jetpack

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What is the difference between these two types of dope? What is the application for each type?

FHHuber

Nitrate is not nitro/methonol fuel resistant. Butyrate is resistant to at least 40% nitro (and can handle 65% for short durration.)

Nitrate shrinks more than butyrate.

You can apply butyrate over nitrate. You can NOT apply nitrate over butyrate.

Nitrate is usually a little less expensive.

When using both on ne plane, initial covering applicaton is done with the Nitrate, and the first 2 to 4 coats of dope will be nitrate. (Nitrate fills and seals quicker than butyrate) The color coats and final clear coat (if used) are butyrate. (if doing a gasoline, electric or unpowered plane... you can do all nitrate.)

RaceCity

Uhhhhhhh correction.


As a regular user of nitrate/butyrate dope on models...

Nitrate has NOWHERE NEAR the shrinkage of butyrate dope.

Nitrate is NOT fuel proof, but that is not what is for.

Nitrate is typically used to apply and seal the material used for covering. Further, you can add talcum power to it to make a slurry and use it for a lightweight, easy to sand filler/sealer.

Nitrate has the ability to "bond" considerably better to a material than does butyrate.

The accepted procedure is to apply several unthinned coats of nitrate to the surface to be covered. Attach the material to the structure by brushing through the edges with a 50/50 mixture of thinner/dope and rubbing it down with your fingers.

Let this dry, trim the excess and then proceed to the final shrinking, sealing, finishing, etc of the project.

This is a really fun way to finish a model! It's not fast, but the results can be spectacular, and extremely lightweight..ask any CL pro!

I really like this process, so if you need a suggestion...just say so!

Go for it!

PS...what's it going on?

somegeek

My Feedback: (2)

Bumping this old thread as I have a question... is butyrate used only for it's fuel proofing properties?

I have a project coming up I'd like to cover with silk secured with nitrate. Can I use just nitrate to secure moistened silk and then seal with more nitrate dope... and then finish with latex or other colors and finally a polyurethane spray to fuel proof?

Not seeing where I would need butyrate for this if the nitrate has some slight shrinking abilities as well as the moistened silk shrinking after being secured.

Appreciate any input!

somegeek

da Rock

Never really thought about it. But if I remember correctly, a few details do stand out.

I never had damp silk dry with wrinkles. The first attempts that had wrinkles were redone before I painted. But a couple of the early paint jobs that had the first couple of coats done with nitrate did not shrink drum tight. I'm pretty sure that I used nitrate on those early jobs for more than half the coats. I remember it as being cheaper, which was why I did that. I had less money than brains, and wasn't long on brains. And the first jobs wound up with wrinkle free, but somewhat soft open bay covering. And those were why I stopped using the nitrate at all over the open areas.

I did a couple of models with epoxy over dope. I did the dope with butyrate to get the tightest open bays. And the epoxy did soften the tightness a bit. The epoxy thinner is pretty strong however. I doubt the latex would have any effect.

Hope somebody has more up to date experience. Because I'd like to know. I'm just answering in case nobody else comes along.

somegeek

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Found the nitrate I need From what I've read, this Randolph taughtening nitrate is the goods as long as you know to add a fuel proof coating.

Stickbuilder

Nitrate Dope is a form of NitroCellulose Lacquer, while the Butyrate Dope is from a Butyl, or Butyrene Lacquer. You can dope over the Nitrocellulose with Butyrate, but cannot overcoat the Butyrate with Nitrate. Nitrate is for application of the fabric, and sealing the weave. Butyrate is for providing an attractive, fuel-resistant finish.

Bill, AMA 4720
WACO Brotherhood #1

Jim Thomerson

Both nitrate and butyrate come in taughtening and non-taughtening varities. Nitrate is considerably more flammable than butyrate, I think.

Stickbuilder

Jim,

The nitrates are extremely more volatile, and thus more flammable. But, one needs to be extremely cautious when using any solvent based chemical in the presence of a heat source (space heater etc.)

Bill, AMA 4720
WACO Brotherhood #1

somegeek

My Feedback: (2)

Thanks, Stickbuilder - never heard it broken down with a 10,000 ft view like this. Makes sense now.

