Clear Yellowing.

[carson]

I guess I should write down what I've used on rocket builds.
I have two rockets built about 5 years ago, give or take.
Both white with clear.
One has yellowed and one seems to not have yellowed.
I have no idea what paint I used on them.
or in what combination.
I'm thinking the clear was either Krylon, Duplicolor enamel or Duplicolor lacquer.
Both were color sanded and rubbed out with a high quality polish.
Does anyone know which paint is better about not yellowing?
I want to do some airbrushing on white rockets, so a clear will have to be used.
I'm not apposed to using automotive clear Uro.
I have the equipment but the weight may be a issue, not to mention the hassle of mixing and cleaning. all for a low power rocket.
I've tried Future finish, but I've not had much luck with it.
Besides I do like the polishing part.
Any thoughts

 

[rocketking]

My own experience with the Krylon White & Clear combo resulted in SEVERE yellowing. This was on an Estes Phoenix missle, too! Your results may vary, of course, and I cannot speak for any of the recent Krylon products at all.

Glosscoat by Testors has been my overcoat of choice since, with fairly good and consistant results. Next up may be the Duplicolor.

 

[RadMax8]

My other hobby (scale models), the clearcoat of choice is Future floor polish. It's an acrylic clearcoat, never yellows. The only problem is you have to airbrush it. It self-levels which is very nice!

 

[fastfreddie]

Go with the Duplicolor as the Krylon is what yellows. Just keep in mind that you MUST use Duplicolor base colors with the Duplicolor clear. Mixing dissimilar paints will cause you all kinds of grief. Stay away from the laquer, unless you plan on using ALL laquer, even the primer. Laquer is like paint remover when put over enamels or acrylics. I use Duplicolor automotive acrylics exclusively any more. They're easy to apply, dry quickly, can be color sanded, and can be easily repaired without lifting or crazing. There's a reason they use it on cars......

 

[Micromeister]

duplicolor spraycan clear yellows just like just about ALL rattlecan clearcoats, which in most cases contain 0% UV resistant additives.

To date the ONLY rattle-can clear that has ANY UV additive is Krylon UV resistant clear in either gloss#1305 or matte 1309. I still don't recommend clearcoating entire models for many reasons but in on-going outdoor tests since june of 2006 these two products are the only ones that have NOT shown any yellowing at all.

If your just trying to protect your decals, try a coat of Nu-Finish Polymer, it doesn't become brittle over time like ALL Clear coats, and can be renewed without buildup by simply applying another coat.
a much better way to keep your decals looking good over an extended length of time.. I'm talking years
Hope this helps.

 

[Stymye]

Go with the Duplicolor as the Krylon is what yellows. Just keep in mind that you MUST use Duplicolor base colors with the Duplicolor clear. Mixing dissimilar paints will cause you all kinds of grief. Stay away from the laquer, unless you plan on using ALL laquer, even the primer. Laquer is like paint remover when put over enamels or acrylics. I use Duplicolor automotive acrylics exclusively any more. They're easy to apply, dry quickly, can be color sanded, and can be easily repaired without lifting or crazing. There's a reason they use it on cars......

yea and it also runs between $4-$5 a can !

 

[fastfreddie]

duplicolor spraycan clear yellows just like just about ALL rattlecan clearcoats, which in most cases contain 0% UV resistant additives.

Never had that happen. It seems silly that they would make paint to repair your car that would yellow when the rest of the car doesn't.

 

[fastfreddie]

yea and it also runs between $4-$5 a can !

Well, I use it on HPR stuff, and if I'm spending $100+ on a rocket, $15 for paint doesn't seem too bad. Besides Krylon is about $3 a can here, so it's not that big of a difference, and I like having the ability to fix or repaint with no issues.

 

[Micromeister]

Never had that happen. It seems silly that they would make paint to repair your car that would yellow when the rest of the car doesn't.

that's simply because it's not ment to be a premanent repair, Read the lable. The last time I checked Duplicolor their rattlecan clears no 0% UV inhibitors, has that changed in the last 3 years, Not that i've seen announced.

Generally topcoat/clearcoat systems used on Cars are 2 or 3 part urethanes, but that's getting into a completely different can of worms, nuf to say here rattlecan clears are generally just "stop gap" short term measures to help reduce underlaying paint in damaged areas from being oxidixed by air before a professional repair and be accomplished.

Again, 1305 gloss and 1309 matte Krylon UV resistant clear seems to be holding up well under on-going testing. If you think you must clear coat you models you might want to give them a try

 

[Stymye]

mine never seem to last long enough to turn yellow. I have one with a future topcoat that has yellowed badly , but when I stripped off the future I found that the underlying white is what had yellowed .so I still believe in future not yellowing. testors is the worse but sure gives a nice finish. the high gloss spray is amazing.

 

[mike_bar]

I like the Krylon UV resistant clear coatings. These are the only ones I have found. I bought mine at the Michael's Arts & Crafts Store. I have NOT started any long term tests.


Krylon Products: UV-Resistant Clear


Krylon Products: Artist & Clear Coatings


Source: Krylon website


Regards,
Mike

 

[Jeremy Lundy]

I plan on using a clear coat over my Mongoose CF body tube. I bought a can of Krylon but after reading the above I am a bit worried. I don't want it to turn brittle over time and start cracking or changing color. Is there any alternative to clear coat can stuff for just glossing up CF? I was going to try going to a local body shop to see if they would spray the rocket but I can only guess at the price due to cleanup. I can see paying a guy $20 but not much more.
jer

 

[Stymye]

isn't there a uv issue with exposed carbon fiber? I notice planes,cars,boats constructed from CF are always covered with a uv barrier primer and/or paint.

plus CF being dark gets quite hot in the sun and a breakdown of the epoxy/cf starts. this is just from what I've picked up here and there mostly from past threads on the forum.

it would be a shame to paint the CF but It would be important to protect it if thats the case.

mabey some of the experts can chime in

 

[Jeremy Lundy]

All good things to know. I know that regular 5-30min devcon epoxy has a very bad lifespan in sunlight and will yellow on its own after few months. Not that I leave my rockets outside for days on end but I'm curious about what you said with the CF. I don't want to have to paint the rocket just make the CF stand out with a durable clearcoat.
thanks
jer