Sealing models with acrylic varnish (experience reports)

In the last months I asked the question about sealing models with varnish in some threads and also pm'ed to some users here. Some of you recommended using clear spray paint, applied carefully in thin coats. There were also brand and product recommendations from you. Thank you very much!
Unfortunately some of these products are more on the US and not the european market (but maybe I did not search thoroughly ). Me not using Amazon also kind of limits the available or easy to find products.

I finally gave it a try, bought a spray varnish and also tried my brush varnish/paints again.
@Rhaven Blaack encouraged me to make a thread about my experience and this I will do now here. Thanks Rhaven!

Because I am currently working on many things parallel I did not have the time and money to try out many products and techniques. In the future I may add reports regarding different techniques, brands etc. here in this same thread. I am also inviting everyone of you, who has experience with that or even does it on a regular basis, to post detailed reports/tutorials here.


I am planning to show my experience on specific brands/products and was wondering if that could violate the forums rules regarding advertisement. But I don't think so. My reasoning behind that is I got the impression every brand/product behaves different during the application, even if it should be the same type of product. There are variations in composition/ingredients etc. (e.g. ratio of varnish and water during thinning out before paper starts soaking and bending). Because of that I can only share detailed experience with the specific products I tested. This way it is possible to warn about not suited products, too.
That's why I hope it is fine to share specific brands/products here. Please tell me if not.


I hope this thread will help people who, like myself, are new to the sealing of models with varnish/clear paint. Before I actually tried my hands on it I searched the tips and tutorial forums here on zealot, but did not find detailed infos about it, just some mentions. Like I wrote in the beginning, others of you recommended techniques and products in some model build threads and where I asked the lasts months. But I think it would be nice to have these infos gathered here in the tips forums in a more condensed and collected manner. For example in this very thread here.

As for me, I hope I can post my first experience here tomorrow, since I still have to write the text and now it is already past midnight again

Spray varnish #1
Vallejo Premium varnish (satin)
The idea of just spraying the coating on the model is really tempting, especially if you consider models with more complex shapes and many fragile greebled details. I got a few brand recommendations from you people, like krylon (US) or colorgin (Brazil), which apparently lead to good results. I live in Germany and limited to the european market if I want to avoid customs and extra shipping around the globe just for my needs. Also boycotting Amazon out of conviction ... yes I'm limiting myself here a little bit

A while ago I started painting plastic models and so I just ordered a spray varnish from a brand I have good experience with their brush paints. Reasoning: if it is good for minis it may be good for paper models.
I tried it on my little Serenity model and on some printed sheets, because there are these two techniques basically: sealing the model after assembly or sealing the parts before.

A few things to consider when using spray paint (or what I have read about it):

- shake well; obviously
- avoid applying in cold environments; I read (here it is winter -> do it indoors)
- go for thin mist-like coats; -> few people here stated that and it makes sense. You don't want to soak the paper and you want to avoid "frosting". Frosting occurs when you apply varnish too thick and it will create milky, slightly opaque layer after drying out. That's why it is recommended in miniature painting to go for thin coats when brushing. With plastic models it is no problem as you can thin out the varnish with more water and apply multiple layers successively until you've reached your preferred sealing thickness. With paper models on the other hand you have to avoid soaking the paper because it could warp. Regarding spray that means careful quick bursts
- spray from a specific distance; -> to achieve the right "aerosol density" and distribution to settle on the paper, I guess. That means experimenting to find out the right distance for each product as they probably all behave differently.

The results with the vallejo spray varnish were terrible, unfortunately. I waited a whole day after shipping arrival because the can was freezing cold to the touch due to delivery during winter here, I guess.
- I shaked it well
- I applied it indoors
- I tried out different spray bursts, really short ones, short ones, longer ones ...
- went for different distances, like really far away (almost 1m, the aerosol plume is quite focused even at this distance with this specific can) to really near the object (20cm something)
- I tried out holding the can stationary and with moving arm, too

I don't know, I tried almost everything I could come up with that day but I encountered at least two major problems and maybe a third but I am not sure it is because of the spray:

1) there were small white dots and flakes on the coat everytime. No matter what technique I used. I could kinda wipe away or smear off these dots before it dried out but they eventually appeared anew.
I hope you can see that in the pictures:



2) problem is the awful smell. It is unbearable for me. And believe me: I am the one with a bad smelling sense. If someone asks "do you think the food is spoiled. It smells not good anymore", "do you smell that? somethings on fire?" - I often have a hard time to make out said smell.
But that spray smells really strong and terrible. It is winter so I had to do it indoors. I have no garage/workshop, just an appartement...
The smell stayed on the testmodel and on the printouts for at least four days and even now, if I hold my nose on them and take a sniff I still smell it.

3) the next day I could tear of the parts of my serenity with ease!!!! (the model assembled prior to spraying) The glued joints came right off without much effort. Once again I lost a Firefly-class...

