# How to Caulk a Crisp Corner



## instock (Nov 17, 2012)

I've been doing mostly repaints and I have never really had to caulk much. When I do come across a crack, I squirt a little caulk on it and massage it with a wet rag until it looks good enough. 

Now I'm working on a new construction. It needs a lot of caulk. I did some googling and there is a lot of info on how to to caulk a tub with a wet finger. But if I use a wet finger to smooth caulk behind window trim, it won't have a crisp 90 degree angle. And it will be impossible to cut a straight line when I go to paint. 

Is there a technique?


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## TNTRenovate (Aug 19, 2010)

I don't caulk cracks, I prefer to repair them.

As for windows, I cut the tube to maybe 1/8", finger the joint and then tool with a 1" knife to get a crisper edge. With caulk I can never get a true cutting edge. May just be me.


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## MarkJames (Nov 25, 2012)

I cut the tip small, tool with finger, and prefer to leave it a bit round. Cut in with a good brush. I do not square the bead since it can just increase the chance it will crack later with additional drying.

Also, if there's variation in the gaps, I may have two tubes/guns with the tips cut differently, say "fine" & "med/fine" - makes things go speedy quick and keeps your fingers cleaner.


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## TNTRenovate (Aug 19, 2010)

MarkJames said:


> I cut the tip small, tool with finger, and prefer to leave it a bit round. Cut in with a good brush. I do not square the bead since it can just increase the chance it will crack later with additional drying.


I agree with the drying issue, but hopefully the trim is tight to the wall and there is very little gap. Knowing when to tool and when not to comes with time.

Do you like a stiff or soft brush for cut in? And do you like a taper or straight? I love a 3" stiff for cut in, just what I got used to.


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## MarkJames (Nov 25, 2012)

TNTSERVICES said:


> I agree with the drying issue, but hopefully the trim is tight to the wall and there is very little gap. Knowing when to tool and when not to comes with time.
> 
> Do you like a stiff or soft brush for cut in? And do you like a taper or straight? I love a 3" stiff for cut in, just what I got used to.


Agreed.

I use the softer brushes. I had been using a couple 2.5" purdy xl's, tapered for a good long while, but just picked up a soft 3" tapered. Like it a lot. One of my paint crews uses mostly 3" straight, soft. They abuse their brushes (bristles flared, etc.) but keep 'em clean (of course) and do an amazing job - and fast, too. 

I did a crown job last year where everything was installed really nice and tight, and I even acclimated the stock. I decided to get fancy and squared my edges extra sharp - never again. I got a couple hairlines in a couple spots after several months, and then a few more when their humidifier broke. All hairline. Thankfully my scarf joints stayed tight (glued, of course).


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## instock (Nov 17, 2012)

Sometimes the gaps are bigger than others. The cabinet is plumb.


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## NCMCarpentry (Apr 7, 2013)

instock said:


> View attachment 107232
> 
> 
> Sometimes the gaps are bigger than others. The cabinet is plumb.


I think that would call for a filler strip.... Cut by someone who didn't do the crown... Thats just nasty


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## MarkJames (Nov 25, 2012)

I would probably tack a piece of scribe molding on that.

Edit: maybe not, depending on what I thought about the top & bottom termination....


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## TNTRenovate (Aug 19, 2010)

MarkJames said:


> Agreed.
> 
> I use the softer brushes. I had been using a couple 2.5" purdy xl's, tapered for a good long while, but just picked up a soft 3" tapered. Like it a lot. One of my paint crews uses mostly 3" straight, soft. They abuse their brushes (bristles flared, etc.) but keep 'em clean (of course) and do an amazing job - and fast, too.
> 
> I did a crown job last year where everything was installed really nice and tight, and I even acclimated the stock. I decided to get fancy and squared my edges extra sharp - never again. I got a couple hairlines in a couple spots after several months, and then a few more when their humidifier broke. All hairline. Thankfully my scarf joints stayed tight (glued, of course).


I will have to look at my knife, it may be a bit rounded on the corner, which is why I have never had that issue. What brand of caulk do you use?


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## TNTRenovate (Aug 19, 2010)

instock said:


> View attachment 107232
> 
> 
> Sometimes the gaps are bigger than others. The cabinet is plumb.


That is not a caulkable joint.



NCMCarpentry said:


> I think that would call for a filler strip.... Cut by someone who didn't do the crown... Thats just nasty


Agreed!



MarkJames said:


> I would probably tack a piece of scribe molding on that.
> 
> Edit: maybe not, depending on what I thought about the top & bottom termination....


Yeah and it would transfer the angle to the cabinet. I like a filler strip.


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## MarkJames (Nov 25, 2012)

I use a fair amount of Alex Plus, but sometimes the stuff from Duron/Sherwin-Williams (forget the name, but maybe 950A?). Regardless, it definitely was the case that there was extra shrinkage on the moulding. (House had forced air, btw.) 

I ran that job by my painter and he suggested not getting them "too, too" tight either for just that potential reason, and his advice is usually spot-on. I'm not talking about round edges you would notice or anything like that - just not 'knife-square". I was being a perfectionist, probably because there was an interior designer involved (client friend). I had used a plastic putty knife (new) on that job.


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## Sabagley (Dec 31, 2012)

Small tip

Tool with finger and wet rag

Paint the caulk with the wall color

Mask off and spray

This way you can use more caulk, which lessens the chance of the trim drying and shrinking from the wall, and still get super crisp lines. 

That's how they do it on the jobs I trim out anyways.


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## mako1 (Sep 1, 2013)

I have used a wet finger for years with good results.Just takes some practice.Now don't laugh to hard but one day while at the hardware store I saw some of those little blue rubber squares with the different corners like they sold on TV.They were half piece so I tried them and they work surprisingly well.More options than the finger.


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## MarkJames (Nov 25, 2012)

If my pinkie finger was a bit thinner I'd be all set.


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## Rustbucket (May 22, 2009)

Pretty much wet finger and rag here. Vary the pressure depending on the joint. Get it as clean as I can. We're not painting cars here!


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## jhark123 (Aug 26, 2008)

instock said:


> View attachment 107232
> 
> 
> Sometimes the gaps are bigger than others. The cabinet is plumb.


Please tell me that is not new construction.


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## Leo G (May 12, 2005)

Well, that's why custom cabinets come with a scribe. To make the walls looks straight and plumb.

You could caulk it but it will take a week to do it. Gonna be lots of layers.


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## totes (Oct 17, 2013)

Wet the crack first, using your finger, then apply the caulk. Never apply when dry. Start slow then smooth it out. Apply more as needed. Be sure to take your time or it can come out too quickly. Lay it on heavy at the end, and keep a towel near by for easy clean up. Shrinkage afterward is sure to occur, just wait an hour or so. Apply more caulk the following day if allowed. Fill as many cracks and gaps as possible throughout the day, latex gloves are highly recommended. 
That's how I do it anyways....


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## davidanbess (Apr 2, 2007)

I have caulked with various fingers for over 20 years and never had a complaint or remark made about round edges or angle's not sharp enough, with all due respect I think you are over doing the importance of the caulk


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## Leo G (May 12, 2005)

Tell the cabinet installer to put a pc of decorative molding over the gap. It shouldn't have been left that way.


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