Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin  |  Contact Global Moderator
August 23, 2019, 04:41:49 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: [1]   Go Down
Print
Author Topic: Paint finish without balsa blemishes for Stunters  (Read 2064 times)
0 Members and 1 Guest are viewing this topic.
Clwally
Guest

« on: July 29, 2008, 07:46:53 AM »

Hi,
 I'm wanting to know how to achieve those great finishes that you see on the large stunt models , where the paint looks like a plastic coating. I've tried putting several coats of dope on the balsa fuselage before painting, but I still get the balsa lines / blemishes appearing through the paint. Any hints please?

Thanks.
Clwally
Logged
Sundance12
Model Airplane Builder
Global Moderator
Platinum Member
*****

Kudos: 70
Offline Offline

Canada Canada

Posts: 1,058


MAAC #25680, VE4BDF (amateur radio callsign)

WWW
« Reply #1 on: July 29, 2008, 08:37:59 AM »

Hi Clwally;

Many of these great finishes are the result of much preparation usually beginning with sanding the airframe to a fine level. Much of the ding and dents from construction are eliminated with light weight filler and then much of the airframe is covered in silkspan tissue and dope. After the covering process at least three coats of regular dope sanded between coats and then perhaps two coats of silver or primer to identify any further depressions. Much sanding between coats is required and the silver or primer are almost all sanded off. Then a last coat of silver or primer lightly sanded and then the color gets sprayed on. Just to remind you that these finishes are sprayed with an airbrush is important to know. Perhaps two coats of color and the required sanding between, then perhaps another coat of clear to go over top, but this last clear coat is an option. Many color finishes are polished with a wax afterward to get the super high gloss sheen that you see in the magazines that present these airplanes. As many as 7 to 8 coats of finish goes on after just the silkspan. I have found that this process takes me double the time it takes to build the airplane in the first place. I mostly just get a cover of silkspan on now with two or three coats of dope and one of color and then I get it into the air.

Perhaps others have a few insights, I have found that finishes on stunters to be a personal activity and everyone has their own techniques.

Sundance12
Logged

Resources and tools for scratch builders and plans builders.
www.northof49tech.com
Black Arrow
Silver Member
****

Kudos: 5
Offline Offline

United States United States

Posts: 127



Ignore
« Reply #2 on: August 15, 2008, 10:25:22 PM »

I am pretty much in agreement with Sundance12 with the addition that I put two or three coats of sanding sealer on the tissue after covering the balsa, sanding between coats, of course. I've never taken one all the way to the level of a frontline finish (with clear coats, show car finish etc.) though, just a pretty darn nice paint job. I just can't justify the time expenditure on something so much at risk (at least in my hands, LOL!). If you want to know all the tricks from a Nats winning CL builder/flier seek out Windy Urtnowski. He actually has a set of video tapes that show every step in the process. I have those tapes in my posession. I bought them years ago. He probably has them on CD's by now. Not really sure how you can get in touch with Windy but if you look around I'm sure you'll find him. He's quite a nice guy and a Nat's CL Stunt winner many times over. I think he lives in New Jersey now. Try inquiring on www.stukastuntworks.com
Logged

The Research Aerosquadron - Death From Above!
Clwally
Guest

« Reply #3 on: August 16, 2008, 08:04:48 AM »

Thanks Sundance and Black Arrow. It's now obvious to me where my problem with finishes lies - I was putting in less time than it took to build the model on the finish Smiley I now have to restrain my impulse to go fly it and put a lot more time in trying to get a good finish!
Logged
Sundance12
Model Airplane Builder
Global Moderator
Platinum Member
*****

Kudos: 70
Offline Offline

Canada Canada

Posts: 1,058


MAAC #25680, VE4BDF (amateur radio callsign)

WWW
« Reply #4 on: August 16, 2008, 09:42:07 AM »

No problem Clwally, the thing is with finishes, is the level of personal preference. Black Arrow has it right, with his comment of how much time to get the top finish compared to the level of risk in flight. I have to get the airplane flying, I need the practice in flight not in the finish so I backed off on my airplane and did two layers of sanding sealer, or dope sanded between, then tissue of the fuselage and silk on the wings with more dope, sanded and then a final two coats of dope to complete it. It took 4 months.

The first picture is my Professor and it lasted 4 1/3 flights, all I have is a skeleton wing now. The second is a picture of my dream plane that I would like to have one day, it's a Stiletto by Les Macdonald in the 70's. This picture has one of those involved finishes but I would only fly this thing in competitions if I could ever get that good enough at flying.

So far I am running a loosing battle in the flying and the finish.

