How we refinished the exterior oak doors of the Pitar Moș church with Kreidezeit pre-coloured varnish

Oil is the option I choose in most cases when I need to finish exterior wood, especially if it's a DIY project. Kreidezeit lakes are among my favourites because they have good resistance over time. More than five years ago I saw the wooden facade of a house on the shore of the Snagov lake being restored and the finish still looks great. The mix of tung oil and linen protect the wood very well against weathering and the high pigment content ensures resistance to solar radiation.

This time we turned to Kreidezeit laziness to refinish some exterior wooden doors. The intricate carving on the surface of the oak doors and the previous finish done with linseed oil in abundance left little room for other options. It would have been difficult to remove all the oil to safely apply a water-based exterior finish. So I stuck with the option I had thought of from the start - pre-coloured oil-based lacquer - hoping that the door cleaning process would not be too difficult. Hopes dashed! 🙂

How I came to be in charge of this "work"

I live near Pitar Moș street, where the church of the same name is located. It is a small and very old church, built at the end of the 18th century. The totally wrong renovation done before 1989 ruined a good part of the mural painting, which led to its not being included in the national heritage. This is why the restoration work on the small church has been slow and often wrong.

Fortunately, for over 15 years the church has had a parish priest who is determined to bring the church back to its former "glory". He has fought hard, talked to everyone trying to gather a community around the church to support his efforts. And he succeeded. The process began many years ago and in the meantime the pews, interior and exterior painting, and architectural lights have been restored. The appearance of the church has changed a lot for the better, which is entirely due to him.

Now it's the turn of the carved oak doors, the double ones at the front and a single one at the entrance to the altar. Knowing what my speciality is, he asked if I could help. I started looking for someone to do the work, but it was impossible to find a craftsman willing to take on such a small job. So I turned to a very good friend, very skilled in working with finishing materials, whom I suggested we redo the doors together. And so the adventure began.

What materials and working method we chose for cleaning oak wood

The first step was to see the actual condition of the doors, the steps and method of working and to get the necessary materials. The doors looked pretty good in terms of wood integrity, but were very dirty and loaded with gummy oil. They had been treated annually, liberally, with linseed oil without, however, wiping off the excess. Linseed oil is not one of the products that can be applied in large quantities to form a film. In thick layers it never dries, forming a very sticky gummy mass that traps all the dust and dirt in the atmosphere. This explains their very dirty appearance.

The next step was to figure out how to remove the dirt and gum. The first thought was water with detergent, but the method was unsuccessful because of the thick coating. Sanding with a sandpaper disc didn't work either, as the paper immediately loaded. A very good solution would have been baking soda blastingbut funds did not allow this. So we decided to use paint stripper, followed by wiping with thinner and sanding.

The last step of the preparations - the necessary materials (which I bought from a DIY store, except for the lye and thinner):

• Paint stripper. Because there was conflicting information about their effectiveness, we decided to take 3 types and see which one worked best. We used Decanol Super/Policolor, Dekapant Gel/Kober and Universal Extra Strong/Supralux stripper.
• Rolls of sandpaper that I used on the drill
• Wire brushes
• Coarse, medium and fine abrasive sponges
• Brushes.

I also used plastic containers, wooden stirrers and cotton cloths. The best wiping cloths are the ones made from old t-shirts. This time, however, I made them out of an old tablecloth and they absorbed very well without leaving lint.

Why it was difficult to clean the wood and how we managed to remove the thick layer of oil

To clean off the thick, gummy layer of linseed oil, I applied the stripper with a brush and after 20 minutes started to remove the soaked layer with a wire brush. The process was difficult, especially because of the carving adorning the entire surface of the doors. I was having a hard time reaching the areas in the second plane and quickly gave up using the sandpaper roll drill for fear of ruining the carving. I stuck with the wire brush, easier to control.

Another problem was loading the wire brushes with gummy oil taken from the door, which quickly made it unusable. Having several, however, we were able to leave the clogged ones in the thinner to clean, during which time we moved forward using a clean brush. For cleaning we used acetone and wash thinner, aggressive enough to make the brush usable again.

