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Author Topic: Clear Coat and rubbing  (Read 1609 times)

Offline Ken Culbertson

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Clear Coat and rubbing
« on: May 13, 2019, 11:20:17 PM »
Does rubbing out the finish improve the planes flying due to the smoother surfaces and if so, about how much does a simple rustoleum 2x clear coat add on a 700 sq" ship assuming that it will be wet sanded and rubbed out?

I have built my first "pig" and it is going to have to get me through at least half of the season before I can finish a lighter replacement.  If smooth helps I will rub it out.  I have a brick lifter motor so it doesn't fly all that bad at 75oz but I know what usually happens when something that heavy gets into trouble overhead.

Ken
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Offline T.J. Vieira

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Re: Clear Coat and rubbing
« Reply #1 on: May 14, 2019, 05:56:20 AM »
are we talking in theory or practice?

i mean, of course wet sanding removes weight, which is always good!

but, as for the coefficient of friction on the surface, given all the other factors in play, I personally would guess it's negligible at our speeds and functions.

However, they do wax F1 cars to get that extra 0.00001 second of lap time.....

Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #2 on: May 14, 2019, 08:31:19 AM »
are we talking in theory or practice?

i mean, of course wet sanding removes weight, which is always good!

but, as for the coefficient of friction on the surface, given all the other factors in play, I personally would guess it's negligible at our speeds and functions.

However, they do wax F1 cars to get that extra 0.00001 second of lap time.....
Thanks for weighing in.  We are definitely talking practice.  I am not going to put lipstick on a pig if it won't make it a better pig and that extra point or two on appearance is not going to mean much.

Ken
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Offline Clint Ormosen

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Re: Clear Coat and rubbing
« Reply #3 on: May 14, 2019, 09:09:27 AM »
I would do it out of personal pride, but it isn't going to to make a bit of difference in flight performance.
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Offline T.J. Vieira

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Re: Clear Coat and rubbing
« Reply #4 on: May 14, 2019, 10:12:18 AM »
if it looks pretty, it'll fly pretty!  right?

Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #5 on: May 14, 2019, 10:41:53 AM »
I would do it out of personal pride, but it isn't going to to make a bit of difference in flight performance.
Too bad, I was hoping for a reason to rub it out.   The pride factor does weigh in but in the alternate meaning of "weigh in", what will a couple of coats of clear to wet sand and rub out weigh considering that whatever it adds will be doubled to keep the CG.  And the even bigger question - assuming the rubbed out clear is about an oz, will a 77oz ship fly any different than a 75oz one?   How did I get myself in a position that I am trying to make "Pigs Fly"? ???

ken
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Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #6 on: May 14, 2019, 11:22:43 AM »
if it looks pretty, it'll fly pretty!  right?
It looks pretty sitting there by the circle and it will fly an expert level pattern, has good tension overhead, lands and takes off approaching perfection, corners and locks up to AMA standards but it is like fighting city hall if you get the wind wrong.  It is not the basket I want to put all of my eggs in but it is the only basket I have till at least August when I can have anther one done.

Sad part is that I have been dreaming about building this plane as a classic for about 10 years and hoped to use it for PA as well.  No such luck.

Ken
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Offline Howard Rush

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Re: Clear Coat and rubbing
« Reply #7 on: May 14, 2019, 01:02:28 PM »
Leaving it rough might work better.  An airplane with a similar paint job to yours won a couple of world championships with several yearsí accumulation of insects on the wing.
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Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #8 on: May 14, 2019, 01:27:06 PM »
Leaving it rough might work better.  An airplane with a similar paint job to yours won a couple of world championships with several yearsí accumulation of insects on the wing.
I think it is more like I have a paint job similar to his.  IMHO One of the most beautiful PA ships I have seen.  The bugs would be easier to add then the clear and they weigh less!

Ken
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Offline Mike Haverly

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Re: Clear Coat and rubbing
« Reply #9 on: May 14, 2019, 06:56:26 PM »
I feel your pain.   I built one last year that weighed more than that; never flew it.  A little math told me that even a six cell system wasn't even going to be enough.  If it flies, and you have enough battery, just fly it!
Mike

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Re: Clear Coat and rubbing
« Reply #10 on: May 14, 2019, 07:01:37 PM »
At the risk of being confused with someone else showing his airplanes, here it is
Mike

Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #11 on: May 14, 2019, 09:32:31 PM »
At the risk of being confused with someone else showing his airplanes, here it is
That plane is just too beautiful to be a hangar queen.  Put in a bigger motor.

