Author Topic: Randolph Dope (Read 3018 times)

James Mills · « **on:** November 21, 2010, 02:47:28 PM »

I'm planning to order some Randolph's clear from Wicks. I want to use their clear for the entire process and mix pigment myself form a local shop. Which clear do I need (anybody have a part number). Is it just one type of clear or will I need a different type (I saw non-taughting and wasn't sure what it was for).

Thanks,

James

Tim Wescott · « **Reply #1 on:** November 21, 2010, 03:10:16 PM »

First: don't believe just me.

Second: You only want to use tautening dope on loose covering -- if the covering is nice and tight already, tautening it more is a Bad Thing.

I've always used coverings (tissue and silkspan) that don't require tautening dope, so I have no experience with it. But my understanding of the process is to put on your covering, then if it's loose then apply coats of tautening dope until it's good, then do everything from that point on with non-tautening dope. I've always been able to do the whole shebang with non-tautening dope (Sig lite-coat clear, and super-coat color, although it looks like I'll have to switch to Randolph).

HTH.

Jim Thomerson · « **Reply #2 on:** November 21, 2010, 03:51:09 PM »

There is tautening and non tautening in both nitrate and butyrate. On open bays; silk, silkspan, tissue, I put on a thin coat of tautening and then go to non tautening. Use non tautening on sheet surfaces. I bought thinner from Wicks as well.

Leester · « **Reply #3 on:** November 21, 2010, 04:04:44 PM »

If it says non taughtening it will still shrink, just not as much (Sig Lite Coat). Also you can put Butyrate over Nitrate but NOT Nitrate over Butyrate.

Allan Perret · « **Reply #4 on:** November 21, 2010, 04:35:38 PM »

On my recent RMD project I covered the wings with Polspan, everything else with med silkspan. I used nitrate only to apply the Polyspan, but then used A-1690 (non-tautening) for the rest of the finish. I plan to simply the process on next project and use the A-1690 for everything.

Bill Little · « **Reply #5 on:** November 21, 2010, 08:52:27 PM »

Hi James,

If you can apply the silkspan really tight, then you can use all non-tautening dope. And using only non-tautening butyrate is not a bad idea.

I have a bad habit of wanting my silkspan to be as tight as possible, and as long as the silkspan is good, it has never been a problem. And I can put it on as tight as anyone before hitting it with dope. Of course, I use a very "old time" program..... nitrate, tautening butyrate, non-tautening butyrate. Then who knows what for colors......

I have actually been asked how I put on the silkspan (never cover the tips separate, and still no wrinkles) but there are no secrets to it.

It all depends on the system "YOU" develop for yourself.

Big Bear

wwwarbird · « **Reply #6 on:** November 21, 2010, 11:51:13 PM »

This post might also answer some of your questions:

http://stunthanger.com/smf/index.php?topic=19162.0

It's not included in the post, but just last week I spent some time on the phone with manufacturers and painters on this very subject. If you're going to use off-the-shelf Randolph, A1690 non-taughtening butyrate is what you want. I haven't actually used it, but after a lot of research I've nailed it down to being the closest off-the-shelf product to Brodak butyrate clear. It does still shrink, just not as much as taughtening. Taughtening might shrink too much for our models and could make your wing curl up like a potato chip.

Neville Legg · « **Reply #7 on:** November 22, 2010, 12:49:56 AM »

The Dope manufacturers say that the first coats, and the coats used to stick the tissue/silk to the airframe should be Nitrate as it has far better adhesion properties than Butyrate.

Cheers Neville

wwwarbird · « **Reply #8 on:** November 22, 2010, 01:27:31 AM »

Everyone has their favorite process it seems. All I do is mix up butyrate and thinner 50:50 and use it on the entire model from the very first coat on the bare wood, all the way through the wing covering and silkspan work, up until I'm ready for color. I Polyspan the wing and silkspan all of the rest of the model and never use any sanding sealers or primers. Works for me.

Randy Powell · « **Reply #9 on:** November 22, 2010, 10:03:11 AM »

I use both Randolph's and Certified (depending on what was on sale when I buy it - they are about the same cost wise). I use non-taunting butyrate from the wood up. Same material. You can get Randolph's butyrate taunting, non-taunting. They tint it so you can see the difference immediately or you can order the crystal clear stuff. I use the crystal clear stuff, though I've used the amber tinted stuff when using a transparent finish because it tends to even out discolorations in the wood.

