Is anyone interested in discussing butyrate dope?

I agree, dope finishes can be costly, take a lot of time, and be disappointing, IF you don't ask questions and get a little direction. Before I started with dope finishes I asked a bunch of questions, thus avoiding much disappointment.

BTW-I also build and fly. Dope and fabric or film, one way isn't better than another. It just another way. Sometimes one is suited for one application over another, i.e film and combat planes.

And as far as "can't wait to see....", If Richard doesn't post pictures and I can't wait any longer, I'll just have to take a little drive to see for myself. It's just one of those sayings.

Duke:

Yes I realize that it's only a figure of speech but it would be more accurate to write "I hope you send pictures soon".

"I can't wait to see" conjures up a image of "can't wait to PEE".  

SD

I put a chart on my club's web site that shows what paints/dopes can be used over/under others.
Fresno Gas Model Club

 Duke & Steve, Thanks for the tips! Steve FF looks like a lot of fun & I'll copy your chart.


  Super Dave....Why be so negative?
I am just an old retired plumber trying to have little fun. I can honestly say its been 55 years since I flew or built any of these models.

RK Flyer  

from now on... I'm going to patiently sit and wait... to see...

OK.....I got the first coat on the fuse today & I guess I didnt thin it enough so I'll sand it tomorrow & start again. Ill be using White & maybe Black on the wing and a dark Grey on the fuse. Ive been trying to come up with an easy pattern for the wing.

This is a scratch built sort of Ring Master, I took the fuse from one set of plans & the wing and elevator form another & Presto!

I am not very good at posting pictures soooo I'll have to ask the wife  


RK Flyer  

Richard
Your a plumber also? I've been plumbing for about 22years.

SD-"... can't wait to see..." is less like the pee pee dance and more like:bounce:    
 Love ya Dave!

Reading this thread, I would like to contribute some of my doping experience. I've done nothing but dope finishes for the past 30 years until the past 5 years. I still do them, but when Sig was having difficulty, so was our local hobby shop in purchasing material. When they returned, the cost didn't just double. The cost increased to the point of not making the product worth purchasing. One qt of Sig clear is $30 without even factoring in shipping and hazmat. The thinner is waaaaaaay over the top which led me to use a substitute which is the Dupont 3608S and not the 3608 VS for those interested. One gallon of Dupont is $25 where I purchase it. It's been over a year since I purchased it and as mentioned to me. The EPA wants all solvent based paints and thinners off of the shelves. They will only be made available to certain specialty markets like aircraft restoration and antique car restoration in which the cost will triple.

I've switched to water based polyurethanes but I use nitrate as a base. Nitrate dope virtually works with almost every finish out there as a base coat. No it's not fuel proof, but either is dope so don't get fooled into thinking dope is fuel proof. Sig dope in my opinion has the highest resistance to fuel and it's also the easiest and most friendly dope to brush. Spraying yields excellent results. THis is due to Sig having the slowest thinner out of what dopes are currently available. It will not blush like Brodak's or Certified dopes will and Sig Lite Coat has the least shrink rate out of ALL of the dopes. Remember you have taughtening and non taughtening dopes. They're all taughtening to some degree but the term is used due to certain dopes having a incredible shrink rate which can crush and distort a model. This is why you shouldn't use full strength dope. Seeing that the majority here probably uses dopes made specifically for the hobby, this is more than likely not going to crush your model. Some of us including myself have purchased Randolph dope directly and the commercial grade dopes made specifically for Ceconite is a very high shrink rate and therefore very careful attention is needed when applying. This means applying both sides with the same amount of dope and allowing the panels to dry equally before reapplying.

Using dope depends on what type of finish your after. I've done the rubbed out dope finishes and I can tell your it takes a lot of material and a LOT of work. I have approximately 8-10 coats of clear on the model prior to color. These coats are first brushed on and after the attachment coats for the covering, I do 2-3 more brushed coats followed by spray coats. I spend special attention to spraying just the ribs over and over including wing tips as well. You don't want to sand through these areas , so building up coats on these high areas are imperative as they will burn right through if you don't have enough material on top of them. After spraying a panel and allowing it to tack up, take the gun and spray just the ribs from leading edge to trailing edge by adjust the gun to a straight pattern vs a fan pattern.

If using Brodak dope, having retarder on hand is a must. It will blush due to the high evaporative rate of the thinner. A splash or two will remedy this problem. Sig isn't so kind to retarder. If you need to add retarder to Sig dope, you picked the wrong environment and day to use it. Once again, retarder is another product and once again, the cost gets even higher. Generally stick with the same products. I've found that I can interchange some, I won't get into details here, but the Dupont thinner works for both Sig and Brodak. If the 3608 S is used, it doesn't like to be brushed, it likes to be sprayed. If you choose to use a brush, purchase the DUpont 3602 S which is the slower drying thinner.

