Best caulk for this exterior application....

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Old 08-08-16, 12:43 PM
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Best caulk for this exterior application....

I have a through wall ac unit. The exterior has a grill that is caulked where the metal case meets masonry blocks. Few questions:


1. Best masonry prep before caulking? After I scrape off old caulk, is there a cleaner or solvent I should use to wipe down the area?

2. A friend recommends Np1. Is that a good choice, and if so, can it be applied when raining?
 
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Old 08-08-16, 12:49 PM
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Lacquer thinner and Acetone are two powerful chemicals that will also remove old caulk remains.

No caulking/sealant can be installed in the rain.
NP1 is ok. np1/basf.us/en-us/products/masterseal/2001
 
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Old 08-08-16, 12:54 PM
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Thanks. Anything wrong with using a wire brush and scrubbing it off? I tested a portion and it removes it quite well, but also removes the finish. Cosmetics aside, does this create any water entry problems?
 
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Old 08-08-16, 01:13 PM
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NP1 would be an excellent choice.
 
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Old 08-08-16, 01:22 PM
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Okay so no rain... but how dry must it be? I live in nyc and it's scattered rain half of the year. If it's damp at all, it will be an issue?
 
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Old 08-08-16, 01:55 PM
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Take your hair dryer out there and blow it off if you have to. The dryer the better.

This is another good product... http://www.geocelusa.com/images/Tech...chData0715.pdf
 
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Old 08-08-16, 02:07 PM
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Thanks I'll check that out. What you think about Lexel? Just found out about it and it can be applied on wet surfaces and get wet immediately after application. AC units usually drip water so this is looking good to me....
 
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Old 08-08-16, 02:19 PM
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I have used Lexel in the past... and I'm not a big fan of it. It does not stay flexible... it gets hard as a rock. I have actually cut myself on the stuff when I had to go back and repair something I had caulked with it. And its very thick, hard to pump out of a caulking gun. And expensive.

The product I linked to (above) is pretty much a homeowner version of this product:

All Construction/Building Products : 2300 Construction Tripolymer Sealant

...and it can be applied to damp surfaces, which is why I mentioned it... but it's always good if you can dry it out as much as possible, using a heat gun or, assuming you don't have one, a hair dryer.
 
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Old 08-08-16, 02:41 PM
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Thanks. How soon would you turn your ac on afterwards with that geocel, assuming it may start dripping?.....

Also, what are your thoughts on flammable caulks? Is it something to worry about around an ac unit grill? I read Lexel is flammable. Not sure about geocel.
 
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Old 08-08-16, 02:53 PM
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Right away. No, nothing to worry about unless you are trying to smoke it.
 
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Old 08-08-16, 02:59 PM
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Nice! Thanks again Xsleeper.
 
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Old 08-08-16, 03:32 PM
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One more... If I was to go with np1, how long until it can be wet after application such as ac drip or light rain?
 
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Old 08-08-16, 03:38 PM
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If the caulk gets wet, that won't matter but if the cement that the caulk it stuck to gets wet, it may compromise the bond. If there is any way that you could staple or tape up some plastic temporarily that might help give it time to cure. Just a day or two would be better than nothing.
 
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Old 08-08-16, 04:06 PM
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I'm in northwest NJ so my weather is very similar to yours. Although the weather people aren't terribly accurate.... you should be able to know in the morning what the day will be like. We very rarely get pop-up storms here.
 
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Old 08-08-16, 04:41 PM
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Brant, what has been your experience with OSI Quad Max? From a class I took from them, they applied it underwater, so it may have been hype, but it sticks quite well. Exterior use only.
 
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Old 08-08-16, 05:11 PM
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So what do you do if it says 60% chance of rain? That's what it's saying over here pretty much every day lately lol.
 
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Old 08-08-16, 06:50 PM
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Larry, I have never used it... I'm still using OSI Quad, original formula. If that's true I guess that would be a good option too.

Earlier, acetone and lacquer thinner were mentioned. Any solvents you use will soak into the concrete, and you probably would not want to put any sort of caulk onto the cement until those solvents have a chance to evaporate. They will repel the adhesion of the sealant otherwise.
 