But Bill's right, you want to make sure the silkspan is tight over open bays before a hitting it with dope if you are using non-taunting throughout.

James Mills · « **Reply #10 on:** November 22, 2010, 03:59:40 PM »

Quote from: Allan Perret on November 21, 2010, 04:35:38 PM

On my recent RMD project I covered the wings with Polspan, everything else with med silkspan. I used nitrate only to apply the Polyspan, but then used A-1690 (non-tautening) for the rest of the finish. I plan to simply the process on next project and use the A-1690 for everything.

Allan,

I plan to use polyspan. Did you use the same thinner in the nitrate as the buturate?

James

Allan Perret · « **Reply #11 on:** November 23, 2010, 06:54:02 AM »

Quote from: James Mills on November 22, 2010, 03:59:40 PM

Allan,

I plan to use polyspan. Did you use the same thinner in the nitrate as the buturate?

James

Yes, it is important to use the same thinner from start to finish. In my case I used an off brand (Finish Pro), others have successfully used Dupont or Duplicolor lacquer thinners, but the safest route is to use thinner from same manufacturer.

billbyles · « **Reply #12 on:** November 26, 2010, 03:18:27 PM »

Quote from: James Mills on November 22, 2010, 03:59:40 PM

Allan,

I plan to use polyspan. Did you use the same thinner in the nitrate as the buturate?

James

Hi James,

Butyrate thinner will work in nitrate with no problem; nitrate thinner will not work in butyrate dope.

Bill Byles

billbyles · « **Reply #13 on:** November 26, 2010, 03:26:17 PM »

Quote from: Tim Wescott on November 21, 2010, 03:10:16 PM

First: don't believe just me.

Second: You only want to use tautening dope on loose covering -- if the covering is nice and tight already, tautening it more is a Bad Thing.

I've always used coverings (tissue and silkspan) that don't require tautening dope, so I have no experience with it. But my understanding of the process is to put on your covering, then if it's loose then apply coats of tautening dope until it's good, then do everything from that point on with non-tautening dope. I've always been able to do the whole shebang with non-tautening dope (Sig lite-coat clear, and super-coat color, although it looks like I'll have to switch to Randolph).

HTH.

Although I figure that you know this already, regarding your comment "(Sig lite-coat clear, and super-coat color...," Sig color is made in the non-tautening (Lite-Coat) format, so it is non-tautening. However, when applying the Sig (or Randolph) color I do add some of Dave Brown's "Flexall" in the recommended amount as shown on the Flexall label. Just for general info.

Tim Wescott · « **Reply #14 on:** November 26, 2010, 06:40:33 PM »

Quote from: billbyles on November 26, 2010, 03:26:17 PM

Although I figure that you know this already, regarding your comment "(Sig lite-coat clear, and super-coat color...," Sig color is made in the non-tautening (Lite-Coat) format, so it is non-tautening.

Sig color is non-tautening, and called "SuperCoat". Sig's non-tautening clear is called "LiteCoat" and their tautening clear is called "SuperCoat". This is confusing as hell until you memorize it, and yes I do know the difference.

I have no idea what the history is behind their naming conventions, but it is rather anti-intuitive.

billbyles · « **Reply #15 on:** November 29, 2010, 10:51:37 PM »

Quote from: Tim Wescott on November 26, 2010, 06:40:33 PM

Sig color is non-tautening, and called "SuperCoat". Sig's non-tautening clear is called "LiteCoat" and their tautening clear is called "SuperCoat". This is confusing as hell until you memorize it, and yes I do know the difference.

I have no idea what the history is behind their naming conventions, but it is rather anti-intuitive.

I have a feeling that they had an extra bunch of "Super-Coat" labels that they just stamped with the color name and stuck on the can...it is counter-intuitive!

Mike Lauerman · « **Reply #16 on:** December 19, 2010, 11:32:38 AM »

Well...
Called Sig for some price/availability on clear dope. Lady on the phone said they're fresh out, not sure when they'll have it again.

Went to my closest hobby shop in Modesto (CA.) which is 40 miles away. They always have what I need, and are a Sig dealer...
They are out of Supercoat, Litecoat, and Nitrate clear. They had 3 qts. of thinner ($14.95) I bought 1, as the counterman said the price was going to double...and not going to have Sig dope in the near future.
They seem to be selling lots of R/C RTF planes & cars, as are most now.

