Paint Question
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Senior User
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Paint Question
I am new to painting. What do you mix enamel with to properly thin it out to spray thru a HVLP gun. I shot some patio funiture with thinned rustolem and it didnt turn out that well. I used paint thinner to thin it. Should I have used some other thinner like reducer to shoot it through a spray gun?
Hotshot
Joined: Oct 2004
Posts: 15,882
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From: Durham NC
Use the thinner the manufacturer recommends for the paint. I've never sprayed Rustoleum except from a rattle can, but I'd expect reducer would be better than generic paint thinner or mineral spirits. Reducers are designed for spraying at specific surface temp ranges and contain drying inhibitors and flow promoters for spraying purposes. The thinner likely dried too fast when you sprayed it and with a HVLP gun the paint needs to be applied in very thin coats, the first coat should look like you barely put any paint on at all. Just watch the recoat time window (it should say on the label something like recoat within 1 hour or after 24 hrs) with enamels if you recoat outside that "window" (say 3-4 hrs after the first coat was applied in the above example) it may never dry. Enamels also take some time to harden completely, don't handle any more than absolutely necessary for at least 48 hrs, even tho it may feel dry it will scratch or chip readily.
Hotshot
Joined: Jan 2001
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From: SE Wisc. (the Rust Belt)
First, I don't spray Rustoleum, it takes forever to dry and doesn't seem to hold up.
When I spray an oil based paint and want to thin it I look on the side of the can to see what chemicals are in the paint. Most of the paints, non-automotive, I use have mineral spirits in them, some acetone. I also use the hardener from Valspar in the oil based paints I sprays, it works great at making the paint dry harder, shinier and faster.
You can also use laquer thinner to make paint dry faster but you have to be careful on previously painted surfaces because laquer thinner strong and could lift the old paint making a big mess. Also, if you thin with laquer thinner you can't let the coats of paints dry too much between coats or you could end up lifting the previous coat of paint. Laquer thinned paint will also dry duller because the laquer thinner dries fasts and takes some of the solids with it.
When I spray an oil based paint and want to thin it I look on the side of the can to see what chemicals are in the paint. Most of the paints, non-automotive, I use have mineral spirits in them, some acetone. I also use the hardener from Valspar in the oil based paints I sprays, it works great at making the paint dry harder, shinier and faster.
You can also use laquer thinner to make paint dry faster but you have to be careful on previously painted surfaces because laquer thinner strong and could lift the old paint making a big mess. Also, if you thin with laquer thinner you can't let the coats of paints dry too much between coats or you could end up lifting the previous coat of paint. Laquer thinned paint will also dry duller because the laquer thinner dries fasts and takes some of the solids with it.
Senior User
Joined: Sep 2007
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From: Baton rouge, Louisiana
I sprayed rustoleum thinned with mineral spirits, and had great success. It held up great and seemed to dry at a verry reasonable time. (Giving i live in Baton rouge and it was in the summer). I hear alot of bad things about spraying rust oleum but i must disagree.
The truck i am working on was my fathers project in the early 80's that he gave up on. The paint he used then was rustoleum and now...about 25 years later the base primer he sprayed still held great to this day. I just dont understand all the bad wrap about rustoleum. Good luck though
The truck i am working on was my fathers project in the early 80's that he gave up on. The paint he used then was rustoleum and now...about 25 years later the base primer he sprayed still held great to this day. I just dont understand all the bad wrap about rustoleum. Good luck though
Hotshot
Joined: Jan 2001
Posts: 16,867
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From: SE Wisc. (the Rust Belt)
I've used Rustoleum many times, I just find it dries really slow. I use Valspar, with hardener, and it dries rock hard over night. I have painted items using Rustoleum and it stays soft for two days.
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Tuned
Joined: Jan 2001
Posts: 352
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From: Elizabethtown, Ky.
I do custom paint on the side, and the first ?s that come to my mind is what are you painting and what brand of paint are you using. As reccomended by bobj49f2, I also would use a hardening agent in the paint. Also as reccomended by AXracer, I would use the the thinner/reducer that the paint manufacture calls for. There are cheap paints that will do a fine job for your frame or undercarriage parts but I would use a higher quality for paint for the exterior, that is jmo. Also, you can use laquer thinner in enamel like stated and I have always got a good shine out of it but after time it has always chalked out, I have not done this since 1986 and won't do it anymore. I think it is always best to use what is reccomended.
