posted
I have a touch up spray gun and have sprayed a few panels with success. last night I was spraying 1 shot Primrose yellow. Thinned it half and half with mineral spirits, plus added 10% 1 Shot catalyst. pressure at 45 lbs. Spraying onto a white panel...scuffed it then wiped with Rapid prep. Got some severe runs. Didn't spray any different as far as method while spraying. Wondering if certain colors, like this Primrose Yellow are thinner to begin with? Now what? As of 10 am today it had been on 12 hours. Should / can I sand it to knock down the runs, then respray? If so, what grit and can I use my Makita random orbital sander? Suggestions on the percent of thinning, pressure, etc.? I'm hoping someone will come through...thanks ahead of time!! Mick
-------------------- Mick Samsel Creative Services Cherokee, IA Posts: 498 | From: Cherokee, Ia USA | Registered: Jan 1999
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Spraying with mineral spirtits at night seems to be the biggest part of your problem! Ms can vary from batch to batch, as far as evaporating speed, and is always slow, sometimes slower! Hardner, in addition to speeding cure, also acts as a thinner. Next time use a low temp reducer...it takes less and will dry faster at night.
Severe runs? Real thick, or lots of them? If thick, I would try shaving them down with a razor scraper, then sanding. If thin, just sand them...using 180 or 220 grit. Coarse grit will leave scratches that are hard to remove.
Yes, some colors behave differently when sprayed.
-------------------- Si Allen #562 La Mirada, CA. USA
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Brushasaurus on Chat Posts: 8827 | From: La Mirada, CA, USA | Registered: Nov 1998
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posted
I quit using MS as a thinner for spraying several years ago. I wasn't able to control the consistancy from one job to the next. Also, there was a tendency to "burn" the paint.
You may want to try using Xylene for your thinner next time. I use 3 parts paint to 1 part Xylene (give or take). I generally spray at about 35psi.
A little xylene does work, as Glenn suggested. However, it is one of the lacquer thinners. Still, if it doesn't burn the paint and it works, do it. I have found that the best all around thinner for spraying lettering enamels is VM&P naphtha. And it's cheap and easy to obtain. Spraying with mineral spirits is almost always "run city."
Your pressure is probably okay. But at night when it's cooler, you need to let your tack coat flash off a lot longer. Put the gun down and walk away from it. Wait five or ten minutes if you have to. Then spray a medium wet coat. If it didn't cover, wait again and spray another medium wet coat. I am assuming you are spraying a panel propped upright. Of course, if your panel is flat on saw horses, the paint will never run.
You're spraying yellow at night? Isn't that a bug magnet?
Brad in Kansas
-------------------- Brad Ferguson See More Signs 7931 Wornall Rd Kansas City, MO 64111 signbrad@yahoo.com 816-739-7316 Posts: 1230 | From: Kansas City, MO, USA | Registered: Nov 1998
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posted
One more note,...the viscosity (thickness/thiness)of the paint can vary according to temperature and humidity and from color to color.Cold and damp can be the cause of this problem too,...the exact same mixture will react differently on a nice warm day than it will on a damp chilly night.The hotter thinners mentioned in the other responses often as not will be the solution but the mixture should vary according to the present conditions as long as those conditions remain consistant.
Hope this helps you,...
-------------------- fly low...timi/NC is, Tim Barrow Barrow Art Signs Winston-Salem,NC Posts: 2224 | From: Winston-Salem,NC,USA | Registered: Nov 1998
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posted
These guys are right about the mineral spirits, that stuff is only good for cleaning up of brushes. I like to use an enamel reducer like Dupont 3812, also thinning half and half is 100% reduction , waaaaaayyyyyyyyyy to thin. Primrose yellow is one of the worst covering colors One Shot puts out, it's also pretty runny straight out of the can. I'd try spraying it about 10 to 20% reduction and crank the pressure up.
-------------------- George Perkins Millington,TN. goatwell@bigriver.net
"I started out with nothing and still have most of it left"
posted
What everyone else said about thinning with Mineral Spirits. As for the runs, try block sanding them with 220 or 320 wet-or-dry paper and soapy water, then respray. Old body shop trick. You may have some problems spraying over the fresh 1-Shot with a "hot" thinner. It may lift the 1-Shot thinned with Mineral Sprits.
-------------------- Jerry Mathel Retired Grants Pass, Oregon signs@grantspass.com Posts: 916 | From: Grants Pass, OR USA | Registered: Dec 1998
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posted
I know this won't solve your problem but hey...quit trying to spray with lettering enamels.
Centari can match any color you need...the finish will be perfect everytime and with hardner the finish is exquisite.Plus you can sand it the next day if you need to (which you can't do now)
Since the problem is this great...break out the lacquer thinner and strip it.
Start over with the centari.
Now here's a cool little trick you can use the next time you get a "curtain" in your paint.
When you finish spraying ,if you see a run begin take some 2" masking tape the length of the run and simply stick it down over the run...remove it quickly it will bring the run with it...let the paint set awhile and tack up then respray the panel being careful not to "hang" another.
"werks fer me ...it'll werk fer you"
[ May 05, 2002, 06:13 PM: Message edited by: Monte Jumper ]
-------------------- "Werks fer me...it'll werk fer you"
posted
you say you got a "touchup gun?" to properly sprya paint you need a good full sized spray gun. home depot, lowes, flea markets all sell DEVILBUS type knockoff siphon type guns for $29-$69. they work just like the real thing(for a while, then you buy another)spraying lettering enamel 1st mistake, 2nd mineral spirits, 3rd sprayin in the evening. 4th way to much reduction. iam witn monty...centari or any good automotive acrylic enamel, iam partial to MARTIN SENOUR. now these paints can be reduced 1/2 & 1/2. but they are much thicker in the can to begin with. nice thing about spraying backgrounds with car paint.....you can letter on them in couple hours, if you make a mistake you can wipe with MS and it wont move the background color. also its cost effective. qt of a/e auto paint is $20. you add reducer and the qt is now 2 qts. i can coat out a 4x10 alum sheet with 1 qt of reduced paint...so i can paint the panel for $10. now i will say ive sprayed ONE SHOT, thinned with mineral spirits...but only a capfull to what i had in the paint cup. didnt get runs. ive also thinned 1shot with A/E reducer....works great drys quick. ive thinned with laqure thinner, got to be real carful not to "shock" the 1 shot, or it will turn into a gob of snot! when i need to paint a board or panel i use car paint.
-------------------- joe pribish-A SIGN MINT 2811 longleaf Dr. pensacola, fl 32526 850-637-1519 BEWARE THE TRUTH.....YOU MAY NOT LIKE WHAT YOU FIND Posts: 11582 | From: pensacola, fl. usa | Registered: Nov 1998
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posted
I spray (or roll) sign enamels on most of my panels using mineral spirits flat on tressle tables. Never get a run Think the habit comes from the fact, although I've been in the sign business for umpteen years, its only in the last five I have had the luxury of a decent sized shed and a "signwall" to work on.
Never had any problems with mineral spirits ... maybe we get better quality down here. But I agree that automotive paints and thinners are the only way to go on vertical surfaces.
Also I never spray at night or late afternoon (especially in winter) as it doesn't take much cold and damp to kill gloss.
That's a neat trick with the tape on runs Monte. Must try it. I usually cut my losses and clean the panel off and start again:)
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