Then I called my favorite store, J&M in San Carlos. (140 miles away) They have 1 gallon of Supercoat, $40. Tempting, but not at the mileage my hopped up '66 VW gets (22 mpg) Nix a 140 mile trip for clear dope!

Called Aircraft Spruce, (this was Thursday afternoon) ordered a quart of Randolph thinner and a quart of Randolph clear dope. Saturday morning, Fedex truck pulled up and delivered the package!
Great service, great prices. Randolph here from now on.

larry borden · « **Reply #17 on:** December 19, 2010, 02:17:07 PM »

Since I have access to a Randolph supplier here, I've been using Randolph with no problem.

Bill Little · « **Reply #18 on:** December 19, 2010, 09:15:56 PM »

Quote from: wwwarbird on November 21, 2010, 11:51:13 PM

(snip) Taughtening might shrink too much for our models and could make your wing curl up like a potato chip.

Hi Wayne,

For years (when I was buying Randolph's from the airport) I used nothing but the" tautening" clear butyrate for fill and final clear. One of those models (A Smoothie built in '64) still hasn't warped. I recovered it about 10 years ago. As a kid, I didn't really know any better!

But it never seemed to warp things up. Around the mid '90s the airport changed hands and I can no longer buy my Randolph's, or anything else, there. Still much cheaper to order Randolph's (or Certified) from Aircraft Spruce than to order any of the "model" company dope. Sometimes it's around 50% of the cost, quart versus quart.

Bob Reeves · « **Reply #19 on:** December 23, 2010, 03:38:57 PM »

Just an observation..

In the middle of a project needed Polar Grey and Brodak was out. Ordered a quart of Randolph and first thing I noticed was it seemed to be allot thinner than Brodak. I mixed my usual 50-50 and started spraying. It took almost twice as much material to cover than what I am use to with Brodak.

Brodak dope has always been advertised (at least by Windy) as having more solids than normal dope and now I'm sure of it. I used Brodak thinner because that is what I had and it worked great but think I'll stay with Brodak dope when I can get it.

Bill Little · « **Reply #20 on:** December 23, 2010, 04:41:23 PM »

Quote from: Bob Reeves on December 23, 2010, 03:38:57 PM

Just an observation..

In the middle of a project needed Polar Grey and Brodak was out. Ordered a quart of Randolph and first thing I noticed was it seemed to be allot thinner than Brodak. I mixed my usual 50-50 and started spraying. It took almost twice as much material to cover than what I am use to with Brodak.

Brodak dope has always been advertised (at least by Windy) as having more solids than normal dope and now I'm sure of it. I used Brodak thinner because that is what I had and it worked great but think I'll stay with Brodak dope when I can get it.

Hi Bob,

I haven't really noticed, but I am sure you are correct. Either way, I will just spray on the amount I am gonna spray on, regardless of the brand.

Ordering a quart of Randolph is less expensive than ordering 2 pints of Brodak in my case.........

The little bit of Brodak I have used (only available to me through mail order) has been good, good stuff. Of course, I have several unopened quarts of automotive acrylic lacquer left over....... and it was free........

That Mercedes Benz Metallic Gray quart will do a couple full size stunters, at least! LOL!!

EddyR · « **Reply #21 on:** December 23, 2010, 05:56:44 PM »

I ordered from Aircraft Spruce yesterday. I use 9701 and add plasticizer as needed. They sell a great retarder also.
Ed

Tom Niebuhr · « **Reply #22 on:** December 23, 2010, 06:25:02 PM »

"That Mercedes Benz Metallic Gray quart will do a couple full size stunters, at least!"

Bill,
Is that a Gray version of the Hunt Bronze?

?

Bill Little · « **Reply #23 on:** December 24, 2010, 12:45:09 AM »

Quote from: Tom Niebuhr on December 23, 2010, 06:25:02 PM

"That Mercedes Benz Metallic Gray quart will do a couple full size stunters, at least!"

Bill,
Is that a Gray version of the Hunt Bronze??

LOL!!!!!!!!!! I think Bobby bought a 55 gallon drum of International Harverster Bronze way back......... He probably still has a couple gallons left!

Bill Little · « **Reply #24 on:** December 24, 2010, 02:11:01 PM »

Quote from: Ty Marcucci on December 24, 2010, 01:07:53 PM

Good Morning Bill. Bob told me it was a Ford pickup color. I tried to make bronze from some stuff I found at Hobby Lobby. What crap that turned out to be, rough as sand paper. Looked great on the weeds in the back yard though!!

