Silicone caulk on aluminum

[edglenn]

I was concerned about an earlier thread that stated to NEVER use silicone caulk because it eats aluminum (which I have done ), so I called DAP Products directly to find out why.
Here's their answer:
The silicone based caulk etches aluminum because of the acetic acid content. It's the Acetic Acid that attacks the aluminum, not the silicone.
They recommended the following caulks, that have 30-50 year service life:
Butyl Flex
Dap 3.0 (Silicone hybrid w/o acetic acid)
Latex

I know that Vulkem (Sikoflex) and Parbond are the preferred sealants, but HD and Lowes don't carry them, and sometimes it rains TODAY, not next week.
Hope that helps!

[lewster]

Just a quick clarification: SikaFlex is not the same product as Vulkem. Also, Tempro (which bought Vulkem as I understand) makes several grades of these essentially one part polyurethane sealants

You can easily get them on-line and store them in your freezer, where they will stay fresh way beyond the expiration date. Also, some well-stocked RV stores carry them, as do many Fastenal stores.

[murreywalker]

Originally Posted by edglenn

I was concerned about an earlier thread that stated to NEVER use silicone caulk because it eats aluminum (which I have done ), so I called DAP Products directly to find out why.
Here's their answer:
The silicone based caulk etches aluminum because of the acetic acid content. It's the Acetic Acid that attacks the aluminum, not the silicone.
They recommended the following caulks, that have 30-50 year service life:
Butyl Flex
Dap 3.0 (Silicone hybrid w/o acetic acid)
Latex

I know that Vulkem (Sikoflex) and Parbond are the preferred sealants, but HD and Lowes don't carry them, and sometimes it rains TODAY, not next week.
Hope that helps!

Your post had me going for a bit.

Because of a leak near the stove exhaust vent cover, I used GE's Premium Waterproof Silicone II.

Just finished a call to their hot line and was assured that their Silicone II contained NO acetic acid. They went on to say that their plain silicone brand DID contain acetic acid and was not suitable for aluminum.

[cameront120]

Sikaflex and Vulkem are not restricted to RV's in their applications, either. They are used extensively by the window and curtain wall industry. So if you have supplier of glazing supplies near you, that would be another source. Failing that, as others have said, order it online.

[Melody Ranch]

Fastenal in Albuquerque, NM | Albuquerque Fastenal - YP.com

[Gringo]

wouldn't 'etched' at the contact point mean the sealant gets a better bond?

[sunny75]

I'm still in the process of removing what seems like gallons of silver/gray silicone caulk from seams, rivets and everywhere imaginable. Please do NOT put silicone on your airstream. It's airstream abuse!

[tphan]

For the umpteenth time, and to reiterate what MurreyWalker posted, I have used GE Silicone ll formulated for Aluminum and Metal (100% silicone; no acetic acid, high-fructose corn syrup, or phosphates) with the same amount of apparent success as the Vulkem, and with better success than Parbond. I have used it to seal, with a small, neat bead, around my window frame-to-skin areas, and around the tops and sides of the running lights. Looks today like 5 years ago, no leaks.
(Disclaimer: I have also used an RV cover to keep the bird s**t and pine sap off my trailer (with 100% success), have mixed greywater into my black tank without killing my family or destroying my trailer, and tow with a non-Hensley hitch. I also put in non-Henschen axles, have no flamingo ornaments, and belong to no club.)

"When silicone is illegal, only illegals will have silicone"

[fourcatos]

I have to agree with sunny. I spent 2 days removing that trash. DO NOT USE SILICONE!!!!!!! Do the job right and have some respect for your trailer.

[tphan]

Originally Posted by fourcatos

I have to agree with sunny. I spent 2 days removing that trash. DO NOT USE SILICONE!!!!!!! Do the job right and have some respect for your trailer.

Sounds like silicone really adheres, which is a plus in my book. I think you'll have the same "problem" with vulkem if you ever decide to remove that. My AS also had a lot of clear silicone smeared on with the PO's thumb, and was indeed ugly and hard to remove. I cleaned it all up, and hope now that the neat bead of silver-grey GE silicone II (specially formulated for aluminum) that I have around the windows is equally durable. It appears to be.
I have respect for using one's powers of observation and reasoning, and somewhat less for the acceptance of "group-think".

[egad]

Speaking as a building contractor, I'm not a big fan of silicone. It adheres to some surfaces, but not others such as asphalt shingles. What it does stick to it sticks very well which can also be a problem when it comes time to repair/replace something. Butyl caulks are far superior IMO, because they seal very well but are relatively easy to remove with ordinary tools. I sealed Betty's fridge vent with this and it worked just fine.

[wahoonc]

Once silicone adheres it leaves a film. The film is very difficult to remove and will stop any other type of sealant from adhering properly.

