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+--- Thread: stoopid question re: silicone seal cure/drying time (/showthread.php?tid=243687)
stoopid question re: silicone seal cure/drying time - SDGuy - 07-14-2020
ok, so I've used my fair share of silicone seal over the years - usually involving something being repaired in a bathroom.
But - this time I was working on a small household project, involving permanently installing a cork into a metal cylinder, where water tightness would be desirable.
So - after the cork was inserted, I put a small bead of silicone seal around the perimeter where the cork meets the metal and set it aside. This was last week Wednesday evening. It's been awhile, but from my memory of past projects - the silicone seal would be cured at least to the point of being just tacky after 24 hrs, and definitely cured/dry after 48 hrs. It's now nearly six days later, and the d*mn stuff is practically the same as it was then, as in touch it and it'll leave a glob on whatever you touch it with - and still easily spreadable. If it helps - after the 2nd day, I've been leaving the thing outside on the porch to be exposed to the open air (with low humidity and temps in the mid-80s during the day).
So - what gives?
For anyone with more silicone seal memory/experience than I apparently have - is this normal? :dunno:
Re: stoopid question re: silicone seal cure/drying time - MrNoBody - 07-14-2020
Been using the stuff for 40+ years, so here's what I know.
100% pure silicone sealant cures to touch within 8 hours, full cure is 24 hours.
Things that inhibit curing: oils, moisture, solvents, and other contaminants.
I would suspect the cork is contaminated or there was something on the metal.
Any chance your tube of sealant got contaminated or is really old?
btw, silicone sealant will not properly bond to cured silicone sealant!
Re: stoopid question re: silicone seal cure/drying time - space-time - 07-14-2020
btw, silicone sealant will not properly bond to cured silicone sealant!
Right, this is why I avoid silicone caulk. It is a pain to remove and clean properly when you have to redo the job.
Re: stoopid question re: silicone seal cure/drying time - fromish - 07-14-2020
Another thing to consider is the 'use by' date on the tube. I have used silicone caulk only 3 months after the date on the tube and it never hardened, but stayed soft and, inside the bead, sticky.
Re: stoopid question re: silicone seal cure/drying time - SDGuy - 07-14-2020
thanks guys - I'm going to guess the stuff is too dated - I know the tube was at least two, possibly three years old.
So - time to scrape it off and start over.
I know - 1st world problem...not overly upset, was just trying to finish this small project with what's on hand and avoid a trip to a store.
Re: stoopid question re: silicone seal cure/drying time - Don C - 07-14-2020
There's ALWAYS one more trip to the store. Who do you think you are fooling?
Re: stoopid question re: silicone seal cure/drying time - MrNoBody - 07-14-2020
One other point, silicone caulk is not the same as 100% silicone sealant.
DAP
The task you've described would be for sealant.
Re: stoopid question re: silicone seal cure/drying time - Racer X - 07-15-2020
I thought RTV sealant needed airborne moisture to cure. At least automotive/marine gasket sealer does. VERY little difference between it a plumbers sealant.
Re: stoopid question re: silicone seal cure/drying time - MrNoBody - 07-16-2020
I thought RTV sealant needed airborne moisture to cure.
You are correct. 100% Silicone needs humidity to cure properly. One of the reasons
dry heat (heatgun, hairdryer, etc.) actually impedes correct curing.
(Learned that watching a vid on all-glass aquarium building!)