Some people say that Sig dope is more fuel proof than Brodak.  I don't know since I've not used Brodak yet.  But my question is this.  If Sig clear is more fuel proof than Brodak clear, can I use Sig clear as the final finish coats over Brodak colors ? 

Bill

The "your mileage may very" part makes me a little nervous.  So If I use Brodak colors and Brodak thinner thru the whole process, including thinning out the Sig lite coat clear as a finish coat, I'll be OK, or is my mileage going to be impacted in a negative sort of way   

I have not had any trouble at all using Sig Lite-Coat over Brodak colors and have done so recently and often. However, I would not use Brodak thinner with Sig dope. Stick with Sig thinner w/Sig dope and you should not have any problems. Others experience may differ...

Pete

If I use Sig thinner for thinning the Lite-Coat, what thinner are you suggesting I use for the Brodak color coats ?    Are you suggesting I use Sig thinner for both brands of dope ?

I have not had any trouble at all using Sig Lite-Coat over Brodak colors and have done so recently and often. However, I would not use Brodak thinner with Sig dope. Stick with Sig thinner w/Sig dope and you should not have any problems. Others experience may differ...

Pete

So you have used Sig Lite-Coat over Brodak colors "recently and often".  Then what thinner have you been using successfully for this scenario ?

As one can see, there are no right answers and lots of opinions regarding dope finishes. One has to find a technique and practice that works for them. For me, it's not mixing brands of dope/thinner. An exception would be Randolph/Brodak thinner as I too believe that Randolph supplies Brodak with dope so they should be compatable.  No question in my mind as to Brodak vs Sig regarding fuel proofing. Sig Lite Coat wins by a mile. It has been my experience that raw fuel melts Brodak clear and mist fuel will damage it. You pays your money, makes your choice, and takes your chances. 

FWIW, I have been using Brodak thinner with my SIG Lite coat for five years, no problems.  This week I ran out of Brodak thinner, but the price is so high, I ordered Randolph's thinner from Aircraft Spruce for half the cost.. $10 for shipping for 6 quarts, got it the very next day, via FedEx.

I can't tell or see any difference in the two thinners, as Randolph's makes or rather cans the thinner for Brodak, except for cost... .

Ty

If you have been using Brodak thinner with Sig Lite coat with no problems, then back to my original question of can I use Sig Lite coat over Brodak colors to get improved fuel proofness (I just invented that word), It seems logical  if I use Brodak or Randolph's thinner all the way, it should be OK.  Anyone disagree with this logic ?

I can sure relate to that. I have stocked up somewhat and have enough Sig clear for a few more models but have concerns regarding the continued availability of Sig, especially clear Lite-Coat. I'm glad that there are alternatives but hope that Sig continues supplying dope. 

 

Bill  Little

So what thinner did you use "all the way through" then ?

Dan

HI Dan,

I use only Dupont 3608S thinner in all my dope and lacquer products.  Have been doing it for about 20 years now.  Never use Dupont thinner with a "V" suffix!

*Your Mileage May Vary* was thrown out for all the guys who insist that you must use only one manufacturer's products all the way through.  It is something I would definitely do if I was charging a customer $20,000 for painting a car, like one of my buddies used to do.  But, if I had to do that on model airplanes, I would probably not have finished a single plane since the '70s.  I use whatever product I have on hand, and nothing has bit me so far.  I mix Sig Dope, Randolph Dope, Certified Dope, Duplicolor Lacquers, and Dupont Chromabase paints.  Never put nitrate over any other paint I use, and I do not clear Chromabase with Dope or Lacquer.  I will put automotive urethane clear over any other paint, including Rustoleum types..   Short version, I mix and match all my *lacquer* paints.

Of course, I have not used Aero Gloss Dope or Testors Dope in well over 30 years.  Those WOULD cause compatibility problems back in the day.

Mongo

HI Dan,

I use only Dupont 3608S thinner in all my dope and lacquer products.  Have been doing it for about 20 years now.  Never use Dupont thinner with a "V" suffix!

*Your Mileage May Vary* was thrown out for all the guys who insist that you must use only one manufacturer's products all the way through.  It is something I would definitely do if I was charging a customer $20,000 for painting a car, like one of my buddies used to do.  But, if I had to do that on model airplanes, I would probably not have finished a single plane since the '70s.  I use whatever product I have on hand, and nothing has bit me so far.  I mix Sig Dope, Randolph Dope, Certified Dope, Duplicolor Lacquers, and Dupont Chromabase paints.  Never put nitrate over any other paint I use, and I do not clear Chromabase with Dope or Lacquer.  I will put automotive urethane clear over any other paint, including Rustoleum types..   Short version, I mix and match all my *lacquer* paints.

