Stickbuilder

I only use Koverall, and have been doing so for years. I normally use 3 coats of nitrate, then proceed to use automotive primer, and then single stage automotive acrylic enamel, and sometimes a 2 stage clear coat finish. I'm doing a 1/5th scale WACO right now, and I have the fuse and tail group and the top wing covered, sealed and primed. I will start to apply the finish next week. This fuselage is one giant compound curve, and I would hate to try to replicate the finish with plastic film. The Corben Super Ace (yellow and black) is over 10 years old, and looks like new. The J-3 is about 15 years old and still looks as new. The PT-19 is over 20 years old, and still maintains the original look.

Michel

Hi Anthony and Stickbuilder

Thanks Anthony for youre support . I showed the sample piece to one of our club members ( to him ARF is a swearing word ), he looked at my work and told me that it was well done . Truthfully I am quite impressed withthe finish . He also told me to be pathent and to follow up with the other coats of nitrate and butyrate . He also told me to put 30 to 40 percent of baby powder in a 50/50 mix of butyrate to make a filler coat after the nitrate . This will filll the weave he said , after to put on a couple of coats of clear butyrate All sounds good to me , I ll most likely follow this information , or is there something that you would like to add to it

Stickbuilder youre planes look great , I wish I could get a close-up look at them . So far I have only seen one plane that was finished in dope , and it was a piper cub it looked great , although I coud not get much information on it

Again thank you very much have a pleasent evening


Michel ( Mike ) [8D]

WacoNut

Michel,
It looks like you have some good advice. I have not used a dope color finish so it sounds like he has you on the right track for that. I prefer useing Latex paint for the color then clear coating over the Latex. Keep us posted on how your plane come out.
Anthony

Michel

Hi Anthony
How are things ?

Anthony , are you telling me that I can put colour latex under the butyrate dope on top of the nitrate dope ? If so you have just given me the most important information that there is to colour my plane . And if this is so do you know how much money you have just saved me . I have read about useing latex but have not considered it yet . and if this is so you have also made two people happy . Myself of course , but my wife , I think you might of made her happyer (maybe ) Is there a certain type of latex to use ? Ohhhhhhhhh I hope this is so .

Thanks a lot Anthony

Take care[8D]

Michel (Mike )

Ectomorph26

Impressive. I hate plastic iron on film to no end. One color shrinks a lot, another not so much. The iron gets somethign on it and ruins the covering so you have to strip it, and start over.

I much prefer painting things so perhaps when I get some room I'll dope my next kit.

Officer - "Do you know why I pulled you over?"
R/C flyer - "No officer sure don't."
Officer - "65 in a 55 zone...whats in the paper bag?"
R/C Flyer - "Dope!"

WacoNut

You can paint Latex over the nitrate or Butyrate dope . I do not think you can put the dope over the Latex. I use Nelson's Hobby Specialties clear gloss. You can look them up on the net. It is good up to 15% nitro and has held up very well on my planes.
Later!!
Anthony

Michel

Hi Anthony
How things going ?
I ve covered the tail section with a powder and nitrate mix . I m getting small fuzz were the seams are . I sanded it down with fine sand paper , wet . I don t wish to add more weight and by adding the nitrate and powder I will be adding weight . I haven t applied any butyrate yet , so I know that I m still in the good . Would it be a good idea to lay down a coat of epoxy primer now ?Or would this just add to my troubles ? It s that darn tiny fuzz thats giving me the worrys and I don t dare use the butyrate yet . I will be useing a poly two part auto paint Sorry it wouldn t be an epoxy primer it would be the primer that goes with the auto paint , but it s still a two part mix , most of it would be sanded off ,but would it take care the fuzz .

I must admite that the finish is very smooth , I am satisfied with that . I believed that the surface is ready to paint over the nitrate . by the way I have already made tests on this paint and it is fuel proof and I have heard that anything will stick to nitrate ( or almost anything ) , like I said it s just the edges and the very tiny , tiny fuzz if I could get rid of this I think I have it made .

As you can see I haven t made all the decisions yet and I d really hate to make a bad call , go with the butyrate or go with the auto primer . Youre thoughts on this might help me make a call But the work dosn t look too bad


Take care


Mike

Stickbuilder

Michel,

I am in the process of priming my WACO at this time. I brushed on 3 coats of nitrate dope reduced 50% with thinner. After sanding to knock down the fuzz, i have applied 2 coats of primer to the fuselage and empannage. I am waiting about 1 week for the last coat of primer to shrink before the final wet sanding, and I am using single stage automotive paint. I may add clear after the fact in order to customize the gloss. You can enlarge these pictures by clicking on the lower right corner of the pic.

