ptulmer

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I was sitting here looking at my new fuse, and had a question. The entire fuse is balsa sheeted. Fuse sides are 3/32 and the turtle deck is 1/32. The structure is very rigid.
How about using sanding sealer and dope? Skipping the sig kover-all would seem to save alot of dope that would be used for filling.(not to mention the weight of the kover-all) It wouldn't be possible for the wings, but how 'bout finishing the fuse that way?
The fuse only weighs 2oz with the motor mount installed and no sanding yet. It will be powered by a throttled VA.

Jim Thomerson

I would cover the fuselage with silk, silkspan, or tissue. Get it nice and smooth and doped shiny first. It will be much stronger and weight will go up very little.

Jim

combatpigg

My Feedback: (3)

The tissue will keep the wood from splitting with age. The 1/32 area will gain more strength, the tissue hides all grain, it's a good way to go. The bare wood should be painted with 50% thinned dope, fine sanded, then apply the tissue with clear dope. At this point you have to consider how much nitro, and how messy the plane will get to decide what top coat to use. I would[if this were my plane] tissue the turtle deck only, then balsarite the whole thing and then iron on some of this new ultralight stuff from SIG. The only paint I trust around 15 to 30% nitro is K&B EPOXY, which weighs a ton.

BMatthews

Tissue is lighter than sanding sealer and it adds a bit of extra cross grain strength to resist the wood splitting along the grain.

rrragmanliam

My Feedback: (1)

Hey Ptulmer, What part of the plane are you going to use the copenhagen on?

Darren

ptulmer

My Feedback: (5)

The Pilot!

You know what? Sig doesn't say that supercoat isn't effective after so much nitro. But other brands do! If you hadn't pointed that out CP, I'd be one PO'd customer. Guess I won't be using dope on anything 1/2a. My fuel of choice is 35%. Teach me to do more shopping around...

Funny thing about the K&B paint... After I started this thread I went to my Dad's house (where my tools are packed away right now) and did some work. He told me to get the roll of monokote he had sitting around for about 15 years. So I started pilfering through his stuff and found 6 cans of K&B paint. Red,white, and clear! My favorite colors! I now have the paint for my CP Express!

xanaphyst

My Feedback: (17)

hey pt...I have enough empty Cope cans laying around that you could just do a Copenhagen covering theme
on it with all the labels !!!

"spits in can and smiles"

xanaphyst

combatpigg

My Feedback: (3)

I have had too many so called fuel proof products come off on the cleaning rag to trust anything except 2 part,[mix it as you go] epoxy paint. It airbrushes on nicely, it even brushes on good if you use the brushing catalyst. I still would rather go with an iron on film in most cases because it weighs less than 1/2 of what paint does. There is a fuel proof iron on that is popular with the OLD TIME STUNT C/L crowd that looks like dope over tissue, but this stuff is much tougher. I can't remember what it is called, but it would look great on your plane. I think it is in the BRODAK catalogah, here it is, MICAFILM. It needs BALSARITE fabric formula. There is also SUPERSHRINK COVERITE which sounds like it would iron on around a tennis ball, probably great for fuselages.

ptulmer

My Feedback: (5)

CP, I've read about micafilm on tower. They've got IT'S NOT FUELPROOF in capital letters. The balsarite fabric seems to be the fuelproof factor. I wonder what kind of finish it makes? It doesn't say how high the nitro can go, but it does say it can be applied to fuel soaked wood to make the fabric stick again!
I've used the coverite microlite on the last one. It's pretty nice stuff. Very easy to apply. Probably easier than monokote. The downside - It has all the strengh of plastic wrap when it's pulled tight!

What is it about burnt fuel that makes it so harsh to dope and paint?

combatpigg

My Feedback: (3)

This ad says it is an ultralight film, with rip stop fibers. The confusing part is it says to only use fabric formula BALSARITE. Must have something to do with the fibers. I have used a similar named COVERITE product that was a fabric, and it was NOT fuel proof, and would have needed a sealer. In this case epoxy paint would have been lighter. Maybe someone here has experience with MICAFILM and can either endorse it[8D] or ruthlessly trash it[>:][:'(]?

ZAGNUT

My Feedback: (1)

i remember Randy Randolph using it for most of his 1/2A designs in the magazines but what fuel he used i don't know



dave

muddy69

My Feedback: (2)

How about the paints offered by Nelson Hobby? http://www.nelsonhobby.com/paint.html. It looks like some good stuff.