Sundance12
Attached files Thumbnail(s):
Re: Paint finish without balsa blemishes for Stunters
Re: Paint finish without balsa blemishes for Stunters
Logged

Resources and tools for scratch builders and plans builders.
www.northof49tech.com
Clwally
Guest

« Reply #5 on: August 17, 2008, 05:49:51 AM »

G'day Sundance - That Stiletto certainly looks nice. It 'd be ok in the morning with me but it'd be coming home in bits if I tried to put it through it's paces! Smiley I have a forgetful issue at the moment when I try going inverted - down is up and up is down... - oh I need to go a bit higher, splat!!!
I think I'll stick to my "rustic" finishes at present until my flying improves like you but at least I now have an idea how those magazine finishes are achieved.
Logged
greggles47
Gold Member
*****

Kudos: 11
Offline Offline

Australia Australia

Posts: 281




Ignore
« Reply #6 on: August 21, 2008, 08:20:53 AM »

Wal,

My finishes are not anywhere near professional, but you can improve yours by (as already stated by Sundance and Black Arrow) getting your basic woodwork as smooth as possible. Like you this is where I get a bit antsy to fly them, so my finishes are limited to several coats of dope & talc. Yes sanded between each coat. then a couple of rattle can spray fillers (check the can because some can be VERY HEAVY). Then a couple of coats of colour. Usually only one colour to 1. save weight, and 2. Save time masking etc etc.

Regards

Greg
Logged

There must be some way out of here, said the joker to the thief,
There's too much confusion, I can't get no relief
Clwally
Guest

« Reply #7 on: August 21, 2008, 08:31:56 AM »

Thanks Greg. I was mixing up very "stiff" mixes of Dope and talcum powder and trying to do just one coat of it. On my recent Spitfire I tried using less talc and a few more coats and the body seemed to be a lot smoother. Alas, applying the paint from the rattle can wasn't too great a success with a few runs etc..
 Walter
Logged
Randy Ryan
Guest

« Reply #8 on: March 12, 2010, 04:11:32 AM »

Here's a bit I wrote for another forum, hope you find it helpful.

One of the things we often hear about is the weight the final finish adds. Now I haven't used many products other then dope and some rattle can paints for my models, so I can speak with some authority on Lacquer based finishes. Regardless, the preparation for the finish is probably of the greatest importance.

This post was sort of triggered by Ty's mention that Brasso is a rubbing compound. That is basically true, but the quality it has over and above compounds made for paint polishing I think is in its grit size and lubricity. That said, what follows are the suggestions I make and I have proven them on my own models.

1. No matter what you cover with, the finish begins before it gets anywhere close to the model. Attention to fits and level joints is paramount. Sure, there are good fillers out there, but here lies the first batch of calories. Balsa is lighter that any filler I've ever used, and I have yet to find a filler that sands the "same" as balsa. Because of that, it will always read through the covering and the only remedy is what else, more filler. So, here is where you can start you weight watchers program, right down to paying close attention to wood thickenss because 1/16 balsa for example will vary from .01 under to .01 over. If for instance you do your sheeting with some that's thick, and cap strips with some that's thin, it will require that you sand a bunch to level the joints. This in turn will cause bumps in the sheeting over all the ribs because the sheeting is not supported between them. Careful selection of not just quality, but thickness will save allot of time and uglyness.

2. OK, you've built the perfectly fitted and joined airframe and sanded it well, now what. Give it a "bath", wipe it down with a wet cloth and leave it to dry. This will raise out small dents and areas that were compressed rather then sanded smooth. In 4-6 lb stock, its very easy to simply compress and burnish the wood, but if that's what you've done, it'll come back and bite you down the line. When its all dry, carefully and LIGHTLY go over it with nothing rougher then 400 grit. Cut the sand paper into ovals about 1 1/2 wide by 2 1/2 long, curl it over the edge of the bench grit side up. This will make the edges tend to pull away from the surface rather then dig in. Still you'll have to be careful. Remember this from now on, you'll want to use it the rest of the way through. If you're using iron on, you're ready to cover, if silkspan, silk or tissue, you're ready to dope. Now the tricks get more subtle. I use all of these materials, but I will concentrate on span although these tips will work on any doped on covering except synthetics. The main areas to watch are the wing, stab, and rudder tips and other compound curved area where you use slits to make the covering conform. When you do that, you double the thickness in areas and that's not necessary. Get a couple coats of dope on the whole thing then start sanding with your little ovals. From this point on, nothing rougher then 400 should be used. concentrate on the lapped joints and even use a couple extra coats to seal them sanding in between to feather them out eliminating the need to apply filler later on. This can be done on the LE, TE and fuselage seams too, but be careful not to sand through. From about 3 coats on, sand lightly knocking off nibs and raised fibers, but be WAY careful if you're using silk. I normally use about 6 coats of full strength dope before I prime. What you want to do is make the surface as perfect as you can BEFORE you prime.

