishing.
Indeed, they seem attractive due to their easy implementation -no mixing to do- and their fast drying.
So I did some research to find out more and some publications mention two drawbacks. One minor, and a second very boring.

-The first disadvantage is that once the jar is opened, the duration of the product would be six months. It’s manageable by buying in small quantities and grouping as many parts as possible to process.

- The second problem is much more questionable because it concerns the lifetime of the resin once it has been placed and subjected to UV. Indeed, some sites say that after a year, the resin would start to tarnish, lose its transparency, and even worse, turn yellow. No importance for the nail industry where ephemerality is the rule but very problematic in our field of expertise. Who indeed wants to see, for example, the counters of a dashboard ruined after a certain time?...

To overcome these disadvantages, I saw that some publications recommend once the UV resin is put in place and dried to cover it with a film of epoxy resin with two components, but in this case the use of UV resin loses all its interest which is above all an easy implementation and without having to mix resin and hardener...

What about in reality? This is where I address those of you who use or have used these resins.
Have you noticed after one or two years of use the appearance of the problems mentioned: loss of transparency, yellowing or others...?

[edsreef@gmail.com]

Hello Gilles,

While I have not done a great deal of working with resin, I can say, that the first dash piece from the Jaguar, granted, I had a couple of spots that did not cure properly, the sections that did cure right, have not dulled at all, and that was easily well over a year ago. Granted, I have not exposed it to direct sunlight, but it is still on my work table, gets some light from outdoors and lots of light from LED light bulbs bit still no dulling of the finish. They even make resins that are UV resistant.

That said, do not know what direct sunlight might do. But I think if they were displayed indoors it might not be a problem. Colin might be able to have a say about this as he has done it much longer that I.

If you go with the 2 part resins, follow the instructions, and mix the parts very well, that is the "trick" to being sure it will cure correctly. Yes, it does take usually a minimum of 24 hours to do so. waiting a bit longer is better. Do a practice piece or two so you can be sure mix and stirring time is good.

I plan to do more resin work on some of the other kits that I have.

Ed

[admin]

G'day Gilles & Ed,

Interesting topic as resins seem to be a love 'em or hate 'em type of process.

It does take a fair amount of practice to get perfect results most of the time, but so many factors can ruin what you think will be perfect.

That said, to address the UV resins specifically, I too have seen those, more for a crafting / hobby user. They seem interesting however noting the points that Gilles made about shelf-life, I have an alternative to suggest.

I guess it really comes down to how you want to use the resin.

- To coat parts to give a lot of depth and a nice clear / polished effect like Ed's dash panels on the Jag, OR
- To cast parts with some depth using a mould of some type

There are also 3 general options for the resins.

- Traditional clear resin - 2 part (A & B)
- Clear UV resin - crafter type (that Gilles is referring to)
- 3D printing clear UV resin - if I wished to 3D print parts in clear this is the resin for that

From there it becomes a case of the right tool for the job.

If you were looking to get a nice clear-coat on a parts (Ed's dash again), then any of the resins should be fine, though pretty much all resins will turn yellow under certain circumstances.

Typically keeping your parts out of harsh direct sunlight, don't try to do thick parts with the clear (over a couple of mm thick), and avoid over-curing the part under the UV light.

The Clear 3D printing resin, and the crafting resin will oxidise over time given the above circumstances. I agree that giving a resin part another coat of a UV stable resin is a bit counter-productive and inviting issues. You would be better off using a high quality clear coat gloss spray that is UV stable. I use that type on my decal sheets and some of those have been sitting in my room for years with no signs of going yellow.

As a side note to the crafter type UV resin, I use a bottle of 3D printing clear resin for all sorts of little projects and tests. It is designed to handle very high power UV light in the printers, and have an extremely long shelf life if kept out of the sun. I have a 500ml bottle of clear 3d printer resin here I opened about 18 months ago, and it's still perfect clarity.

I use it as an adhesive when I am test building the parts (superglue doesn't last long enough in the tube for how I use it), so a quick swab over the part with a cotton tip dipped in the clear printer resin, couple of seconds under the UV light, and it's as good as, if not better than any superglue bond. I've also used it to fix a broken plastic shelf in our refrigerator that cracked around the little stub that holds the shelf in place. Nice and clear like the shelf, and has held up in that environment now for over 6 months.

You can use it to cover parts for a gloss finish, and you can cash with it but I wouldn't go too thick with the parts if you're casting. It's very heat / over-curing and heat sensitive, but once set, come up nicely.

The third option and the one I would honestly recommend is the 2 part resins. Not all these are created equal either. The best one to use is made by a company called Alumilite. They make a range of clear resins that are extremely durable, and very easy to mix (typically 50/50), and will last a very long time if stored in the cupboard. I have some bottle of Alumilite Clear on my garage shelf, have been there for around 5 years and still are clear to look at.

To really avoid the yellowing and breaking down of the resin over time, it would be worth considering the intended / end use of the resin. Many of the Alumilite resins are designed for wood working, pen making and other professional / serious hobby applications.

The ones for pen making in particular are extremely durable and resist any yellowing as they are designed to be made into items that are used and ''abused'' on a daily basis in the case of pens and other trinkets.

Before anyone asks, NO, I don't get anything from Alumilite, no affiliate links etc, I've just used their products for years and have always had consistent results.

To give examples of this, I produce some resin coated woodgrain dash panels for the 1/8 Pocher Alfa Romeo. I covered these in 2 part Alumilite clear, and some of my left-overs sit on the corner of my workbench in the full Australian sun for at least 5 hours every afternoon, and no signs of yellowing at all. A much as I should clean my work bench and move those panels, they have been there for about 2 years and every now and then I pick them up and look over them, almost like a stress ball for me now! They still look as good as the day I made them.

I've attached a pic of the dash panels to show you the finish.

You can also manipulate the pot life, curing times a bit with the Alumilite depending on the temperature of the resin, and the ambient temp. They will also happy take to deep casts.

Here is a link to the Alumilite for interest - https://alumilite.com/search?q=clear

I do apologise for not giving perhaps a better answer, but if you let me know what you are wanting to achieve, coating, shallow casting, deep casting into a mould, and the part, I'd be happy to give you a bit more of a detailed explanation of how I would go about it.

I have cast resin in 2 and 3 part silicone moulds, pen making, polishing, and of course messed around with all sorts of resin with the 3d printing and other random applications so while I still don't consider myself an expert at all, I am happy to share what I know.

[Gilles]

Thank you very much to both of you for these detailed answers.

I think that I will not take any risks and settle for transparent two-component resin (I retain the Aluminite brand).
My use will mainly be on the meter windows and covering some decals like the one in the center of the steering wheel.