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General control line discussion => Open Forum => Topic started by: kevin king on July 04, 2020, 10:21:11 PM
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What's the difference between Brodak Clear and Brodak Crystal Clear?
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What's the difference between Brodak Clear and Brodak Crystal Clear?
This is what I use and the link https://www.wicksaircraft.com/shop/?searchTerm=dope&ids=120010,120388,120392,120414,120418,
Clear Butyrate Dope
$18.70 – $302.96
All purpose dope proprietary formulated contains high total solids. Normally considered one of the best dopes for finishing fabric because of its slower curing rate, butyrate dope can be used on cotton or fiberglass fabric over nitrate dope for good tautening and filling. Can also be used over nitrate dope on dacron polyester fabric. First coat should be brushed on cotton fabrics, and thinned with butyrate thinner #9703. Remaining coats of clear #9701 may be spray applied, thinned 50- 100%.
Non-Tautening Butyrate Dope
$16.85 – $315.25
This formula has a slight increase in plasticizer and will not continue to tauten excessively. Longer drying time between each coat is required. Non-tinted is clear. Tinted is tan in color. Quarts and gallons must be sent UPS ground only. Thin one to one with #9703 Butyrate Thinner before using. Hazard.
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John had developed the Crystal Clear just prior to his Shoestring build. He did in fact use Crystal Clear to spray it. Brodak 1085 clear is quite amber in the can, it also yellows a fair amount when exposed to UV. As a result, white looks cream and blues look greenish. In addition, several of the metallics were fading badly due to UV and he received some complaints in regards to it. I spoke with John when he attended a contest in Palisades Park. He told me that he wanted to develop a dope with similar water clear like characteristics similar to Sig -Lite Coat. He also mentioned that to date, Crystal Clear was also living up to it's expectations in regards to preventing fading.
From my personal experience, I always have used Sig -Lite Coat on light structures or a finish top coat due to it's low shrinkage. I've always experienced Sig Lite Coat to be the most fuel proof top coat of the butyrate dopes I've used. John said that he felt the fuel resistance of his Crystal Clear was also on par with Sig Lite Coat. I have never personally used Crystal Clear so I can't reinforce what he told me. Cost wise, it's relatively similar to Sig Lite Coat.
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My experience with Brodak Crystal Clear has not been very good. The fuel resistance is non-existent. The gloss disappeared when I wiped fuel off of it. And, that fuel was wiped off almost immediately.
I had two cans of it go bad. I opened them to see just how clear it was. Yes, clear like it should be, no amber tint. I capped them up and put them away. A year later, when I opened them to use for a final clear coat, both turned an ugly brown. I have no idea if some contaminant got in there but the cans were capped tightly with the original lids.
I will stick with the Randolph non-tautening clear. I heard that Sig Lite Coat clear is more fuel resistant than any Brodak clear product or even Randolph clear. I sprayed one plane with Sig Lite Coat clear as final clear coat over Brodak and Randolph color dope. I did not notice any difference in appearance or fuel resistance.
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I can agree with Jim's experience with the Brodak Crystal Clear. When I received it in the can, it is clear as water. Several months later it is an off color brown. When sprayed right away it seems to remain clear, at least on the several models I have used it on. There is all most no fuel resistance to it at all. Any where fuel touches it, it dulls immediately. I have been using it over Brodak Butyrate dope after I wet sand the colors to bring back the gloss. I wax over it once it has dried for several weeks. Several of my friends use it to bring up the gloss on their gas models with no ill effects.....Gene
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Starting in 2015 I changed from Randolph A1690 clear to Certified non tautening dope for all my clear useage. I had been trouble with Randolph when clearcoating my models that were finished in lighter colors. They started yellowing about half way through the flying season. Talking to Gordon Delanie at the 2014 Golden State he suggested the swithc to Certified. I bought a gallon and never looked back. Another bonus is that buying a gallon, it will yield about 3 gallons of usable product. It is slightly more costly than Randolph but to my mine is a superior product. Dries faster, goes faster and buffs out better than Randolph. Use Randolph or Certified thinner or spend half as much for Kleen Strip lacquer thinner from Home Depot. Certified is available from Aircraft Spruce.
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There is no compatibility issue with using Certified clear over Brodak or Randolph dope?
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Use Randolph clear, forget about the Brodak stuff. I had a few new and unopened cans of Brodak clear turn dark on me too, same hue as Root Beer.
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Interesting. Ken answered Kevin's question....
Randolph was made in NJ....mayhaps Rutherford? Windy and John worked with them to proving colors that had more tint than their regular blends....
Brodak initially had the product shipped in large pails of each color.
Then the product morphed as EPA rules changed and Brodak began blending some of the colors with thinner and clear in house.
When Randolph was sold all colors were blended at John's place.
As to the clear....it really bothered John when Danny's Mustang yellowed. Especially since none of Windy's had. Hence "Crystal Clear".....no additives....
Randolph held that the paint/clear was too thick after application.
There are very few companies that blend dope today (EPA, plus superior alternatives) and several brands come from the same factory.
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Jim, I have used Certified for the past 6 models and have not seen any issues over Randolph, Brodak, Sig or acryjic lacquer colors. I also have not had problem using Randolph thinner or the lacquer thinner I mentioned. I use lots of thinner in tbe course of finisning my models so saving a bit of money is smart.
All my models are finish*ed with various brands of colors but Certified clear from base coats to filler and final clear coats.