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Old 08-08-16, 09:53 PM
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So tmr I'm going to pickup two caulks and test them on an adjacent spot on the exterior wall to see how they are to work with, and in damp weather. One will be the 2300 tri construction sealant. What would be a good second brand to try? I don't think I'm able to purchase the np1 myself in nyc, or I'd try that one. I was still interested in the lexel, which Lowes sells here. How long ago did you use it when it hardened on you? As far as I've seen, it has great reviews...

I have noticed the 2300 and lexel around here only come in clear. That seems undesirable. Won't it be difficult to identify any voids in it when applying, as well as cracks down the road, if any?
 
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Old 08-09-16, 01:24 AM
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Just because its clear does not mean it's invisible. LOL

Haven't used it in years but I doubt it has changed any. Its been around for 20 yrs or more.
 
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Old 08-09-16, 04:44 AM
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Having a rag damp with the appropriate thinner will aid you in dressing up the caulking and help keep your fingers cleaner. If I'm not mistaken that would be xylene with the 2300 [double check the label]
 
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Old 08-09-16, 05:31 AM
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Anything wrong with buying these on amazon? My local stores all had to order them which would take longer, so I just ordered two geocel proflex on amazon and also np1. Geocel is sold by deerso and fulfulled by amazon. Np1 sold and fulfilled by amazon. The only issue I could think of is getting expired or near expired tubes. Guess we will see.

Same day shipping and one next day. Hard to beat that.

SONNEBORN 1025616 One Part Urethane NP1 Sealant, Aluminum Gray to be exact. Is this the right one? I just read they are now masterseal. I hope I dont get an expired tube....

What do you guys use for extension tubes for hard to reach places? My through wall ac has an exterior grill that needs to be caulked around. I'm on 3rd floor and ladder is not option. Fortunately, it's right under a window, so I can lean over it and reach it, but it's still a reach. Was going to put a piece of physical therapy tubing onto the end of my caulk tube to use as extension. It fit well but haven't actually caulked through it yet. Do you guys have any other methods?
 

Last edited by axxel; 08-09-16 at 05:57 AM.
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Old 08-09-16, 06:49 AM
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You can buy clear poly tubing by the foot in most hardware stores. 3/8" seems to work well. You have to hold it onto the nozzle with one hand and squeeze with the other so it isn't real easy but sometimes you have to do it to reach a hard spot. Its a great way to caulk your hand if you don't hang on tight.

Vaccum hose or fuel line would probably also work. Parts stores would sell that. And maybe you could get a hose clamp there too.
 
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Old 08-09-16, 06:57 AM
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Is the clear poly tubing the hot water hose in plumbing section?
 
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Old 08-09-16, 07:02 AM
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I guess home depots site calls it pvc tubing... Sioux Chief 1/2 in. x 3/8 in. x 10 ft. PVC Tubing-900-01163C00201 - The Home Depot ...poly tubing is harder. I use the rubbery stuff because it's flexible. But yes, it's clear.
 
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Old 08-09-16, 12:44 PM
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Cool, just picked that up. Hose clamp fits good too. I'm anxious to get this done but likely will wait until next week as it should be dryer.

BTW, does anyone know of a good handyman in NYC? PJmax, do you know anyone, being that you live in NJ? I'm disabled and very limited in what I can do. Bad shoulders, and it's embarrassing asking my wife to reach overhead everywhere we go to grab things off top shelf haha. Always looking for good handyman to help me with repairs.... I'll probably post this question in another thread here....
 
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Old 08-09-16, 02:17 PM
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We don't recommend contractors/handymen. Your best bet would be to check locally, word of mouth is the best method imo.
 
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Old 08-11-16, 07:35 AM
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We went ahead and did my ac yesterday. It barely rained at all. We went with the np1 my friend recommended. It is good stuff! Very sticky. It's almost 24hrs now and I can tell it's curing pretty well and hardening to a firm yet flexible bead. Feels similar to silicone.

There are a couple spots I'd like to add some more caulk to later on. How long should I wait before applying more on top of it, and what's the best method for tooling it? It was very sticky and hard get nice smooth beads.

I really appreciate the input here guys.
 
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Old 08-11-16, 07:40 AM
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You can use paint thinner to tool it neatly. A scissors and a plastic milk jug will give you some plastic to use as a spatula. Apply as much caulk as you need then tool it. Dont try to add more caulk once you start using the thinner to tool it.
 
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Old 08-11-16, 08:00 AM
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Thanks can I add anytime or wait a few days?
 
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