R_G

My Feedback: (1)

Because of the blistering issues that developed with the butyrate sanding sealer I've decide to bag the dope finish plan. I've poked around a bit and blistering seems to be a consistent problem even with the low shrink variety of dope. There have already been too many times where I've had to back up and punt with this build and I sure don't want to do that with the finish.

So, I went through my inventory of 15 year old acrylic lacquer and discovered that there is enough left over for this project. I even have all the colors I want to use!

What I didn't have was any type of lacquer primer, so off to my local auto parts/paint store I went. Had a very interesting conversation on the future of paint with the resident "Paint Guy" at the store. Water based paint is definitely the way of the future. I asked about the chemical resistance of water based paint. He told me that the colors will still be clear coated with a solvent based clear, so chemical resistance is very good. Good news for us alcohol & nitro addicts! Most likely this will be my last solvent based paint job! []

At any rate, I came home with a rattle can of grey lacquer primer. I opted for the spray can for convenience instead of going through the trouble of breaking out the spray equipment. This [link=http://www.u-pol.com/product-cat/121/high%235%E2%84%A2-high-build-primer.htm]U-Pol[/link] primer is made in the UK. It came highly recommended by a friend who does a lot of automobile painting. I don't want to give anyone a heart attack, so I won't mention how much this stuff costs! [X(]

To get a feel for this stuff I primed only the control surfaces this morning. Since this is a "High Build" primer I tried to apply it very lightly to avoid making things heavy. Even in light coats it covered very well and dried super fast. The instructions say it can be sanded an hour after application, although I'll give it much more time. So far I'm happy with this primer. Hopefully it will sand as well as it goes on!

I need to build a couple fixtures to hold the fuselage and wing before they can be primed.

RG [8D]

doxilia

My Feedback: (3)

Ralph,

Good to see you get to this stage. That primer is no doubt the bees knees. I suspect it is of the same caliber (or better) as the German SprayMax stuff ($20-30 a pop?). Is it a 1K or 2K product?

David

R_G

My Feedback: (1)

David,

I have to admit that I had to Google "[link=http://www.eastwood.com/1k-coating-vs-2k-coatings]1K & 2K[/link]". Had no clue what that meant! But now I know, the U-Pol primer is 1K.

I did a little sanding on the rudder this week and this stuff sands very well, wet or dry! I was impressed at how well the primer powdered while dry sanding with 400. No gumming up of the sand paper at all. I'll be wet sanding though, the dry sanding was just to satisfy my curiosity.

Since this primer has such a high build quality I think for future paint jobs I'll be able to skip the sanding sealer step and go straight to the primer after the silk span. Should save a lot of time. [X(]

RG [8D]

speedracerntrixie

My Feedback: (29)

David, I am a big fan of the Spray Max stuff. The cowl, canopy, wheel pants and spinner of my Laser was primed with Spray Max 2K primer, the base is Pactra R/C car sprint white ( Perfect match for Mono and Ultra ) and trimmed with Duplicolor in red and blue. The clear is Spray Max. I doubt I will be shooting primer or clear out of my spray gun ever again.

bem

My Feedback: (1)

speedracerntrixie,

Just curious - what are the advantages with Spray Max as far as spraying and the final result? Is the Spray Max clear also fuel and nitro safe? Is it Spray Max 1 component or 2 component clear spray You have used? Is it expensive? Does it stay clear and do not become slight yellow by age/sun? Can it really be as good result as using an conventional spray gun in your opinion?

/Bo

DougC1

.....and potential weight penalty compared to thinned clear?

Thanks for your help.

Doug

boomerik

And you have to finish the 2k can in one go i guess????

speedracerntrixie

My Feedback: (29)

Lets see if I can get all these questions answered. For the surface area we are working with the Spray Max clear works great. You can get around a fuse or wing and still have good flow out. The spray quality ( Nozzle ) is every bit a good as the HVLP gun that I have. In fact to get good flow out with the gun actually requires more paint. It is quite thin leaving the can but covers really well. I was able to clear all my parts on the Laser with a single 12 oz can. It is a catalized urathane so it will not yellow and is gas/glow proof. The 12 oz cans run about 20.00, far less expensive then auto cleas and primer. You will need to plan ahead as once mixed you have to use it in 24 hrs for primer and 48 hrs for the clear or loose what is left in the can.

R_G

My Feedback: (1)

The fuselage has been primed.

RG [8D]

stuntflyr

Now we're talkin', Ralph. Beautiful.
Chris...

PatternPilot

My Feedback: (58)

Ralph,

Great painting mount !!

scott
cpa#2

R_G

My Feedback: (1)

Thanks guys! It's good to see everything the same color, even if it's just primer!

Got the wing primed today. Time for some wet sanding.

RG [8D]

R_G

My Feedback: (1)

Well, after taking a closer look at the primed surfaces I noticed thousands of pin holes! [] As I wet sanded, the pin holes multiplied into millions! The more I sanded the worse it got! [:@] ARRRRGGHH!

My first thought was that there was some sort of reaction between the primer and the sanding sealer. But, after sanding away most of the pin holes (I managed to miss a bunch of 'em ) in the primer right down to the dope, a lot of the pin holes reappeared after shooting the first coat of paint. This led me to the conclusion that it was the SIG Sanding Sealer that was the problem!

I have no clue what went wrong with the sanding sealer. I didn't notice anything unusual while sanding it. In the past I've always had issues with butyrate dope. I don't know what I was thinking when I decided to use butyrate dope for this project, but I am done with that stuff! Never had any trouble with nitrate dope.

