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Urethanes, can we talk about these?


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Greetings guys, I guess what I want to have is a better understanding on your favorite brands. I've never used them for clear coating my models but would like to start at some point. My questions are:

1- Best place to purchase them? Internet? Local paint jobbers? Stores?

2- Is it true that the hardener has a shelf life? If so, what methods should I use to make it last longer?

3- Brands? Which are your favorite? Which ones go on thinner or flow better?

4- What mix ratio, PSI or anything else you guys can add to explain the use?

5- Which airbrushes work better for you when it comes to shooting these?

In the meantime I will be googling some info on the subject but I think it's always best to consult people through the forum, I want to hear opinions from my fellow modelers. I have heard of a few favorite brands from some people but I like to have this kind of info on paper so, the more people join in to discuss, the better. Thanks guys!

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Marcus I have been using the Matrix Brand from House of Color for the last 6-7 years. I originally started with MS 52 with the MH005 hardner and their reducer. That was a 4 clear to 1 hardner then I added 2 parts reducer.

I now use MS 47 which has a higher solids content. It is 2 to 1. I then add 1 part reducer which I am using MH006 hardner which has a slower cure time.

I still polish these like any other paint.

I haven't had a self life issue but I do keep the paint in the house so it stays at around 75 degrees.

Edited by Len Woodruff
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Marcus I have been using the Matrix Brand from House of Color for the last 6-7 years. I originally started with MS 52 with the MH005 hardner and their reducer. That was a 4 clear to 1 hardner then I added 2 parts reducer.

I now use MS 47 which has a higher solids content. It is 2 to 1. I then add 1 part reducer which I am using MH006 hardner which has a slower cure time.

I still polish these like any other paint.

I haven't had a self life issue but I do keep the paint in the house so it stays at around 75 degrees.

Len, thanks for the response, funny that the last guy I talked to actually told me this is the brand that he is also using and loves it. Do you buy yours through their website? Can you provide me with a link?

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1- I buy from my local supply house.

2- From what I understand, humidity is the killer for most hardeners. As soon as I pour the hardener, I wipe the threads of the can clean and replace the cap immediately. Cleaning the threads is important as I've had cans weld themselves shut from the hardener drying between the can and cap.

3- My favorite is Nason. Cost and how it flows out are the reason for my choice. I am currently working with a house brand, but I'm having a hard time getting it to flow out nicely.

4- The factory formula usually works fine. If the brand you decide to use has a reducer available as an option, you might want to try adding it or adding a bit more than the suggested formula. Clear is designed for the much larger air cap of a spray gun reducing it will help with atomization. I spray at about 20psi.

5- I usually use a Paasche VL5 for clearing. I have had excellent results with the number 1 tip and needle also. I recently tried my Badger Krome to see if it would handle the thicker clear an it to worked great.

I will give you this tip, not all urethane spray and flow the same. I've had some spay like a thick glue, but flow out beautifully. You need to practice to learn how the brand you choose will flow out.

Edited by Psychographic
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I took Fatkidd's suggestion and use Nason Selectclear 497-00 with Nason Selectclear activator 483-78 and I get them at the local Car Quest. WARNING - use eye goggles, respirator mask, gloves, and a long sleeve shirt when shooting urethane. I use an Iwata Kustom TH-HP for shooting urethane.

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I don't currently use urethanes on models, but I've used them extensively on 1:1 cars and aircraft over the past 35 years or so.

All I have to add is that they typically have higher build than hobby-specific 1-part clears, so fewer coats will be necessary for sanding and polishing, and many will flow out so well you may not need to sand and polish.

Also, HEED Jim's ADVICE ABOUT PROTECTIVE GEAR. The hardeners typically contain isocyanates, which are damaging to lung tissue, eyes, may be absorbed through skin (and even latex gloves), are extreme allergens to some people, and can sensitize the user if proper safe handling precautions are ignored. They can also trigger lifelong asthma.