John Cole

My Feedback: (4)

The Nelson clear coat is a water-based urethane, and is marginally fuel-proof as is. But they advertise a 'crosslinker' additive, which apparently makes it fuel proof to 50% nitro or so. I just bought some for a scale project, and havn't tried it yet. Nelson has been at this game for many years, I'd like to think this stuff will work out well.

John

ptulmer

My Feedback: (5)

Uhhhh, wow. That's alot of color choices. 50%? That's well above what I'm using. And it's lighter than dope?! I'm ordering!

Tom @ Buzzard Bluff

I've been using Micafilm for @ 15 years. It's very lightweight and very strong, but the thing I like best about it is it's ability to hold it's original 'set' after shrinking. I have wings that have been stored in a barn for over 10 years that are still straight and still hold the washout put in with the original covering job without ever feeling a heat gun since. Just try that with Moneycote. I've never has to retighten properly applied Micafilm. To get those results it goes without saying that you must build a straight wing to start with and you must use enough Balsarite to firmly anchor the covering. But it pays big dividends over time. FWIW I use the Balsarite thinned down almost to a water consistency. I have to use 2-3 coats, BUT I get great penetration of the wood and Balsarite is very fuelproof.
It seems to resist punctures as well as the polyester films and I think it is more resistant to tearing. The basic material is heat expanded Mica fibers in a random matrix covered with a plastic. I have never had fuelproofing issues with either diesel or glow but I only use it on flying surfaces since it doesn't like compound curves as well as the plastic films. HTH, Tom

combatpigg

My Feedback: (3)

WHAT DO YOU MEAN YOU AREN"T GOING TO USE 50%?[:@]Somebody slap this guy, XFIST, you're closer to him than I am....take care of him, will ya?

combatpigg

My Feedback: (3)

PATRICK, If all you want to use is 30%, we wont think any less of you.

ptulmer

My Feedback: (5)

THAT'S IT! I'm ordering a g&z and some 80% nitro![>:] Uh...why are my knees shaking? LIKE ELVIS!!! Now I just need to get some extra labels from XFIST for the covering job.

Hey, 35% is the best sport choice for this area and small engines. I've tried lower nitro and in the summer heat it makes a difference. I'll look into the higher nitro soon enough. (When the CP Express is finished)

ptulmer

My Feedback: (5)

Let me restore your faith. Here's the VA installed in a "Hotfoot". Now...A sub 13oz airplane with a VA... Ya think it'll be fast?

combatpigg

My Feedback: (3)

HEY PT, You never know what you'll see around here sometimes! I will take another look at the NELSON paint, seems like I already did a while ago, and the wordage was" nitro RESISTANT" up to 50%, not "nitro PROOF"?

combatpigg

My Feedback: (3)

Looks like a nice fit. Those VAs are awesome, I'll bet it is the best all around 1/2A engine out there. The CL version revs to high heaven.

combatpigg

My Feedback: (3)

HI TOM! I'm sold! Thanks for the info.

BMatthews

You guys should form a team and hit the comedy circuit... CP, where did you get that drawing? That was a hoot!

A misconception is that the exhaust and oil will eat into some finishes. That's not the case for anything that advertises itself to be fuel proof or resistant in any way. It's the nitro, nitro and alky or nitro and additives in the raw fuel spilled around the nose and on the hand holding the model that eats the finish.

If you guys would only learn to be surgical in your application to filling and priming you could get away with cheaper finishes....

ptulmer

My Feedback: (5)

It's a little of a tight fit. Here's a pic from the bottom.

Bruce, you saying to go ahead and dope it? As long as I don't spill raw fuel it should be ok? I've got Sig sanding sealer and supercoat. The colors I have are Midwest Aerogloss.

combatpigg

My Feedback: (3)

HI BRUCE! Glad you got a kick out of it! I was laughing at it pretty good too, couldn't wait to see PATRICKs' response, which got me laughing even more. I got the drawing from R CRUMB, who did the underground comic work 40 years ago. There probably haven't been that many onlookers to this thread, so maybe we can use the same joke on someone else around here? LARRY? AJC? BILL?

PT, as far as I know, even the most fuel resistant dope finishes don't get fully cured for about a month. No question that you can get the most beautiful wet sanded and rubbed out finish doing it this way, but 1/2A is a pretty messy deal.