Caulking Paint-Grade Woodwork
Woodworkers discuss whether and how to caulk a paint-grade mantelpiece. November 19, 2005
Question
I have a customer who wants a paint grade mantel with many different moldings. I need a good caulk that will not yellow or crack. They have a painter but I would prefer to caulk it myself as a bad caulk job can make the piece look terrible.
Forum Responses
(Architectural Woodworking Forum)
From contributor A:
I am curious why you are concerned about caulk before you even build? Are you under the impression that paint grade equals open season on open joints? You said "A bad caulk job can make the piece look terrible". I say "Good craftsmanship can make any piece look desirable".
From contributor B:
The questioner is concerned about those gap lines that can't be filled with paint. I just did a rather intricate mantel with lots of built up mouldings, i.e. 3 large crowns. I like to use Alex Plus. It spreads nice and cleans up well with water. Another thing to consider is whether it hardens enough to cut it with a chisel or utility knife. Bed every moulding in caulk and you will be good to go with a couple of coats of heavy primer.
From contributor C:
I hate using caulk. It means that I have failed to get the proper tightness on a joint or a mitre. I strive for a perfect joint that when painted will yield a seamless transition from molding to molding and on all miters. This means all my molding edges are sharp so they lay on top of the next molding flat and tight. I agree about the Alex Plus - I use this when I am caulking a molding that is on a wall or a ceiling on the rare occasion that I have an open joint. And if I have to use it for an open joint I have failed in my craftsmanship.
From the original questioner:
The mouldings I am referring to are embossed mouldings. These can not be applied without some type of caulk to fill the space between the mouldings and the mantel. I have seen mantels that are not caulked and although they may have been tight at one time, they look absolutely terrible once the wood moves.
From contributor D:
The job mentioned requires a paint grade situation. If the finished product is pleasing to the professional eye, then using any method necessary is nothing to be ashamed of, and I consider it a job well done.
From contributor E:
I build mantels professionally with tight joints, and I caulk every joint when building paint-grade because the finished product simply looks cleaner when painted. I don't generally trust painters - if it is not caulked, they will caulk it no matter how tight or perfect the joint is, and they won't be as attentive to perfection as I am. My favorite caulk is Dynamite, which I buy at Kwal Howes. It has less water in it than the DAP products, and doesn't seem to shrink at all. It applies easily and excess cleans up easily. It also dries fast - ready for lacquer-based primer in about 1/2 hour. And finally, it costs less than the premium caulks from the local big box store.
