Question about silcone RTV

[P.W.Royce]

I have a 1lb. batch of QSI purple silicone RTV. On the catalyst bottle the mix ratio is listed as "100 parts base material to 10 parts catalyst". Isn't this the same ratio as 10 to 1? Or, is 10 parts catalyst the minimum amount to be used, even in small batches. I have been having trouble getting the stuff to cure when I mix up small amounts. I have made molds with other brands of material, so I understand the basics of measuring, mixing, pouring, silicone. Any help would be appreciated. Thanks guys.

[cobywan]

I have a 1lb. batch of QSI purple silicone RTV. On the catalyst bottle the mix ratio is listed as "100 parts base material to 10 parts catalyst". Isn't this the same ratio as 10 to 1? Or, is 10 parts catalyst the minimum amount to be used, even in small batches. I have been having trouble getting the stuff to cure when I mix up small amounts. I have made molds with other brands of material, so I understand the basics of measuring, mixing, pouring, silicone. Any help would be appreciated. Thanks guys.

It is the same ratio. But here's the thing...it's by mass not volume. So you need a very precise scale in order to do small volumes.

[Excillon]

It is the same ratio. But here's the thing...it's by mass not volume. So you need a very precise scale in order to do small volumes.

This is true. I've had a disaster relating to this.

[Chas]

This is true. I've had a disaster relating to this.

For small batches you could pick yourself up a good quality digital kitchen scale that goes up in increments of 1gram for under $50.00. (cover it with plastic wrap before you pour though - makes clean up a snap.