Bill, AMA 4720

Michel

Hy guys

I finally fininsh my LT-40 , and it looks great I know that it has been a while since you have heard from me but it takes time to do the first cycle . I built myself a paint booth for the toxic fumes of the dope and the paint spray , and may I say I am glad that I did . I took the plane out for it s first flight last Sunday , had to wait for the weather to clear . Up hear in Saint-Jerome ( north of Montreal ) all we get is rain , rain , and when thats over a little more rain . The plane flew great with very little trimming , I was doing the , shaking all over thing . The guys in the club were very impressed with the finish , even thougth it was my first . I wasn t so proud of it because my expectations are a little higher, they made me feel it was a great job done . Although it came out a little bite heavy it still flew well at 7LBS 5OZ , I had my Saito 56 on it with a 12x6 prop , it dose fly heavy , I made a beautiful 3 point landing For my firt plane I m pleased

My next project is the Tiger 60 with retracts from Carl GoldBerg ( I ve already started ) , I plan on putting an OS 91 in it This is only because I will be planning on putting the 91 in my nezt plane , I m just trying to save a little money by purchaseing one engine . If it s too powerful I ll just throudle back . The engine weighs the same as an OS-60 The guys at the club said it was a good second plane .

Sorry I cann t send pitures I would love for you guys to see it . I will contineau to do my planes in Koveral , the difference is in apperance and durability very happy that I did this . I have retired my trainner ALPHA -40 and very happy to do so

Thanks for all youre help

Michel ( Mike ) [sm=teeth_smile.gif][sm=teeth_smile.gif][sm=teeth_smile.gif][sm=teeth_smile.gif][sm=thumbup.gif][sm=thumbup.gif][sm=shades_smile.gif][sm=wink_smile.gif]

buzzard bait

Congratulations Michel--I'm glad to hear you went through with it. I never tire of looking at my painted models. The plastic film ones get boring fast. You've got yourself a set of skills that will give you satisfaction for years to come. Jim

andrew66

i have a little question about the use of latex paint.
can i use top flite lustre coat clear coat over a latex paint?
i do believe that the luster coat is fuel proof

the_flyer

Lads,

I have been reading your posts re Koveral covering with interest.

I have only used it once on a large scale sailplane and was impressed with its performance and general ease of application.

One problem I did have, however, was 'pinholing' on open structure sections of the fabric and found it almost impossible to stop. I'm sure it's just a question of bad sealing technique so any advice would be much appreciated.

Incidentally, this is a common problem in the full size world with their similar but heavier grade shrinkable fabrics.

Michel

Hi

There are two possible things that I can help you with #1 , What type of brush are you useing . I found out that a good brush helps , I bought a camelhair brush and it really made difference in the appication , I can only think that it s the softness of the hairs ( or brisels ).

#2 I make sure that I dilute it at least 50/50 with the proper thinner . And maybe , just maybe the stroke (appication ) .

I hope that you will find and appriciate the kind of finish that dope and Koveral gives you , I did

Hope this helps

Michel ( Mike )[8D]

the_flyer

Michel,

Thanks for the reply.
I too use a camel hair brush but it only has short bristles. Not good, me thinks?

Also, I had only applied two coats of nitrate thinned 50/50 before the primer - thought this would be enough. I think I need to do a little more experimenting!
Rob

buzzard bait

Rob, two coats won't do it. Three might, but I use at least four. It looks better and fills the weave more, so it will be easier to keep clean. But I don't use any other primer--just the nitrate, followed by butyrate.

What are you using for primer? I'm guessing that you are using it to fill the weave, right? I'm not trying for a completely filled weave.

Jim

Michel

Hi
Jims right here , don t forget the more you try to hide the weave the heavyer it will be , besides the weave looks good . I think you have the right mix , just add another coat . My first plane that I did it came out too heavy because I used auto primer, but you must use it very sparingly . I am presently working on a plane that I won t be trying to remove all of the weave . May I ask what plane you are working on ? I ve been told that leaveing the weave makes the plane look better , depending on the plane

Take care

Michel ( Mike ) [8D]

Stickbuilder

I know that you guys are getting tired of seeing my plane/s, but I have the base color on the WACO. The sheeted areas appear as metal. There is the faintest hint of weave in the open areas. Just what I was hoping for. I still need to add the trim color, and the graphics. The difference in weight before application of paint and after is less than 20 ounces. That may sound like a lot of weight, but on an airplane this size, it's not much.