Perhaps the new formulations of silicone are an improvement, I honestly don't know. What I do know is that Vulkem/Trempro or equivalent sealants from Sonneborn or Sikalastic are much easier to remove and reseal when the need arises.

Aaron

[lizpickering]

I went by my local RV repair place and asked what to use to seal around my plumbing vent pipes on top. He handed me a tube of Manus -bond silicone rubber sealant. It doesn't say it contain acetic-acid. Is this okay to use on our 66 ambassador? Thanks.

[Jenniflow]

OK, it sounds like there are some subtleties involved here, this is very helpful.

(See also the thread: http://www.airforums.com/forums/f456...aks-66628.html, which has a more thorough discussion of the varieties of silicone.)

But here's the thing. If you find that the PO has used lots of silicone, what IS the best way to remove it? Is there are good, safe solvent for it? Or is it just a matter of scraping with a plastic tool or something? 'Cuz I got some silicone and it ain't pretty!

[Someday'59]

Use this stuff to get rid of the silicone:
(McKanica Silicone Caulk Remover Gel)
Vintage Trailer Supply - parts and supplies for vintage travel trailers and campers!

Not that I <ahem> have any experience with that or anything. But, if one were to somehow accidentally had a reason to remove silicone from their trailer then I would recommend using that stuff. (It's worth waiting for it to come in the mail!)

[Jenniflow]

Thanks Someday '59. If you were to have a secret, it would be safe with me.

[Dan and Liz]

I recently traded several emails with Lyn Dickinson who is our area rep for Tremco (they make a raft of sealants). Based on another earlier post, I wanted to try their Dymonic poly sealant, but couldn't find it. Her recommendation:

"I would use Spectrem 2 for what your doing - its a silicone will last 20 yrs + - if you don't want silicone then Dymonic FC would still be next best - Dymonic was formulated for Canada and works okay but is an older technology sealant and will need to be replaced in 5yrs or less
I just re-sealed my windows on my 5th wheel (2003 Alpine Light) with Spectrem 2 and wouldn't use anything but - "

I asked her about reported damage from silicone. Her response:

"...that's a myth to a certain degree - what they are referring to is "acid cure" silicone - old 50-60 technology - the neutral cure silicones do not react with aluminum. Consider every high rise aluminum frame/glass building in the world is sealed with neutral cure silicone for the last 30 years."

Anyway, I've asked for samples of Spectrem 2, Dymonic and Dymonic FC to try out. You can ask for free samples of these products at the Tremco web site.

[tphan]

Originally Posted by Dan and Liz

I recently traded several emails with Lyn Dickinson who is our area rep for Tremco (they make a raft of sealants). Based on another earlier post, I wanted to try their Dymonic poly sealant, but couldn't find it. Her recommendation:

"I would use Spectrem 2 for what your doing - its a silicone will last 20 yrs + - if you don't want silicone then Dymonic FC would still be next best - Dymonic was formulated for Canada and works okay but is an older technology sealant and will need to be replaced in 5yrs or less
I just re-sealed my windows on my 5th wheel (2003 Alpine Light) with Spectrem 2 and wouldn't use anything but - "

I asked her about reported damage from silicone. Her response:

"...that's a myth to a certain degree - what they are referring to is "acid cure" silicone - old 50-60 technology - the neutral cure silicones do not react with aluminum. Consider every high rise aluminum frame/glass building in the world is sealed with neutral cure silicone for the last 30 years."

Anyway, I've asked for samples of Spectrem 2, Dymonic and Dymonic FC to try out. You can ask for free samples of these products at the Tremco web site.

Good- another myth debunked forever, or at least untill another new sealant thread appears.

[Jim Flower]

GE Silicone caulking is used extensively in industrial environments to seal aluminum jacketing on piping and equipment. Most major owner or engineer generated specifications will specify a silicone caulking as their preferred sealant and most often this is GE 1200. Look at any industrial facility, an oil refinery for example, and you will see all this nice shiny aluminum jacketing on most of the piping,tanks, towers, and vessels. The laps and penetrations on this jacketing are normally sealed with silicone caulking. The installation can last 20 to 40 years. The stuff works and does not cause deterioration of the aluminum. Now, taking it off is a different problem that I know nothing about since I have never had to take it off.

[Rhino33]

Sorry - we are new to Airstreaming and are working on rehabbing a 1980 International that had leaked in both the rear bedroom and front by gaucho. We had been previously advised to use Acryl-R on the roof seams/around vents and Adaseal on the sides/windows to skin. We had not heard of using Vulkem and now we're not sure what to use where!
Also - some of our windows have a white-ish old 'caulk' that had been applied to the outside of the glass between the seal and glass itself?? When I washed the windows, it just flakes off, but do I need to put something back on?? ACK!