Paint cracking on exterior door

The paint on our heavy panelled exterior front door has cracked along joins between stiles and rails, as well as along the edges of some of the panels. I spent much time last year on preparing the door for painting, including filling all the crack lines with car body filler, but the (moderately) immaculate finish I then achieved has been marred by cracking has recurred in a similar fashion to how it was before. Presumably this is because of expansion/contraction, and "working" of the different parts of the door against each other. (?) SWMBO is agitating for me to remedy this, in order to reinstate the finish that was in place when I finished the last round of work, but I'm at a loss as to how to achieve this without the same problem showing up again within months. Any suggestions? I've been trying to think of ways I can improve the stability of the door but haven't come up with anything that's practicable.

Reply to
Appelation Controlee
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Flexible decorators caulk,putty, mastic, or don't use wood.

Reply to
The Natural Philosopher

Perhaps I should have added that it was the flexible variant of car body filler that I used. That leads me to wonder whether it was its flexible charcteristic that contributed to the problem?

Reply to
nog

Not a lot you can do, nature of the beast etc. Wait for a dry spell and fill the end grain top and bottom with candle wax.

Reply to
Stuart Noble

Car body filler is not flexible enough for wood joints that are subject to movement, a softer wood type filler should be used, something like Brummer filler for example.

ste

Reply to
ste

Brummer stopper is 100% clay, and we know how flexible that is!

Reply to
Stuart Noble

Hi,

I'd just wait til the door has dryed out as much as it will, fill the cracks with paint using some small artists brushes then paint it again.

A paint that's claims to be (relatively!) flexible and resists cracking would be best.

cheers, Pete.

Reply to
Pete C

Clay?, that's totally unsatisfactory as a base filler for wood, even a car body filler would be more flexible than clay.

Can you not obtain lead fillers these days? or have these been banned on heath & safety grounds like lead paint was, although I think you can still purchase lead based paint from some outlets.

ste

Reply to
ste

You can add flexing agents into paint but I don't think this is the cure for expanding wood.

ste

Reply to
ste

While expansion/contraction is, I think, bound to be involved, I think the biggest problem in our case is movement of the different parts of the door relative to each other. The paint, btw, is Buckingham Green from International.

Reply to
nog

Wood gets narrower, but not significantly shorter, as it dries. There is no paint that can withstand the kind of movement that can occur where horizontal meets vertical. If the door is properly kiln dried to start with, and the wood dense enough to resist moisture, the movement shouldn't be excessive.

Reply to
Stuart Noble

It doesn't really matter what filler you use as nothing will stop the relative movements of the wood hence whilst a flexible filler won't itself crack it's the paint overcoat that will.

Any chance of filling the cracks with a coloured caulk/sealant/wax? Of course the closer the match the better but I would've thought even something moderately close would stand out less than what I assume are black/dark voids of the current cracks.

Mathew

Reply to
Mathew Newton

i have a similar situation, the wooden window frames on my victorianish house have cracks, and are very rough where water has sat on them for years, i was advised to wire brush them then use car body filler to smooth them out then paint with oil paint... or should i fill the bigger holes with wood, softwood would rot quicker than car body filler, as its the frames they dont move like doors so is car boddyfiller ok?

Reply to
dicegeorge

Yes, but do it in the summer if possible. A few weeks later the wood around the filler may shrink and you will need to fill the new cracks. After that, all should be well IME.

Reply to
Stuart Noble

Its very very good IF - and it is a big IF you either cut back to sound wood or stabilise any rot. A very thin polyester resin (the sort you use to lay up fiberglass) will probably do this, or there are maybe some specially formulated resins that are thinner and more penetrating.

Reply to
The Natural Philosopher

The wood won't move more and more, just in cycles, I'd just paint it when it's dry as possible, and use a paint that's more flexible.

If the gaps now are an eyesore, I'd try masking off and filling with paint.

cheers, Pete.

Reply to
Pete C

You can sort of mix body filler with lay up resin. The catalyst seems to work for both, but the hardening time is much longer, often several hours in thin layers and cold weather.

Reply to
Stuart Noble

Perhaps a better quality paint could be the answer.

The more oil that is built up on a paint layer the more flexible it will be, a long oil is better than a short oil which is why coach paints are always long oil. Applying thin paint over thick paint will crack, but applying thick over thin will not, because the thicker long oil paint remains more flexible.

Over thinning will reduce the thickness of the long oil and the paint will become less flexible, becoming more like a short oil.

ste

Reply to
ste

Is it a synthetic oil alkyd? You could add some raw linseed oil to counteract the faster hard drying alkyd resin, I know boiled linseed oil is used in some paints but using raw linseed will keep the paint more flexible.

ste

Reply to
ste

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