How to handle Problems of Painting Vehicles in Low Temperatures

Tags: Enamel · Paint Additives · Primer · Urethane

Be Sociable, Share! of the worst problems for Hobbyist Painters is dealing with off season painting. For some of us it is the extreme temperatures in the summer and for the rest of us is waiting too long in the fall and watching the thermometer drop below optimal temperatures.

I have heard a few people describe how they painted their vehicle in an attached garage with the door open to the home and a fan blowing the last cubic foot of warm air into their garage.

Other people setup oil coil heaters with no open flame heating their garage as hot as they can get it then applying one coat at a time hoping they can turn off their fan and regain temperatures before they run into runs…

Honestly this is a pretty difficult situation for most of us.

Altering Paint Chemistry to Offset Cold Temperatures

Unfortunately altering your paint chemistry is really not an option once temperatures get below about 60F.

Proper mixture of hardener and selection of reducers and activators is essential for all paint jobs.

There are basically three settings when it comes to chemical temperatures .. You have really slow chemicals that allow you to paint over 90f then you have your standard temp chemicals that let you paint from 70f to 90f and then you have your quick chemicals that are used for low temperature down to about 65f and for spot jobs that need to flash and cure quick.

If you have maxed out on your standard chemicals then you do not want to add extra hardener or activator to your mixture to try to compensate for low temperatures because it will not help and most likely will cause problems.

Altering your paint technique to compensate for low temperatures

When temperatures get cold enough that the surface of the vehicle you are painting is cold to the touch there is not much you can do to alter your painting methods to overcome this.

If you mixed your paint correctly with fast drying chemicals you can try to apply thinner coats to reduce the amount of flash time necessary between coats but doing so could alter your paint color.

About the only thing that I could suggest is that you can still paint primer if you can warm your workspace enough to warm the vehicle and then reduce the amount of paint that you are applying to only a single coat between full flashes.

Not only will you want to wait the full flash time but you will want to wait an extended period of time to allow out gassing that is not normally a problem in standard temperatures.

Final Note

Unfortunately there is not a lot that you can do as a hobbyist to compensate for low temperatures. And as you will find out just like when painting in extreme high temperatures paint defects show up much more often.

Using small heaters will only help a minimal amount and if your garage is attached to your home you do not want to use it as a reserve.

In professional body shops heaters are positioned in the workspace to allow constant heating of enough air to keep the work area at a proper temperature while painting.

I worked in a dealership where thousands of feet of buffer space were available to suck heated air into the paint booth and even then everyone in the building knew exactly when we were painting and they also complained about it a lot.

I think the best advice I can give you is to watch the weather channel’s 10 day forecast. Often you will find that the day before it rains temperatures go up.. at least on the east coast this is true. And often you can find a day within your work window that is a little warmer then all the rest.

If you pick the best day and paint just after lunch until about 4 pm that is the warmest time of the day. However watch that forecast .. both the 10 day and the hourly… they are usually pretty accurate give or take an hour or so.





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