Bill, AMA 4720
WACO Brotherhood #1

the_flyer

Guys,

Thanks for all the replies and advice.

I'm clearly not applying sufficient coats of nitrate dope.

There never has been a problem with the weave. Indeed, I would agree that in many cases it is desirable to see it - particularly in my field of scale sailplanes. The problem I had with Koveral was 'pinholing'. So bad in places on the open structure sections, if you held it up to the light it looked like the sky on a dark clear night out on the prairie - if you see what I mean!

Yes I do use auto primer (high build) but it is cut back almost to the fabric so there is little weight added. I've never used butyrate dope so perhaps I'll give it a try.

Curent project is a 1:3.5 Slingsby Skylark 3F on the drawing board - comes out at a touch under 5.2 metres. Glad the wing is in three pieces!
Rob

Michel

Hi
Sorry Stickbuilder , this is one time you are absolutly wrong , it is absolutly impossible to get tired of seeing good craftsmanship . I m personaly in this hobby , TILL DEATH DO US PART , happy to say . Rob I beleive that you will find a beter finish , with more coats of nitrate . It s building season and were all haveing a great time

Michel ( Mike )[8D]

woodbutcher

Hey flyer
I know what you mean about the pinholeing. I've done one plane so far in Koverall and dope and had the same problem. All my application was with an HVLP spray. I felt I was having to put more paint on than necessary and still getting some pinholing. Everything came out great except for that and it's minor.

I read afterwards on RCU(sorry, didn't save the link) that wiping down the Koverall with solvent first helps remove something in the fabric manufacturing process that causes this. I will try this next time, probably alcohol, MEK or something, experimenting first.


After using Koverall, I'll never go back to Monokote.

the_flyer

As an aside to all this, the technique used by the microlight and full size vintage boys is interesting.

I was involved in some full size glider restoration some years ago (7th assistant or something of that order!) and learnt quite a lot about modern fabric application.

The stuff the full size boys use is more or less the same as Koveral - just heavier grades. The actual application process is a multi stage affair and much more complicated than our meagre efforts.

The important bit is though, the initial 'sticking down' and subsequent weave filling must be done with a brush to drive the dope through the weave. Many inspectors, if not all of them, require a mild tint in the dope so they can see the pooling on the inside of the fabric after it has dried to ensure it has gone through. One inspection I witnessed he wouldn't pass the job as one bay in one wing showed no pooling.

One thing also of note, dope tended to be used very thick with little or no thinning - maybe too much thinners aggravates the pinholing problem?

Having said all this, pinholing is still a problem even at these scales and sizes!

Upward and onward.
Rob

Stickbuilder

It is better to thin the Nitrate 50/50 and brush in different directions. I put the first coat on in a vertical movement, the second in a horizontal movement and the last 2 using a bias motion upper left to lower right, and then upper right to lower left.

You can wipe the Koverall with lacquer thinner prior to doping the first coat. Koverall is a woven fabric in the neighborhood of 0.5 oz/yd2. It is woven from 30 denier Dacron polyester yarn, This yarn is made of two disimilar polymers that are spun and drawn together. The white polymer is the heavier of the two and makes up approximately 80% of the threadline. The clear polymer is the glue or binder and is used in a lower percentage. The melt temperature of the clear (co-polymer) is much lower than is the White (ho-polymer) which has the higher melt temperature. When you rub the fabric with the lacquer thinner, you begin to deform the co-polymer and this helps to minimize the openness of the weave and therefore requires less product to fill the porous area. The pinholes are from inadequate saturation of the filler material. That is why you should inspect the doped surface with a direct light (incandecent bulb) before adding any primers or colored finish material. The light showing through the pin holes is easy to repair by application of more Nitrate dope to the area.

Hope this does not come across as a Smart alec reply, but in this instance I do know whereof I speak. I used to make the stuff.

Bill, AMA 4720
WACO Brotherhood #1

woodbutcher

Stickbuilder

What kind, size brush do you use? Do you put any retarder in the mix to avoid brush drag? Thanks.

Stickbuilder

I used a 1" bristle brush (the throw away kind that Home Depot sells. I cut the Nitrate 50/50 with Dupont Acryilic lacquer thinner (6062) and did not have brosh drag issues. I sand the coats with 400 wet and the finish stands for itself.

Bill, AMA 4720
WACO Brotherhood #1

the_flyer

Bill,

Have no fears, there's nothing smart Alec about someone who knows what they're talking about!

Many thanks for the info - more helpful stuff to get to grips with Koverall.
Rob