I'm gonna order 5mm Habotai silk from Dharma Trading. Have read that the Thai silk is a bit preshrunk already?

somegeek

Stickbuilder

I could not tell you about the different types of silk. I use Koverall exclusively. Here is one that is over 13 years old. Butyrate over Nitrate, still getting tighter, and not a crack in the finish.

Bill, AMA 4720
WACO Brotherhood #1

Campy

My Feedback: (1)

You can do that. Latex wll adhere to almost anything if the surface is clean and oil free.

Be advised that Waterbase polyurethane does not yellow with age, however it is FUEL RESISTANT with te following caveats:

1. Let the poly dry for a minimum of 7 days before exposing to glow fuel residue.

2. Do not let the exhaust residue remain on the plane for over 4 hours. After 4 hours the finish (polyurethane ) will soften.

Oil base poly is alleged to be fuel proof, however it does yellow with age (typically 6 - 8 months ). The yellowing is HIGHLY noticeable on light colors.

dennis

My Feedback: (90)

Unfortunately dope continues to dry and shrink almost forever. Most of those old C/L or R/C planes that you see on the auction site have cracked or torn covering. They all have the tell tale curl of shrunken dope. We never have made the perfect covering for an airplane that will last indefinitely but I guess that we never cared as we never expected a model to be around for 25 or more years.
However, if your doing one today then you need to use non taughtening dope after your base coats of nitrate to at least slow down this process. And keep your planes out of the sun and heat as much as possible. Even with plastic coverings ultra violet in the sun will really fade your finish and make it brittle.
Dennis

Stickbuilder

Yep,

The only things that seem to be everlasting, are death and taxes.

Bill, AMA 4720
WACO Brotherhood #1

da Rock

Back in the 70s, I never saw tautening or non-tautening dope, but did see plasticizer and retarder. When I started flying C/L stunt (where a beautiful finish was part of the competition) both those additives were explained to me by a number of the top flyers. One happened to live in Miami (land of humidity) and yet turned out flawless paintjobs. He also could FLY even better. And I wound up living down there a couple of years. And retarder is wonderful stuff.

I noticed that Sig is still selling dope. And have not ever seen them sell 4 types. And they no longer seem to sell it in gallons.

So we've seen a link to Randolph's tautening nitrate. Which I think was what they sold years ago only without the "tautening" on the label. Because we could buy it at FBOs and additives to go with it. And the plasticizer was a necessity if you wanted the finish to last. Any link to anybody's non-tautening? Or a link to plasticizers?

Retarder was used to slow the drying to defeat fogging.
Plasticizer adjusted the shrink rate.

Stickbuilder

You can buy a retarder from your friendly local auto paint supply house. Just ask for their lacquer retarder, or better yet, just buy some slower thinner (that is not a joke, it really does exist) that will delay the kick off time for the lacquer. Automotive lacquer thinner is an effective thinner for both nitrate and Butyrate dopes. Instead of a plasticizer, try adding a few drops of Swan brand Castor oil to the Butyrate. It helps the dope flow much better before it dries. That is an old trick that we used to use 50 something years ago, and it still works well.

Bill, AMA 4720
WACO Brotherhood #1

chashint

When I talked with the customer service guy at Aircraft Spruce he highly recommended that for my next order I go with the Stits Poly Lite products. Since I was calling to talk about my accidental order of tauntening nitrate dope vs. non-tauntening it was a little bit to late to go with the Stits products. He told me that he did not recommend the tauntening product for model airplanes because it will continue to shrink for years and could crush the Balsa structure. I have a significant supply of nitrate andbutyrate dope along with the thinner and retarders for each. Once I work my way through it I will try the Stits products.
http://www.stits.com/store/index.html

jessiej

I learned never to put nitrate over butyrate many years ago when I had just completed a rather nice butyrate finish on a team racer and then sprayed on a clear topcoat of nitrate. My lovely little racer then looked as though it belonged in a leper colony.

jess

croweville

My Feedback: (23)

Hey All,
Great Thread and I know it's MANY years old but, some really great information here !! It brings back some fun memories and makes me want to build a silk and dope plane just for the fun of it....lol The "modern" builders just don't know what they are missing... I still have castor oil for the slick finishes that we ALL tried to get on our plane just to SPLATTER them...LOL
TTYL,
Bruce