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Post  rsv1cox Thu Aug 13, 2015 3:35 pm

The brushed on kind anyway.  I don't know about Top Flights "LusteKote" spray as I haven't used it over silkspan.  

I just completed this C/L Nieuport 28 this past spring and already the covering has checked.  Discouraging as I have not flown it yet.  While my mono coated P-40 finished 35 years ago is intact and ready to fly.  

I'm done with dope Loft_p10

BTW, that P-40 is a great flyer.  Inverted, loops, do great.  I don't know about the full pattern though.  Enya .15 powered.
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Post  stuntflyr Thu Aug 13, 2015 6:33 pm

What kind of dope?
Old silkspan?
All of the dope the same maker?
Non-tautening or unknown?
Thin the color with the same manufacturers thinner/reducer?

I use all Sig dope. I build in dry seasons usually to avoid blushing. I use all of the same manufacturers products up to clear, I usually use car paint to clear them. I add flex-all flexing agent to the dope so it resists cracking when flexing and vibrating. Also the old silkspan was always very thin and crack prone in my opinion.

I used airport dope (Randolph) on a profile Midwest P-63 King Cobra model a while back (1980's) and it did last a long time with medium silkspan from that era from the hobby shop (not from the kit) and painted with K&B Super Poxy. But nowadays I use polyspan, you can drop your keys on the open bays and it'll bounce off and dope shrinkage won't pull it open. No way. I used medium on a Skylark too, it didn't last a long time but the finish did and I painted it with all Sig in buildup and all lacquer for the color and finish clear.

I know it's a real bummer when these things happen to your finish, but the Top Flite LustreKote is no solution. My Staggerwing project I presented to my Dad has cracked in a million little lacquer-check type cracks. The model was built up with dope, then primed with LK primer and LK color and then LK clear so I did it to the letter. What a drag to see it crack in front of my eyes. It started about 9 months after the finish was complete.

My Tigercat discolored over time with LusterKote too, looked good for about 6 months.

I would not use anything but Randolph dope from the airport, Sig or Brodak from the manufacturer. Only use their thinners, color, etc. Use non-tautening dope, Sig Lite Coat, not Super Coat. Super Coat will warp a foam wing, I know because it happened to me on a Magnum kit wing. Not the greatest wing, i'll admit but certainly strong enough so I was impressed with the shrinking power of Super Coat Clear from Sig. Lite Coat doesn't shrink like that. Color is used to a much lesser amount than clear, so Super Coat color shouldn't cause shrinkage damage.

Good luck with whatever you do, sorry about your trials there, I know them too!

Chris...
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Post  larrys4227 Thu Aug 13, 2015 7:11 pm

I wouldn't give up on the dope .... but something funky is going on there. If thats the way most models turned out ... nobody would use it. Take some tips from stuntflyer's post above .... Smile

More than half the control line planes I have are covered in some kind of plastic. I simply can't stand the stuff. Constantly doing maintenance to it .... once oil gets under it, it's a constant problem ... for me anyway.

Good luck!!
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Post  roddie Thu Aug 13, 2015 7:22 pm

Geez, that's too bad Bob. I have brushed dope.. but not with the intent of shrinking a covering. I don't know for sure, what would cause the checking. The discussions here on finishing with dope fascinate me. I'm not a painter by any stretch of the imagination.. but I've learned many helpful hints here on the forum. My only experience with dope is Pactra's Aero Gloss, brushed onto sheet-balsa surfaces. Sanding-sealer, fuel-proofer, color-coats.. no thinning.. Ambroid glue.. somebody open a window.. Shocked I love the smells of balsa-wood modeling! Regarding the Iron-ons.. mine have held-up really well too. I purchased a roll of white econo-kote a while ago.. and it's still unused. I'd like to build some built-up 1/2A wings covered with it. White is a nice base for graphics.. especially if they pop.
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Post  getback Thu Aug 13, 2015 8:42 pm

I think Bob was using Aero Gloss , I also have a deal of this but have not did any tissue in a while for I have a plenty of mona-kote around from time back and sales ... when I did it dope wood, dope sheeting on and 2 coats clear 1 color I think was the way it went with the same stuff // I got several yrs out of most of them that flew the others were moving accidents   DAMMIT!   Sorry to see that work do that to you Bob had to have been a bad mix of chemical 'S ?? And I have no extra's until I can reup Laughing silly boy. Are you going to coat it with plastic or try the tissue again ? Rolling Eyes  Eric
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Post  Ken Cook Fri Aug 14, 2015 4:32 am

Aero Gloss is and always has been problematic for the past 30 years. It's very different from traditional butyrate dope. As Chris mentioned, Sig is superior to most. Sig dope covered with Sig Lite coat will yield the highest fuel proofing qualities above the rest. Brodak dope has very little fuel resistance and 10% will readily attack it. The solution is to put Lite Coat over it. John has now come out and offered Crystal Clear Brodak. This is the clearest of clears and this greatly improves the fuel resistance. It's also a lot more money than the standard clear.  Randolph makes Sig, and also Brodak but all of them including Randolph are slightly different. Sig uses the slowest thinner amongst them. What this means that you can have a bit more open time using the product which allows for brushing and a stroke free finish provided it's thinned properly. You need lots of thinner and this doesn't come without a high price tag. While it's suggested to use the same thinner from the same manufacturer, this doesn't have to be the case with Sig, Brodak and Randolph. The universal thinner for Sig, Brodak is Dupont 3608S. A qt of Sig thinner is $20. A gallon of 3608S is about $29. Dupont recently changed the name and it's now known as Chroma Color but still retains the 3608S#.   Dupont does make a 3608VS and this is not the same and this is used for acrylics which doesn't work and will instantly gell your product. Dupont 3608S however will not allow for brushing very easily and in my opinion must be sprayed. If brushing is your only option, request 3602S which is slower.  Dupont 3608s has little to no open time and evaporates the fastest when compared to Brodak which is also in my opinion a thinner too hot which dries to fast. What does all this mean? It means that you don't receive proper layering adhesion if your using a thinner that dries to fast. I've always had to use retarder with Brodak dope which I despise because your playing tug of war with the paint on the model. Your using a thinner that wants to dry fast and your now making it dry slower which can cause problems especially in and around trim color transitions.  You need a form of mechanical adhesion which is where most of the problems begin. The paint needs to melt into the next layer and when this doesn't happen properly due to faster drying or not enough thinner, problems as cracking and checking can certainly take place. However if Aero Gloss is the product, this can take place no matter what you do. White Aero Gloss was notorious for checking. Aero Gloss has little to no flexibility and I have several models from the 80's which show similar damage.


Last edited by Ken Cook on Fri Aug 14, 2015 4:29 pm; edited 1 time in total
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Post  rsv1cox Fri Aug 14, 2015 6:20 am

Thanks for the compassion guys, I love those Nieuport 28's.  

The problem is probably 50/50, half me half the dope.  The olive drab and darker tan colors are Aero gloss, the brown and light tans (underside) are Brodak.  All four colors cracked. The Aero gloss dopes are old, ebay bought because you can't find camo colors anymore in Aero gloss.  That's how I finished my first 28 and wanted to repeat the process.  

I used fresh Aero gloss clear thinned for the base, three coats brushed.  Then the colors.  The silk span was old, came with the kit, but appeared to be in good shape.  I think I will just patch it, fly it a couple of times then strip down to the bare airframe and try again, this time with flat OD monocoat and trimmed with period decals.  

I love working with spray LusteKote.  It did really well on my two latest builds, sans silk.
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