4. Priming. Here is where some will part company with me, but that's OK, I've proven my point to those that have seen my models, so I won't argue. I am a big fan of Duplicolor rattle can primers. They make a filling primer and a basic sandable primer. No matter what you use, the principal will remain the same. The prime should not be seen as the opportunity to fill small imperfections, you should have already taken care of that. From the first coat of primer never use anything rougher then 400. You need to some roughness here referred to as "tooth" to give the color something to latch onto. I can't stress enough how important this phase of the finish preparation is. Sanding can be tedious, but it is necessary, you do not want to be filling imperfections with clear at the end. Remember the paper ovals. Sand fillets with rolled up paper, and oh yes, this is one place you may want to go just a bit rougher, I use 320 grit on the fillets. DO NOT use progressively fine grits to get to 400!!! Start and finish with it. Progressively sanding with finer grits really just takes longer, and the fact is, you will only be trying to sand away the scratches from larger grits and in fact will miss allot of them. If you have done the building and covering well, you will notice that the primer sanding goes quickly and levels instantly. By holding up to the light and looking down the surface you should see one unbroken continuous surface. If you see irregularities and the primer is intact, sand a bit more. If the primer is gone, SPOT prime, not need to add where its not needed. You're looking for that all over sheen when you look across the surfaces.

5. Color; use only as much as you need and NO MORE! If you use silver, then give it a coat of clear before you go on to trim, this will seal and bind the pigment and keep the silver pristine. Trim edges, here's another place to cut some serious calories. Don't be afraid to lightly feather the masked edges of opaque colors, even translucents can be feathered because they are generally heavier at the masked edge and therefore darker, but be CAREFUL. Use 2000 grit for this, and do it wet. I'm not talking about massive sanding here, mostly just a rub down, You will not get a total feathering at this point, but you WILL knock off the raised edge that takes some much clear to fill later. OK, now you have all your trim done and lightly feathered. Ready for clear coats right??!!! WRONG!!!. Now get your air brush good and squeeky clean and carefully put 2 or 3 thin coats of clear on all the trim edges, 2000 grit between coats. You will be amazed at how fast the edges disappear and the surface levels. Carefully and LIGHTLY go over the entire model with 2000. Once again holding up to the light and looking down the surface you should now see one unbroken continuous surface. No little shiny spots, stippling, no little hollows.

6. Clear at last. Here is where we tend to get carried away. We use clear coats the try to fill all those ewglies that read through. If you look at my Sabre Stunt thread you'll see the finished product. This model has only 2 coats of thinned clear on it. A tad bit of retarder to let it flow a bit. After the first coat, it was merely "rubbed down" with 2000 grit. After the second coat it was thoroughly sanded with 2000 grit wet and polished with Brasso. This model tips the scales at 38 0z using an OS .40FP, so you can see that the finish weight is down.

So you see, the "trick" of the good finish is really many little ones along the way. We are always anxious to see and fly the finished product, but don't let that make you skimp along the way and cost you allot of work and flab in the end.

My Gladiator in Brodak dope.
Attached files Thumbnail(s):
Re: Paint finish without balsa blemishes for Stunters
Logged
blklion
Guest

« Reply #9 on: March 16, 2010, 08:43:37 AM »

As stated no filler sands like balsa does and can cause some problems if you're not observant and careful. The thing is that while you're building and prepping the model you're sanding off balsa. If you catch and save that balsa "dust" (and there's a load of it) you can then mix it with thinned clear dope and make filler that sands the same as doped balsa. Even doped balsa sanding residue can be reused as filler the same way.
Logged
gcb
Bronze Member
***

Kudos: 1
Offline Offline

United States United States

Posts: 70



Ignore
« Reply #10 on: May 05, 2013, 11:55:00 AM »

A few comments and opinions:

A couple of items I didn't see mentioned (or I missed) and that is...type of dope. Most use nitrate for the surface prep part because it dries quickly. By quickly I mean a few days. Butyrate can gas off for a month. One famous modeler finished a plane quickly for a contest (Nats) and had to refinish a month later because he could see the grain in places.

Silver...this serves two purposes. First it shows ALL blemishes so they are easier to find and correct. Second it forms a "blocking" coat - an opaque surface. Some folks prefer to use gray for this because it does not contain metal particles so it may be lighter.

