One material used to make furniture, especially bathroom and kitchen furniture, is MDF. There are factories that use only MDF boards in their production, which they process and cover with various colored finishes. MDF is a material wood derivativehomogeneous and easy to machine. With a well-chosen finish, it is possible to create special furniture, which to the uninitiated may look like solid wood. So fool and I'm the guests with kitchen furniture made many years ago. That's why in the following I will say what I think is important when finishing MDF.
Choose quality MDF
MDF boards are made from wood, like chipboard. But they are denser and more homogeneous than chipboard. In short, MDF boards are made by hot-pressing a material obtained by partially removing the lignin from wood and then spraying it with an adhesive. The adhesives used are usually ureoformaldehyde (urelit) and this involves formaldehyde emission, that persistent and pungent odor. To avoid problems with these emissions, I recommend that you do your homework when buying MDF boards and do not choose on price alone.
In recent years, due to restrictions on formaldehyde emission, materials that reduce formaldehyde emission (free formaldehyde scavengers) have started to be used in production, or even ureoformaldehyde adhesives have been replaced by formaldehyde-free ones. Indeed, MDF made with such materials is more expensive, but this avoids the problems you may have with customers because of odor.
Another problem MDF boards can have is porosity. Sometimes cheaper, low-quality MDF can have tiny pores that are invisible to the naked eye, but appear as tiny pinholes in the film or tiny air bubbles trapped in the film (this is air that escapes from the board and cannot escape from the film). These flaws are spread all over the surface, but not uniform. Finishing MDF is usually done with white primer, making the bubbles even more visible. To avoid such a problem it is a good idea to use a sealer as a first coat. This will create a protective layer and seal the MDF board, preventing air from escaping from the pores. It is an operation that can save you many problems later.
Finishing tips
The insulator is also good to use if the MDF board is mechanically processed. It is precisely this milling that makes MDF furniture look like wood. This can be used to reproduce the doors with a door leaf, frames, crown moldings and cupboard tops.
Finished with pigmented products or skated In a believable way, with well-chosen products, MDF can be the perfect choice for a vintage kitchen.
Milling the boards gets into the inner layers where the MDF lacks the surface hardness. The milled area is softer and absorbs more material. The loose fiber, coated with primer, will make sanding more difficult and sometimes more primer will need to be applied to get a quality finish. The problem is solved by applying a coat of insulator.
photo source: autohaus-fleisher.com
photo source: homenk.com
Sanding is very important
Milled areas should always be sanded before applying finishing material. Polishing is done with 180-220 grit sandpaper or medium abrasive sponges. This reduces deep absorption and fiber lift.
Sanding between coats is very important for a quality finish, especially if it is glossy. It is sanded with 280-320 grit sandpaper for matt finishes and over 400 grit for glossy finishes. The gloss will magnify any surface defects, and any small ripples from sanding with coarse sandpaper will show up as scratches on the surface of the furniture.
Use quality paints and apply them as instructed
Always check sample color before application. It is much harder to repair afterwards. Also check how well the paint covers. If you will have to apply 2-3 coats for good coverage, the final color will be darker. A more expensive paint is preferable, but one that has a higher paste content in the composition and covers better with fewer coats. The offer now on the market has colored paste content between 20 and 30%. It's best to ask first and choose the one that suits you.
Using a good product is not enough to achieve a quality finish. Working conditions, thinnerThe use of a catalyst other than the one recommended can significantly alter the appearance of the film. In a dusty environment it will be impossible to get nice glossy furniture without polishing the surface to remove impurities trapped in the film.
The wrong choice of thinner can cause the film to dry too quickly, before it settles properly or air can escape. This is what happens orange peel or rough appearance.
The wrong catalyst can greatly change the gloss level, turning a gloss varnish into a matte one.
photo source: forums.shoryuken.com
photo source: aliexpress.com
I hope that these few ideas on choosing and finishing MDF will help you achieve a beautiful, well-finished piece of furniture.
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Thank you!
With pleasure! 🙂
Hello,I bought a children's bedroom with painted MDF fronts.I asked questions about the MDF paint and I was told that it is lead-based.Then there is the problem of formaldehyde which I understand is gradually eliminated over a period of 5,10 years.Considering that it is a children's bedroom,what do you advise me to do?Should I give up the bedroom?Thank you.