  I have a Cobra 3520/14 in mine and it is not overly taxed to pull my pig through a pattern on a 6s battery.  I have done it on a 5s as well but it was a bit tail heavy.  Even at 75oz, that motor will lift the plane straight up out of your hands with an 11-6 three blade.  The problem is wind.  In anything over 10mph it winds up on the inside loops something fierce and the last corner of the hourglass could easily become the last corner period. ~^


ken
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Offline wwwarbird

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Re: Clear Coat and rubbing
« Reply #12 on: May 14, 2019, 09:50:56 PM »

 Some will argue I'm sure, but at 700 squares and 75 ounces it certainly isn't the end of the world. If it's a good design, is trimmed out well and has enough power, I'd think it should perform at least as well as the pilot. 

 Also, if you're able to sand an ounce of clear off this thing, well, let's just say I hope that wouldn't be possible.  :)
Narrowly averting disaster since 1964! 

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Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #13 on: May 15, 2019, 12:20:43 AM »
Some will argue I'm sure, but at 700 squares and 75 ounces it certainly isn't the end of the world. If it's a good design, is trimmed out well and has enough power, I'd think it should perform at least as well as the pilot. 

 Also, if you're able to sand an ounce of clear off this thing, well, let's just say I hope that wouldn't be possible.  :)
Unfortunately there is no clear yet.  I am attempting to lightly rub out without the clear but it isn't going well.  You might be right on the weight.  It may be that I am not used to a heavy plane and I am judging it too harshly.  I have always built between 10 and 11oz wing loading.  This one is right at 13.  I designed it in the early 60's but it is definitely not a "60's" design.  More like an early 2000's design.  Built it for Classic and planned to also use it in PA.  Maybe I still will if I get used to the different feel in time.

I am encouraged by a post on the Counter Rotating prop thread where using a plane of similar size and weight they are getting "excellent" F2B patterns.  Maybe, just maybe, some lipstick for the pig is in order after all. #^  Does "Slim Fast" make a battery?

Thanks for the encouragement - Ken
« Last Edit: May 15, 2019, 06:46:21 AM by Ken Culbertson »
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Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #14 on: May 15, 2019, 03:07:29 PM »
Carefully remove the canopy and remove all the stuff in the cockpit, it is dead weight. Reinstall canopy. D>K Grams build up to ounces. H^^
Then who is going to fly the plane?  Weighs next to nothing.  The glue to put the canopy back on would weigh as much as what is in there.  It is a vacuform head and the rest is painted typing paper.

Ken
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Offline Dave_Trible

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Re: Clear Coat and rubbing
« Reply #15 on: May 16, 2019, 12:07:17 PM »
At the risk of being confused with someone else showing his airplanes, here it is
Mike thatís nothing a RO Jett .76 wouldnít fix...they donít pull a truck load of balsa.  They pull the truck it came in on.

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Offline Mike Haverly

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Re: Clear Coat and rubbing
« Reply #16 on: May 16, 2019, 12:27:31 PM »
Mike thatís nothing a RO Jett .76 wouldnít fix...they donít pull a truck load of balsa.  They pull the truck it came in on.

Dave

No, it would not.  Besides, it's already been recycled.  I still have the wings and may revisit the project later.
Mike

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Re: Clear Coat and rubbing
« Reply #17 on: May 17, 2019, 10:04:19 AM »
I know that's frustrating.  I've scrapped out three new ones in the last 5-6 years once I got them on the scale.  This was due mostly to trying different finishing stuff or methods and they just get out of control.  I also tend to overbuild hoping to get the dang things to take the punishment of a sort of rough flying field.  My newest planes are a pretty good compromise but do sit towards the upper limit of competitive weight.  Fortunately the engines never complain about whatever I throw at it.  The .76 is able to carry significantly more load than the .61's.  Hard to beat HP.