Bear in mind also that guys who apply these finishes usually have many planes under their belt and seldom crash. If you are just starting out avoid putting so much effort and time into a plane that you are afraid of crashing it. That's why beater planes were invented.  Shocked 

George
Logged
Steve Thornton
Copper Member
**

Kudos: 0
Offline Offline

United States United States

Posts: 5




Ignore
« Reply #11 on: October 01, 2013, 01:19:42 PM »

One more time I'll try to post a pic of my White Lightning.  Great design Bruce.  I painted this with rattle can Rustoleum over silk span. With the TD ,051 and 3/4 oz tank it weight 10.05 oz.  Is this too heavy? Next time I will use the dyed silk span instead of "weight in a spray can."
Thanks for any advice,
Steve
Attached files Thumbnail(s):
Re: Paint finish without balsa blemishes for Stunters
Logged

Sometimes I believe I can and sometimes I believe I cannot, but whichever I believe, I am almost always correct.
ST
Sundance12
Model Airplane Builder
Global Moderator
Platinum Member
*****

Kudos: 70
Offline Offline

Canada Canada

Posts: 1,058


MAAC #25680, VE4BDF (amateur radio callsign)

WWW
« Reply #12 on: October 01, 2013, 02:37:46 PM »

Heavey? Well proof will be in the pudding Steve. That wing is pretty large so with more wing loading it will glide a bit faster and behave better in some wind. So you will just have to make it go. I build light, and have not experienced this plane in heavier form. Might be just fine.

Looks Great....

Thanks

Bruce F.
Logged

Resources and tools for scratch builders and plans builders.
www.northof49tech.com
Steve Thornton
Copper Member
**

Kudos: 0
Offline Offline

United States United States

Posts: 5




Ignore
« Reply #13 on: October 02, 2013, 02:20:08 AM »

Bruce what type glue do you use to join flying surfaces to fuselage, and what goal should I have for the weight?
Steve
Logged

Sometimes I believe I can and sometimes I believe I cannot, but whichever I believe, I am almost always correct.
ST
Sundance12
Model Airplane Builder
Global Moderator
Platinum Member
*****

Kudos: 70
Offline Offline

Canada Canada

Posts: 1,058


MAAC #25680, VE4BDF (amateur radio callsign)

WWW
« Reply #14 on: October 02, 2013, 06:30:36 AM »

Anything from epoxy, to white glue to CA, it depends what parts and what stage. However, I like white glue alot as I know that it's going to get covered with silkspan and dope finish or something similar. Perhaps the membership can help with this question.

Cheers

Bruce



Bruce what type glue do you use to join flying surfaces to fuselage, and what goal should I have for the weight?
Steve
Logged

Resources and tools for scratch builders and plans builders.
www.northof49tech.com
RK Flyer
Bronze Member
***

Kudos: 1
Offline Offline

United States United States

Posts: 11



Ignore
« Reply #15 on: October 07, 2013, 03:47:28 PM »

Steve......I am thinking of building the White Lightning for my Tee Dee 049 sooo how did yours fly at that weight?
Also what type of tank/ pressure bladder did you use.

Very Nice looking Plane!

Thanks RK Flyer
Logged
Sundance12
Model Airplane Builder
Global Moderator
Platinum Member
*****

Kudos: 70
Offline Offline

Canada Canada

Posts: 1,058


MAAC #25680, VE4BDF (amateur radio callsign)

WWW
« Reply #16 on: October 07, 2013, 09:33:32 PM »

Video if the prototype WL in flight by Warren...

http://www.youtube.com/watch?v=4qonrzwTXeI

Used a .051

Bruce
Logged

Resources and tools for scratch builders and plans builders.
www.northof49tech.com
Steve Thornton
Copper Member
**

Kudos: 0
Offline Offline

United States United States

Posts: 5




Ignore
« Reply #17 on: October 11, 2013, 06:20:47 PM »

Steve......I am thinking of building the White Lightning for my Tee Dee 049 sooo how did yours fly at that weight?
Also what type of tank/ pressure bladder did you use.

Very Nice looking Plane!

Thanks RK Flyer
Thank you!  I have not flown it yet-vacation, honey-doos, but mainly because it is tail heavy and so I am putting new landing gear on it and some weight under the engine, and I may replace the 3/4 oz tank with a bladder, so I'll post as soon as I get 'er in the air.
Steve
Logged

Sometimes I believe I can and sometimes I believe I cannot, but whichever I believe, I am almost always correct.
ST
Pages: [1]   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!