Of the three strippers used, by far the best was Supralux extra strong. It acted deeply so we didn't have to go back several times to totally remove the old oil. We also had satisfactory results with the Kober brand stripper, the worst being Policolor Decanol. In the end, regardless of the stripper used, we "washed" the surface with thinner. I used a professional paint thinner, due to the high acetone content which makes it more effective. Washing was done with a brush to get into the most difficult places. In the end the surface remained clean, free of oil gums and not sticky as it was after stripping.

Cleaning the doors of the old, gummed-up oil was the most difficult part of the job. When protecting wood with linseed oil, the excess oil that remains unabsorbed MUST be wiped off. Otherwise it will turn into a gum that retains all the dirt in the atmosphere and quickly spoils the appearance of the protected object.

Finishing with Kreidezeit lacquer

After removing the old oil layer and washing the surface with thinner I sanded the entire surface with a medium abrasive sponge. The surface became pleasant to the touch without being very smooth so it could absorb the grease. After wiping off the wood dust with the cloth we started brushing on the Kreidezeit pre-stained light oak varnish, a colour very suitable for the solid oak doors of the church. The application was done in excess and after 45 minutes, during which time the wood had absorbed as much as it needed, I wiped the entire surface with a clean cloth, insisting on the carved areas so that no hidden oil remained.

The minimum drying time for the lacquer is 24 hours, but we allowed more than that. It's not a problem if you leave it longer, the problem is if you apply the second coat before the first is completely dry. We left it longer because it has been a very hot few days, and it was hard and risky to apply the oil in hot conditions.

After the very hot days passed, we resumed our work. The second coat of varnish was also needed for good resistance over time. In order not to darken the colour of the doors too much, we decided that the second coat should be colourless varnish. The first coat provided enough colour to protect the doors from the sun's rays, especially as they were not directly exposed. The back door is almost never "seen" by the sun, and the front doors, in addition to the protection provided by the tall trees in the yard, have an awning to provide additional protection.

I applied the colourless varnish the same way as the coloured one, with the brush, in excess, then wiped off the unabsorbed oil from the wood with a clean cloth. The waiting time was also 45 minutes. The result was a beautifully coloured surface, pleasant to the touch and most importantly, clean.

ATTENTION! Oil residues, rags and soaked sponges can burn themselves, especially on very hot days and if left in direct sunlight. This is due to the volatile oils in the solvent. To prevent any problems, all leftovers should be placed in empty oil containers and covered with water. Used tools should be washed thoroughly with thinner and then wiped well or kept in water. We also put all the used rags in the empty containers and covered them with water.

In conclusion

Now the doors of the Pitar Moș churches look good again. After the whole process we were left with a good feeling because we were able to do this, but also with some conclusions:

• Oil should not be left in excess unless recommended by the manufacturer (there are oils with film-forming hardener). In general, natural oils do not form a visible film as varnishes do, and the unwashed excess does not dry but turns into gummy, sticky surfaces that attract dirt and dust.
• Oil turned to gum is very difficult to remove, especially if the surface is not flat. It quickly clogs sandpaper and wire brushes, making them unusable. The most effective solution was stripping followed by wiping the surface with thinner.
• The paint strippers used had different strengths, the most effective being the extra strong, Supralux brand.
• For best resistance over time, oil-based varnish is applied in excess, left on the wood to absorb well, then the excess is wiped off. Apply a minimum of 2 coats. At least one of the coats must be pigmented (semi-transparent coloured) to make the finish resistant to UV radiation.
• Oil residues and soaked rags or sponges should be placed in containers of water and covered as they can self-combust.

I will track the behavior of the doors over time and take care of maintenance so as to extend the life of the finish as much as possible. As soon as their appearance becomes duller, without the specific sheen given by the oil, I will apply another coat of lacquer. Lack of gloss is a sign that rainfall has "washed away" the oil and to maintain water resistance another coat needs to be applied. At that point the retouching will be simple, without stripping and sanding, because I have now applied the materials correctly, respecting the working technology.

I hope you find the information interesting. If you have any queries or would like further information, please leave your questions in the space below. I'm sure I'll answer them.