Solarex Brush on UV Cure?

[templelandsguitars]

Hey there folks, 

Once again I've gone down the rabbit hole of finishes! Has anyone had any experience with Solarex Brush On "I Can't Believe It's Not Lacquer" as a clear coat finish? Apparently cures in the sun in about 3-5 minutes which seems a bit hard to believe.

I've been using Ken Parker's method of epoxy and Tru-Oil with great results but anything that offers a faster curing time is always that carrot on a stick. ;)

Any experience or thoughts on this product is greatly appreciated as always.

Regards, 

Robin

[Paul Slingerland]

I used the Solarez for about a year.  Just like any finish it has a learning curve.  It is nice that it cures in the sun.  You probably also need some UV lamps from Amazon.  The Solarez light is too expensive.  I found it difficult to get the finish to lay out flat.  That meant lots of leveling, some burn through and touch up that never seemed to blend.  

The reason I stopped using it is simply that it is toxic as hell!  You can feel your brain cells dying with a chemical respirator.  I even ventilated my area with open windows and a furnace blower to no avail. 

It also peels off like a shell.  Not really sticking to the wood.

I have decided that these toxic finishes are not for me.  Nitro, poly, activated spray cans, Solarez.  

 

I am using Bright Tone or Osmo Poly X.  

I hope this helps. Keep yourself healthy. 

Paul

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[Charles Tauber]

Hi Robin,

I'm in the midst of testing Solarez brush on "I Can't Believe it's Not Lacquer". Here is what I've found so far. 

It does, indeed, cure hard in 3 to 5 minutes in bright sunlight - longer if cloudy or less sunny. It will also cure in 3-5 minutes using an inexpensive, small UV light - part of a $30 kit for UV resin - and a fairly standard UV flashlight, $40. The challenge, for using artificial light, is to scale it: a small light source will take a long time to cure a large area. One can buy a variety of inexpensive UV lights, but they must be the right wavelength, 385 nm to 395 nm. Many of those reporting problems with UV finishes eventually conclude it was the lighting they used. "Recommended" lighting is expensive but even the smaller ones will cure a 2 foot square surface area in a few minutes. Lighting isn't necessary if you can apply the finish on sunny days that are sufficiently warm, which can be pretty limiting depending upon your climate. 

The challenge with applying it without spraying is laying it flat and having no dust particles. One nice aspect of the material is that it is self-levelling, to a point: it won't harden until exposed to UV light. I've found dust a problem. The worst for dust seems to be foam brushes. There is a seemingly similar product called Clean Armor. One of its suppliers suggests using a short piece of PVC pipe wrapped with a specific cloth/rag that is lint-free. I haven't tried the technique yet, but looks promising. I did buy the specific cloths, an odd, stretchy natural fibre. 

They also sell a Grain Sealer/Filler. I've done extensive testing on pore fillers. I like this one very much. Apply it with a squeegee, self-levelling, cures in 3 to 5 minutes, sands very nicely. Even if I don't end up using the I Can't Believe top coat, I might continue to use the pore filler. I tested it on white oak and wenge, two difficult woods to fill. It takes 3 coats, on those woods, but I'm done in less time than it takes for one coat of most other products to dry. I tested with and without the use of the Grain Sealer/Filler. Definitely better result using the Filler. The top coat seems harder than the Filler and doesn't sand as easily. 

Although the test pieces I've done are relatively small, a square foot, I haven't found the smell or fumes objectionable and haven't worn a respirator. (CA glue, for example, can make many peoples' eyes water, headaches, etc. There is a brand that doesn't.)  I found Poly X gave me a headache in a short time. A friend of mine hates the smell of the Bright Tone pore filler, which I found does not sand well and takes many coats to fill pores.

Solarez does not give a shelf-life for their product, claiming it is stable "indefinitely" until exposed to light. By contrast, Clean Armor gives a 1-year shelf-life and cautions that it will not adhere well to certain oily exotic species. The two are likely not the same resin formulation.

Both Solarez and Clean Armor are expensive products but contain no solvents. So, what you put on the wood stays on the wood, unless you sand it off. You don't loose 30 to 70% of what you apply in off-gassing of solvents. At least in theory, that gives a quicker finish build.

I would definitely continue to user their product on other woodworking projects. I've not tested adherence, witness lines, etc. sufficiently yet to commit to using it on guitars.

I'm reminded of Sergei de Jonge's experiences with finishes. He sprayed nitrocellulose lacquer for many years that he said affected his health before trying a variety of water-based finishes that he said were worse. He French polishes these days. There is no perfect wood finish and no free lunch in applying them. One chooses the one that has the least compromises for one's situation and application. There is a lot to be said for shellac, alcohol and wood dust or pumice. It's about the experience you want to have.