Hello,
For children's furniture there are special requirements. Formaldehyde emissions must normally be very low and the paints used must not contain heavy metals (including lead). The manufacture of paints containing heavy metals has long been banned in the European Community. Now, it depends on where you got your furniture from and how well the manufacturer of the furniture complies with the requirements. If the smell of formaldehyde is strong and persistent, I would find another use for that furniture and remove it from the child's room. It is best to ask the manufacturer for more information.
All the best.
The manufacturer's representative said, when I asked for a certificate of conformity, that their paints contain lead, that they are thinner based and I panicked pretty badly.In your experience, how long are the furniture pieces toxic in this case?
Thank you very much.
It also depends what kind of paints they are. For example, polyurethane paints, once the reaction is totally finished (max 2 weeks) are totally inert and no longer a problem. But I'm still surprised that they still use paints containing lead. But you should know that for years these paints have been used. Lately paints containing heavy metals have been considered dangerous. And as you can see, they are still being used. The lead content of these paints is not high, and we are not talking about emissions, but about the possibility of the paint getting into the child's mouth, coming into contact with the skin for a long time, problems like that. Much more dangerous is formaldehyde. If the formaldehyde emission is very low I don't think it's a problem. Is the furniture for babies or is it something like youth furniture?
I will ask for a quality certificate and if you don't mind I will keep you informed.Good evening!Thank you very much.
Very interesting article, thank you! I'll have to look for a furniture manufacturer that follows the manufacturing procedures for children's furniture too. Maybe I'll find it at the Expo Top Construct.
Hello,
I hope this is not offtopic.
For baby furniture, if you are a distribution company, you can contact me.
Hello! I have a small personal joinery workshop and I want to start making my kitchen furniture from MDF.
I can't find the MDF insulator anywhere, can you recommend where I can find it? Thank you!
Hello.
I don't think you'll find insulation in regular DIY stores. You can find it at companies that sell professional wood finishing products and at their distributors (Sirca, Ica, Renner, Milesi, Sayerlack, etc).
Good evening! I also have a question related to mdf, if someone can help me.Recently I was proposed a collaboration with several photographers who want mdf bales for sublimation.Does anyone know what paints, varnishes are used for this process? Thank you in advance!
Hello.
I have not come across this topic before and that is why I had to research it. It seems that polyester paints or varnishes are suitable for sublimation because they retain the sublimated paints on the surface. I also found references to paints or varnishes used for cars.
You can find here more information.
All the best!
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Hello,
The person from whom I got the offer of MDF furniture told me that he uses water-based paints.
1 - Do you have any idea if they are good or not?
2 - Could you recommend a good / very good brand of paint / primer that does not smell over time?
3 - Is one coat of primer, one coat of paint enough? or should more than one be applied?
Thank you very much!
Ovidiu
Hello.
1. Water-based paints are good and have been used for some time for painting mdf. Their advantage is that the furniture will not smell of solvent immediately weeks after painting.
2. It is best to use professional products, i.e. those used in factories and made specifically for such applications. Some of these brands: Sirca, ICA (Lomilux distributor), Renner, Sayerlack, Milesi. As I said above, water-based paints have no smell after drying.
3. Not enough. Minimum 2 coats of primer, sanding after drying to obtain a smooth surface and a final coat of paint.
All the best!
Good evening! I have a kitchen cabinet with glossy red fronts made of mdf. I'm sorry I chose this colour and would like to paint it myself. Can this be done at home? What products should I use?
Good evening!
It can be done, but with a lot of work.
You can use ordinary water-based paints. Before painting the furniture, it is essential to sand it, otherwise the new coating will not adhere.
Sanding is done lightly, without removing the existing coating, with 280 or 320 grit sandpaper or fine abrasive sponge. After sanding the surface will whiten and a red dust (like furniture paint) will result. Dust and brush on the first coat. Allow to dry and apply another coat.
You can also do it without sanding if you use Annie Sloan-type chalky paints. But they must be fixed at the end with wax or varnish. As it is a kitchen furniture, it is better to use varnish, not wax, it is more resistant.
Below are links that may be helpful.
All the best!
https://revistadinlemn.ro/2020/10/29/ce-trebuie-sa-stii-daca-vrei-sa-revopsesti-mobila-sau-usile-de-lemn/
https://revistadinlemn.ro/2018/01/23/vopsele-cretoase-annie-sloan-chalk-paint/
https://revistadinlemn.ro/2021/02/11/vreau-sa-pun-in-baie-o-comoda-veche-ca-suport-pentru-chiuveta-ce-trebuie-sa-fac-sa-reziste-la-umiditate/