I'll repair the holes with spot putty and re-shoot the white. Hopefully it won't turn into a brick! [X(]

RG [8D]

speedracerntrixie

My Feedback: (29)

I don't know why you would get pinholes in silkspan but when I have a fiberglass part ready to prime I first rub it down with some lightweight spackle. I just grad a small handful and smear it on like I was taking a mud bath. This usually gets it in all the pinholes. After a couple days to dry, I sand smooth with 320 and then prime. I usually have very little pinholes to worry about this way.

Roguedog

RG,

It won't be brick as long as you sand the primer back off.

Alot of people believe that they need to have primer for paint to stick, This is just not accurate. When you watch the TV programs where they strip all the paint and primer off a car to repaint it, it is normally to find out if and than how much body damage there is. Old paint is thebest primer as longas itsnot pealing off or iscracked lacquer.

As long as the balsa is sealed some wayeither with butyrate dope, nitrate dope, sanding sealer, or epoxy resin (my choice)that substrate should bea good base for painting. I refinishfloors fromtime to time an the pin hole problem always shows up regardless unless thefloor is sealed some way.If you've ever used a paint brush to apply clearonto bare wood youwill see tiny air bubbles develope as the clear soaks into the wood.That's air being displaced in the pores of the wood by the clear and it looks horrible when it drys as alot of those tiny bubbles don't pop.

Same thinghappens with dope, sanding sealer, and resin until the wood pores are sealedhence the term sanding sealer. You apply thesealer, than sand, check for pin holes, if they exist thensand as much off the sealer off as possible, then reapply the sanding sealer, thensand and check for pin holesover and over until nothing soaks into the wood. Pain in the arse but until the wood is completely sealed those pesky pin holes will always show up. Spot putty is a stopgap step to save time from having to reapply the sanding sealer IMO

A thin layer of epoxy laminating resinscaped off with an oldcredit card then heated up a little with a heat shrink gun will cause the resin to flow into the the pores and the bubbles to pop. If you mix the epoxy right it will be very sandable when cured.

After the wood is sealed I use primer very liberally than let dry, thenmist black primer on the gray so low spots will show up and then sand most of it back offas a means of checking for surface imperfections. I use a different colorprimerafter sanding it backoff, e.g. light gray then dark dray, each timeas a layer check. If I'm satisfied that i've fixed the blemishes and that there's not a ton of primer left on it thenI spray a very light coat of white or light colored finish paint as the base for all other colors. This at least gives me a base canvas all the same color to design a color scheme on.

Bryan

dhal22

Well said Bryan.

doxilia

My Feedback: (3)

Bo,

Just to add to SRT's reply, you'll love The SM system when you try it. There is nothing quite like it out there as a system (there are other brands like the Upol Ralph is using).

The spray nozzle is "pumped" and has a similar action to an HPLV gun. No drips or nasty spray patterns. SM is an automotive system so every bit as good in quality. The paint within can be any of 4-5 main brands (eg, DuPont or PPG) either solvent based or water borne (the preferred and mandatory choice in some countries now). Both 1K and 2K CC's exist but obviously the catalyzed 2K self contained can is best for our application. It cures to a smooth buttery feel and in the right conditions, flows out leaving no orange peel. All that's needed once cured is a good polish to get the "butter" out and the "silk" in - so to speak.

Unlike epoxy and dope, being a catalyzed acrylic urethane it is virtually impervious to UV effects and should remain crystal clear for many years. It is very glossy! In my opinion it wants nothing from an HPLV finish.

Cost wise, it is possible that a complete SM system finish might cost more than a gun approach but not all paint applied need necessarily be SM. Like SRT did on his glass parts, I also mixed and matched different paint systems. The SM CC is really a great product for our application and being a catalyzed urethane can be applied on virtually all finished surfaces.

'nough said!

David

doxilia

My Feedback: (3)

SRT,

Regarding the spackle, do you not run into situations where there is a gap larger than a pin hole and then you wind up with a "soft spot" in the primed surface?

Perhaps you make sure that any surface imperfections are first filled with something stronger (eg, epoxy and MB)?

I might try the spackle on the next glass fuse...

David

doxilia

My Feedback: (3)

How's she coming Ralph?

David

R_G

My Feedback: (1)

Still sanding! I am soooooo tired of sanding this thing! []

Gene Margiotti

My Feedback: (4)

Keep up the great work, Ralph!!

Gene

doxilia

My Feedback: (3)

Yup, the longest job of a pattern build - paint.

I'm surprised you wound up with pinholes on your wing though! Seems like the dope/sealer approach didn't quite work with the silkspan?

David

vasek

My Feedback: (4)

Any great finish requires lots of elbow grease...

R_G

My Feedback: (1)

Yeah, it was a big mistake using the sanding sealer. I should have just applied a few extra coats of nitrate and then gone straight to primer. Live & learn I guess! You can bet that I'll never use SIG Sanding Sealer again!

RG [8D]

R_G

My Feedback: (1)

At any rate, everything is sanded and ready for the re-shoot!

I don't have enough of the white PPG lacquer to re do the entire airframe, so I had to find a source for acrylic lacquer. Fortunately I found a place in New Jersey that is one of the few places left in the country that sells automotive lacquer. [link=http://www.paintforcars.com/acrylic_lacquer_paint.html]Trinity 1945[/link] carries a full line of acrylic lacquer. The down side is that it's only available in gallon cans, but I was glad to find this place. Had the paint four days after it was ordered.

The plan is to shoot the white again tomorrow. I have a feeling I'm going to run out of painting weather pretty soon. If that happens it'll be late Summer, early Fall before this thing sees the air! []

RG [8D]