Best method to refinish - Looking for ideas

[Paul Taylor]

I know I'm not the first to build a chunky monkey 🐒 so I'm looking for advice on refinishing a plane.

My stunt ship came out way to heavy so I would like to make an attempt to save the plane.
Looking for ideas on how to finish it and best methods to remove the old. I'm also thinking about putting lighting holes in the sides of the fuse to try and move the CG forward and maybe the vertical fin.
If I can get it down to tissue again and see where I'm at on weight to see if I need to get down to bare wood again. I was also thinking about a quick finish with monokote on the flying surfaces due to humidity being around until Christmas. 

 Any input would be greatly appreciated.

[Dave_Trible]

Paul I've refinished two in the past year and doing a third now.  It ain't easy.  You can wet sand most of the dope off over solid or sheeted surfaces with a ream of 400 grit paper.  Open bays with covering are a lost cause and just needs to be stripped with acetone.  I get about 1 1/2 gallon of acetone and two rolls of paper towels.  Put on rubber gloves-the acetone can get unbearably cold on your hands.  Pour some acetone into a pie pan or similar.  Swipe on one panel to soften the dope some first then keep wetting and wiping.  At some point you should be able to prick up a corner of the paper and start peeling.  Repeat all over.  Let it dry overnight then sand the balsa and start over.  I can usually get one stripped in a couple hours.

Dave

[RandySmith]

I would use a gallon of acetone, pus a roll of Bounty towels and  wipe  the old finish off.  I think  Curt Contrata  wrote a piece  about this a while  back

Randy

[john e. holliday]

I think Randy Powell had the best idea of using DADS Paint remover on his planes.  Use out doors with lots of air movement.

[Peter Nevai]

As far as the monokote is concerned if you want to drop the most weight go with one of the monokote transparent films, at least for the wing and any other built up surfaces. A Brodak Vector 40 I did several years ago came in at 44.5 ounces.

[Curt D Contrata]

I would use a gallon of acetone, pus a roll of Bounty towels and  wipe  the old finish off.  I think  Curt Contrata  wrote a piece  about this a while  back

Randy

As I recall, it took me about 3 hours to completely strip my Katana. I would not hesitate to do it exactly the same way again, it was incredibly easy. The article I wrote was in Model Aviation several years ago.

Curt

[RandySmith]

I would urge  you to  NOT  use a paint stripper, they can cause major problem, and can contaminate  the balsa

Randy

[Paul Taylor]

As I recall, it took me about 3 hours to completely strip my Katana. I would not hesitate to do it exactly the same way again, it was incredibly easy. The article I wrote was in Model Aviation several years ago.

Curt

Thanks Curt. Do you remember what issue?

[Curt D Contrata]

I just found the issue(s), and it seems that I used cheap lacquer thinner from Home Depot and not acetone. I would have sworn I used acetone. Be sure to use Bounty Select-A-Size paper towels.

Part one is in the June 2004 issue of Model Aviation and explains the process.

Part two is found in the May 2005 issue of Model Aviation and covers what I did after stripping. per the article, it took 20 minutes per wing panel and four hours for the entire model.

In the pictures, you will see that I stripped off the paint and was able to leave the carbon veil untouched on the tail and flaps.
In the 2005 issue I got back to work on it making modifications to the model and completed the re-finishing process.

The transformed Katana was re-born as a Super Staris in 2006 and won the KOI in 2014.

Curt

[Larry Fernandez]

Hi Curt, is that the same Katana that won the Pilots Choice award at the 2000 NATS?

Larry,Buttafucco Stunt Team

[Curt D Contrata]

No, my Tempest II won it in 2000 - it is the one in my signature.
The Tempest II is still shinny and on the wall.

Curt

[Paul Taylor]

I would urge  you to  NOT  use a paint stripper, they can cause major problem, and can contaminate  the balsa

Randy

Noted. Thanks.

[Paul Taylor]

I just found the issue(s), and it seems that I used cheap lacquer thinner from Home Depot and not acetone. I would have sworn I used acetone. Be sure to use Bounty Select-A-Size paper towels.

Part one is in the June 2004 issue of Model Aviation and explains the process.

Part two is found in the May 2005 issue of Model Aviation and covers what I did after stripping. per the article, it took 20 minutes per wing panel and four hours for the entire model.

In the pictures, you will see that I stripped off the paint and was able to leave the carbon veil untouched on the tail and flaps.
In the 2005 issue I got back to work on it making modifications to the model and completed the re-finishing process.

The transformed Katana was re-born as a Super Staris in 2006 and won the KOI in 2014.

Curt

Thanks Curt.
Seems I remember reading it now.
Going on a search mission. 😊

[Sean McEntee]

I was also thinking about a quick finish with monokote on the flying surfaces due to humidity being around until Christmas. 

 

Dude!  Get a dehumidifier--one with a drain.  Hook up a garden hose and run it outside so you dont have to empty the bucket.  You will be good to go!  I got one at walmart in the 150 dollar range and it takes my 1-car garage down to 30% in about 15 minutes.  There were days I was painting my magnum while it was thunderstorming outside and pouring rain!  It also just makes it more comfortable to work in there with the higher temperatures.

[Dennis Moritz]

Respirator. I'd recommend use of one. Plus latex gloves.


Sent from my iPhone using Tapatalk

[Fredvon4]

Paul

Sean is spot on for his rental garage building area---- the humidifier worked very good

My 16 x 24 barn/shop is well insulated and I just put in the very el cheapo $95 little window 110Vac Air Conditioner units

OAT today 99F
H 78%
In the shop with only one of the two running
Air 75F
H 51%

I mostly do paint crap out side---- but if I need to, I cover every thing with used sheets and put on the cheap respirator and get after it....inside my conditioned space

[Randy Powell]

I've used paint stripper. It works OK but as The Great Mister Smith, noted, it can cause problems. It will strip everything. Takes covering off easily and it tends to dry out the balsa and can cause warps due to sucking all the moisture out. I prefer wet sanding.

[fred cesquim]

with all the wood preparation for painting, i would not advise to use monokote or ultracote. will be hard to adhere properly and may develop bubles and sag on the sun

[Peter Nevai]

with all the wood preparation for painting, i would not advise to use monokote or ultracote. will be hard to adhere properly and may develop bubles and sag on the sun

If you give the exposed areas a light sanding then the kote will stick no problem. But the surface must be completely dust free. As I mentioned for the lightest weight use the transparents, certain kote colors then to sag more than others in the heat and bright sun. Predominantly the dary colors, Black and Navy Blue are two of them. Obvioulsy if you use transprents you would be giving the wodd an good sanding as any blemishes or discoloration would show right through. BTW keep away from the gold color as it is not completely opaque as I fould out after applying it and then saw every pencil and ink line I had drawn on the balsa underneath.

[fred cesquim]

it will stick, but won´t "breathe" allowing the glue gas to expand properly.
i am absolutely positive on using monokote as a covering and base color on wing and tail.
to be honest, IMHO , he most time-consuming part for me is the finishing, and you will have to double the work here (strip and re-finish) not knowing if the final result will worth the effort.
Building is the fastest part, so i would start a new plane and fly this one for fun. I am pretty sure looks gorgeous, as i have seen your projects before!

[Curt D Contrata]

...to be honest, IMHO , he most time-consuming part for me is the finishing, and you will have to double the work here (strip and re-finish) not knowing if the final result will worth the effort.

It only took 4 hours to remove the finish and after I stripped my model, it easily took the new finish. I did not strip it to bare wood, just down to the paper and carbon veil. I did recover the open bay areas, but the entire process was easier than starting a finish from bare wood or building a new ship.

Curt

[fred cesquim]

It only took 4 hours to remove the finish and after I stripped my model, it easily took the new finish. I did not strip it to bare wood, just down to the paper and carbon veil. I did recover the open bay areas, but the entire process was easier than starting a finish from bare wood or building a new ship.

Curt

i am a lazy finisher Curt! that´s the problem for me lol

[Scott Richlen]

Paul:

When you built the plane did you weigh  the components so you know which parts are over-weight?  With a little luck, its a heavy stab so you can build a new, light-weight replacement.  (Since you mentioned cutting holes in the fuselage sides, I assumed that meant your weight was back there.)

Of course, if you are nose-heavy that won't help.  If you are nose heavy,  can you find a lighter muffle?

I have disciplined myself to use the Tom  Morris "glue dot" method when building and  that has helped reduce my building weight.

Good Luck!

[Paul Taylor]

Paul:

When you built the plane did you weigh  the components so you know which parts are over-weight?  With a little luck, its a heavy stab so you can build a new, light-weight replacement.  (Since you mentioned cutting holes in the fuselage sides, I assumed that meant your weight was back there.)

Of course, if you are nose-heavy that won't help.  If you are nose heavy,  can you find a lighter muffle?

I have disciplined myself to use the Tom  Morris "glue dot" method when building and  that has helped reduce my building weight.

Good Luck!

Thanks Scott for your input.
Yes it is tail heavy. I did weigh it as it was built and I think I got heavy handed on the spray gun. 
I will strip it and see where I'm at.
Please explain Toms "glue dot" method. !!!

Curt - Have download your article. So you don't strip the wing and stab. Just pull the covering?

Thanks

[Scott Richlen]

Paul:

One of the ways that I was building heavy was by using too much glue (you'll probably notice that when you wreck a plane, the break is in the balsa not in the glue.)  Tom uses a little plastic glue applicator bottle with a tube to apply the glue (you can probably find them in Sparky's store).  He fills it with white glue and places dots of glue spaced 1/4th inch apart.  I use Gorrilla brand white glue (not polyurethane!)  thinned about 15% with water in my glue applicator.  Works great!

To save weight I have replaced stabs.  I use Windy's method of building them from 1/16th sheet, plus I mold the leading edge from 1/16th also.  Basically, lay down a sheet of balsa shaped to the stab outline, glue the molded leading edge to the front, add a piece of square balsa for the stab trailing edge (to hold the hinges), add 1/16th ribs spaced about an inch apart and then add the top sheet of 1/16th.  Sometimes I'll add some reinforcing pieces at the center, but that's about it.  Done!  These use a flat airfoil which works fine for most of us not in the Walker Cup hunt.

Hope this helps.

[Paul Taylor]

Gotcha No CA.

The stab is already built up. This was built from a Vector Kit.

What about cutting openings in the fuse sides like an ARF Nobler. Also converting the Vertical fin to a built up?

The old saying a hole is lighter than wood. 😊

[Curt D Contrata]

Paul,
I went back to re-read my article and looked at all the photos I took during the process so I was sure to give you accurate information.
 
In a nutshell, I simply wiped off the old finish to the point where I wanted to re-start, you don't need to go to bare wood. This process, if done as described in the article, leaves you in complete control. I must stress the part about working in small areas, and not let the thinner run all over the model. Have a goal for a session, like the underside of a wing panel, then stop to re-group.

On the wings, I decided that pulling off the silkspan completely would make the edge of the fillets and hinge lines an issue for refinishing, so I left the covering on all the sheeted/solid portion of the wings and stripped the paint down to the silkspan over all balsa surfaces (including capstrips). I never pulled off any silkspan. I left the open bays alone and carefully cut those sections out later, leaving the capstrips, TE, LE, and Center sheeting covered. The edges of the capstrips and sheeting were then carefully sanded with a small radius.
 
I re-covered the open bays of the wings and tore the edges of the silkspan against a metal straight edge so that it would not have a scissor cut hard edge and would then blend easier with the sheeted center sections and LE sheeting that were already covered (only over lapping a 3/4 inch or so).

On this model, the flaps and tail surfaces were covered in carbon veil, and those surfaces did not fair as well to the stripping process so they were re-covered with light silkspan over what veil remained.

The Fuselage needed the most modification. I re-shapped the cowl, replaced the canopy, reshaped vertical stabilizer as well as belly of the fuse. In spite of all that, the tissue was preserved around the fillets and new silkspan was applied everywhere with soft, torn edges to make blending easier. I never pulled tissue off a covered surface, rather I blended them with new tissue.

I hope this helps, I would not hesitate to do it again. PM me if you would like to talk about the process over the phone. To be clear, this is not my method. Credit and thanks must go to Randy Smith and Frank McMillan for walking me though the process.

Curt

[Scott Richlen]

Paul:

In the case that the stab is already a built-up you may not save much weight, but it all depends on the construction of the stab.  It still could be heavy.  A stab built of 1/16th sheet with a molded leading edge should always be lighter.  Take a look at the Windy videos where he is building the stab on some of his later ships.  Did you keep a table of weights when you were building this airplane so you know the original stab weight?  If you rebuild the rudder you have to go all out to get your weight savings.  Use light 1/16th sheet only, no solid sticks.  Mold the leading edge and use sheet to make the trailing edge.  I'll even "swiss cheese" the ribs.

I am not enthusiastic about cutting holes in the sides of the fuselage since that often weakens the fuselage and allows it to twist.  If the fuselage extends behind the stab, yes, make as big a hole as you can behind the vertical plane of the control horn position.  At Eastern Shore last weekend a bunch of us were watching the profile event (and participating in it) and focusing on the twist in the fuselage of most profiles.  You can see a distinct difference in the horizontal plane of the wing and that of the stab.  This is probably why most profiles never fly as good as a full fuselage ship.

By the way, don't ignore Curt's recommendation about "tore edges".  In any repair, a torn edge can be "disappeared" long before a sharp-cut edge.

Scott 

[Paul Taylor]

Ok lots of good info.

After I get back from the WKSI contest I will start the process as I'm waiting on on the weather to shoot clear on my current project.

I'm sure I will have more questions.

I will post up on my progress.

Thanks everyone for you help.