Add new life to your 2 part tin cure silicone repair kits.

[CJD]

Hello. I havent had much luck with keeping the catalyst for very long for my 2 part repair kits. I have 5 kits in all and 4 of them, the bottles have cracked or shattered allowing moisture to spoil the catalyst. The other just went bad but it was almost 3 years old.

To save my older kits I though I would try some Factor 2 catalyst for tin cure silicone to try with the silicone from my 2 part repair kits. Since it came in a 16 oz plastic bottle, I wanted to keep a small quantity for up and comming repairs while keeping the rest in the original bottle.

I found a small glass perfume bottle. I washed and rinsed it out with MEK and let it dry overnight. I also made a rubber gasket for the cap hoping this will be enough so I can use quantities from this bottle several times without it going bad.

the lable on the original bottle says to mix in a 10 part silicone to 1 part catalyst ratio by weight..but since I dont have an accurate scale to measure very very small quantities..I though I would give the volume measure a try. what could I lose.

I measured out 1.00 ML of silicone and 0.10 ML of catalyst and mixed them for 2 minutes
Note: I see first hand how much the catalyst hates moisture. some of the risidual water turned milky white within 10 minutes after rinsing out the syringe I used to measure the catalyst with.

Within the first 10 minutes I noticed it getting thicker
20 mins- it has the consistancy of honey.
30 mins- it was thick enough to consider working into a repair. (but could wait another 10 mins)
40 mins- it started to become stringy.
60 mins- it has the consistancy of snot.
1 hour 20 mins- has the consistansy of thick gum.
2 hours after mixing, the silicone is nearly cured but not quite yet.
3 hours after mixing, the silicone is pretty much cured, but soft


I hope this will hellp those of you who have 2 part silicone repair kits with expired catalysts get more life out of your kits!

[Mechwizard]

That's god work CJD. I've done the same in the past.
Usually the silicone dealers will tell you not to mix silicone and catalyst from different batches, but testing a small amount will tell you whether or not the silicone/catalyst mix will work. The stuff I use from Dalchem is mixed 10% by weight of catalyst, so 9 grams of silicone mixes with 1 gram of cat. With tin cure its not important to be exact, but getting as close as possible is the best way to ensure you get a batch that will cure properly. Slightly less cat will mena a longer cure and sligthly more will make it cure faster.