Senior User
Joined: Sep 2007
Posts: 129
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From: Baton rouge, Louisiana
first off, i am far far from an expert on paint. If rustoleum is not a good choice to prime the cab of my truck someone please stop me and direct me to a resonable priced paint i can use. I just use it cause its locally found and it seems to hold up, But if it does not hold up i would appreciate someone steering me in the right direction thanks
Hotshot
Joined: Jan 2001
Posts: 16,867
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From: SE Wisc. (the Rust Belt)
I have been told you shouldn't spray automotive paint over Rustoleum primer because the paint won't adhere to the primer. I don't know if it will hold or not, I have never sprayed automotive paint over Rustoleum primer because of the slow dry time plus the binders in the auto paint are a lot stronger than the Rustoleum and might lift. I prefer using a good quality epoxy primer over bare metal for auto body painting followed by a good quality filler primer so I can sand out minor imperfections in the body work.
Hotshot
Joined: Oct 2004
Posts: 15,882
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From: Durham NC
I'm about to try a direct to metal epoxy primer from Sherwin-Williams that has two different hardners available. With the one hardener you can spray it like a high build primer, with the other you can squeegie or roll it on like a surfacing putty then block it.
If you sand thru it, no big deal just spot in some more. No separate etching primer, high build primer, or sealer needed, it's all in one product. You can putty or polyester surface putty over it as well.
If you sand thru it, no big deal just spot in some more. No separate etching primer, high build primer, or sealer needed, it's all in one product. You can putty or polyester surface putty over it as well.
Hotshot
Joined: Jan 2001
Posts: 16,867
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From: SE Wisc. (the Rust Belt)
AX, the S-W primer sounds very interesting. What primer is this? I went to their web site and they had a few different epoxy primers. After you have used it a while please get back to us on your opinion of the product. I have had good luck working with epoxy primers and would like to find one that could be used as a filler primer.
I probably won't be able to get it at the S-W store I go to though. I go there on a regular basis because it's close by, they match the odd ball colors my customers' project require and the paint is pretty good but every time go there I get a new counter person who tells me they either can't match the paint or they don't have the type of paint I need. I usually have to persade them to look in their books and on their shelf to find the paint, which they finally do. I have a feeling if I ask about an epoxy primer it will really blow them away. Would you please give us the name of the primer you're using so I have something solid to give them so they can find it for me?
I probably won't be able to get it at the S-W store I go to though. I go there on a regular basis because it's close by, they match the odd ball colors my customers' project require and the paint is pretty good but every time go there I get a new counter person who tells me they either can't match the paint or they don't have the type of paint I need. I usually have to persade them to look in their books and on their shelf to find the paint, which they finally do. I have a feeling if I ask about an epoxy primer it will really blow them away. Would you please give us the name of the primer you're using so I have something solid to give them so they can find it for me?
Tuned
Joined: Jan 2001
Posts: 352
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From: Elizabethtown, Ky.
Dupont has been reccomending this for awhile(spraying epoxy primer over metal). I spray Uro-Prime right on bare metal with no ill effects. The stuff I'm using is a 3 part mix; primer, activator, and a reducer, but the new stuff they coming out with is 2 part mix. I'm pretty sure the # I'm using is 1120S but I'm at work and can't remember for sure.
I would never use any of that spray can primer unless you desparately need to protect it and plan on stripping it off later. I think some one makes primer in a spray can but even that can't be that good because when you add the mix to the epoxy primer it has a short pot life so the stuff in the spray cans can't have a good hardener or activator in it, if it did it would set up in the can before you bought it.
I would never use any of that spray can primer unless you desparately need to protect it and plan on stripping it off later. I think some one makes primer in a spray can but even that can't be that good because when you add the mix to the epoxy primer it has a short pot life so the stuff in the spray cans can't have a good hardener or activator in it, if it did it would set up in the can before you bought it.
Senior User
Joined: Jul 2007
Posts: 220
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From: Spartanburg, SC
All painters recommend starting with one brand of primer and using the same brand all the way to clear coat. Never use one brand primer, another brand base coat, another brand clear coat, etc, etc.
I found this out the hard way!
I found this out the hard way!