Acetone vs. Lacquer Thinner

evildocrsx

Petty Officer 1st Class
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Aug 1, 2009
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Why is Acetone used instead of Lacquer thinner for cleaning before glass layers?
 

Genonbamagirl

Petty Officer 2nd Class
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Re: Acetone vs. Lacquer Thinner

Why is Acetone used instead of Lacquer thinner for cleaning before glass layers?

Acetone cleans the surface. Lacquer thinner is used to remove really hard paint. Acetone is nowhere near as harsh on the surface being treated.
 

ondarvr

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Re: Acetone vs. Lacquer Thinner

I would say the main reason is that when you're working with polyester resin acetone is never far away, so since its handy, it gets used.
 

evildocrsx

Petty Officer 1st Class
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Re: Acetone vs. Lacquer Thinner

So it won't damage the or weaken the fiberglass then?
 

jspano

Senior Chief Petty Officer
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Oct 30, 2009
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Re: Acetone vs. Lacquer Thinner

i agree with Genonbamagirl lac thinner is 10-20- % acetone along with other Ingredients probably not needed for your app.
lac thinner
ACETONE; DIMETHYL KETONE (10-20%)
TOLUENE (40-50%)
PROPYLENEGLYCOL MONOMETHYL ETHER ACETATE, 1-METHOXY-2-PROPANOL ACETATE (1-5%)
ISOPROPYL ALCOHOL (10-20%)
PETROLEUM DISTILLATES (10-20%)
 

Aviator5

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Re: Acetone vs. Lacquer Thinner

Lacquer thinner is used for thinning lacquer based paints, and contains all necessary ingradients to do it so paint won't loose it's properties. Acetone is a pure solvent.
 

Alpheus

Lieutenant Commander
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Re: Acetone vs. Lacquer Thinner

What about using M.E.K. as a cleaner???
 

ondarvr

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Re: Acetone vs. Lacquer Thinner

Most solvents aren't going to hurt the laminate and even if they possibly could it normally takes long term contact to do it. Methylene chloride would be the only one that can really dissolve cured polyester resin in a short period of time.

Each solvent has its good and bad points for cleaning the surface, so don?t stress over it, I would say that most of the time I don?t clean a freshly sanded surface with a solvent of any type, I just remove the dust with a rag, by blowing with compressed air, or with a vacuum.

Depending on the contaminate on the surface (if there even is one), the solvent used and the method you use to clean it, you may just be moving the contaminate around and spreading it to surfaces that were clean to start with.
 

drewpster

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Re: Acetone vs. Lacquer Thinner

I contacted Mas epoxy on this back when I was fairing the deck of our little cruiser. They recommended Lac thinner instead of acetone. It flashes off a little more slowly than acetone which allows you to use a second dry rag while cleaning. (two rag method) They also explained that Lac thinner itself is a little cleaner. They said acetone generally has more contaminates in it. (not sure what they base this on)
I use acetone most of the time for anything Polyester related. I have also used MEK. MEK works just like acetone except it dries off much more slowly than acetone. The problem with MEK is that it smells awful and is very strong. I ventilate the shop anytime I am using it even if I am using a respirator.
 

erikgreen

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3,105
Re: Acetone vs. Lacquer Thinner

What about using M.E.K. as a cleaner???

Bad idea. I'm going to assume you mean MEK, and not MEKP (MEKP is the poly resin catalyst, and is different from MEK in every way but the name).

Here's the emergency overview from the MSDS:

Appearance: colorless liquid. Flash Point: -7 deg C. Danger! May cause
respiratory tract irritation. May cause severe eye and skin irritation with possible
burns. May cause fetal effects. May cause central nervous system effects.
Extremely flammable liquid and vapor. Vapor may cause flash fire.
Target Organs: Central nervous system, eyes, skin, mucous membranes.

Basically the stuff is ridiculously flammable and you should wear a respirator to work with it. Cleaning a whole boat with it near griding, tools, or sparks of any kind is a recipe for an explosion and fire.

Erik
 

drewpster

Commander
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Oct 17, 2006
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2,059
Re: Acetone vs. Lacquer Thinner

Good to know. I have been using it in small amounts. I guarantee you wont want to use it to clean a big area. It is very strong.
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Re: Acetone vs. Lacquer Thinner

Bad idea. I'm going to assume you mean MEK, and not MEKP (MEKP is the poly resin catalyst, and is different from MEK in every way but the name).

Here's the emergency overview from the MSDS:

Appearance: colorless liquid. Flash Point: -7 deg C. Danger! May cause
respiratory tract irritation. May cause severe eye and skin irritation with possible
burns. May cause fetal effects. May cause central nervous system effects.
Extremely flammable liquid and vapor. Vapor may cause flash fire.
Target Organs: Central nervous system, eyes, skin, mucous membranes.

Basically the stuff is ridiculously flammable and you should wear a respirator to work with it. Cleaning a whole boat with it near griding, tools, or sparks of any kind is a recipe for an explosion and fire.

Erik

Almost all of the solvents carry the same, or similar warning, none are considered safe, so large scale solvent wipes aren't normally done.
 

PeterMcG

Seaman
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Nov 3, 2009
Messages
61
Re: Acetone vs. Lacquer Thinner

If someone wants to get bent out of shape over the flashpoint of a compound, wrap your mind around this:

flash point of acetone = -18C

lacquer thinner is a (non-specific) mixture, so its FP will vary based on composition, but is typically in the vicinity of -5C to -15C
 
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