I have been having some issues with the paint at my glue joints on doors being visible and some times slightly cracked. We spray with primarily ML Campbell lacquer and Ben Moore Advance depending on the job. More lacquer lately. I only use TB-1 on all my door and face frame glue ups. Try to let sit for 24-48 hrs. before sanding on my widebelt. Iv'e been told there is still some water in glue joints and after 48 hrs the water level diminishes which should eliminate the "slight" visible glue joint. But now I am getting some slight actual cracks at glue joint primarly only in lacquer which I know is very hard. My shop is in New England with many humidity changes. My finisher has always sprayed vinyl primer lacquer topcoats. Would I get better results using a different product or should I just stick with the oil based hybrid product for more flex in the topcoat?
Tired of doing what I perceive as a very good door and then get call back that my doors are cracking and it's always only the paint line.

I have found this to be inevitable. Sometimes it happens quick and sometimes it happens after several years. This is just the nature of wood expanding and contracting across its grain in two different directions. I this is not joint failure, and this is exactly what I tell my customers. MLC agualente primer tends to shrink over an extended period. Most who want to avoid this are switching to one piece mdf doors for paint grade. I have discussed this with another local painting contractor, and he says that they minimize this by waiting at least two days between primer and top coat. some people also smear 3m glazing putty over every joint before their last sanding step

Is there something to be said that using an oil hybrid ( Advance ),
or old school oil (Satin Impervo) would have more flexibility / "stretchability"
than lacquer thus allowing some wood movement and maybe solving some of these problems? What about priming in oil instead of vinyl?
I know wood will always move but trying to solve this issue.

I've never had a problem.

TB1 is the best because you don't get creep since it's hard. Did you glue get frozen at any point?

Use plenty of glue. Make a mess. Leave enough that you have to sand it off. Do not take a wet rag and wipe off the excess.

We've been gluing in plywood/mdf panels for 40 years. That definitely prevents panel cracking. Do you pin your doors?

If your face frames are glued/pocket screwed and glued to the box they should not move.

We primarily use MLC Aqualente primer, never had any issues with it shrinking.

Spreading glazing compound on things would definitely cause telegraphing.

Adam it happens all the time with all kinds of coatings. Wood moves. if you do everything reeealllyyy well it will take a long time(years). If the coating was rushed or the furniture was exposed to high and low humidity then it can happen pretty quick. I had a Job last month (coated with agualente primer and topcoated with GF Enduro Poly) that had hairline cracks because there was a heat register blowing directly on the cabinetry. Its not actual cracking of the Joint, its a hairline crack in the paint from wood movement. as for the putty im just regurgitating information, I dont do it myself but Im imagining that its sanded well enough not to telegraph

Makes total sense. I always leave my Bondo or wood filler proud to accomodate shrinking. Why would I not let my glue harden in the joint and sand later. I have typically wiped excess glue off joints with the assumption that if I wait 2 days and remove 1/32" from both sides I would be beyond any shrinking area. I still feel using oil based products instead of lacquer could help with slight movement.

Jonathan,

He’s talking about pervasive cracking. You are talking about specific incidents(heat register). Obviously that increases the chance of cracking by orders of magnitude.

I’m talking about zero cracking. We’ve been making and finishing our own stuff for thrifty years. We get almost zero cracking in painted cabinets. This is all high end beaded inset stuff. The Builder, customer or I would accept cracking.

We only build 5 piece doors out of soft maple with glued in mdf flat/raised panels.

Adam He said sometimes cracking. If you make your own doors you can glue the snot out of them and get pretty close to perfect. If you outsource your doors this is a fairytale. MLC Agualente primer has been around for about 15 years? I would question whether or not your jobs show any wood movement over the 5 year mark. I have cabinetry here that was done 22 years ago in all oil enamel, and even they show wood movement and hairline cracks here an there. This is why there is a big swing toward 1 piece mdf doors. Who knows how long the doors will last..., but they wont crack the paint.

To Troy, if you want to continue making 5 piece doors you need to do as Adam says and GLUE EVERYTHING. It would also help to stick with a homogenous coating system. Ask your MLC supplier to set you up with a more flexible primer and topcoat combination. Putting WB/Hybrid enamels overr lacquer primer works but isnt Ideal. Also I let the doors rest over night after priming when I can.

