Sign blank background paint

[Rick Bowerman]

I used the search function and couldnt find any specific threads

Got a question about what works for back ground paint on sign blanks, Like on MDO board and maybe metal other than chromatic

Ive been useing Alkyd enamals.
I was wondering if any one has used the newer "water based" alkyd enamal or urathane acrlyc water base stuff if seen at the stores or this Rustoleum painters choice latex stuff.
I read some house type paints have a mildew controll additive that isnt good for sign painting work

[Danny Baronian]

Rick,

you have to be logged in to see the search tab.

Once logged in choose the search tab under The Hand Lettering Forum at the top of the page, center tab.

You can search for all defined terms as well as the author.

Others can chime in regarding paints, but I've found Benjamin Moore Aura line to coat out, and hold up well.

[Rick Bowerman]

Benjamin Moore Aura line

Looked that up, thats a interior house paint. I should of said outside gloss enamal type paint for metal signage that can be used on MDO etc, outdoor work too.
Id use automotive paint but thats expensive , so im cheaping out trying to use Alkyd enamals like quarts of Rustoleum(works pretty good) So I was wondering about the newer low budget water born stuff

I was useing foam rollers with gloss rustoleum on MDO board and I can get it to lay down pretty good

I have some 2'x3' metal sign blanks im going to respray rustoleum with a auto paint gun. I read reducing with a little acetone works good for a slick no orange peal gloss laydown and quick dry time. Dont use mineral spirits to reduce rustoleum, it stays wet to long

[Danny Baronian]

BM Aura is a premium grade latex paint, available in both interior and exterior; it's not just an interior formulation. Certain colors will not hold up well outdoors (reds, green,yellow) but that's not limited to Aura, that's across the board with most latex paints.

Try a sample when reducing Rustoleum with acetone. While rustoleum contains acetone and toluene - at least in rattle cans, adding more acetone, and painting over previously painted surfaces will attack the surfaces if they're incompatible.

Overall, auto body paints are extremely durable, but a quart of waterborne paint which is the standard in California now runs $ 150 - 175... a quart, and requires multiple coats for acceptable coverage.

[Mike Jackson]

Rick,
For what it is worth, I have never been much of a fan of Rustoleum. It always seemed to have a lot of oily slime and less pigment and binders. I assume that is to try to keep the price down, but this is just an observation.

The sign industry sells paint that seems to be better paint than what you find at most paint stores. Again, it is just an observation and not based on any kind of scientific data. Occasionally, we have to use commercial paint because it has to match the paint the contractors are using on other parts of the project. I seldom think that paint is superior, dries fast enough or covers as well as the industrial paints we have at our disposal.

Kent Smith will probably respond on this topic. He has a good background on this topic and worked with Chromatic Paint a long time ago.

I will throw this out for discussion. Back when I first started, I met a sign painter named Glen Newcomer. He used to paint his MDO with layers of industrial enamel. The first coat soaked in fairly quickly and would build up some on a couple of passes. After dry, he'd apply one and sometimes two more coats. After I started going to a lot of the early Letterheads meetings, I learned of the product called Block Out White. It was a primer used by quite a few of the people I met. BOW dried quickly and had a slightly chalky feel that could be lightly sanded. Final finish coats of industrial enamel could be rolled over the BOW.

Okay, we did that for years and it worked very well for us. Something has changed now, however. Over the past 10 years or so, we are seeing a lot more paint failures with the primersand top coats simply peeling off the background. We've had the problem and we see it all around us. I don't know if the problem has to do with changes in the MDO, such as more oils or silicones, or if something changed in the BOW formulation. It'd help to know which one. It appears to me the primers are not permanently binding with the substrate. Anyway, we have now switched back to the way I learned it from Glen Newcomer. I know the first layer is soaking into the wood surface and each layer is able to stick to the underlying layer.

http://www.montanamoulding.com/#sign_product:20
http://www.montanamoulding.com/#sign_product:130

Chromatic is owned by OneShot now, but they kept most of the old Chromatic paints and formulas. Besides the industrial black and industrial white, check out the Bulletin Enamels.

Ultimately, this is the old school method. There are all kinds of water based products out there now. For a spray finish, if you are adding thinners to an already pigment starved paint, I suspect you will be having problems.

Hope some of this helps,
M. Jackson

[Kent Smith]

Thanks for the push Mike. The bottom line is that both the plywoods and the paints have changed. This is partly due to regulations which have outlawed the use of some chemical compounds as well as manufacturer's trying to hold the line on costs. Background enamel (aka industrial enamel) and bulletin enamel are both alkyd resin based but have more pigment loading for better coverage in fewer coats than conventional retail paints. It has always been possible to just use multiple coats of an alkyd enamel instead of using a primer, it is just that a good primer will yield a good finish with one coat primer and one coat enamel. A decision had to be made when the mandate to go lead free came into play while Chromatic was still based in NY, I think 1984. It was not possible to load the resin in block-out white enough to make it a good primer and still have it function well for blocking out copy on billboards. Because that was the bulk of the business, we changed making it better as a block-out rather than a primer. It was at that time we developed the waterborne acrylic primers to fill the void (pardon the pun). The advantages of this primer was that it would adhere well to the new fromulations on plywoods as well as every other substrate except polycarbonate plastic. It also adheres to the ply edges and in the high build formula, fills the porosity of HDU. We were very careful to choose an acrylic that had no vinyl or rubber for good adhesion and one which could be sanded to a smooth finish. I assume that Spraylat Corp., parent company of 1Shot, Chromatic and Dana has not changed the formula especially since the base resins are readily available. The resin for the alkyds however changed frequently and is subject to cost and availability on the market. Most paint chemists and batch chemists tend to think there is little difference in alkyds but there is and that can explain how one can of black differs greatly from another. Age, heat in formulation as well as how quickly or how slowly the alkyd itself in synthesized makes a huge difference in adhesion properties, drying, shelf life etc. Having said that, alkyd enamels are a good choice for signs because of their friendly application, quick dry and deep brilliant colors. Two component urethanes also have the same brilliant colors but require multiple coats for coverage and are not user friendly. Waterborne and water based resins cannot by nature carry the same high pigment loads and some rich colors just will not stay suspended. The other factor is that these resins tend to appear milky in color and that means certain brilliant colors just do not work in them, ie yellows, reds and greens. Many have good results with these finishes and when you are willing to work within their limitations, they are a viable alternative.