I am planning to paint a sign (you can see it on the design/cost workshop board) that will have black outlines and backgrounds for the letters. I had planned to use a black sheet of diBond and paint the main colors over it, leaving the outlines nice and sharp when I am finished.
Working with an HVLP gun and automotive enamels, do you think that I will have any trouble with opacity of the lighter colors over black? Should I consider another paint choice?
Thanks in advance for any comments.
-shane
Posted by jmathel (Member # 526) on :
Shane, Automotive enamels are quite opaque by nature, and you should have no problems applying a lighter color over the black as long as you spray an even coat.
Posted by Shane French (Member # 2098) on :
Right on, thanks Jerry.
By the way, does anyone use hardener in acrylic enamel (for signs), or is that overkill?
-shane
Posted by Joey Madden (Member # 1192) on :
the cheaper the paint, the less its gonna work.
Posted by old paint (Member # 549) on :
i shoot most A/E autopaints without hardner....they will tell you at the paint place it wont dry without hardner..but thats bull-crap. hardner is a added chemical to make the paint HARDER, in turn making it last longer. on my step van i sprayed with A/E AND HARDNER, because i wanted it to last as long as possible. i do mdo and alum panels with A/E, good reducer and sun dry. i can usually paint on it within 2 hours after spraying. and ive not had one background fail without hardner.
Posted by Dave Grundy (Member # 103) on :
Shane...I have used automotive acrylic enamel to spray signs and spent MANY years spraying vehicles with it. Despite what Joe says, acrylic enamel is formulated to be used with hardener and the ratios are quite specific.
To start with, if you spray it as a background, without hardener, and then plan on spraying over it the next day...figure on problems with wrinkling, masking tape leaving marks etc. if you end up with unacceptable dust or bugs in it and plan on sanding and respraying the next day, forget it. If there is the slightest possibility the sign will be cleaned with or be coming in contact with any kind of harsh cleaner or solvent, forget it.
As Joey is prone to say...use the proper paint for the job and mix it up according to the manufacturers specs. Acrylic enamel is a great paint but it NEEDS hardener to cure the way it was intended.
by the way...use proper breathing and skin protection..not only while spraying but while mixing the paint as well.
Posted by captain ken (Member # 742) on :
some automotive eurathnes will cover well, but may not end up being the color you wanted in the end.... best bet is to lay down a white base coat then shoot your color, it will also help make the color more brilliant
Posted by George Perkins (Member # 156) on :
Man, this post shows just how old I am I remember when they came out with "hardners" for acrylic enamel. I can also remember when the acrylic enamels came out. Previuosly all there was were the types of synthol enamels like "Dulux" Now spraying those really seperated the men from the boys The acrylics were such an advancement at the time and the hardners were aneven greater improvement . The acrylics can be shot without hardners but like Dave pointed out not without problems. Ken brings up a good point about shooting a base coat of white to insure getting the proper color, some colors like yellow really get thrown off. There's one thing to be aware of when doing that. You will end up with a hairline outline of white around the letter, actually it's the thickness of the coat of white paint underneath the letter, it's usually no big deal but one to consider if the sign will be in "smelling" range.
Posted by Gavin Chachere (Member # 1443) on :
Shane this is just my opinion here,but if you're going to go with the design you have posted,on this monitor the majority of the sign looks to be light brown,red,and gray....these 2 guys b4 me are right you would need a white base so the red doesn't look orange toned and muddy and to keep the brown from looking about 2 shades darker than what you have in the can.....the areas that are black look to be minimal so i would start off with white dibond and save having to lay the white base.....Masking off the enamel like that is going to always leave a tiny edge/ridge that you could easily follow with a brush and some black or tape around and cut in with a small roller if your more comfortable with that....and yes you can use the acrylic enamel to do it you just may have to add a touch more reducer while you keep the ratio of hardener the same.
George,you ain't that old...i remember that stuff too and i'm younger than you are,although i guess that maybe isn't much consolation cuz maybe i'm just closing the gap ......I also remember having probably half the DITZCO black(same as dulux but PPG) and white we sold going to sign painters and production sign shops cuz they could letter with the black in one hit and use the white to roll right over pre painted panels(instead of block out white or sanding etc) when they were being cheap and wanted to save time(not that that would ever happen),they also used to buy something called DITZ-CHROME to letter with (taxi's mostly)so they wouldn't have to spend the time dusting with aluminum powder when someone wanted a bright silver and didn't wanna spend the money for it. And now that i'm starting to date myself here it's time to shut up...
Posted by Gavin Chachere (Member # 1443) on :
Shane I forgot to ask what brand? Like Joey said aboe if it's something thats too cheap you may be better off without it.