Jonathan / Adam,
When you say glue EVERYTHING do you mean apply glue in panel groove thus gluing the panel to stile and rail? 95% of my 5 piece doors are either 3/8" medex rabbeted into groove or 3/8" medex with corresponding veneer pressed both sides then rabbeted into groove. So therefore I never saw a need to glue in panel but allow the panel to "float" so the wood has a slight amount of room to move. Obviously the rare order for solid panels would never be glued to allow for expansion.

if its medex or mdf glue it

Troy,

I never use medex. We use 3/8" Plum Creek super mdf and back cut it. 5/8" Plum Creek for raised panels. Many years ago we would use 1/2" cabinet ply for flat.

The panels are glued entirely into the groove of the stiles and rails. If you think about it the wood expands away from the panel(the entire door gets bigger or smaller). You use a glue bottle with a smaller tip and run it down the face side of the groove. You only need glue on oneside.

We get zero cracking around the panels. People on WW talk about caulking panels to prevent cracking. Its a waste of time and gives you sketchy results.

If we use timber panels, we put a little dab of glue in the groove in the middle of the panel. This replaces the pinning. High end doors get no pins. We leave them in the clamps a bit longer so we don't have to pin the rails.

Jonathan,

I’ve got a very expensive kitchen I built in 2007. I see it a couple of times a year.

Inset beaded FF. Small applied moulding doors. Those are typical 5 panel soft maple/mdf with a 1/2x3/4” soft maple moulding glued and fixed with a 23 gauge pinner.

The finish was MLC Polystar with their Polystar primer which smells & tastes just like my favourite Aqualente primer.

The kitchen has huge exposed ends crown, appliance panels, etc.

Thousands of potential cracks. I’ve never seen one since 2007.

It is possible. Use lots of glue.

Adam, I would disagree with your statement that you should entirely glue an mdf panel into a wood frame door.
The issue the OP is having is at the stile and rail joint. The groove on the rail shouldn’t be glued to the panel. By gluing it, it will force all movement outward, making the glue line much more pronounced.By not gluing it, the rail can expand both outward, and inwards, splitting the difference. Gluing the panel to the stile groove is fine, as the stile expansion is all outward due to the rails.
Another thing to consider is mdf does move alittle. Most cabinet doors are 24” or less wide, so the panel is usually less than 21”, not enough to worry about moving. If you have a tall pantry door or frig panel, sometimes the panel is 80” or more tall, a fully glued in panel will push alittle extra on the rails, stressing the joint, making the glue line that much more visible. Remember, mdf moves equally in both directions, unlike wood.

Most of the homes I work in have large fluctuations in RH from summer to winter. Perhaps the ones you work in do not.

Matt,

We've been gluing mdf & ply panels into cabinet doors in the New England for over 30 years. The climate of humid summers and dry heated winters has as wide a range as you will find. We have done many many full height fridge, end, and pantry panels.

You are writing theoretically. I am talking reality. Your theory is wrong.

It prevents doors cracking. Believe it or not.

I don't know, whats going on with what you're doing, I don't have these issues with my work. I don't do a lot of face frame cabinets, but when I do they are mortised not pocket screwed, and my doors I never glue the panel and I don't have the issue, I run them through my timesaver and then I prime and spray, I don't use Campbells products anymore, since sherwin Williams bought it out it went to crap, I use an other product line which I have found to be the best I have ever used.

Adam , why not help us all out and let us know the Product Line so we can have the same amazing results. Thank You for your help.

Adam,

I am not “writing theoretically”. I am not sure why you would assume that.

I do have some experience with the New England climate. I would expect it to be a tough place to build modern wood products. However, I would say my hometown in northern lower Michigan, on the east side of Lake Michigan, gives much higher swings in RH than the areas of New England I am familiar with. We have similar winters, but a more humid summer, coupled with the inherent ground dampness(old swamp areas and natural springs), and people having their windows and doors open enjoying their summer, I would say I’m working in a much tougher environment, at least when it comes to swings in RH.

Perhaps you are writing ignorantly on the that topic? Or possibly your reality is not the same as mine.

I would like to ask you, what share of your projects are for city dwellers, or are new construction, which is more likely to have better regulated moisture inside the home or apartment? Does that contribute to you having less problems with stile and rail joint lines showing? I personally have much less of an issue on the work I do inland, on new construction.

I’m not saying I have cured the issue, but am getting better at minimizing it. I am always looking for a better way to build cabinet doors. I’m glad you are having so much luck with your process. Your amazing success is why I questioned it, to see what variables there might be. The suggestion I offered was a good one I felt. It was not based on theory, nor incorrect from my experience.