Assuming all is good and the model is covered and your ready for your brush coat, don't land a loaded brush of dope in the middle of a open bay. This will load that one area making a shiny spot later in the finish and it can also lead to a stalactite formation of dope through the covering. Start on the sheeted area and work from leading edge to trailing edge. DON'T brush from fuse out to the wingtip. The brush will be squeegeed up against the next rib and will force excess dope out of the brush and it will puddle up adding unecessary weight and more material which will need to be smoothed out with sanding. Once a few coats are on the model, then the dope can be brushed perpendicular to the ribs. This is also true as your brushing from leading edge to trailing edge, use caustion as the brush is being applied to the trailing edge as the dope will once again be squeegeed out. I pretty much paint the perimeter and starting with a loaded brush on a solid area brush out with the intent that when I do brush onto a intersecting area, the brush is now dry. It's must to keep the brush loaded when brushing so that you have a wet edge constantly. Otherwise the color will drag. Sig is much more forgiving here and the finish will look like @#$% but once the model sits for a hour or two, the finish will look truly professional as all the dope will level revealing a very professional look. THis is why spraying is the ticket but not all have access to spray equipment. A Pre-Val sprayer can be used from Home Depot and will give fair results . The bottle with the sprayer has graduations and is glass making a very valueable tool for dope users when it comes time for mixing. Baby food jars work equally well if your using small amounts.

Documenting your cutting rates of thinner to clear or color is a must and should be used as a tool . How the material leaves the gun or brush is another valueable tool. Keep your eyes on the dry rate and keep the thinner nearby when brushing. many times, I have to stop and splash in some more thinner due to the open container. The thinner is evaporating and therefore needs to be replenished. I hope some of this helps for those who never tried to do a finish like this. I'm not trying to discourage, but it's a very costly finish if your striving for a really nice finish. It's also one that's going to require maintenance. Ken

Ken explains in much greater detail than I did my concerns with moderen butyrate finishes.

The "learning curve" with modern butyrate is shallow, time consuming and expensive.
Accept those constraints and you'll do fine.  "Old Timey" Aero-gloss it ain't.

(The source of Aero-gloss was destroyed some years ago by fire.  Owners decided not to rebuild due to decreasing demand from the hobby industry and environmrntal regulations)          

SD

Hey Dave, Midwest still carries Aero Gloss is the same stuff as the old Aero Gloss?

True Ron but the Midwest equivilent of Aero-gloss only comes in clear.

Correct me please if I'm wrong.

SD

SuperDave wrote:True Ron but the Midwest equivilent of Aero-gloss only comes in clear.

Correct me please if I'm wrong.

SD

That said; I wonder if it's possible to add a compatible "pigment" for color... if you could find it? You could then custom-blend your own colors.

"Super Dave....Why be so negative?
I am just an old retired plumber trying to have little fun. I can honestly say its been 55 years since I flew or built any of these models."

-RK Flyer

Can't see that I'm being negative.  I'm warning the inexperienced of the potential problems involved in applying a butyrate finish.

OK?

SD

(I'm a 76 year old retired high school teacher trying to pass on the knowledge that I've acquired from building models for over half a century)

Aero Gloss at ONE TIME was the cat's meow. It would have a gloss that was truly amazing. Testor's however had some really good dope as well. I loved Testor's butyrate. Aero Gloss always was different in terms of it was unique to itself in which other products couldn't be intermixed. We all know it's best to not intermix, but as modelers we tend to use what we have. That being said, if you have old Aero Gloss, use it up. The formulation has been changed many many times and sometimes the product won't even work with Pactra thinner. My advice would be to use it for something you don't care about. The white was horrible and would check really really bad.

I had good success with the old Red and black Pactra cans that Rod displays. My favorite all time color was the silvairre aluminum. It truly looked terrific for silver. The newer Midwest stuff isn't even close to the old Aero Gloss . If your just looking to burn up the sky, by all means paint away. I just wouldn't use it for anything nice. A little goes a long way and sport type airplanes go through a lot of punishment and abuse so attic stock you have is perfect for this stuff. Ken

This is a great thread. Thanks to everyone who has contributed. It has been very helpful. Andy

It seems most are shying away from dope finishes in this thread, and I'm not sure why.  It does cost more and is harder to get the materials, but other than that is just a learning curve. It would be hard to do it by yourself and learn from ground zero, but that's the same with monokote or any other film.  But we have each other to learn from and not make all the same mistakes, just like anything else, starting an engine on a bladder, rebuilding an engine, and ect.  Dope finishes really isn't that big of a deal, unless you are shooting the for a finish like these.  Theses are all dope finishes, all hand done, and no decals.
The Crossfire-designed by Bob Hunt
Another Crossfire

A Starfinder Painted like a Super Chipmonk

And Paul Walker's Impact he calls the Predator or the Dwag plane he won the NATS with this year and says it perfect and he won't fly it again until NATS 2014

The Starfinder and the Impact were done with maskings a friend makes on the computer and they all go on and you peel off layers as you spray the next color. These planes have finishes as good or better than a car. Of course these are all "Expert" PA planes, built and flown by "Experts". Now I build like a Beginner and fly like a Beginner, and with any luck I make the next step building and flying soon.

