Sorry your first RTV try did not work out so good. Sounds to me like you either did not mix thoroughly enough or did not get the proportions absolutely correct.
Read the instructions for the proportions for your product. Mine was 50:50 by volume. BUT, also had a sticker giving the proportions by weight. This was 100:118. If you have an accurate digital gram scale, this is a much more accurate way of measuring out the proportions. But, use the figures provided, NOT mine!
If you have to measure by volume, tall, narrow measuring containers are better than wide, shallow containers.
For mixing, I use clear plastic disposable cups. So when mixing, I can visually examine the mix at the bottom of the cup, to make sure there are no streaks of unmixed components. After mixing, the result should be smooth and constant in color. Try to work the air bubbles out before pouring. A vacuum will greatly assist this, but I don't own one.
Be thorough and fussy about measuring and mixing. Mistakes with this stuff are expensive, as you have discovered. All part of the learning curve.
Good luck with your next try.