Can You Apply Polyurethane Over Lacquer?

There are many finish options when it comes to woodworking. You can layer one finish after the other to boost its wood-protecting benefits. However, many are asking: can you apply polyurethane over lacquer? Considering lacquer and polyurethane’s properties, the answer is no.

In this post, I will discuss why it’s not a good idea to top lacquer with poly together with alternatives you can consider.

Can you top lacquer with polyurethane?

Since lacquer is vulnerable to scratches, it seems like a layer of polyurethane is a great way to protect the wood.

Many woodworkers often wonder if they can re-finish an old lacquer layer with a new poly application. Unfortunately, this will not work. Take note that lacquer over polyurethane won’t work as well.

First of all, polyurethane won’t bond well with the lacquer surface. If you apply poly on top of the lacquer finish, it will not dry or harden as it should. Over time, the poly layer will chip off fast, which will strip off the wood’s protective barrier.

If you’re keen to use polyurethane on a lacquered-finish wood, you have to sand off the original finish. This way, you can access the wood pores, and the poly will have a strong grip.

However, there’s one way to make poly over lacquer work. You have to apply a barrier coating before using the poly finish. This will give you better adhesion on the wood surface, though results vary widely. Also, this means additional expense, much so if you’re dealing with a large project.

Overall, if you want to repair an old lacquer finish, the best option is a fresh layer of lacquer itself. Make sure that you sand the old finish lightly to give the new coat a good grip.

Also, there’s no point in putting poly over lacquer because they are two incompatible finishes. Also, with the right number of coatings, lacquer would be strong enough to protect the wood.

If possible, look for a catalyzed lacquer finish. This product doesn’t respond to thinner, which means it doesn’t require additional protection.

What can I use instead of polyurethane?

Aside from lacquer, you can also consider using alkyd varnishes. This is a type of polyester resin with excellent grip, not to mention that it’s also easy to repair or touch up. Another good thing about alkyd varnishes is it doesn’t become yellow over time.

Overall, I recommend a glossy alkyd finish since it matches most lacquer finishes. However, you should never apply lacquer on top of the varnish. This will lead to the lacquer eating up the varnish underneath since it has a higher solvent content.

Which is better, lacquer or polyurethane?

Since poly doesn’t match lacquer, you’re better off choosing just one. In this case, you’re probably wondering which one is the best pick. Here’s my quick take on these two finishes:

Application

When it comes to application, polyurethane is trickier because of its thick consistency. You need to use a high-quality brush, but the technique is more important. This is to avoid brush marks that will ruin the results once dry.

On the other hand, lacquer is a bit runny, so you need a low-pressure sprayer and woodworking respirator to apply it. But once you have the equipment, the application would be a breeze. In conclusion, lacquer is easier to apply than poly.

Finish quality

If we’re going to talk about durability, there’s no doubt that polyurethane is the clear winner. While it’s harder to apply, the result is a strong and durable coating that will protect the wood.

Nevertheless, many lacquer finishes nowadays are also durable. However, this is more prone to discoloration and scratches over time. So if the quality is your paramount consideration, you’re better off using polyurethane.

Drying time

Most woodworkers prefer lacquer because it dries faster than poly. However, it’s also at the expense of durability, so you should choose the trade-off you prefer.

Overall, polyurethane may take a couple of hours to dry, while lacquer will harden in as fast as 10 minutes.

Both lacquer and polyurethane are excellent wood finishes. You have to pick the right one based on the project you’re working on, the turnaround time, and the results you want to achieve.

Can you put epoxy over lacquer?

Epoxy can adhere to the lacquer, but don’t expect a seamless finish. I still recommend stripping and sanding the old finish before pouring in your epoxy. This will give you better hold, and it will remove the scratches that will be amplified over epoxy.

Overall, pouring epoxy over lacquer has varying results. I suggest that you test this on a small piece of wood to see how the two finishes will hold up. This will save you from expensive repairs later on.

How do you protect a lacquer finish?

Many woodworkers usually use poly to seal the wood. But since it doesn’t adhere over a lacquered surface, here are my recommendations to protect the finish:

  • Keep it dry. Lacquer finishes last longer in dry and clean environments. This means it’s not the best finish for outdoor use. In case something spills into the lacquer finish, you should wipe it right away. This will prevent the moisture from seeping through the wood pores.
  • Avoid putting heavy items on it. You should avoid putting heavy items on top of a lacquered surface. Remember that this finish is prone to scratches, and a heavy appliance or décor can scrape off the coating quite easily.
  • Practice regular dusting. Dust tends to show more on lacquered surfaces. It can also build up into hard particles if not removed right away. This is why you should wipe lacquered wood using a lint-free cloth. Wiping will also help keep the lacquer looking glossy.

How do you make lacquer shiny?

One way to make a lacquer finish shiny on wood is to apply at least four coats. Make sure that you sand each one after drying using 400-grit sandpaper. After that, let the lacquer cure for around a week before wet-sanding the surface.

Wet-sanding will help you remove rough spots and other imperfections. Keep sanding until you achieve the gloss that you want. You can also sandpaper grits 800 to 1200 if you do not see enough sheen on the lacquer finish.

My only tip is to be careful when sanding the edges to prevent chipping the finish. Coats usually get thin at the edges, and it’s easy to ruin the project if you don’t pay enough attention to this area.

Conclusion

Applying polyurethane over lacquer isn’t a good idea. These two finishes are incompatible, and you will not get a good result. Instead, you can refurbish an old lacquer finish with a fresh layer of lacquer. But if you’re keen to use poly, you should strip the old coating first. That way, you won’t have to redo the project later on.

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