Here's a good article dealing with the safety aspects of using the material. Don't think that just using them on little models is OK without adequate protection. It isn't.

http://www.bodyshopbusiness.com/Article/2923/your_lungs_your_skin_your_life.aspx

Edited by Ace-Garageguy
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I have been told different things by different people about shelf life of paint. Some say it has a life span but I've used left over urethanes and enames from when i was painting 1:1 cars that was ten years oold or more and jhonestly, I never had any problems. Again, with freezing, some guys insist that freezing will ruin enamels and urethanes but I have also used paint that I know sat in below freezing temperatures with no adverse effects. The secret is I believe, that virgin paint willlast a long time if the cans are sealed. It's always a good idea when a can of paint that has been opened and resealed sits, to turn the can upside down andthen right side up periodically as it does not allow a film to form on the top of the paint as it sits in the can.

The newer water based paints which many body shops are finally realizing and admitting is BLAH_BLAH_BLAH_BLAH for the most part would of course not take to cold temperatures very well. Latex ( water based ) house paint becomes instant garbage if it freezes, I do know that much. Oil based house paints do not seem to be bothered although it is best to keep it warm.

I am not a professional painter but I did paint here at home for over 15 years and I still have lots of part cans of paint to draw from for model building.

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Cruz,

I strictly use urethanes paints (DuPont) To me they are the better then anything else on the market.

To answer some of your ?'s

#2 Hardener does have a shelf life, I can't tell you how long because where you live your humidity is different then where I live. The only way to make it last longer is to buy a can of Bloxygen. After you open your paint, hardener, & clear coat spray a little then close it.

#3 DuPont

#4 I mix my paint different then the next person its just a preference, I spray my paint at 15-23 psi.

#5 I use a paasche to an Iwata to sata airbrushes & a sata jet

post-750-0-13372400-1398986002_thumb.jpg

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  • 2 weeks later...

Cruz, you don't need to use urethanes to accomplish a good paintjob, you have already shown us how great your work is just by sticking with the basics. No disrespect to Jimmy but if you look at that Merc, the panel lines are completely gone. To me, the urethanes are way too thick and yes, I am gonna hear some people suggesting that if you thin them and shoot them the right way they can certainly be used. I know of quite a few people that use them but 1 out of 10 have the trick mastered, the others just have an idea.

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I used Due Pont Hot Hues for a long time and then change over to Du Pont 7900 crystal clear as it flows a lot nicer and thinner then the hot hues line did which is the same line as the Nason 4600 line.

Easier to wet sand and buff as its not a panel clear.

Yes it has a shelf life but not sure on how long as I do change it out every 4 months.

I use a vl pro with a #3 needle with no troubles and no redueser add.

Like any thing else you get what you pay for when you start moving up into this stuff

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Kevin,

Kevin I didn't take it at disrespectful. The model that I posted the panel lines are not gone. If you could see it in person you could tell. What I do is before I primer is cut the panel lines a little bit deeper so the clear coat won't fill in.

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Cruz, why fix something that's not broken? You are very well known for your awesome paint jobs, you don't need those thick and dangerous urethanes, just keep doing what you're doing and save yourself the hassle and your money. Jimmy, no disrespect but yes, your lines are there of course but sorry, they are completely full of clear, there is really no detail left on your panel lines.. Looks nice, just too "syrupie".

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I just can't jump on the urethane bandwagon. I love a good gloss finish (and I think my finishes using mostly the Testors Wet-Look Clear shine with the best of them), but you can often spot a urethane finish a mile away because the thickness of the clear coat just doesn't work in scale. It isn't just about the gloss, which urethanes absolutely provide, but scale fidelity should count for something too. Marcos, your work is delicate and very realistic, and that effect would be completely ruined by a thick, out-of-scale coat of syrupy clear.

Edited by jaymcminn
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Marcos, I too have seen your work, if it ain't broke don't try to fix it. I would also echo Jason's remarks, after attending and judging several show, urethane on models appears to me as the finished model was "dipped in plastic". Just my opinion, but way to HEAVY for model cars. Keep them realistic in scale just like the models of yours I have seen.

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  • 2 weeks later...

Marcos, you are not allowed to use any Urethane clears, you're already better than all of us! :D

I use Nason myself, but not on everything. It lays down smooth as glass, which means any polishing is minimal at best. Here's a few examples of Nason on mine. And I've got to disagree with Craig, none of them look like they were "Dipped in plastic", but I also only use one to two coats, the ones that look dipped may have been laid down much heavier.