Regarding problem 1)
I may did something wrong during application. The reviews on this product at the online shop did not mentioned these small white dots. This specific problem was mentioned in a review of another brand and because of that I did not bought from the other brand, funny right?
Maybe it has something to do with it being satin, not glossy but a little bit matt. Maybe the stuff that makes the finish matt did coagulate/came together somehow, resulting in these small dots. If I went for the glossy spray I may not encounter this problem.

Problem 2) on the other hand was so much a problem that I will keep my hands off of that specific product. The smell actually was mentioned in some reviews of it. But other reviews said it is not soooo bad. (btw. where is the vomiting smiley?)

Problem 3)
???Why did the glue came off???
In the evening that day I banned the test subjects to the outside on the balcony because they smelled sooo bad At this point the varnish was dried out. I could touch it with the finger, the finger got stinky but it was dry apparently.
I see three things here: the spray with its compounds, the glue I used and the cold temperatures outside (I think it was a little bit below freezing temperatures that night).
Could something or all of it cause the problem?

Conclusion:
Perhabs I did something wrong and you can see it in the description of my application method. There are people here saying spray can lead to good results. I may just grabbed the wrong product. It is a big market I guess. If you have good experience feel free to write something about how you apply the spray and how to not. It was my first try with spray paint and that's why I cannot write much about the technical aspect.
But because of the smell I say: Don't use vallejo premium varnish spray. And the breaking of of glued joints is also I mystery to me that I don't want to encounter again.

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That's my first entry regarding this topic. I hope I expressed everything clearly and understandable. I will not say I personally abandon spraying. But after that disastrous attempt I tried a acryllic varnish for brushing and it came out with excellent results (fun fact: varnish product of the same brand). I will do a report about that the next time and there I can actually say something about how to do it properly and what mistakes you have to look out for.

In the meantime, everyone, feel free to contribute here with reports, tuts and tips. Let's create an extensive and comprehensive collection about that topic (especially for people like me who tend to overthink even quite simple tasks to an absurd degree, lol)

Revell-Fan said:

Yo, this thread is a great idea! I live in Germany and do not have access to many product from overseas, so it's particularly interesting to see what the German market offers. I have stayed away from sealing my models because I always fear to lose them during coating. But finding a way which works could be a tremendous game changer. Do you use inkjet or laser printouts for the tests?

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I just own a laser printer and when I bought that printer last year I started paper models again. I just use this printer and it is a rather cheap one. Someone few months ago mentioned cheap ones may not use so much heat to burn in the toner (or something like this). Perhabs it was you @DanBKing , since you said to me wet fingers and water is not the problem causing the loosing of the print. It is more like it gets scratched loose through by simple touching and folding it, due to cheap printer. Short time after you made your excellent watershaping tutorial.
But I am okay with the prints my printer is doing for me. Don't have money for a better one, just for paper modelling

micahrogers said:

Your problem with the Vallejo spray was temperature, if the ambient temperature is below 55 degrees F (12.7 C) do not use Vallejo, or really any spray.
The white dots are the matting agent (very small particles of Titanium Dioxide) that are not fully dispersed in the binder, shake the varnish more vigorously and for a longer time. A heat gun or hair dryer can be used to speed up drying time.

Vallejo is an acrylic polyurethane resin, use only in a well ventilated area ( a spray booth power vented to the outside if it must be sprayed indoors) if it is taking more than 24 hours for full cure, then it was too cold to work with. The resin cure is an endothermic reaction, that takes heat from the environment.

Most all spray paints now are acrylic polyurethane or acrylic lacquers. I'm in the US so I tend to use Krylon acrylic lacquer as my top coats. I use Vallejo brush and airbrush paints.

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Thanks. That means I could wait for spring or summer here in Germany, if it wasn't for that awful smell.
But by that time I could try out other brands

mijob said:

I use clear varnish from a company called "Action" its very commen in Germany, Belgium and the Netherlands. The spray brand is spectrum.
View attachment 223889

I have used this paint outside with different temparatures 10 to 25 degrees and left the can inside between spraying the layers. I wait 10 min. before aplying a new layer. I use 5 to 6 layers of spray on my models no warping, color runs or glue problems.

After spraying my models turns out feeling like a plastic kit. So for me this is a good spraying paint to use.

View attachment 223890View attachment 223891

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I recognise this spectrum logo! Thanks for the tips on how you use it. That's what I wanted to achieve with this thread. I know application methods can sound simple and obvious but it's always some small details which count and I am sure there are others like me, who tend to overthink stuff instead of trial and error until it works (and why waste so much prints and models in the first place *sobs, looking down on broken Serenity parts*)

micahrogers said:

Okay I told you it would be a quick test...
raw plaque folded and glued from my last build (no top coat).
View attachment 223881

The varnish used is Vallejo Gloss Varnish # 70.510
View attachment 223882

and brush painted gloss finish...
View attachment 223883

my findings... The varnish does not make the print bleed, but if you use water color pencils to edge color, it will bleed the edge color.