Charles

[Robbie O'Brien]

Charles,

Have you tested it on rosewood or other only exotic hardwoods like cocobolo?

Robbie

Sent from my Galaxy

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[Rick Molloy]

I've been using CleanArmour and it is working well so far on mahogany, pau ferro Malaysian Blackwood.

I did buy a big uv light because was having trouble with the small flashlights and outside isn't great in Seattle in the winter.

I've been using kimtech lint free wipes - that I was using on epoxy before.

-Rick

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[templelandsguitars]

Thanks Paul. That's really helpful. Didn't realize the toxicity of this product so that ends the discussion for me. 

Much appreciated.

[Paul Slingerland]

You are welcome.

This is my Osmo finish

This is my Bright Tone finish

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[Paul Slingerland]

This is my Tru oil finish

[Charles Tauber]

Robbie,

I have not tested it on cocobolo/rosewood. But, I'll be happy to do so and will report back in a week or so.

Charles

[Robbie O'Brien]

Thanks. I once used it on a sample piece of rosewood and it wouldn't fully cure.

Robbie

Sent from my Galaxy

-------- Original message --------

From: 'Charles Tauber' via Robert O'Brien Guitar Building Forum <obrien...@googlegroups.com>

Date: 9/21/25 1:50 AM (GMT+01:00)

To: Robert O'Brien Guitar Building Forum <obrien...@googlegroups.com>

Subject: Re: Solarex Brush on UV Cure?

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[Rick Molloy]

Clean armour is quite different than solar ez (no vocals), I'll check as well when I get back first week of October. I haven't had curing issues on Malaysian Blackwood, ebony, maple or mahogany.

I did have curing issues though and when I talked to them about it they said I was putting it on too thin with my wipe on application and so I put it on a hair thicker and it hasn't been a problem since.

-Rick

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[Fred Brooking]

Paul (et al):

I was a tech service rep for an international ink and coatings manufacturer for a number of years. UV cure coatings were our bread and butter. I was in the printing industry for over 40 years.

Simply put , this product “comes off in a shell” for you because it did not crosslink completely. This is a common technical issue.

UV cure product are considered 100% solids. They are made up of pigments, monomers, oligomers and photo-initiators which when exposed to the correct range and intensity of light crosslink or polymerize. It is very easy to undercure UV coatings and even if the coating appears to have hardened it still may not adhere to the guitar.

For the purpose of this discussion we need to understand that even with clear products application film thickness is critical, as is the proper wavelength and intensity of light. Both factors effect our ability to cure the coating. Again think of the light as the catalyst, too little or too much and you have an incomplete chemical reaction and a possible failure.

As a UV cure product begins to harden/crosslink with exposure to light,  it also begins to become more opaque to that light energy. So, it is critical that the intensity of the light (in the proper wavelength range) is enough to penetrate the coating, bounce off the surface of the substrate (in this a case a porous wood) and exit the coating before the coating becomes opaque to the UV. 

If the UV light energy is not intense enough to penetrate the full coating thickness and return, then a top cure condition can be created. This condition means that you have a hard layer of finish floating on top of a thin film of uncured material that may never finish crosslinking.

The problem of light intensity becomes more critical when pigments are added (think pore fillers , or solid colors). UV Cure products that contain black , white, yellow, blue or green pigments can add significant exposure time / intensity requirements to the cure as these pigments absorb UV energy. Remember the light must penetrate to the surface of the deepest pore in the wood and bounce back through the coating film in order to properly crosslink the coating/filler.

In the printing industries for example,  UV coating thicknesses are controlled to ensure proper cure and are ideally in the 8-15 micron range on flat, relatively clean, non oily, non porous surfaces; products that are nothing like the woods used in lutherie.  for comparison purposes spray on UV cure finishes suggest that they can be applied up to 3 mil thick, but must be cured with light in the 365nm range @ 1W/cm2 intensity.  In production environments light energy needs to be focused, controllable and monitored because the coating or film must be exposed to a certain range of energy for a certain duration to ensure a complete cure.

So far we have been discussing coatings on a “flat” surface where the distance from the light source can be controlled , the light can be focused with reflectors to maximize its effect at a specific height from the coated surface and the energy being applied can be monitored by a radiometer that is measuring light at the specific distance from the lamp. Another reason for monitoring output is that UV lamps degrade over time, with some types losing 40-60% of their output after less than 500 hours. So printers and most other industrial users of UV cure products employ a device called a radiometer to monitor the output of their light sources. Modern LED lamps do not degrade as quickly as traditional mercury lamps but the coatings selected must be compatible with the output characteristics of the lamp(s).

