" " wisno wood furniture finishing: Mold problem on M.D.F.

Monday, March 31, 2014

Mold problem on M.D.F.

M.D.F has a wide usage in woodworking industry. It is used lot to make panel, boards and any other flat product replacing the solid wood. As the engineering product, M.D.F actually give lot of advantages then the solid wood. It is more uniform, more stable and less expensive than with a wooden plank. See our previous article : M.D.F. for furniture. But, instead of his benefit, the M.D.F is also has some disadvantages. One of the disadvantages of M.D.F is high risk to get fungal problem.

M.D.F is made of wood fiber, wax and resin. The wood fiber the resin and wax are heated and mixed evenly and then molded forming certain thick boards. The melamine resin is layered at the M.D.F. surface that gives the smooth surface. The melamine resin is the coating layer at the M.D.F. surfaces that gives protection for the product. But naturally the melamine resin also produces formaldehyde gas which is considered harmful to human health. Since the 2000's many countries restricted the formaldehyde for their products. There some regulation that also affect the woodworking product including the M.D.F. product. Now the M.D.F product must not emit formaldehyde gas exceed to a certain threshold to fulfill the environment regulation law in many countries. 

mold at the mdf surface
 The fungi at the naked M.D.F.

The regulation force to the M.D.F manufacturer to reformulated the process of manufacturing M.D.F. They have to change the melamine resin to reduce its formaldehyde emission and this condition also effect to its protection properties. Now we found more issues about fungal problem at the M.D.F product compare than before 2000,s. The mold problem is more often found at the back panel of the woodworking products that use M.D.F. There are many mold of fungi problem issues found at the back panel of top table, side panel, inside drawer, etc. 

The fungi problem is less found at faces panel that are well finished. The face panel that are layered by:  veneer, vinyl, decorative paper or coated with thick film finish usually away from the fungal attacked. The fungi or mold problem issues is commonly found at the unfinished M.D.F. or at back panel as the unexposed part that is layered with thin coating or keep unfinished.
But, however the presence of fungi even in the unexposed part will directly degrade the quality of the product. The fungi will ruin the product appearance and make the product look bad. The fungi also potentially cause health problems because it will generate a dust spore that is spread in the entire room.  
 
Here are some action that we can do to prevent and overcome fungal attack on M.D.F.
  • Clean the fungi at the surface
If we found the product has infected by the fungi, then we need to clean the fungi. Wet cloth with paint thinner or cleaning fluid then wash and rub the surface until all fungi are removed. Make sure the liquid is not solve and ruin the finish layer. Let it dry then do scuff sand to the surface, then apply coating layer to the surface. Add some anti fungal additive into the coating to minimize the fungal problem for film coating. Make sure we apply enough thick coating to give enough protection to the product, but make sure we choose the proper finish according to the product looked.
  • Keep the product to be dry.
The wet and humid conditions are the major factors that prompted the fungus to grow. The wet surface is the ideal media for fungi to grow. One of the best ways to avoid the fungi is by keep the product to be dry. Keep the M.D.F and the product resulted to be dry. Store the M.D.F. product at the air conditioning room or warm room to keep its moisture content under 10%. Keep the room to get good air circulation to keep the room fresh and dry.
  • Apply good coating at the M.D.F. product.       
The M.D.F. is hygroscopic material. The open and naked M.D.F. will adjust its moisture content to its environmental air humidity. We can coat and paint the M.D.F. surface to close the surface and reduce its hygroscopic properties. The coated M.D.F. will be more stable and safer from the fungus. The catalyzed coating as the PU or AC coating will give better protection then the 1 component coating (NC or water based). If necessary we can add some more anti fungal additive at the coating layer to give more protection from the fungal attacked. 
The  uses of water based coating must be carefully done. The water in the coting will increase the moisture content of the M.D.F. and finally lead to the fungi to grow. Make sure the day is hot and dry we we apply the water based coating. If the weather is cold and humid, then we absolutely need oven to control the drying process.

1 comment:

  1. Very well described post by author. I am a writer and also a frequent reader. I have read so many posts but not like this. Simply amazing post. Mold remediation

    ReplyDelete