Cured silicone calk in duct collector pipe –contaminate shop with silicone?

  • Advertise with us

« back to Finishing forum

Forum topic by d38 posted 12-04-2017 04:12 PM 4854 views 0 times favorited 10 replies Add to Favorites Watch
View d38's profile


142 posts in 1038 days

12-04-2017 04:12 PM

Looking back, don’t know why I made a real dumb decision, but this weekend I used silicone calking to install 2 saddles onto snap-lock hvac pipe for my new dust collector setup.

Now that its cured, will the silicone molecules stay put? Or will my dust collector pull silicone off of it, blow it into the bag, then literally contaminate the entire shop with silicone?
I have not turned on the DC since installing the saddles onto the main pipe going into the DC. So if I need to, I can shell out $$$ for 2 more saddles and another 5 ft snap lock pipe and start over.

As I got into the project and felt the slippery silicone on the rubber gloves, I instantly knew I made a bad decision using silicone. So I’ll buy some naptha and try to clean the hand tools the best I can – but also realize hand contact can spread it everywhere.

I’ll be HVLP spraying waterbased top coat. So I hope I didn’t destroy my chances of a nice finish job.
I don’t know how I could have been so stupid.

Thanks in advance

10 replies so far

View dhazelton's profile


2839 posts in 3073 days

#1 posted 12-04-2017 04:18 PM

Once it’s cured it’s cured. No silicone molecules will attack the shop.

View pintodeluxe's profile


6158 posts in 3589 days

#2 posted 12-04-2017 04:24 PM

No, you’re fine. The risk with silicone is direct contact with wood while it’s wet. IE:coating your saw and jointer with a silicone based lubricant.

The other real bummer with wet silicone caulking… it’s a high level irritant to the eye. I made the mistake of changing my contacts after working with silicone caulking. I felt like I’d been maced.

The biggest disadvantage with silicone, duct mastic, or any other caulking for D.C. systems is that it’s permanent. For that reason alone, I prefer foil HVAC tape.

Cheers and good luck.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View rbrjr1's profile


208 posts in 982 days

#3 posted 12-04-2017 11:53 PM

foil tape everything…!

I’ve laid down hundreds of yards of the stuff over the years and I dont think I’ve ever worked on a single piece of ductwork.

the stuff is awesome and has uses well beyond ductwork.

-- only an idiot dismisses an intelligent statement because they dont know anything about the person delivering it.

View bondogaposis's profile


5791 posts in 3127 days

#4 posted 12-05-2017 01:40 AM

Yup, you’re screwed. Only solution burn your shop to the ground and build a new one.

-- Bondo Gaposis

View TheFridge's profile


10859 posts in 2262 days

#5 posted 12-05-2017 02:33 AM

No worries.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View Jim Finn's profile

Jim Finn

2836 posts in 3698 days

#6 posted 12-05-2017 02:58 AM

I am a retired Sheet metal worker and we used smelly silicone caulk, like you have, a lot. Not an issue at all.

-- No PHD just a DD214 Lubbock Texas

View Fred Hargis's profile

Fred Hargis

6245 posts in 3270 days

#7 posted 12-05-2017 11:54 AM

You’re good to go and are worrying about nothing.

-- Our village hasn't lost it's idiot, he was elected to congress.

View d38's profile


142 posts in 1038 days

#8 posted 12-05-2017 04:08 PM

Yup, you’re screwed. Only solution burn your shop to the ground and build a new one.

- bondogaposis

sounds like a great plan!

On a serious note, I’m glad its not as bad as I thought. Hope to get all the piping finished by this weekend. Between fall yard cleanup, deer hunting, going to local collage football games, etc, this whole project is burning months off the calendar—but I guess that’s called life.
Thanks everyone!

View cliftonpark's profile


7 posts in 994 days

#9 posted 12-07-2017 01:12 AM

I worked in a silicone manufacturing plant for 33 years. Am now 81 and going strong. Silicones are non-toxic. They are used in food products, cosmetics, gaskets, ant-acids, water repellants, shampoo, contact paper, and many other common products. Many manufacturers of products that you ingest or use on your body use the term dimethicones when they list the ingredients rather than calling them silicones. Some silicone caulks contain a curing agent that releases acetic acid (vinegar) when the caulk cures. If you are especially sensitive to acetic acid it may cause irritation to your eyes and respiratory tract. Cured silicone caulk is inert and cannot cause any sensitivity reaction. By the way there are some silicone caulks that use a different curing agent and do not have the unpleasant vinegar smell.

Bottom line: Don’t worry. Use all the silicone caulk you want. It can’t hurt you.

View Dark_Lightning's profile


4103 posts in 3885 days

#10 posted 12-12-2017 03:50 AM

Certain types of silicon compounds can cause problems with paint, causing fish eye, for example. But caulk should not be an issue, as the silicon is pretty well bound to the matrix of the caulk, and you won’t be grinding it up to make a powder anytime soon. If you can eat a salad with vinegar and oil, you are not allergic to acetic acid. Vinegar is a weak acetic acid.

-- Steven.......Random Orbital Nailer

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics