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Author Topic: Previous Finishing Methods  (Read 1932 times)

Offline Bruce Guertin

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Previous Finishing Methods
« on: May 31, 2019, 07:02:15 AM »
In the early 80s when I was modeling my preferred finishing method for built up wing aircraft was to Monokote the wings and stab and then use Pactra Formula U or colored Varathane on the fuselage. Foam wing aircraft were Sig Butyrate from start to finish.

I'm assuming that Polyurethe then was only oil based as "clear" was really a light amber color. I found this out by sealing FasCal seams on combat ships with the clear stuff.

Now days there is oil based and water based polyurethane. The water based stuff seems to be water white (like clear Hobby Poxy was) in the clear version. Is the water based stuff as fuel proof as the oil based stuff?

Can I buy clear polyurethane and color it with pigment from the auto paint store? Anybody tried that?

Also. Is there an alternative brand to Monokote/Econokote? What about the Hanger 9 stuff? Or Koverite?

Sorry I have so many questions but, I've got 35 years of changes to catch up with.
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Online Ken Culbertson

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Re: Previous Finishing Methods
« Reply #1 on: May 31, 2019, 07:40:07 AM »
Quote from: Bruce Guertin on May 31, 2019, 07:02:15 AM
In the early 80s when I was modeling my preferred finishing method for built up wing aircraft was to Monokote the wings and stab and then use Pactra Formula U or colored Varathane on the fuselage. Foam wing aircraft were Sig Butyrate from start to finish.

I'm assuming that Polyurethe then was only oil based as "clear" was really a light amber color. I found this out by sealing FasCal seams on combat ships with the clear stuff.

Now days there is oil based and water based polyurethane. The water based stuff seems to be water white (like clear Hobby Poxy was) in the clear version. Is the water based stuff as fuel proof as the oil based stuff?

Can I buy clear polyurethane and color it with pigment from the auto paint store? Anybody tried that?

Also. Is there an alternative brand to Monokote/Econokote? What about the Hanger 9 stuff? Or Koverite?

Sorry I have so many questions but, I've got 35 years of changes to catch up with.
I feel your pain.  Family and career took me out in 1981ish.  Came back in the fall of 2017.  It is a brave new world.  Every part of the sport is different and I am finding out that in most cases it is better.  What actually brought me back was this site and the way the top fliers, both past and current treated all of my stupid (to them) questions. 

Ken
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Offline Mike Haverly

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Re: Previous Finishing Methods
« Reply #2 on: May 31, 2019, 09:37:09 AM »
Go to the auto paint store and ask.  Most will give you all the information you need and more.  It can be overwhelming. 
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Offline Brett Buck

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Re: Previous Finishing Methods
« Reply #3 on: May 31, 2019, 11:11:49 AM »
Quote from: Bruce Guertin on May 31, 2019, 07:02:15 AM
In the early 80s when I was modeling my preferred finishing method for built up wing aircraft was to Monokote the wings and stab and then use Pactra Formula U or colored Varathane on the fuselage. Foam wing aircraft were Sig Butyrate from start to finish.

  My Monokote airplanes were largely done as you describe, although I much preferred Chevron paint, since Formula U usually came out the consistency of rubber. I switched to two-part epoxy long ago (K&B and HobbyPoxy at the time, Klass-Kote now). If all you are doing is the fuselage, it's perfectly practical do do it all with an airbrush and airbrush compressor, no real compressor required.

   I only did a few airplanes with dope all over, again, two-part epoxy and urethane is superior in every way except for not being as forgiving as dope, lighter when done correctly and VASTLY more durable.

     Brett

p.s. I would add - two-part epoxy actually works pretty well for *brushing*, if you can believe that. K&B had and I think Klass-Kote has a brushing catalyst (which is slower than the regular catalyst) to make sure it flows out well. It works vastly better than dope in this regard. It's not perfect, but not out of the realm of possibility if you have no other equipment.

« Last Edit: May 31, 2019, 12:48:31 PM by Brett Buck »
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Online Howard Rush

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Re: Previous Finishing Methods
« Reply #4 on: May 31, 2019, 11:15:00 AM »
I looked for Varathane at the hardware store recently. No Varathane. I still have some Formula U, but the lids are stuck on the jars.

Reports are that Monokote ain’t what it used to be. Oracover, sold in the US as Ultracote, is really good stuff.

Aerogloss, my favorite dope in the old days, is extinct. Most folks are using Randolph now or Brodak, which is probably nontautening Randolph.

Mark Scarborough can give you the lowdown on car paint.  Some guys use car paint toners in dope and clearcoat with catalyzed polyurethane. Search for the Granderson finishing system on flyinglines.org   


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Offline Bruce Guertin

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Re: Previous Finishing Methods
« Reply #5 on: May 31, 2019, 01:23:17 PM »
Quote from: Howard Rush on May 31, 2019, 11:15:00 AM
I looked for Varathane at the hardware store recently. No Varathane. I still have some Formula U, but the lids are stuck on the jars.

Reports are that Monokote ain’t what it used to be. Oracover, sold in the US as Ultracote, is really good stuff.

Aerogloss, my favorite dope in the old days, is extinct. Most folks are using Randolph now or Brodak, which is probably nontautening Randolph.

Mark Scarborough can give you the lowdown on car paint.  Some guys use car paint toners in dope and clearcoat with catalyzed polyurethane. Search for the Granderson finishing system on flyinglines.org

Howard, I think we have a common friend, Steve Kott.
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Offline Bruce Guertin

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Re: Previous Finishing Methods
« Reply #6 on: May 31, 2019, 02:02:10 PM »
I still have my Binks/Badger touch up gun. Of course, I have a compressor.

On the Monokote/Polyurethane system I started brushing the urethane to cut done overspray. The results weren't the best. So I tried the Pactra spray can stuff as it seemed to match the Monokote colors pretty well. The Midwest P-51 in my avatar is finished that way. I was happy with that system.

Brett, I'll have to try the two part paint you suggested.

Howard, I saw some Ultracote in the nearly local hobby shop I was in the other day. This supposed to ARF (STARF) I have is going to need to recovered. I thing I'll build some framework to bring my skills back to snuff before I attempt that.
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Online Dennis Toth

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Re: Previous Finishing Methods
« Reply #7 on: June 05, 2019, 07:35:09 PM »
Brett,
With the Klass-Kote epoxy do you apply a final clear coat? Does it get hard enough polish out (I had used Hobby-Poxy and that stuff needed years to get hard enough to polish out)? I like the epoxy material, could you describe your finishing method to keep it light.

Best,   DennisT
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Offline Brett Buck

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Re: Previous Finishing Methods
« Reply #8 on: June 05, 2019, 09:38:36 PM »
Quote from: Dennis Toth on June 05, 2019, 07:35:09 PM
With the Klass-Kote epoxy do you apply a final clear coat? Does it get hard enough polish out (I had used Hobby-Poxy and that stuff needed years to get hard enough to polish out)? I like the epoxy material, could you describe your finishing method to keep it light.

     It doesn't have the "cures like rubber" effect of Hobby Poxy. I actually think it is essentially the same product as HobbyPoxy, but that every single can of HobbyPoxy is long, long past it's shelf life. Al Rabe told me he never had any issues with it back in the day. I suspect that Petit made one run of HobbyPoxy paints, in the 60's, and then sold it off ever after, past the expiration date or not.

    It is not the rock-hard cure of SuperPoxy, which was like refrigerator enamel, but still plenty hard enough.

   I have only used clear in cases where I was going to polish it, car paint urethane. The clear KlassKote is amber, but they make a two-part urethane clear, too, which I have and will try probably next week on a repair. Properly applied, the colors come out very shiny.

   The process I use is here:

https://stunthanger.com/smf/building-techniques/klasskote-epoxy-substrate/msg8903/#msg8903

   About the only think I will do differently is to use the Klass-Kote primer instead of superpoxy, and lean *much* harder on the paint when color-sanding. It's really tough stuff.

    By the way, in a pinch, or a non-critical operation, it brushes on pretty nicely, much better than dope, and will level out brush strokes to a reasonable degree.

      Brett
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Offline Randy Powell

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Re: Previous Finishing Methods
« Reply #9 on: June 06, 2019, 04:20:25 PM »
My finishing method is somewhat like Phil Granderson's method. Phil built very pretty planes.
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Offline Lauri Malila

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Re: Previous Finishing Methods
« Reply #10 on: June 08, 2019, 04:53:37 AM »
Is Klass-Kote and other hobby epoxy paints in some way better than the standard 2-component acrylic clear from car paint shop? The car clear is allways easily available, cheap, seems to resist allmost every fuel and in my opinion easy (but time consuming) to sand and polish. And as it’s for cars, it’s never too hard or soft, and has an excellent UV-resistance.
I have used several brands (Sikkens, Sestriers, Spies&Hecker..), they all seems to have more or less similar chemistry and I haven’t found much difference in use between them. Allthough I have heard from many sources that PPG brand is the best.
I’m just wondering why to use something that is getting more and more obsolete? I have never used the Klass-Kote, that’s why I ask.

Lauri
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Offline George Truett

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Re: Previous Finishing Methods
« Reply #11 on: June 08, 2019, 08:01:29 AM »
Lauri, My understanding is that Klass Kote is better mostly from a health standpoint, I believe there is no isocyanate in the catalyst for epoxy paints.  That does not mean there is no harm in breathing epoxy fumes and I still wear a respirator and protective suit when I spray Klass Kote.  I have found no great difference in the ability of either to resist nitro fuels but all epoxy clear coats I have used have yellowed over time as mentioned earlier.  This goes all the way back to Hobbypoxy.  One thing we did find out years ago, if you use something like automotive basecoat with no nitro resistance and then 2K clear coat it, if you ever rub through the clear, fuel can get into the basecoat and make a huge mess.  Epoxy finishes don't seem to have that problem or at least not as bad.
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Offline Lauri Malila

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Re: Previous Finishing Methods
« Reply #12 on: June 08, 2019, 10:11:21 AM »
Thank you, George.
I agree with the 1-component base problem. I have finished 10 or 11 models with automotive 2-coat system with 1-component (acrylic enamel?) colour followed by 2-pack clear. Small repairs were real pain in a**, and also when oil creeped to paint from inside.
I'm no expert but I think the problem with those paints in our models is that it's impossible to respect the recommended time window when you should spray the clear after spraying the colour. Also, we use far too little clear to make the colour polymerize well with clear.
In cars it's not an issue as, if I understand correctly, they spray more wet-on-wet and use hell of a lot more clear over the paint.
My solution is to make all with 2-component products, from filler to clear. I use 2-component polyurethane paints, especially the metallics are very light when used correctly.
I don't know about health & safety risks, but there is a big risk of neglecting them with products that do not smell so bad. Especially the new generation water based car paints are really dangerous in that sense. I don't paint so often, hardly every year, so I don't think the risk is much higher. Of course I do use a good respiratory mask, nitrile gloves etc.

Lauri
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Offline Brett Buck

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Re: Previous Finishing Methods
« Reply #13 on: June 08, 2019, 08:33:49 PM »
Quote from: Lauri Malila on June 08, 2019, 04:53:37 AM
Is Klass-Kote and other hobby epoxy paints in some way better than the standard 2-component acrylic clear from car paint shop?

  I use 2-part car clear for the clear, but Klass-kote for colors. In my case, Klass-Kote works and is available, car basecoast/clearcoat systems cannot be shipped to my house, whereas I got an order from Klass-kote through the mail in 2 days recently. Most of the common car materials are hard to get or unavailable in California without some extra work.

    Brett
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Online Dennis Toth

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Re: Previous Finishing Methods
« Reply #14 on: June 10, 2019, 05:02:04 AM »
Brett,
The method discribed in the link thread is pretty straight forward. What do you do on open bay covering?

Best,   DennisT
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Offline Brett Buck

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Re: Previous Finishing Methods
« Reply #15 on: June 10, 2019, 11:35:05 AM »
Quote from: Dennis Toth on June 10, 2019, 05:02:04 AM
Brett,
The method discribed in the link thread is pretty straight forward. What do you do on open bay covering?

   I haven't done that. Other people have used K&B and HobbyPoxy over open bays in the past, the only issue is the sanding of the primer, as far as I know.

    Brett
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