Odd, Ty! Bobby actually told me about 20 years ago that it was an I.H color........... Hmmmm.... maybe it was a top secret "Govrnmnt Project!"

There is a company in NJ (can't remember the name) that's been doing business in "powders" that mix in paint for close to 60 years, atleast. I know that one of their products: "Venus Gold Dust" was mixed in clear lacquer to paint Rex White's (1959-1964) and Smokey Yunick's (1956-1962) NASCAR entries. I actually have some of the stuff from Louie Clemmeons' son, Mike, that Louie used for painting Rex's cars. It's not a metal flake, it is actually a microscopic dust. So fine that it pours like a liquid! I am using it for the trim on a classic plane to duplicate (with a slight touch) the original paint scheme.

Tom Rounds · « **Reply #25 on:** January 05, 2011, 05:33:59 PM »

Someone awhile back was talking about hazmat charges on dope. I talked with Aircraft Spruce company today and was told that they can ship 2 gallons or 4 quarts in one box and no hazmat fees.

Bill Little · « **Reply #26 on:** January 05, 2011, 05:55:38 PM »

Quote from: Tom Rounds on January 05, 2011, 05:33:59 PM

Someone awhile back was talking about hazmat charges on dope. I talked with Aircraft Spruce company today and was told that they can ship 2 gallons or 4 quarts in one box and no hazmat fees.

Thanks, Tom! Last time I checked, the quarts didn't apply to Haz Mat, but any gallons did. Glad to see that I can get a gallon and not pay an extra $20 or so for the "Feds' Fees". Sure would hate to see what the impact would be on the environment foa gallon of dope that spilled........ not!

Big Bear

Mike Lauerman · « **Reply #27 on:** February 07, 2011, 06:12:13 PM »

Quote from: Bill Little on December 24, 2010, 02:11:01 PM

Odd, Ty! Bobby actually told me about 20 years ago that it was an I.H color........... Hmmmm.... maybe it was a top secret "Govrnmnt Project!"

There is a company in NJ (can't remember the name) that's been doing business in "powders" that mix in paint for close to 60 years, atleast. I know that one of their products: "Venus Gold Dust" was mixed in clear lacquer to paint Rex White's (1959-1964) and Smokey Yunick's (1956-1962) NASCAR entries. I actually have some of the stuff from Louie Clemmeons' son, Mike, that Louie used for painting Rex's cars. It's not a metal flake, it is actually a microscopic dust. So fine that it pours like a liquid! I am using it for the trim on a classic plane to duplicate (with a slight touch) the original paint scheme.

Bill...I know of the company in NJ. My friend Doug was from there, and he was painting Harleys (1976) He went around back and saw some guys working, they had paper surgical masks on and were covered in silverish soot!
He asked what it was, and they said "Mother of Pearl". One of the guys gave Doug a pint jar of it, said "It's O.K., we waste that much grinding it up."
When he moved out here to Calif., Doug had pearlescent paint on more than one B/Team racer! He still had some in the jar.

Bill Little · « **Reply #28 on:** February 07, 2011, 06:55:49 PM »

hi Mike,

Louie had it in quart cans. He would pour the gold dust in clear lacquer and spray it over white. it was the most striking gold I have ever seen in paint. Not a metal flake, nor metallic, just a layer of shiny gold!

Bill

John Leidle · « **Reply #29 on:** February 28, 2011, 01:52:39 PM »

Hi Bill,
I had a 1971 Internatonal painted Bronze, Beautiful. As far as the gold dust I did just that on my Motorcycle I picked up some colored flakes & dumped it in the clear & shot it. Turned out fine.
John

Bill Little · « **Reply #30 on:** March 02, 2011, 09:49:02 PM »

Quote from: John Leidle on February 28, 2011, 01:52:39 PM

Hi Bill,
I had a 1971 Internatonal painted Bronze, Beautiful. As far as the gold dust I did just that on my Motorcycle I picked up some colored flakes & dumped it in the clear & shot it. Turned out fine.
John

Hi John,

I have already used some of this "Venus Gold Dust" in clear lacquer shot through the airbrush. I noticed something on my skin....... got my optivisor and it is microscopic bits of gold. The individual specks are almost too tiny to see with reading glasses. it is really "ultra fine" stuff.

I also picked up some House of Kolor red flakes to use the same way for trim. it's all neat stuff to use!

Bill

Author Topic: Randolph Dope (Read 3018 times)

larry borden

John Leidle