A New Finish?

[clipper1801]

When I was a little Clipper my dad ran a Vocational College and I had run of the facilities and teachers on my off time. I remember learning how to paint cars in the auto shop one summer and the instructor was very glad to teach me how to paint my own motorcycle tank and frame. It started with a lot of sanding and priming, wet sanding and more priming. When it came to the color I was instructed to spray a light tack coat, let it set until it was sticky to the touch, then spray a medium heavy "wet" coat on, being careful not to allow it to run. As Ii drove the 900 miles back from Boise the other day/night my mind began to wonder . . . the problem we have with the Shapeways WSF is its porosity. The surface is made up of tiny granules of plastic the are fused together and there are zillions of micro sized holes that need to be filled. Am I right so far Zoe? Now we give out models many coats of "filler" which seals the material and builds up a "skin" on the surface of the model. What if you could put a "tack" coat of very sticky and super fast drying paint, follow that coat up with a "wet" coat of super fast drying gloss paint. The tack coat would stop the wet coat from completely soaking in before the layers set. After 10 hours of driving I began to believe it could work. But what paint? The trick is having it dry super fast and not completely have one layer dissolve the previous one and let the first coat cure without blushing the second one. Most of our paints are water based acrylics which have a slow drying time and some will dissolve the first coat if it is not completely dry when you add the second. With me so far? Enter the latest order from Shapeways, 8 Fokker DVII's!



After a quick wash and dry I went out to the shop to do some looking on the paint shelf. Lots of left overs. In and amongst them I found a set of cans of spray acrylic lacquer from my old Bronco that I had done some body work on, one of the cans was a linen white . . . Dupli Color Brand (solvent based acrylic lacquer)



What to do? Risk a model? That's not how Clipper rolls, why risk just one when you can risk several at once? I decided to risk 8. In this next picture I try to show the impact, the gloss of the paint is easy to see on the board under the model.



Here on the bottom of the model you can see the gloss from merely 2 coats of the paint applied as planned . . .



Here is the top side, you can see the gloss and the fill to a small degree



Or here



Meanwhile now I have a squadron of 8 Udet DVII's!



The finish is hard, smooth and very shiny! It worked! Two coat finish! Now to give them a light roughing up with fine steel wool to allow the water base final colors to work! I have used these paints before on wood models, the only shortfall is that some spray dull coats will crinkle the surface. I have since switched to a brushed on clear acrylic for a dull sealer. Imagine sealing your Shapeways with two spray coats in 30 minutes!!!! The elves are VERY nervous!

Here it happens in blue



See the gloss on the lower wings!



Could it be true? I'm sold, no more layer and layer and layer for me!

[gully_raker]

Good one Clipper!
I presume that was an Automotive Touch up paint you source from a Automotive spares store.

[clipper1801]

Sharp as ever, you are correct. They have a wide variety of strange colors, not too many we want, but for a base coat to paint who cares? Did I mention one can covers several fenders and many minis? And lasts for many years in a 90 degree F garage!

[greenalfonzo]

Wow, that makes even a hobby craft-phobic person like myself consider getting into the customizing game. Looks about 7 steps simpler than Zoe's method, which I could not even consider attempting. It would be hard even for me to screw up two passes of spray paint in 30 minutes!

[gully_raker]

Sharp as ever, you are correct. They have a wide variety of strange colors, not too many we want, but for a base coat to paint who cares? Did I mention one can covers several fenders and many minis? And lasts for many years in a 90 degree F garage!

Thanks for the quick response David!
I have actually used some of those in a metallic Grey colour for painting Warhammer 40K buildings.

[clipper1801]

The real trick seems to be the light tack coat followed by a wet coat and fast drying acrylic lacquer. Enamel turns to a never drying goo . . .

hey the tower looks cool, my son says awesome. The elves are still asleep . . .