346012-vi.jpg

CivicC035-vi.jpg

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Marcos, I use House Of Kolor and PPG products exclusively (I have been doing 1:1 custom paint for 35+ years) Ace-Garageguy (Bill) is spot on!!!! this stuff can be nasty. When Imron first came out in the 70s I had a friend almost die from Iso poisoning. A couple of things! I always stick with one system. Paint, Reducers, Hardeners or other additives, never cross mix. If I use PPG as a base I use PPG clear. Obviously this is not as critical on a Model as 1:1. I can't afford to redo a 1:1 $10,000 paint job. I have never used Bloxygen, I have used Argon in the past but don't anymore, I personally don't think any of the purge methods work, the only way you could insure a fool proof seal would be to pull the container into a vacuum, I feel that once you break the seal the cats out of the bag. I and all the custom painters I know do store their hardener in the refrigerator, this does extend the shelf life. Make sure you have the hardener at room temperature when you mix. Once you mix you have a pot life, DO NOT put that mix back in the original can it came from.

I get most of my materials from my local jobber although I do use Coast AirBrush, they are a great resource for large and small quantities of House of Kolor products.

I do use some Dupont Hot Hues striping urethanes, it's a great product for Lettering, Pinstriping and some Airbrushing, you could use it as a color coat for models with great results. I have used Dupont and I am not a fan of the rest of their product line.

I don't use any modeling paint for body color coats, I do use various modeling paints for brushing and detail.

As far as the dipped in plastic look go's that's a bunch of hooey!!!! Chances are you are going to scuff and buff and that takes care of that look. At least 90% of the 1:1 Customs and Restorations have a Urethane clear coat and what are we trying to duplicate with our Models 1:1. Look at Custom Mikes finishes they are realistic facsimiles of 1:1 (nice work Mike)

Give it a try, but please read Bills information!!! (Thanks Bill) this stuff can hurt you!!!! I have way to many guns to list, However I just purchased a Iwata HP/TH Airbrush, It has interchangeable nozzles, it can spray a fan pattern or a conventional airbrush conical pattern. I don't have allot of time with this one in my hand but this thing rocks!!!!!

I hope this helps, jwrass

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Mike, Be it models or 1:1 we all have difficulties with paint as their are so many variables to contend with, it's all learning process, what you learn from your experimentation and failures ultimately make you better.

You said you are on your third paint job on your latest build, think back on what you did or are doing that is causing your failures and trouble shoot the process, take notes that you can refer to. I have pages of documentation of every 1:1 paint job I do. Think back on what you did on your successes and repeat the process.

Keep the Faith!!!! the paint on those two builds was outstanding!!!!!!! jwrass

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James, I'm working on an Aoshima Toyota Aristo. Being that I don't build Japanese kits very often, I didn't know that Aoshima is similar to Revell in the fact that both use a plastic that is overly sensitive to hot solvents. I used my normal Dupli-Color Primer/Sealer on it, and painted it the first time with some Dupli-Color Bahama Blue. Lots of issues popped up, mold lines, a strange swirl in the driver's side front door, and a line in the roof and hood, along with a bit of crazing. So I stripped it, prepped it again, and painted it the second time with some Testors Sublime Green...have I mentioned yet that I cannot use Testors rattle cans at all? There's a reason I use nail polish. Dupli-Color and House of Kolors paints, because to me, Testors rattle cans are the Devil's handiwork! I ended up with the worst orange peel I've had in well over two decades of painting cars, so it got stripped again. Now it's waiting for the fresh primer to dry, so I can lay down some Tamiya Racing Blue on it,

it'll be fine this time...or it'll be melted down with a blowtorch! B)

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Mike, You need to step away from that BLAH_BLAH_BLAH_BLAH they sell at the big box stores. You some need big boy paint! Most paint failures start in the prep procedures and products you use! Through that thing back in the pond if you used Dupli-Color primer and let's start fresh with some raw styrene

Send me a PM and I will share with you what you should try.

Cheers, Jimmy Rass

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