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Offline Mike Haverly

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Re: Clear Coat and rubbing
« Reply #18 on: May 17, 2019, 10:40:21 AM »
Dave, the electric system has plenty of power to pull this thing straight up and over with no problem.  The issue is to carrier enough fuel (battery) to finish the pattern.  That and I have flown enough heavy airplanes to know what happens in the wind, and this one was really heavy, I would have been happy with 75 oz.  It was designed and built for electric power, IC is out of the question.  I'll build another and hope to have it at Muncie next year.


It sounds like Ken is going to be OK.
Mike

Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #19 on: May 17, 2019, 11:20:55 AM »
Dave, the electric system has plenty of power to pull this thing straight up and over with no problem.  The issue is to carrier enough fuel (battery) to finish the pattern.  That and I have flown enough heavy airplanes to know what happens in the wind, and this one was really heavy, I would have been happy with 75 oz.  It was designed and built for electric power, IC is out of the question.  I'll build another and hope to have it at Muncie next year.


It sounds like Ken is going to be OK.
And now for the weird part.  I started this journey 24 hours after spraying color tipping the scales  at 75oz.

Encouraged by the experiences of others with heavy electrics I decided to go ahead and give it enough clear to rub it. So last night I shot two light and one medium coat.  This morning I placed a burnt chicken next to the scale as an offering and weighed in...73 oz...what?  I was expecting 77-78.  So I am really happy but confused.  Same scale, same battery, same position on the scale.  Only difference 1 month on the wall and three coats of clear.  All I can come up with is that Rustoleum color really lightens with age and clear is really lightens quickly or maybe the weight of the electricity in a fully charged battery is 5oz more than when it is in storage mode.  According to my scale, I shot 6oz of Rustoleum 2x clear at least half of which actually hit the plane and I lost 2 oz of overall weight.

My flying crowd has labeled this plane "Snake-bit" because of all the "it never happens" things that have happened to this plane.  Do you suppose the snake fell out?

Ken   
« Last Edit: May 17, 2019, 11:37:38 AM by Ken Culbertson »
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Offline Dave_Trible

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Re: Clear Coat and rubbing
« Reply #20 on: May 17, 2019, 12:14:02 PM »
Very good Ken.  Once that clear cures out in a few weeks and you sand and polish you should be in great shape.

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Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #21 on: May 17, 2019, 12:21:35 PM »
Magic, voodoo, hoodoo, gassing off? LL~
So that is what that strange noise was coming from the shop late at night - the Snake gassing off!
It is powered by a Cobra...humm?

ken
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Online Dave Hull

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Re: Clear Coat and rubbing
« Reply #22 on: May 17, 2019, 11:58:41 PM »
First, you dance in front of the plane while chanting. This causes hypoxia, which alters your mind state.

Then, you immediately bite the head off the snake.

The measureable weight is now less, and also in your altered state you will feel free to read the scale in creative ways. Perception is reality.

Then you can add as many clear coats as you like--it does not matter.

Then you rub, rub, rub all the while continuing to chant. Some suggested themes are: "Heavy Stunt, Heavy Stunt, Heavy Stunt." Or, "I will only take you out and feed you if you never stall, never stall, never stall."  And rub, rub, rub.

Of course, I am forced to admit that tonight I may also be hypoxic, having had the weight of an OPP* collapse my workbench. This caused the fuselage to fall on the floor and break in half. Right aft of the motor mount, which had only two thin strips of balsa holding the entire plane together. So I will not have to bite the head off the snake tonight. It sacrificed itself as a token of subservience.



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*--Other Person's Plane

Offline Lauri Malila

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Re: Clear Coat and rubbing
« Reply #23 on: May 18, 2019, 03:32:53 PM »
I've worked hard to achieve a consistently rough surface in my FF glider wings. Compared to shiny molded carbon surface, these models behave much better through all speed range, and much better than with any other turbulation we have tried. And we really have tried.
It would be interesting if somebody who knows what he is doing had balls to try the same in a stunt plane, too. I have a feeling it might be good.
Basically, we use about 600 mesh glass or polymer granulate mixed with 2-component clear. L