[Jager]

Just to be clear (for the slow of thinking; hey, it's been a bad week), you used 2 coats of the acrylic lacquer, first one light, second heavy?
And is the first one completely dry before the second?
Karl

[Flying Officer Kyte]

Sounds a great solution Clipper.
I have used silver grey car body on Nieuports as an undercoat, but never knew about the tack and second coat whilst still sticky trick.
Guess I will have to give it a try.
Rob.

[Warchariot]

I'll have to give this a go.

[freebird-52]

Me to, me to!

[clipper1801]

Karl "Just to be clear (for the slow of thinking; hey, it's been a bad week), you used 2 coats of the acrylic lacquer, first one light, second heavy?
And is the first one completely dry before the second?"

First coat wants to be still tacky to the touch. Try it on a sheet of cardboard, a light quick pass of spray, let get tacky and then a second wet coat that is shiny wet but not puddle-ly. As soon as the last coat hardens all should be happy and filled.

[Jager]

OK, Thanks.
Karl

[Rat of Vengence]

Do you do the first coat all over, or do one side (both coats) at a time mate?

Dave

[Guntruck]

Only two coats? Where's the fun in that? I'm orf to Halfords to see what they have got

[somaliavet]

Hmmm, might have to start looking at Shapeways if I could knock it down to a 2-coat prep. My compliments to the elves' test department.

[clipper1801]

Yes I have a couple dozen minis lined up for this evening after real work to get into the paint booth. Mrs Clipper is returning home Thursday after getting the new wing man settled in to his home, so my binge building must soon give way to carving a path through the laundry and dishes so the house looks semi-normal. The elves are well disciplined in domestics so thankfully I can enroll them to assist.

The process has evolved to arranging the minis inverted on a sheet of cardboard with a 2" gap betwix each. Then a light tack coat is applied to all the sides, surfaces of all wings as well as front and rear aspects. Wait ten minutes or so (while you paint another sheet of minis). When the bottoms are tacky I apply the heavy wet coat and carefully lift each one up with tweezers and place on a clean sheet of cardboard (Pizza boxes are awesome for this). This allows the very wet models to dry without them sticking to the heavy and still wet overspray on the base card board. By moving from one set to another the process goes quite quickly. The wet coat dries in less than 30 minutes at which time the minis are set on their wheels and the process is repeated on the top surfaces. This also gives opportunity for the sides and hidden areas to get a few extra coats. If I remember I will snap photos tonight as I do it so the narrative makes a bit more sense. . .

[Rat of Vengence]

Thanks Clipper, that is perfectly clear

Dave

[kduke42]

Two questions.
1 why does it have to be glossy?
2. In the pix, it looks like the paint is very heavy, especially in the bottom view...almost pooling and becoming a thick layer on the surface that is taking out surface detail (tho I see a bit of ribs). Is the photography exaggerating the effect (gloss could do that) or is it really this thick?

[clipper1801]

Two answers at once? Pushes my mental ability, maybe, I'll try.

1. Gloss, yes it is the best for filling since it has a higher ratio of solids dissolved in the solvent. That way it can only soak in so far then begins filling the pores in the material.

2. Heavy coat indeed, the photos at this scale show the slight dome of the paint sitting on the surface just as the paint was sprayed. In a few minutes most will soak in and flow out in the drying process, but one must be careful to prevent running and detail loss, I have a paint brush ready to address the runs! The acrylic lacquer shrinks as it sets as well, causing some flattening. The tack coat serves to adhere the top coat to itself and the rooted matrix below which prevents excessive separation at extreme corners. A mid satin coat would do, however most of these paints are working towards a high gloss finish. I have dulled it from time to time with different speed solvents, which makes the chemist in us blush as well . . . a little trade humor . . .

[Hunter]

These look better than you verbalized to me, Dave. Awesome indeed.

[freebird-52]

After completing two Shapeway minis using Clipper's method of spray painting, I will have to try adding one more step next time; spray a light coat of flat primer - either white or gray. That way when I go to paint the different colors, they will adhere better with less coats.

