Oil Paint over Mod Podge Collage

Will Oil Paint Adhere to Mod Podge?

I have made a collage using glossy Mod Podge to adhere and seal pieces of fabric.

I would now like to paint using oils over the seal of Mod Podge. Will this work? I feel like the oils are not drying.

Thank you.

Alana

The short answer is "Yes, I think it will work".

Plaid, the manufacturer of Mod Podge specifically designed this versatile product as a glue, sealer and finish for "all porous surfaces".

You're using it a bit differently by putting oil paint on top, but both surfaces touching the Mod Podge qualify as porous, so it should work. In fact, you're using it like a size for oil painting and it is very similar chemically to some of the most popular sizes in current use. Understanding some basics of paint theory may help you assure the proper conditions and desired result.

Although oil paint is a common material, paint technology is complicated science. That said, oil paints are very versatile and will stick to just about any surface.

Two things need to be considered: whether the base and paint are chemically compatible; and whether the base has properly cured before the oil paint is applied. If the first condition is met, all you need is a bit more patience before applying the oil paint.

If the first condition is not met, the oil paint will never cure properly.

How to Cure Mod Podge

Mod Podge is water-based, which means it dries and cures by evaporation. In a room of 100% humidity, it would never cure because no evaporation could occur. There need to be dry spaces in the air for the moisture to leave the Mod Podge and enter the atmosphere. The drier the room's air, the more quickly evaporation can occur.

As well, the Mod Podge needs to be exposed to the air so that it can cure. If you put on the oil paint before the Mod Podge is completely cured, the oil paint won't be able to adhere and the Mod Podge will not cure because of the moisture trapped between.

Allow a week for the Mod Podge to cure; more if the room is very humid.

How to Cure Oil Paint

Oil paint, being oil-based, cures by oxidation. Oxygen in the air is attracted to the oil molecules in the wet paint and chemically combines with them to form linoxyn. The oxidized particles rise to the paint's surface and dissipate into the air.

Four key variables affect the rate at which oil paint cures.

One, the proportion of oil to solvent in the paint formulation: the more oil, the longer it will take to cure.

Two, the thickness of your application: the thicker you lay on the paint, the more oxidation must occur and the longer it will take to cure.

Three, the colors you use: drying time depends on the type of pigments contained within the paint. For example titanium white (derived from titanium oxide) dries slowly but flake white (derived from lead) dries very rapidly.

Four, air circulation: the better the ventilation, the more quickly the oxidized particles will be whisked away.

Oil paints will dry to the touch between one and two weeks after application. Six months is the recommended cure time for oil paints before a varnish coat.

Compatibility of Mod Podge (PVA) and Oil Paint

Finally, as to whether Mod Podge and oil paint are chemically compatible, I believe they are. For oil paint to adhere to a surface, the first coat must be able to lock onto the base material. This is where the more complicated science comes in and I am not a chemist! But, Mod Podge is a polyvinyl acetate (PVA) formulation.

Oil artists who paint on stretched fabric or panels always prep the surface (or buy pre-prepped surfaces). Prepping serves two purposes: it isolates the acidic oil paint from the surface material; and it provides the tooth for the oil paint to lock onto. Since oil paint is acidic, it would eat it away the substrate over time if applied directly.

PVA size is a popular type of size for prepping stretched fabric to receive oil paint while preserving the fabric fibers. Theoretically, the PVA base you used (Mod Podge) provides an appropriate barrier to keep the oil paint from eating the fabric underneath and also provides the teeth to lock onto the oil paint.

I hope the information above helps you create the conditions necessary for proper curing and adhesion of Mod Podge and oil paint. Once you're achieved that, you may want to protect and preserve the bonded surface. Read more about durable finishes for decoupage.

Here are more decoupage articles.