SuperDave wrote:"Super Dave....Why be so negative?
I am just an old retired plumber trying to have little fun. I can honestly say its been 55 years since I flew or built any of these models."

-RK Flyer

Can't see that I'm being negative.  I'm warning the inexperienced of the potential problems involved in applying a butyrate finish.

OK?

SD

(I'm a 76 year old retired high school teacher trying to pass on the knowledge that I've acquired from building models for over half a century)

SD, No worries!
I think I am learning exactly what you are trying to tell me after applying the 2nd coat of paint & several coats of clear today. Still looks rough!

The next project I'll try some kind of MonoKote! RK Flyer  

Being a traditional doped tissue, silk and nylon chap - when I had finished the Night Hawk - I used butyrate dope. I had read that it was fuel proof.

Three thinned coats, 24 hrs between. It looked right, smelled right but --- IT WAS NOT FUEL PROOF! It softened with time and the area around the engine turned messy. I wasn't impressed!

I have 2 litres of this and will now only use it up on stick and tissue (non IC aircraft) with no other finish.

From quite a few forums - I have come to the conclusion that paint formulations constantly change and I wouldn't want to take the risk of anything reacting adversly when at the final stages of finishing. Butyrate is incompatible with too many finishes.

Trying to remove the mess would be a chore to me and I would resort to a box of matches!

Ian:

To which brand butyrate are you refering?

Are you postive it wasn't nirate?

SD


(It's always good deal to check the compatibilty of dope on a sample before applying to a surface to be finished)

Aerogloss was always my best friend, or worst enemy.  It could add the shining touch to a beloved and hard-earned project, or it could tick me off and send me tearing open a new pack of sandpaper.

As with just about everything in this hobby, it comes down to personal preferences of effort vrs results vrs time invested vrs pure dumb luck. It doesn't matter though, I STILL want to make try to make the stuff work.

These are some of the Great (on my scale) Successes I'd had while raising a volatile chemical cloud that used to get me chased out to the back porch when I was kid.

Dave Robelen's "Sperry Messenger"
Scaled 10% up from Dave's Plan in the June '69 M.A.N., with the Tee Dee .010 up front, it STILL flew more like an over-powered Pitts than a 3-cylindered, radial-powered dandelion hopper. The warping nature of butyrate dope was actually used to create an "airfoil" in the flat 1/16th wings. It has held this curve since the 1990's, and I'd love to credit my "Mastership of Building/Finishes"...but really ain't got a clue and am just happy that the thing has stayed relatively true.





Dave used an exhaust restrictor on his .010, but I didn't want to hurt this little sucker. Besides, Dave's Sperry was Single-Channel Pulse, where I had a trimable elevator, so I could, in the words a of a crop-duster bud, "Put 'er nose down and let'r eat !"

I'd intended to do a light yellow airbush on the wings, but wanted to try it in clear to see if the thing would actually fly. After I got it going, I was too lazy to go back and paint it, so the wings stayed "Natural". The Aerogloss, for whatever reason, managed to survive many doses of high-nitro fuel.



It was guided by a two-channel Cannon radio with the servo's mounting ears lopped off and shoe-horned into the almost-too-tiny cockpit. I intend to stick a couple of Bernie's Icon servos in it and put it in the air again.

SuperDave wrote:Ian:

To which brand butyrate are you refering?

Are you postive it wasn't nirate?

SD


(It's always good deal to check the compatibilty of dope on a sample before applying to a surface to be finished)

Positive



I use 20% nitro fuel and 5 hours worth of engine running. A wipe down after each session and a good clean before storing.

OK it's "Five Star" butyrate and apparently NOT fuel-proof. I'd be talking to the folks that sold it to you.  

Did you make the selection based only on the price rather than checking it first?

Guess you learned a lesson although the hard way.  

"Cheap ain't good and good ain't cheap." - from the collected "Timeless Wisdom's of SuperDave

SD

SuperDave wrote:OK it's "Five Star" butyrate and apparently NOT fuel-proof.  I'd be talking to the folks that sold it to you.   

Did you make the selection based only on the price rather than checking it first?

Guess you learned a lesson although the hard way.    

"Cheap ain't good and good ain't cheap." - from the collected "Timeless Wisdom's of SuperDave    

SD

Not many alternatives!