Now imagine the chaos created by a three dimensional object with a porous surface , which limits your ability to control the coating thickness, the actual time, and energy application to all surfaces equally during the process. As you can see, the issues that effect proper UV curing on a guitar are compounded by its shape and the materials from which it is made. 

The irregular shape of a guitar, makes focusing light energy more difficult, the natural oiliness  of some woods can act as a surface contaminant / barrier preventing adhesion, the pores make the surface irregular leading to potentially uncured material being trapped under the surface and reducing adhesion. So surface prep becomes another critical factor, some very oily woods and may in fact require another product that acts as a barrier / bonding layer to allow the finish clear to adhere properly.

Adhesion testing on samples is fairly simple procedure called a “cross hatch tape test”. There are many videos on this procedure available online.

All this is why products that advertise/ highlight the feature that they can be cured in the sun present severe credibility issues for me;  and in truth, I tend to view these claims as hyperbolic at best, and flat out deception at worst.

Yes, UV cure coatings will "harden" in the sun.

Unfortunantly none of us can control the amount of uv exposure, and effect a consistent cure, and subsequently good adhesion, by using the sun as a light source.  It is at best an unreliable curing method, at worst it is a recipe for expensive failures. 

Time of day, latitude, season, cloud cover, altitude, air quality (ozone), and solar activity all effect the amount of UV available.  Something that “worked” fine today may not tomorrow, or next month. I put worked in quotes because my definition of “worked” includes not being subject to catastrophic failure  or delamination in the foreseeable future. As a small builder/hobbyist I don't want to spend my limited time and resources dealing with finish failures.

Caveat Emptor. Get the technical data sheets for any UV cure product you are considering,  compare the wave langths (Nanometers) and power requirements (Millijoules of energy) match it with an appropriate light source and follow the instructions from both manufacturers rigourously, control the film thickness and you have a fighting chance of success.

Finally, adopting UV cure coatings is a decision usually driven by the need for high production speeds, and waste stream reduction. There are viable UV cure systems for guitar makers but the ROI doesn’t work for me given the small number of instruments that I build annually. Hope this helps.

I apologize if this is overlong - editing is not my strong suit, "tech dump" is my default setting.

Best 

Fred

[barry...@gmail.com]

Thank you Fred ! Good info here.

In His Name - 

Barry

On Sep 27, 2025, at 2:36 PM, Fred Brooking <fbst...@gmail.com> wrote:



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[Dick Fulco]

Thanks Fred, really helpfull info👍

Met vriendelijke groet, Dick

Op za 27 sep 2025 om 21:57 schreef <barry...@gmail.com>

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[Charles Tauber]

Thanks, Fred, for sharing your expertise. 

My experiences thus far with Solarez have reflected your statements. Specifically, curing using sunlight and/or inadequate UV lighting sources is very hit and miss. 

In the last few days, I've applied Solarez sealer/grain filler to a test piece of cocobolo. The first two coats picked up oils/colors from the wood to the point of turning the otherwise clear resin very dark. That could be a challenge if finishing cocobolo adjacent to lighter coloured woods. The first thin thickness coat went on well and cured quickly. The second thin coat cured in some places and others remained tacky. I put on a heavier third coat, with reference to Rick's experience. It did not cure even after hours in full sun and the use of a small UV light and a UV flashlight. It remained a gooey mess. Cocobolo: fail.

In the last few days, I've attempted to refinish a guitar neck with Solarez. The customer removed the finish on much of the mahogany neck, leaving the heal and head with the original nitrocellulose lacquer. I decided I'd try leaving the finish on the heel and strip the back of the head. The Solarez sealer/grain filler went on okay and cured okay as a pore filler. However, being too large a surface area for the small UV light or flashlight, I relied on the sun to cure it. That was hit and miss. In full, bright sun, mid-day, it cured in a few minutes. In partial sun, 15 minutes to half hour. In full cloud, much longer than that and the need to reposition the guitar to obtain direct exposure. Part of the reason to use a UV-cured finish is speed and ease. The variability of curing in the sun largely eliminates that advantage. 

One thing I've learned from the experience is that without proper lighting for curing, there probably isn't anything gained by using UV finishes. One really needs to invest the $$$ in the appropriate lighting. My purpose in testing it was to see if it could be a viable finish. Probably it is, but I'm not able to fully determine that without investing in the lighting. Having it work only on certain woods, and not others, diminishes its potential viability. 

Charles

[Don Parker]

I'm in the midst of experimenting with Clean Armor, and using their approved Cuvo curing lamp.  So far, it is pretty promising.  The line of products they sell for instruments is the 800 series.  I have tinkered with the sealer, the pore filler, and the topcoat.  No serious problems so far with any of them, but I always start with the sealer, just to be safe.  I will report back when I have more to say, but as of right now, the 800 series of products from Clean Armor ticks a lot of boxes for me.