n our Facebook Group, the question comes up a lot about the best way to bring shine and a nice glossy finish back to the dried paintings. Acrylic paints can dry rather dull and darker than when wet, but adding back a glossy finish and brightening up those colors again is easy!
For your convenience, here are store links to items we mentioned in this article.
- Varnish: An older form of finish that contains alkyd resin, oil, and solvents (not recommended)
- Minwax Polycrylic Protective Finish: Glossy, matte, satin, or semi-gloss finish that self-levels and smooths out like a resin
- Water-Based Helmsman Spar Urethane: Glossy finish that won’t amber over time
Why ‘protect’ your acrylic paintings?
A protective top coat on your paints can keep off dust and other dirt or marks that could build up over time and discolor the painting. It would also protect it from splashes and create a water-resistant finish, ideal for acrylic paint on wood. That doesn’t mean you should rinse off your painting under the tap if it’s dusty, but a wipe with a lightly damp rag shouldn’t do any harm.
Colors and shine
Acrylic paints can dry rather matte and dull and often look a bit disappointing when compared to how they shine when they are wet. By adding a glossy coat on top of the dry painting, you can really make those colors shine again, and it helps to brighten them up – like a wet-look again.
If your painting dries with a few pinholes or more texture in the paint than you would like, you can usually smooth out the surface by using a self-leveling protective finish. The more layers you add, the less any unwanted little bumps or textures will be noticeable.
What is the difference between a protective finish and a varnish?
You may have heard varnish used as a generic term for any finish, but traditional varnish describes an older form of finish that contains alkyd resin, oil, and solvents and is therefore known as acrylic resin varnish. When applied to surfaces indoors or out, varnish cures into a thin and glossy film with a faint yellow or amber tint, similar to the finish achieved with oil-based polyurethane.
So although we might talk about ‘varnishing’ our paintings to protect them, we aren’t actually using a real varnish to do that. A varnish would be oil based and typically has a slightly yellow tint – not good for our paintings!
On a side note, to complement your Acrylic Pours, I highly recommend using a Cricut Machine (my personal favourite is the Explore Air 2 machine) to design and print yourself beautiful crafts on all sort of supports. Check it out here! Now back to a good protective finish.
What makes a good protective finish for your acrylic paint?
You will be looking for something that has these features in order to top-coat an acrylic painting:
- Water-based (not oil based), with easy soap and water cleanup for your brushes
- Glossy finish (or matte if you prefer – in case of matte varnish, make sure to go for an isolation coat)
- Doesn’t show brush strokes
- Non-toxic (as is the case with acrylic polymer varnishes)
Why I love the MinWax Polycrylic Protective Finish
he Polycrylic protective finish is an acrylic polymer varnish that checks all the boxes for me when it comes to protecting my artworks. It’s easy to use for sealing acrylic paint as well as for sealing painted wood, you can really put it on nice and thick and there are never any brush strokes. It self-levels so it spreads and smooths out a little like a resin. It’s glossy, and it’s not too expensive. I can easily wash out my brush after and it never hardens, making it an ideal medium to seal acrylic paint.
There were questions raised in the Facebook group about whether such acrylic varnishes would yellow so I wrote to MinWax and asked them all about it, and which of their product range would be best for protecting acrylic paintings. They said:
“the only products we offer that will be suitable for use over paint would be the Polycrylic or the Water-Based Helmsman Spar Urethane. Neither of these coatings will amber over time or will harm the paint underneath, which is typical with other polyurethane type products. To apply this product, however, you will need to allow the paint to fully cure (at least 30 days) first. This will prevent the solvents in our waterproof acrylic sealer from reacting with those still remaining in a still-curing paint coating, avoiding the color running, discoloring or hazing. Apply your clear finish per label directions. You should have pleasing results for your painted surface. “
That was interesting advice about allowing the acrylic paint to fully cure before applying the thin coat on top and I think that would be good advice to follow whatever top coat you decide to use. I usually leave it about 10 days and so far (fingers crossed) I’ve never had any issues with this finish.
The Polycrylic comes in matte finish, satin finish, semi-gloss and glossy finish. You can get it in the form of a spray paint (which I’ve never tried) or in various different sized cans. Recoating time is 2 hours and it’s fully dry in 24hrs. So if you are looking for a nice glossy and easy to use finish for your paintings, especially those on a wood surface, give Polycrylic acrylic sealant spray a try. You can get it here:
How To Seal Acrylic Paint: Using Foam Brush and MinWax Polycrylic Protective Finish
One issue I found when using some of the thicker sealants like polycrylic is that when spreading with a brush you will sometimes get brush marks in the final piece. So to solve this problem I use a good quality synthetic brush on varnish instead of a traditional brush. Here’s how I do it:
- Pour a small puddle of polycrylic in a corner of the painting
- Using the foam brush work the sealant outwards from the corner. Use light even pressured strokes. The foam brush should be barely touching the surface of the polycrylic, and try not to break the surface tension.
- Continue until the whole painting is covered evenly
- Clean the brush and dry thoroughly between coats
- Rinse brush in warm water until all sealant is out of the foam
- Lay on top of a cup to allow air circulation to dry the brush before applying the next polycrylic coat
- Make sure brush is completely dry before moving to next coat
- Wait at least 2 hours in between coats and apply between 2 and 4 total coats of polycrylic spray varnish to finish sealing your painting
Once you’re finished you should see a thin layer of sealant covering your painting. Depending on the finish used it should be glossy, matte or another type of finish. Congratulations, you just sealed your painting!