Posted by Shane French (Member # 2098) on :
Thanks for all of the replys.
Gavin, it is DuPont brand, I didn't get the series, that is what my local paint supply store carries.
It looks like I will just have to experiment a bit to see what will work best. Should be fun, I'll post my results. I'll go ahead and shoot it with hardner added, just in case I screw it up and have to shoot it again.
I figured on doing colors over black because it seemed the most efficient way to accomplish this. Spray the background colors and mask off after each one. After the last color is dry, remove all masking and plotter-cut mask material. What's left will be sharp outlines, all I have to do is put on the white lettering whether it be vinyl or routed-letters.
If the black outlines were simpler, I would try it with a brush, but I don't think I'm ready for that yet. Someday. On second thought though, maybe that's just a defeatist assumption of mine. Maybe it's totally doable, even if I am a total novice.
In any event, it would seem that even if I have to shoot a lighter base coat on first, it wouldn't interfere with the original plan.
OK, sorry for typing so much. I really appreciate all the thoughts.
-shane
Posted by old paint (Member # 549) on :
well i guess iam just the dummy here...cause if i can spray A/E no hardner....and never have problems. like i said 2 hours after i spray it i can paint on it with 1 shot and if i make a mistake i can wipe it with mineral spirits and not even move the background paint. i to was around when A/E came into being, was an outside saleman for NAPA, and you could take any A/E paint, reduce with 3 different speed drying reducers, and the paint would dry faster and smoother then the old synthol enamels. hardners didnt come into the formula untill a couple years later. now since i mixed car paint and was an saleman for it i also can suggest if you get A/E paint mixed, ask the person mixing it for a half pint of DRIER additive(this is what makes it dry, not the hardner) and if your have a day that is cooler then 70-75 you can add some of this to your paint(in the cup) no more then a 1/2 teaspoon to a qt cup. this will help it dry a little faster. when i was a kid 17, got some free black paint(synthol enamel) and all the label said was ACME PAINT CO. little did i know this was mixing black, paint without any drier additive in it. painted my 50 ford with it....waited a week for it dry, never did, had to wash the whole car down with reducer!!!!!!
Posted by Shane French (Member # 2098) on :
You're no dummy, Joe. Obviously, acrylic enamels are used to paint cars all-the-time without hardener. Granted, it's a cheap paint job, but that's a car, not a sign, and people do it all the time. I'm sure you get excellent results without hardener, but for someone like myself who has very little experience spraying stuff like this, I'm sure you would agree that it's good insurance.
Take it easy, -shane
Posted by Gavin Chachere (Member # 1443) on :
Joe,self realization is the first step..... no seriously,heres the str8 deal... Back in 6 B.C.,when you worked at NAPA,very few people used catalyst,it was brand new blah blah,and the paint was formulated a little different than it is now....the assumption was that the end user wasn't going to use the catalyst,and if they did,well that was a plus. Now,the assumption is that the end user is always going to use the catalyst,a few technical things are diff and they really don't plan on you not using it . Of course you can get away with not using it especially in your climate,but its not the recommended practice. Alotta times if the resin in the A/E doesnt crosslink right even though it feels hard to the touch,its still soft underneath to a degree and all the problems that were decribed earlier in this post rear up and bite you in the a**. For the benefits the catalyst gives you,it's cheap insurance. Also....be careful of adding extra drier to automotive stuff....It should be added to the system when they mix it,it should never be external like that anymore....but the ratio has to be exactly right,too much drier won't make it dry faster or better but it may keep it from ever curing like it should even with the catalyst in it.
Shane Dupont is fine just spend the money on the Centari line and stay away from the Nason,down the road you'll thank yourself.
Posted by Brad Ferguson (Member # 33) on :
One more point about adding hardener: Since without it the cure time is so greatly extended, sometimes when installing vinyl lettering on an acrylic enamel finish, I have had to wait days for the off-gassing to stop enough to not cause vinyl to orange-peel.
Using automotive paints for backgrounds and lettering makes for beautiful and very durable sign work. You get a surface that's like glass and is hard as a rock. I have even marbleized using acrylic enamels (with retarder). They work well on HDU, too.
![[Frown]](frown.gif)
I remember when they came out with "hardners" for acrylic enamel. I can also remember when the acrylic enamels came out. Previuosly all there was were the types of synthol enamels like "Dulux" Now spraying those really seperated the men from the boys ![[Smile]](smile.gif)
The acrylics were such an advancement at the time and the hardners were aneven greater improvement . The acrylics can be shot without hardners but like Dave pointed out not without problems.