Refinished Kitchen Doors Cracking

Cracking from wood movement is a common situation, calling for good communication with the customer. June 17, 2009

Question
I recently refinished a maple kitchen. It is now a solid cream color and some of the doors are cracking where the stiles and rails join. I stripped all the doors and washed them down with lacquer thinner followed by Methyl Hydrate. The doors were then sanded and a coat of Zinsser was sprayed on (Shellac base) followed by two coats of pigmented WB Lacquer from Sherwin Williams and two clear coats for added protection. There is major expansion/contraction going on and the doors are moving like Iíve never seen before. I am convinced they turn down the heat when they're not home and increase it when they arrive, causing drastic temperature changes in the house. The client seems to think that it is the lacquer but there are no signs of adhesion failure or contamination. I refinish on average 100 kitchens per year and I have never had any problems like this. Even on doors that were in worse shape than these. Any ideas would be much appreciated.

Forum Responses
(Finishing Forum)
From contributor B:
Well, the cracking is from the wood moving. Did you fill the joints with wood filler? Did you use a water wash stripper?



From the original questioner:
I did fill all gaps with a two part wood filler and no water after-wash.


From contributor A:
Take a look at the technical data sheet for the Sherwin Williams lacquer. Note the "coefficient of elongation". This is the amount off stretching the coating will withstand before breaking. It should be a minimum of 60%. If there is no specification, call SW and ask what it is. If they tell you they don't specify it for this product that means that it is essentially 0%, which means the coating won't take much expansion and contraction before cracking. The thicker the coating, the prone it is to cracking. In general, acrylics have lower elongation, urethanes are higher. You can plasticize an acrylic so it doesn't crack, but the plasticizer can migrate out of the coating.


From contributor B:
I do not fill the joints for that very reason so it all looks uniform. What contributor A said is correct, it sounds like you put too much finish on. Also, stay away from putting clear over paint unless its glazed. The clear can yellow and cause problems. If youíre doing 100 a year you don't have time to do it twice.


From contributor W:
I hate it when that happens! I have refinished a lot of furniture and sometimes it does not adhere right. This sounds like it is due to the contraction/expansion problem.


From the original questioner:
I have explained in detail how wood moves but recently I refinished their dinette set and when I brought it back I was told, "I hope the lacquer doesn't crack." In a joking manner of course but it was obviously not a joke. The rest of the kitchen is intact and looks beautiful except a few places that have joinery. What boggles my mind is that after explaining until blue in the face I was told that it's like buying a new car and finding out the engine is not working.


From contributor C:
Having been in the stripping/refinishing business for years, I have run into this problem more than a few times. When I look at a refinishing job now, I try to make note of any cracking at joinery prior to my bidding the job. I then show my potential client these areas and explain to them how wood moves. I then explain that the new finish will not correct this and if changing from a clear wood finish to an opaque finish, this may be more obvious than at present. I also include this into my actual contract and have them sign off. Unfortunately, there is little you can do to correct this problem.