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Thread: Temperature / Reducer question

  1. #1
    Join Date
    Mar 2006
    Posts
    14

    Default Temperature / Reducer question

    Hi all,
    I have a part I need to paint and have some Nason ful-thane urethane, catalyst, and medium reducer (65-85*F).

    The temperature here in VA is in the 50's and should hit the 60's later this coming week. My question is, the temperature that the reducer is for, is that more significant for the air temperature it is sprayed at, or the temperature the paint will cure at?

    The reason I ask is, if I have the part and the paint inside the house at room temperature, and then take it outside in say 60-65* weather and shoot the paint, and then bring the part back inside the house to cure, would it be ok even though the reducer is for 65-85*? Or would I be better off just taking the reducer back and getting some fast (50-65*) reducer? I figure this will not be the last project this year, and the weather is only getting warmer, so I went with medium...

    Lastly, I have a little electric heater, and was going to put it in the bathroom (smallest vented room in the house) to warm up the air in just that room to 80-85*, or whatever I can get out of it, to help cure the paint, let it set-up for a day, and then just leave the part in there without the heater on for another couple days with the fan on to vent any annoying fumes out. Is this a bad idea?

    One last thing, the part I'm painting I will be shipping wrapped in plastic. The technical info says the urethane will be hard overnight at normal temperatures. What is normal? If I give it a good week at in side room temperature, 70*, would that be enough of a cure for the paint finish to not get that "haze" from the plastic wrap sticking to it?

    Any suggestions would be appreciated.

  2. #2
    Join Date
    Nov 2005
    Location
    Rochester NY
    Posts
    1,372

    Default

    The temperature listed on a product or it's "P-Sheet" is the ambient air temp the product needs to be mixed and used. The panels or parts should be at or around the same temp as well

    It is most certainly not the temp it's cured at, the P-Sheet will list other temps for that (forced air, baking, infra red curing lamps).

    I've never noticed Auto re-finish paint having an odor to it after I've stopped spraying. The fumes come from the atomization of the product with air as you apply it. Stop applying it, the fumes go away.

    Not using the right reducer to the temperature you'll be shooting at most always causes probelms, either during the application of afterwards but your so close ( 5 degrees).

    If it was me, I would keep the medium reducer, unless you can always get the temps down to 50-60 degrees where you paint at. Maybe someone else will chime in but I don't think 2 to 5 degrees is going to make that much of a difference.

  3. #3
    Join Date
    Nov 2005
    Posts
    27,769

    Default

    You'll get a certain about of off gassing from a freshly sprayed vehicle as the solvent escapes from the surface for a while after it's sprayed. The amount of solvent (as well as other chemicals) is greatest during the spraying but continues to some degree until the surface is dry and hard.

    As far as which reducer to use at which temperature I would almost always go with the paint manufacturer's recommendation. If they say fast for 60 to 70 degrees F then that's what I use for those temps.

  4. #4
    Join Date
    Mar 2006
    Posts
    14

    Default

    Thank you for the info, that definitely helps.

  5. #5
    Join Date
    Nov 2005
    Posts
    3,384

    Default keep in mind...........

    I read what Len and Roch Greg said and agree. The thing you need to also remember is you can't paint something at specified temps and leave it to cure when temps drop like overnight. In CT we can have a 50* day with temp drops to 17* or less overnight. You need at least 8 hours not less than 55* for the cure process. If temps take a dip and keep going down right after painting your finish will get rough and if too cold will not cure.
    I hope you are not painting inside your house!!!!!
    Plastic; I have a problem with plastic wrapped tightly around fresh paint. I would lay a sheet of household wax paper around the item then pack with styrofoam.
    I use U-POL clear a lot and it is very sensitive to reducer speed. I was closer to 60* with a medium reducer and this stuff reacted terribly in the flow I got. I stopped a complete paint after one panel displayed this and waited to repaint. I know now to keep some fast reducer around for the next time. Do what the P sheet says to do and remember the temp of the part being painted. Good luck. Let us know what happens. Henry

  6. #6
    Join Date
    Nov 2005
    Posts
    27,769

    Default

    If it's a small part you can probably get away with bringing it indoors if you keep the area vented during the curing process but I wouldn't recommend it being part of your living space for about a week. I sprayed our kitchen table then brought it in the next day and had to take it back out because of the fumes it was generating.

    Using a slower reducer will work as long as you allow enough time for the paint to flash between coats. Using a medium reducer during cooler conditions will extend the flash time so spray the first coat and allow extra time until you can touch the surface without moving the paint then apply your second and third coats.

    Different paint products take on different characteristics as they cure. Some paints get very hard in a week while others never get real hard. If the part is kept warm for a week and packaged properly you should be able to ship it without hurting the finish but there are no guarantees.

  7. #7
    Join Date
    Nov 2005
    Location
    NJ
    Posts
    159

    Default


    What kind of paint?

    Do you have kids in the house?

    I really would not consider exposing my family to freshly painted parts in the bathroom. It is not worth the risk.

    I brought some week old parts into the bedroom for safe temporary storage and had to put them in another room because the smell was not good.

    If you can keep the parts at 55* or more than leave it outside. PPG told me that Concept should not get below 55* for the first 24 hours (I think that was time). If the paint gets below 55* the reaction for the ureathene stops and does not restart when it gets warmer.

    Anyway, some things to consider.

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