Rough Alclad

I have also had a lot of trouble with Alclad and have quit using it.  However, others on this forum have had good results with it and continue to use it.  My advise is to practice on scrap sheets of plastic, until you are comfortable with it.

Its not Dull aluminium is it? no matter what I do it always looks like that.

Alclad is all about getting a smooth base before you spray it. I've never used Krylon as a primer with it but if its not mirror smooth you can't get a mirror finish. As Snids says if its Dull Aluminium it always looks rough

Phil

It's just the regular aluminum.  And I thought I had the Krylon down pretty smooth, but perhaps there's room for improvement there.  What type or primer do you use for your NMFs?

I use the Alclad ones, I know they can be more expensive but they match the paint better. Also you need to sand the primer before shooting the Alclad paint, I've seen people get to 20,000 grit in stages before  using the paint. Alclad goes on very thin as you know so you should be ok now if you sand what you have as high in the grit as you can go then hit it again.

Phil

Ah, I think now with careful reading of the original post, that I see the problem.  Krylon primer is a pretty flat, rough primer.  It MUST be sanded to a smooth finish with fine wet/dry paper.

Also, Alclad can be confusing.  Folks talk about the primer beneath the Alclad.  I prefer the term undercoat.

The plastic should be primed.  Then, undercoated with a gloss black.  That undercoat is critical. It must be very glossy, and flawless!  So sand the primer with #600 or #1000, then apply a good gloss black.  Alclad makes a good gloss black undercoat, but I always use it or whatever gloss black I use over a primer.  And I usually use the Krylon primer.

As a few others have said, the problem is in the primer not in Alcad.  The surface that you apply the Alcad to must be polished out as any blemish will show through in the color application.  After the primer dries, sand it with 2000 and 4000 grit, then apply the color.

You could always use grey gloss as a primer if you want. Never had a problem with Alclad sticking to Humbrol enamels. If you need to sand a primer, 1500 or 2000 wet and dry used wet will give a great result,

Thanks for the tips everyone. I think I'll give Alclad's gloss black a try for my next NMF build.

I sanded it and reapplied the aluminum.  I switched to my DA airbrush and put down some heavier coats this time, and it turned out better.  I masked off some panels and sprayed some different shades of aluminum.  Post shaded the panels lines with dark aluminum.  Pretty happy with it so far for my first NMF build.

I am getting a new problem now.  After spraying for awhile, these cob web looking strings start appearing near where I am airbrushing.  I'm not sure if they're coming off the airbrush or developing on the model itself.  Cleaning the tip with thinner seems to help temporarily. Anyone else had this phenomenon?

Drew

I've never had ther issue you mention, what pressure are you using? Alclad likes a pretty low pressure and prefers you gravity fed brush ( the Aclad guys themselves admitted that to me in preson) so with a syphon like the 200 you will need a bit more pressure. Are you in a dry climate? that can have an effect on drying times. Its a guess but that could explain the dry tip, are the "cob webs" affecting the finish?

Phil

I'm using my Badger 100 gravity fed at 15 psi.  Very humid down here in Florida.  Fortunately I can just stop when I see the cob webs start appearing and wipe them off without them affecting the finish.

Well looks like your doing the right thing with a good brush so that should give you a good finish. I've never seen any cob webs but then on this side of the Atlantic I dont think we get the same humidity as you do! I cant see why that would affect it as it shold increase the drying time.

Over to people with more idea about the issue with humidity

Phil

I use a siphon feed brush, and have used Alclad for several years. I do use a low pressure (15 psi).

While I have never had the problem with Aclad, I have had some spitting with other paints that require me to clean nozzle periodically. I use a Q-tip and thinner- just a quick swirl, and back to painting.

Are you thinning the Alclad with something?

I never thin it. Just use it straight from the bottle. Shake well, then shake some more before pouring.

I love the stuff. Always goes on real smooth for me. Low pressure (10 - 15lbs), over Testors gloss black enamel or lacquer undercoat. I usually use enamel and let it cure at least a week before the Alclad. If I'm in a hurry I use the gloss black lacquer and let it cure overnight (Alclad is hot and likes to crinkle your undercoat if it's not fully cured).

I don't thin Alcad either- I find the fresh stuff just the right viscosity for airbrushing.  However, I recenty did throw out a very old bottle that had seen a LOT of use. I don't know whether it had just lost too much thinner, or whether it went bad for some other reason, but it began to spit and slobber, while stuff from a newer bottle worked fine, so it wasn't an airbrush problem.  I think that older bottle was about three years old and had been used for at least half a dozen models.  And I pour excess from airbrush jar back into the Alclad jar when I am done airbrushing, so it certainly had a lot of opportunity to lose thinner.

Don

I'd guess if you pour it back in you could get contamination doing that which could give problems. I never have but then you have much more knowledge than me on airbrushes etc

Phil

Hey Drew, I think you'll find your problem is with the Krylon paint. Someone said they changed the formula a little while back. I have used it in the past decanted into an airbrush and it went on terrible. Very rough and pebblely. I'm afraid your best bet is to use the Alclad primer (pretty expensive)

I sprayed t  his rear bumper with Alclad 2 ,Not bad!i235.photobucket.com/.../001_zpsc6f00dbd.jpg

Gloss black enamel is only used on high shine Alclad colors such as chrome, polished alum and airframe alum. I use Testor's gloss black enamel from the small bottle and it works like a charm.

Using black with the non high shine Alclads will not provide the depth it does with the high shine ones so greys and whites are ok to use. If the primer coat is not smooth, then the Alclad will have an oxidized weathered look, not rough and grainy.

I also live in Florida where it's VERY humid and have never experienced any of the issues you are having. I have a good moisture trap that captures tons of water and works just fine.

Starting with the plastic before priming, I polish the plastic up to 12,000 micromesh pads to get it looking right then shoot your primer, preferably Tamiya's white or grey or gloss grey enamel. Make sure the primer goes on glass smooth and let it dry for a day or two. If using a flat primer, then you need to lightly polish the area just to kill some of the flat texture. You can use an old T shirt to lightly polish the flat primer.

The next step is spraying the Alclad which you DO NOT thin and shoot at 8-10 psi in very thin coats.