[AT] Acrylic enamel paint hardner????

Fri Feb 4 05:49:22 PST 2005

Hardener is a clear liquid.  If left out to dry on its own, it dries
into a hard plastic like substance.  Therefore, I believe it has some
type of chemical reaction to the paint.  Usually the hardener comes in a
16 oz can, so the mix ratio is 8:1.  That is 8 parts unreduced paint to
1 part hardener.  I have seen hardener come in 8 oz cans that have a mix
ratio of 16:1. Once you add hardener, you usually have a 4 hour pot
life.  You need to get the unused stuff out of your gun and get it
cleaned up.  Do not put actived paint back in the can with unactived
paint, it will ruin it for future use.  You also really should use an
air supplied respirator.  I use a regular respirator. I keep my filters
changed.  Do not spray activated paint with a dust nuisance mask or
nothing at all.  This stuff will mess up your lungs.  It can also make
you sick.  If you handle with respect, you should not have any problems.

The can should have instructions on it.  If it doesn't it, the dealer
should be able to give you a copy of the product information sheet.

I cut and pasted a section from Dupont's website dealing with orange
peel.  It is below.

Lou

ORANGE PEEL 

Orange peel, poor flow, poor leveling, pebbling 

Description 

Uneven surface formation - much like that of the skin of an orange -
which results from poor coalescence of atomized paint droplets. Paint
droplets dry out before they can flow out and level smoothly together. 

Causes / Origin 

1. Improper gun adjustment and techniques. (Too little air pressure,
wide fan patterns or spraying at excessive gun distances causes droplets
to become too dry during their travel time to the work surface and they
remain as formed by gun nozzle.)

2. Extreme shop temperature. (When air temperature is too high, droplets
lose more solvent and dry out before they can flow and level properly.)

3. Improper dry. (Gun fanning before paint droplets have a chance to
flow together will cause orange peel.)

4. Improper flash or recoat time between coats. (If first coats of
enamel are allowed to become too dry, solvent in the paint droplets of
following coats will be absorbed into the first coat before proper flow
is achieved.)

5. Wrong thinner or reducer. (Under-diluted paint or paint thinned with
fast evaporating thinners or reducers causes the atomized droplets to
become too dry before reaching the surface.) Too high viscosity. 

6. Low shop temperature. Too little thinner or reducer.

7. Materials not uniformly mixed. (Many finishes are formulated with
components that aid coalescence. If these are not properly mixed, orange
peel will result.) 

Prevention 

1. Use proper gun adjustments, techniques, and air pressure.

2. Schedule painting to avoid temperature and humidity extremes. Select
the thinner or reducer that is suitable for existing conditions. (The
use of a slower evaporating thinner or reducer will overcome this.)

3. Allow sufficient flash and dry time. Do not dry by fanning.

4. Allow proper drying time for undercoats and topcoats. (Not too long
or not too short.)

5. Select the thinner or reducer that is most suitable for existing shop
conditions to provide good flow and leveling of the topcoat.

6. Reduce to recommended viscosity with proper thinner/reducer.

7. Stir all pigmented undercoats and topcoats thoroughly.

Solution 

Compounding may help - a mild polishing compound for enamel, rubbing
compound for lacquer. In extreme cases, sand down to smooth surface and
refinish, using a slower evaporating thinner or reducer at the correct
air pressure. 

Produced Due To Or During: 

Application
Use/Preparation of Product
Others: Temperature / Humidity 