Everyone has different factors driving the experiences that help formulate how they work and build things. I can only imagine what someone in the Pacific Northwest experiences in their building environment

My suggestions are rooted in education and experience. I am wise enough to know that what works for me, may not always work for another person. Environment, shop setup and tooling are what i have found to be the biggest variables when applying other peoples suggestions to the way that I work.

Matt,

My apologies for being a bit blunt. If you read your previous post, it comes across as that will not work.

You don’t “believe” it works. I know it works. It will work in your climate/environment as well.

I encourage you to do a couple of test doors. See what happens over a few months. Let us know.

I encourage you to

Scott,

The issue with doors/panels cracking is a fabrication problem not a coating problem.

We primarily use MLC finishing products. Mostly waterborne and 2K solvent as needed.

My apologies to Adam, this question should have been to Adam C.
Please let us know what product line you found to be the best. I'm sure it would greatly reduce our finishing headaches. Thanks

Thanks guys. Been away for a few days. I think I will try some test doors using the great advice from all of you and see what results I get. I had asked earlier in this discussion if anyone had an opinion on stile to rail movement resulting in slight paint cracking being minimized by avoiding pre-cat lacquer topcopats and using a more " flexible " oil based /WB product? I unfortunately have my finishing done for me and to be totally honest don't have the full knowledge of different products and there pro's and cons. I do know I did a high end kitchen finished with Ben Moore Advance 16 months ago and recently visited my client for another project and carefully looked at my door stile to rail joints and they were beautiful. Another job I did 12 months ago in pre-cat lacquer and after inspecting those same stile to rail joints and there is some slight paint cracks from movement. Same door making process on both. Just different finishes.
My door panel to stile/rail edge I get very little cracking but when I do again maybe I am crazy (yes at times) but it seems to be in lacquer not Advance.

I agree with Adam, lots of glue, we use Titebond 1, put lots on and glue all the mdf panels in as well. There is no movement in mdf, if that is moving you have way bigger problems than with your doors, you should also be looking for mold everywhere.
You do not glue solid wood panels as they move. That is where you use your space balls.
In another forum Karl mentioned some good tips about tooling and techniques for building doors, that is very important. I use Royce shaper cutters and everything fits like a glove.

I would like to hear what products Adam C is spraying.

Cost of project, and being beaded inset have zero factor in wood movement. Mortises help, double gluing helps, using wood that is the right moisture content helps. But it all just helps. I cant believe that in 30 years of making cabinetry Adam has never seen any wood movement. We do a lot of outsourcing of doors, which means we have no control over the amount of glue used. Ive sprayed every waterbased product that is available in my state, and while some do better than others ive never seen ONE that is 100%. The ones that are flexible enough scuff and mar too easily, and all of the harder ones want to crack if the wood moves too much.

To Troy, if you are spraying solvent based I would tell your MLC distributor what your issue is, and see if he/she can offer you a more flexible system that go well with each other. If waterbased, the agualente system is pretty good, but as I stated before let the primer set and shrink if you do more than one coat of it
We Purchased a CNC last year and are beginning to move over to 1 piece mdf doors so that we can use harder faster drying products that are more prone to cracking on a 5 piece door

I would say that out sourcing doors would create quite a bit of variance and more problems for you. There is lots of companies that build fantastic doors and lots on the other end of the scale as well. That would be a trial and error thing with you trying out the different companies.

I think not having any movement in 30 years is just a blanket statement, anyone in business that long has had the odd issue.
I know a guy who has a 10 year warranty on his doors and finishes. In the last 15 years he said he had 2 jobs where he ended up with a few cracks and had to replace some doors.

As for your comments on MLC Agualente, that is a water based lacquer much the same as the solvent based Krystal or Becker Acromas acid based lacquers, everyone has a similar product. They are not a great coating with a ton of solids . However they are cheap and economical and generally easy to apply, thus very popular.

Jonathan,

Scott explained my experience correctly. To the best of my knowledge, I have not seen cracking in our work that could not be explained by something other than “wood movement”.

Does the very rare face frame crack when the installer drops the box. Sure.

Our doors do not crack. Our face frames don’t crack.

They didn’t crack when they were shop primed/field painted in the 90’s. They didn’t crack when we sprayed solvent in the 2000’s and they haven’t cracked since we switched almost exclusively to waterborne around 2010.

If you want cracking in painted doors, buy solid maple ones that are put together with little glue (makes a mess for the door companies) and assembled with space balls.

I believe glueing the panels in makes the panel structural. That significantly prevent cracking caused by slamming with floating panels.

How much of the cracking is caused by true wood expansion/contraction or by physical cyclic opening & closing???