Of course, I have not used Aero Gloss Dope or Testors Dope in well over 30 years.  Those WOULD cause compatibility problems back in the day.

Mongo

Bill Little

   OK Bill !!!  You told it so even I could understand it clearly.  Thank you for your "seasoned experience".  I feel I can trust what you are saying. I'll be buying some of that Dupont thinner. And yes I know about the compatibility issues of nitrate vs butyrate, and used to use AeroGloss & Testors dope as a teenager, so I remember the issues there.  You have given me good information for sure.  My whole point for raising the question about Sig vs Brodak compatibility is a moot point right now cause I can't get the Sig Litecote clear to put over the Brodak color dope.  So I guess I have to come up with another "clear" that I can put over Brodak to make it more fuel proof. I was hoping to be able to brush it on as opposed to spraying, but that may not be workable.  Tell me if you will what options I can use that won't turn yellow. I appreciate you taking the time to help me out.

Best Regards

Dan

Hmm, you guys have me thinking now. What does a gallon of 3608S typically go for? I would imagine that you can just pick it up at your local NAPA or something?

HI Wayne,

The last gallon I bought was right at $20 for the 3608S.  3602S is also fine for our purposes, just better for high humidity (according to Ward-O).  NEVER use the *V*.

As to the clear question, Dan, I would use clear automotive urethane in a spray can, if you can find it, for the top coat.  I only spray everything now that I have had a compressor for years.  If you use urethane, give the dope a week or so to completely gas off.  It *could* lift in areas if the dope is not finished gassing off.  The urethane is a mechanical bond versus the chemical bond for the lacquer types of paint like dope.

Big Bear

Now you are opening a can of worms.  Patching a finished surface is like painting a replaced fender on a car.  It will never match up completely.  I watched one of the best in the KC area do paint on repaired cars.  He even told customers that do not look at the finish for at least a month.  I even heard tell them not to even wash it with soap for about the same length of time.  Usually the customers that listened came back and thanked him.   Painting and refinishing is an art that takes lots of time and practice.

Bill

This sounds like a win, win situation. Thanks for sharing your "seasoned experience".

Dan

And a qt of Randolph color is about 22.00.

If you like Sig Lite Coat or ANY Sig dope, hope you have it stockpiled....
The Lady on on the phone last Thursday said "That's all Folks!"
Well.....SHE didn't say THAT  
But she DID SAY "Sig dope is no longer available." 

"Tight Lines!"

Wes

I hope I'm not to late, I ordered some thinner today as I have plenty of dope but want to make sure I have enough thinner to finish my project. Guess I'll find out tomarrow.

Just received notification from Sig that my thinner is to be shipped, so they have the thinner still but for how long

I have used Dupont 3608S in both Randolph and Sig dope for years without problems. It is getting higher in price. I just bought a gallon yesterday and it was up to $25.00. I use to get it for around $14.00 ten years ago.

Hi Jim,

Yep, it has gone up slightly in the past couple years.  But so has everything else! LOL!!  I remember when I could get it at a jobbers price of about $11.  Last was about $20.  Haven't had to buy any lately, I still have 2 gallons, but I expect it will cost me close to $25 when I do.  I always get multiple gallons (as much as I can reasonably afford) so that I can work at 3:00am if I want to! LOL!!

I never had a problem with Randolph clear as a top coat back in the day.  I am missing some of the "fuel proof" part of this discussion.  No dope is fuel "proof", and the burnt fuel never seemed to attack the finish.  Just am careful about raw fuel on the finish.

I always have a can of PPG Flex Additive (plasticizer) on hand, plus PPG Fish Eye Killer, also..

Big Bear

Hi Lee,

The PPG Flex Additive, and Fish Eye killer are automotive paint (acrylic lacquer) additives that I add to dope (a "lacquer paint").  I cannot claim this idea, I got it from Windy maybe 20 years ago.  A couple drops of fish eye killer and a small amount of flex additive to the thinned paint.  I have no exact equation, but the cans have some instructions on them.  With Sig dope (which may or may not be available n the future) not much of the flexative is needed since it already contains plasticizer.  The fish eye killer is simply to help prevent fish eyes from contamination.

Big Bear