Offline Randy Powell

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Re: Clear Coat and rubbing
« Reply #24 on: May 20, 2019, 01:27:39 PM »
Weigh it without the battery. It will make you feel better.
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Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #25 on: May 20, 2019, 02:09:52 PM »
Weigh it without the battery. It will make you feel better.
I do, It Does. #^
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Offline Howard Rush

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Re: Clear Coat and rubbing
« Reply #26 on: May 20, 2019, 04:50:33 PM »
I've worked hard to achieve a consistently rough surface in my FF glider wings. Compared to shiny molded carbon surface, these models behave much better through all speed range, and much better than with any other turbulation we have tried. And we really have tried.
It would be interesting if somebody who knows what he is doing had balls to try the same in a stunt plane, too. I have a feeling it might be good.
Basically, we use about 600 mesh glass or polymer granulate mixed with 2-component clear. L

At what Reynolds numbers does your wing operate?
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Offline Lauri Malila

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Re: Clear Coat and rubbing
« Reply #27 on: May 20, 2019, 11:52:48 PM »
At what Reynolds numbers does your wing operate?

I don't know. Average chord is about 120mm, speed varies between 10 and over 200km/h.

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Re: Clear Coat and rubbing
« Reply #28 on: May 21, 2019, 12:57:31 PM »
It totally makes a difference.
The plane that you rub out you KNOW will fly better, therefore you will concentrate BETTER on FLYING it better, and that said, you WILL fly better!

That is my theory AND practice.

R,
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Chris
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Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #29 on: May 21, 2019, 02:30:27 PM »
Ok, the plane gets rubbed out.  OK, you guys talked me into rubbing it out so pony up with some answers.  This is after all my first non dope rodeo:

I am used to being able to start the process when light sanding with 800 does not clog the paper.  Switch to wet and sand till the shiny places are all gone.  I tried that and I am not getting the same feedback with Rustoleum clear (Sorry guys but 2k Automotive is just too heavy and I already had 4 cans of Rustoleum).  The sandpaper just pushes the water around and never turns into that thin paste that let you know it was working.  Is that normal or is a week not enough dry time?

I used to wet sand with 800. With Rustoleum, do I use a coarser grit, finer grit, or find a man with true grit?

Does Rustoleum respond the same way to Rubbing Compound and Polishing Compound as Dope?

Can you spray more clear over the rubbed parts.  I just can't stop fixing things and I know I will be stopping ti fix every ding.  Rubbing is a procedure that you have to do in small doses or you will find that you spent 2 days on the nose then get impatient and just wipe the bottom of the stab with a paper towel.

Thanks for talking me into it.

Ken

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Offline Ty Marcucci

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Re: Clear Coat and rubbing
« Reply #30 on: May 21, 2019, 04:21:32 PM »
Try 600 grit.  I go 400-600-800-1000 wet. Then Brasso. Then I get tired and say screw it, go fly the damn thing.  Most points I ever got was 17. I was happy with that. D>K
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Online Mike Alimov

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Re: Clear Coat and rubbing
« Reply #31 on: May 21, 2019, 05:46:34 PM »
Iíve used Rustoleum, and love it - for the simple reason that it doesnít need to be rubbed out. Assuming all the previous steps were done right, the last coat goes on medium wet, and flows out to a shine. Not a 20-pt Nats front row finish, but good enough for me.
To answer your question, one week is not nearly enough for Rustoeum to dry hard enough to be wet sanded with 800. I think I figured once that after a year or so it was hard enough to wet sand. By which time you have already built something better anyway.
Iíd say leave it as is and just fly.

On a different topic - Iím surprised that at 75 oz, yours loses line tension overhead. I built a Strega at 75 oz a few years ago, and that beast was ready to lift me off the groundó overhead!! Not the best flying plane, but the best wind plane for sure. I had to use 73í lines to reduce line tension, and flew it in 15-17 mph winds without a problem.

Offline Ken Culbertson

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Re: Clear Coat and rubbing
« Reply #32 on: May 21, 2019, 06:31:44 PM »

On a different topic - Iím surprised that at 75 oz, yours loses line tension overhead.
Don't know where I said I was losing tension.  Quite the opposite.  It has more tension overhead than most lighter ships have in level flight.  I an quite surprised how many folks have weighed in to let me know that heavy is not the end of the world.

Bummer on the wet sanding - Ken
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