I must have brushed painted 4 coats just to get the color right.

Would I use his method again? You bet, in a heartbeat!

[PRS]

Hey Clipper, I finally got around to trying this but I ended up with a pretty matte surface instead of a glossy hard coat. I may have waited a little too long after the first coat, and when I started to see a lot of pooling on the second coat, I backed off. Have you ever tried a third coat after the first 2 are dry? Before I do that, I'm going to experiment with painting on the underside of the wings. I'm doing a night fighter and I was using black acrylic lacquer, so if I can get a dark greenish brown tint over it I may leave it as is.

[clipper1801]

Here is my latest (two days ago) This one was 3-4 coats with the last ones quite wet . . . had to level the things to keep the pooling level without letting runs form . . .



The auto paint can be super glossy or flat depending on ambient humidity . . .

[Lt. S.Kafloc]

Great idea to speed things up David, and so simple.

[prymus]

Hey Clipper, a question, not so much about this technique, but a problem I'm having using acrylic paints here in the DRY southwest. I've not yet done any Shapeways craft, but am planning to. I have been painting minis here in AZ for 30 years and a problem I have with sprays is them drying on the way to the subject. Then ending up with a dry dust like mess all over my mini. I have now tried to paint when the humidity is high(right, there is no humidity in AZ) but that limits severely the times I can spray. Have you, or anyone here, had this problem? Can you give me any tips to stop this from happening? I also have had the problem of paints brushed on drying extremely fast, and I've used a ton of retarder, sometimes 2 to one retarder to paint ratio.

[clipper1801]

Good questions William, I have done a lot of spray painting (lacquer/acetone based) over the years, cars and real aircraft as well as models. I have found plasticizers and retarders to be so much voodoo. The range of speed of the various thinners can get expensive as well. I have restricted my sprays to cans since I no longer have a walk in spray booth and those are as shown in the thread (normally gloss colors since they are higher in solids and fill almost too well). I do put the spray on rather heavy and wet. Some primers, especially the filling type do dry before they hit the model and can create more trouble than help, that is why I skip the priming stage and go for the base color right away. The light coat followed by the wet coat within a few minutes helps the paint adhere, fill and flow out. Some runs are going to happen but once you get the hang of it it goes quite well. I normally paint a dozen at a time which uses the drying time up efficiently. I then use water based acrylics for the color layers and detailing and finish with a clear dull coat spray. Hope this helps! I will venture out into the garage this weekend and gather the balloon patterns for you : )

[prymus]

Hi David, thanks much for the info and help. No problem on the balloon patterns, whenever you get to it. I used the measurements I found on shapeways to help me get started on a "Drachen" "type" balloon which is coming out pretty cool. I don't think it would win any "Historical accuracy" contests but will be good for what I want. Will post some pics when done. Thanks again.

[Doug]

David you have realy done you homework I will give it a go on my next shapeways model (though after my sons have got the right paint for me, bit hard to read whats in the cans when you go shopping without my reading glasses).

[Dom S]

Very interesting - I tried something similar a while back ("filler primer" for respraying scratches and such) with rather underwhelming results, but never thought to try respraying while still tacky - will give it a go.

[fast.git]

Looks like I need to go shopping...

[boomerpete53]

I love what you done, have you ever use "DULLCOAT" spray paint to get rid of shine? have used it on my model trains for years.

[clipper1801]

Dull cote is often difficult, it dulls silver almost to black at times and can react to the surface paint, always best to test a bit before committing that super finish. When I am in doubt I use the water based dull clear from Testors or such.

[prymus]

One more observation on Dullcoat. I love the stuff and use it a lot, but if you use super glue (CA) for assembly the Dullcoat will give CA a frosted finish if the glue is not completely dry. A CA accelerator will do the same, but not quite as drastic as Dullcoat can be.

[Flying Officer Kyte]

A good observation William.
Rob.