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Building Tips and technical articles. => Paint and finishing => Topic started by: Chuck_Smith on December 09, 2012, 03:36:14 PM

Title: Question re:Brodack Dope
Post by: Chuck_Smith on December 09, 2012, 03:36:14 PM
Guys, long-time Supercote and Lite-coat guy here. I use Supercoat only over open bays to taughten, and then Lite-Coat from then on.
Are Brodack colors or clear a taughtening dope or not?

I'm really fanatical about "straight and light". Back in the early days I had Randolphs turn good wings into pretzels...

That said, I always am looking for something new.

Should I just bite the bullet and start using automotive finishes?  My reluctance there is that I have painted cars and know how heavy DuPont or House of Color usually goes on, but those metalics sure look awesome on some guitars I've painted.

(I always wanted a stunt ship with a bass boat flake finish... that would look soooooo cool in the air on a sunny day!)
Title: Re: Question re:Brodack Dope
Post by: larry borden on December 11, 2012, 08:23:27 AM
I Talked to someone at Randolph, who supplies Brodak with ingredients for his dope. According to them the colors are non-taughtening.
Title: Re: Question re:Brodack Dope
Post by: Bill Little on December 11, 2012, 05:05:58 PM
Hi Chuck,

You can get tautening and non tautening clear butyrate or nitrate from Randolphs, and at a much cheaper price.

For metallic finishes, get the toners with out the carrier/binder and add it to clear dope.  Just tell the counter guy that you just want the toners for say a pint.  It will probably cost the same as buying a "full pint".  Of course you can get several different sizes of "flakes" and pearl powders also, to add to clear.  HOK also offers candy concentrates that are added to clear dope.

Bill
Title: Re: Question re:Brodack Dope
Post by: Chuck_Smith on December 12, 2012, 10:19:10 AM
Bill, that's a great idea. I have a few paint shop contacts that can get me the toners.

Thanks!

Chuck
Title: Re: Question re:Brodack Dope
Post by: Randy Powell on December 12, 2012, 02:10:50 PM
House of Kolor makes really good additives, too. Both flake and pearl.
Title: Re: Question re:Brodack Dope
Post by: Bill Little on December 12, 2012, 02:16:21 PM
House of Kolor makes really good additives, too. Both flake and pearl.

Yeah, I meant to add the flakes and pearl powders in with the candy concentrates being available from HOK........ ;D  (PPG also carries the pearls/flakes)

BIG Bear
RNMM/AMM
Title: Re: Question re:Brodack Dope
Post by: Howard Rush on December 13, 2012, 02:27:47 AM
Back to the original question: Windy Urtnowski said that Brodak clear is somewhere between tautening and nontautening dope.  I discovered when I used it on silk that it leans toward the nontautening.  I had to resort to Sig to get the wrinkles out of the silk-covered airplane.  Brodak brushes nicely, and I used it successfully on a silkspan-covered stunter without any supplemental tautening dope.  You can use Brodak and Randolph interchangeably.   On the last two planes I built, I used Polyspan with Randolph tautening and nontautening dope used as you used the two Sig dopes.  I think most folks use that combination now, although some start with nitrate.  After the clear is on, folks diverge to different combinations of dope and car paint.  The best writeup I've seen on how to get a good finish (20 points at the Nats) was Phil Granderson's in Model Aviation about 2006.  He starts with dope, then uses car paint toners in dope, and then Isocyanate Death Paint clearcoat. 
Title: Re: Question re:Brodack Dope
Post by: Dave_Trible on December 19, 2012, 01:05:41 PM
My comment is to say I had significant warpage issues with Brodak but I otherwise liked it.  Went to Certified non-taughtening clear and Sig colors which mix well.  You can use cheap laquer thinner with it fine.  Do throw in a little retarder.  The Certified (Aircraft Spruce) solved my issues and is actually cheaper anyway.

Dave
Title: Re: Question re:Brodack Dope
Post by: Randy Powell on December 19, 2012, 02:44:55 PM
OK, I'l forego my usual lecture about using non-compatible materials.
Title: Re: Question re:Brodack Dope
Post by: john e. holliday on December 20, 2012, 07:31:22 AM
Can I blame the use of Brodak dope for the severe warpage of my Sweet Sweep.   No way, as I have used Brodak clear on many planes without any problem.  The problem on the SS was my construction of it. 
Title: Re: Question re:Brodack Dope
Post by: Avaiojet on December 20, 2012, 02:23:40 PM
OK, I'l forego my usual lecture about using non-compatible materials.

Randy,

An extremely good point worthy of further discussion.

On another related note. I'm absolutely positive I read in a Thread that Brodak dope was not fuel proof?

Charles
Title: Re: Question re:Brodak Dope
Post by: Mike Keville on December 20, 2012, 05:50:19 PM
. . . I'm absolutely positive I read in a Thread that Brodak dope was not fuel proof?
Charles

Gee, that must come as a real shocker to the hundreds of people who're successfully using it!

No dope is completely fuel-PROOF, though some butyrate dopes are fuel-RESISTANT, up to a certain Nitro' content.
Title: Re: Question re:Brodak Dope
Post by: Avaiojet on December 20, 2012, 06:50:52 PM
Gee, that must come as a real shocker to the hundreds of people who're successfully using it!
No dope is completely fuel-PROOF, though some butyrate dopes are fuel-RESISTANT, up to a certain Nitro' content.

Mike,

Do you clear your dope with automotive two part clear?

To play it safe I will. I may not even use dope.

Charles
Title: Re: Question re:Brodak Dope
Post by: Mike Keville on December 20, 2012, 07:51:16 PM
Mike,
Do you clear your dope with automotive two part clear?. . .
Charles
======================================

No, I didn't.  That was on a 1/2A Free Flight "Zeek".  25% nitro fuel pretty much 'ate' the clear dope off the front end, but that was probably my fault since I used an automotive thinner rather than the recommended Brodak brand.

Live and learn . . .
 
Title: Re: Question re:Brodack Dope
Post by: Steve Helmick on December 26, 2012, 10:50:00 PM
A "Zeek", huh? And I pictured you as more of a "Fubar" kinda guy, Mikey.  010! Steve
Title: Re: Question re:Brodack Dope
Post by: Mark Scarborough on December 27, 2012, 10:43:48 AM
OK, I'l forego my usual lecture about using non-compatible materials.
as will I,,
( I think I will write up a disclaimer, keep it in a word file,, and then I can copy paste it on each new discussion about paint and using cheap thinner in it)