I just opened a can of Sig Lite-Coat clear, given to me by a guy who's been out of the hobby for about 20 years.  It's discolored.  I'm pretty sure that it's rust color, but I can't tell (I'm partly colorblind, so I can tell it's somewhere between brown and dull red, and that's as far as I get).

It was an unopened can, no signs of dope around the rim and with those nifty clips that Sig puts on their dope cans.  But it's old enough that the price sticker says "$5.99".

So -- if I use it for base coats, will it be OK, or might that discoloration migrate up through the finish to bite me later on?  I'm applying silkspan now, so I have a ways to go before any color goes on.

I had a quart can of Sig Butyrate that did the same thing. Once it starts turning the best thing to do is try to use it up soon. It doesn't get better with age. I've seen a few that looked like Hershey's chocolate syrup.

I just opened a can of Sig Lite-Coat clear, given to me by a guy who's been out of the hobby for about 20 years.  It's discolored.  I'm pretty sure that it's rust color, but I can't tell (I'm partly colorblind, so I can tell it's somewhere between brown and dull red, and that's as far as I get).

It was an unopened can, no signs of dope around the rim and with those nifty clips that Sig puts on their dope cans.  But it's old enough that the price sticker says "$5.99".

So -- if I use it for base coats, will it be OK, or might that discoloration migrate up through the finish to bite me later on?  I'm applying silkspan now, so I have a ways to go before any color goes on.

Hi Tim,

Late reply but when dope turns to a definite amber color and develops a peculiar smell (to me fresh Sig Light Coat has a kind of "sweet" smell) it is time to discard it.  It becomes acidic with age and this affects the film strength and reduces the intercoat adhesion.  Depending upon the extent of degradation it may still be usable...depends on whether you want to roll the dice on the labor/material factors.

Tim, hop in your car and drive up to Spencer Aircraft at Thun Field and buy Randolph.  Much less expensive, even with the gas you'll use to get here and back.  They have both tautening and non tautening.  Good idea to call first.  They will ship too, don't know about hazmat charges.  Probably about 140 miles from where you live.

Tim, hop in your car and drive up to Spencer Aircraft at Thun Field and buy Randolph.  Much less expensive, even with the gas you'll use to get here and back.  They have both tautening and non tautening.  Good idea to call first.  They will ship too, don't know about hazmat charges.  Probably about 140 miles from where you live.

I was given this big box of Sig stuff, and folks have mentioned that you don't want to mix Sig and Brodak, at least not much.

My plan is to use up most of the dope in the box, and then switch to Brodak or Randolph.  A special trip up to Spenser, if it's still there when I'm ready, sounds good.  Or y'all could organize more contests there and I could pick the stuff up on the way...