Touchup paint and temperature
 

Does touchup paint have any temperature limitations in terms of how cold outside it is when the paint is applied? My car has a few little chips that I'd like to cover up and protect, but it's been fairly cold out and I'm sans garage ( :( ). I know some paints need a certain ambient temp to dry correctly. What's the word on touchup paint? Certainly does not come with much in the instruction department!

I have used it down to 30 degrees and it dries fine, It just takes a bit longer.

The touch up paint may dry in an acceptable manner down to 30°F., but, it certainly won't flow very well there.

If your intent is to do the best possible job and minimize the "touch up" look, you want the paint to flow out and flatten itself in the depression. This is best done at warmer temperatures. If in very dire need of the touch up, I'd recommend the use of a hair dryer to keep the paint and the body warm while it dries.

Before applying the paint, you need to remove all the rust from the chip, if any, to provide a solid base for the paint to adhere. This is best done carefully with an "Exacto-knife". If the chip has been around for awhile, the rust may have grown underneath the surrounding paint. This means more work and a bigger "touch up".

You want to apply the touch up with the smallest possible brush you can find. Sometimes a toothpick is preferred. The tendency is to put too much paint on and it dries with a blob sticking up above the surrounding paint. :mad: Less paint is always preferred. You can always add more on a second application.

"The tendency is to put too much paint on and it dries with a blob sticking up above the surrounding paint. Less paint is always preferred. "---BC

Well, I grew up in the age of painting where the object was to prep the hole ( read featheredge it ) put enough paint that it would dry above the final surface determined by the paint already there... and use elbow grease and the proper fine abrasives with good backing (read sanding block,perhaps a hard rubber squeegy) to take the extra down to that original line going in alternating diagonal strokes with the longitudinal axis of the sandpaper holder held steady and in line with ( some relationship to the curve whose name I can not come up with this early in the morning ).

I agree with the professional way of doing it Greg, but, this is probably outside of the scope of most folks.

Furthermore, I would also like to know how you manage to take down a blob of paint that is less than 1/8" square, using sandpaper as described, without ever touching the paint surrounding the chip??? :confused:

Take a pencil eraser and glue a small circle of sand paper on to it.

I just put a small drop of the paint in the chip or a very light coat with larger areas. My problem is wax always seems to collect in the touched up chips; makes for little white spots all over the car.

"I agree with the professional way of doing it Greg, but, this is probably outside of the scope of most folks."--BC

Well, it does not hurt for people to know the alternatives....

"Furthermore, I would also like to know how you manage to take down a blob of paint that is less than 1/8" square, using sandpaper as described, without ever touching the paint surrounding the chip??? "--BC

Blob of Paint... LOL
First I would try to avoid ' blobbing' .... by planning on using a sprayer to apply the paint. Either an airbrush or perhaps one of those small self contained spray canisters to which you can use your own paint... but also check to see if one of the spray cans of matching paint is available from auto stores or autopaint stores.
The tricks would be to round your actual paint lacking hole.... then fillet the edge and then featheredge out in a gradual manner out to at least one inch from the center of your attentions... then tape off the rest of the area to protect from overspray.
Then you spray a tack coat and then a flash coat.... and in the winter force dry as mentioned above (having warmed everything first )... give them at least one day and preferably longer to stabilize... and then use the very fine and solidly backed wet abrasive to take down the paint just until you can not see the line around the one inch taped circle in this example...
This way you are not trying to keep your blocking behind your sandpaper level with the paint plane while trying to take off that " blob"...

This is not an alternative for a person who is going to do a touch up in their driveway at temperatures of 35°F. She doesn't have a garage or a compressor or an airbrush, or a pint of paint for that matter. :rolleyes:

With this approach, although quite proper technically and requiring considerably more skill and expense, the risk is high that you will obtain a perfect one inch round dot that stands out worse than the original chip. As you know, it's nearly impossible to get a good color match on 18 year old paint.

This approach is best left to a professional.

"This approach is best left to a professional."--BC

The only difference between a Dedicated DIY'er and a " Professional" is that the latter is being paid by someone else... A DIY'er has the option of taking more time to get it right (or starting over) (and applying more careful elbow grease... the most important element ) ... which is most important in paint jobs because of the time needed by the paint which has swelled the lower coats by the absorbtion of the carrier and which should be allowed to exit before ANY sanding is done. This is something which on a full car would typically require weeks to happen (between each application of primer and of the paint ).. which pretty much takes 99 percent of " Professionals" out of the game due to needing to deliver their product....

Clearly, you are taking the word "professional" quite literally. Fine.

I'll rephrase it so it's clearer for you:

This repair is better left to a person with an air compressor, a temperature controlled garage, an airbrush, more than just a quantity of "touch up" paint, a selection of various grades of sandpaper, a proper sanding block, masking tape, polishing compound, and the technique required to make such a repair successful.

The person also better have the resolution to return to the paint supplier several times in order to get a proper color match because, odds are, that the first application of the color won't be the best match and it will need to be done over.

If you think that most of us can effect such a repair, and have it match the results of a true "professional" painter, then you are kidding yourself.

Clearly it would be best to wait until warmer weather... but you went with ' warming things up ' and just filling the hole with paint...

I just checked at the local small town O'Reilly's and it has both the ' kit' of this product at $4.50 and the power refill at $3.30. Which negates the need for an air compressor or air brush....

http://www.prevalspraygun.com/home.htm

I assume no one would have a car with just ONE nick which they are going to tackle...

wet and dry sandpaper can be had in single large sheets for ? Even if they are $1 each you would only need three for the whole car full of nicks.. due to the fact that wet and dry used wet will last many many times as long as regular sandpaper....

If your paint is very faded then the addition of a couple of drops of white to your paint may help match the present color.

Didn't mean to start a battle. :eek:

I appreciate both your advice, though. Brian's assessment of my resources is pretty much accurate in that they are, well, limited. I do like to do the most careful job possible with what I have, but at this point don't have the time slot or weather (cold is one thing, sleet is another) to do what I want. My current needs are to cover a few of the small dings before they become huge ones. The "chips" that are already big, which I have on the door panels, I'm planning on carefully working over with POR15 (and all the steps that co. recommends) when the weather is better and I have a large time block.

A couple weeks ago I did several tiny spots on my hood, using a fine-bristled paintbrush that I normally use for artwork. The paint is indeed a slightly different shade, but I got it fairly smooth and am pleased with the results considering the time and effort I was able to put into it. I did take an artist's approach and was painstakingly fine with the brushwork.

Hey, if I can paint Sandy Koufax on a baseball ...

No battle here.... but I have painted two complete cars myself... and they were much better looking than anything except a Custom Car painter would do... for the reasons already stated... take time with the prep, put on plenty of paint, apply correct amount of Elbow Grease.

I wouldn't have a battle with Greg. He has more knowledge and resources than most of us on the board. Sometimes, however, he minimizes the need for both. :)

adhesion problems
 

My only remark is to use the hairdyer to warm the metal up to over 60 degrees 70,80,90 degrees no problem either. Make sure the paint is at room temperature in the bottle or whatever as well. The reason is have found some auto type paints will not adhere properly if metal is cold initially. Perhaps a wery small invisible layer of frost if below 30? No particular reason to keep heat on after the application stage other than the faster drying. Does no harm if what I believe is wrong. Years ago I used to borrow the wifes hair dryer, she hides it now I believe. :)