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Thank you very much!
This varnish I also used. I'm goin to write a detailed report about the procedure I did after the failed spray method.
Quick question: did you dilute it or used it right out of the bottle?
For me I found that a ratio 2(varnish):1(water) still worked without soaking and warping the paper I use. More water began to cause problems. I wanted to thin out the varnish with water because otherwise it can get expensive and I feared frosting (but did not encounter)

Brush Varnish
Vallejo Gloss 70510

I did try the brush varnish a few months ago. But I thinned it out too much. Too much water for the paper and the wing of the Viper (siriusreplicas) lost its flat and level surface. I thinned out because in miniature painting you do that (at least youtubers told me )

Test #1

This time I started without diluting. Again I used some fresh printouts and as second test object I used that viper from the first try. The quick test was simply put some varnish drops on a lid, take some with the brush, wipe off again to not having too much on the brush and then paint an even and thin layer to the object. No soaking, no warping, no damage to the printed colors. Nice! I applied 3 to 5 layers without problems and that wing of the viper became really shiny and protected.

I wondered how much I can dilute with water before trouble starts. Because I thought not diluting could lead to a high varnish consumption. Costs, resources and environment. You know the drill.

I mixed 2 parts varnish with 1 part water. Worked good. Multiple layers, just few minutes drying time in between. Nice finish.
A ratio of 1:1 was already too much water. The paper on the printout bended and the hull of the viper warped a bit, round surfaces became weak and could be dented easily (one layer of 190g paper I think).
Btw. I tried the not diluted as well as the 2:1 and 1:1 ratios on both, 120g and 190g papers. Both papers behave more or less similar during my tests.

Now I am asking myself: is diluting necessary? does it really safe varnish? If I use 6 layers of 2:1 ratio, would it be the same if I just apply 4 layers without diluting at all? (if I have done the math correctly now)
But there is always loss of paint. In the brush what I wash out of it eventually (and constantly, because I don't want to ruin my brush), on the mixing palette (plastic lid) and so on. With dilution I may reduce that to some degree. What do you think?

I went for diluting because I feared frosting effect, too (milky, slightly opaque layer after drying out). But that I did not encounter even with a bit too much on the brush and applied rather thick on the paper. Perhabs frosting is not a big issue with glossy varnish?
So it really just comes down to the loss on all those other surfaces during the process.

Advantage of the brush varnish over the spray: no awful smell!

Brush Varnish

Test #2

It was time to really coat a new fully assembled model to complete the test of that brush varnish.
Few weeks ago I assembled the number 86 of the astro racers, legendary wings. With some laminated details. I really like that model.
In the picture below you can see how improvised my working space is everytime. Living in an apartment in the big city I lack a proper working place and switch between my desk, the dining table or in this case the small table in front of the couch.
In the small glass vial in front of the varnish bottles is the 2:1 varnish dilution which I used. The beige lid I use as a palette.


For everyone who is new to brush painting I make that step by step:

- I wet the brush with clear water, then wipe it off on some cloth (I just use an old shirt).
- I dip the brush in the varnish (the dilution in my case) and put that on the lid/palette. There I spread it a little to wipe off excessive varnish from the brush.
- Then I apply nice even layers on the model surfaces.
- To cover some hard to reach inner edges I pick a little bit more varnish and let it flow into the spots. Be sure to thin it out again with some brush wipes as you do not want to let dry out some varnish drops. Also risk of frosting again. Especially if you use matt or satin varnish.
- when you paint colors you have to apply a layer, let it dry and then do the next on top of it. If you do not wait long enough you will clearly see the brush strokes in the colored surface. With glossy varnish it is not so much a problem because it is transparent and you can only really see it, if strong light gets reflected directly. But for a really smooth surface you should wait until it has dried enough to not get scratched by the brush hairs. In my experience a few minutes were enough. During that time I cleaned the brush, and coated the next surface.
- I clean my brush everytime I finished one or a few surfaces. Because I do not want to let the varnish dry out between the brush hairs. For that I just wash it in a water filled glass and wipe it off on the cloth. Then I repeat the whole brushing business.

In the end I built up 4 to 6 layers on the whole model. The brush method surely takes more time and dedication compared to spray paint and here it was a really small and easy model. But if we were not for time consuming and dedication demanding tasks we would not do paper models, right?
Just listen to some music or podcasts and brush away I would say.




EDIT: as you can see I used a black pen between the greebled plates and on some edges. It was a black pigment liner and the varnish did not cause bleeding. I think because it is pigment and not water based like in your example @micahrogers

micahrogers said:

Thanks for your report! I use it diluted but no more than 70% varnish, 30% thinner, I use Vallejo Thinner Medium 70.524 not water.

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Nice, and that's more or less the same ratio, just a few percent off. Do you know what that thinner is made of and what could be the advantages of using thinner instead of water?