What's your paint prep process?

[rficalora]

After cleaning several parts, I wiped them off and then let them dry for a day or two. I then sanded any old paint to smooth the surfaces with 80 grit and followed with an acetone wipe down before painting. I let the paint cure for several days. I decided to test the paint adhesion by scraping a couple of areas with a screwdriver and am finding I'm not getting good adhesion.

I'm using a good quality DTM (direct to metal) oil based paint that's worked well for me in the past so I have to believe there's still too much oil/grease in the metal. In similar situations I would normally heat the part with a propane torch to raise the oils and re-wipe with acetone. I'm hesitant to do that on the lathe parts for fear of distorting parts that have shafts running through them.

What is your process to get good paint adhesion when restoring older, greasy/grimy machinery?

 

[Bone Head]

On old engine blocks/cases I have steam cleaned, wiped down with old towels, a tack cloth and a non-petroleum degreaser. Started the painting process as soon as dry.

 

[tq60]

Scrub with whatever the paint identifies as it's thinner.

Sent from my SM-G781V using Tapatalk

 

[f350ca]

Petroleum based cleaners simply dilute surface oil, with enough washings you may reduce the oil film to the point the paint may stick. Water based cleaners emulsify the oil and it is carried away when rinsed with water.
A good surface test is to mist the surface with water, it it beads there is an oil film, if it evenly wets the surface your good to go.

Greg

 

[markba633csi]

I've had great results degreasing with Coleman camp fuel (naphtha, lighter fluid) then painting with Rustoleum brush enamel in warm weather.
Rock hard finish with very little work. You can mix colors too and get custom shades
-Mark
ps Rustoleum also has a line of spray paint called "industrial choice" that works real well on metal. I think I ordered it from Zoro
The Royal blue is a very nice deep navy blue

 

[rficalora]

Good input everyone. Thank you!

 

[FOMOGO]

Attach brush to dogs tail in a small space with object to be painted, and yell squirrel. Mike

 

[erikmannie]

Try as I might, I have usually had disappointing results with painting at home.

After my finishing (e.g. fly cutting, grinding but usually sanding), I use acetone.

I try to paint in the garage (as opposed to out in the wind), & I try to plan the painting job in warmer temperatures.

I can do nice work if the paint is flat (as opposed to gloss).

 

[rabler]

I would add that many of the metal paints take *weeks* before really hard, so I would not be surprised if they came loose in a couple of days. This is especially true if not kept fairly warm. Heat lamps can help.

I normally clean with mineral spirits followed by a wiped down with IPA just before painting. Acetone flashes off so fast I find I can't make any progress before its gone. But I doubt that matters as long as you're doing a decent job.

 

[JBTEK]

For cast iron and steel lathe parts, I soaked them in undiluted Purple Power overnight. I believe that removes any oil even from pores. Then rinse and wire brushed with running water. Then dried them for a day or so, sometimes adding a bit of heat with a small industrial heating pad beneath them.

The downside is that most everything got a light flash rust which I would sand or wire brush off before a final wipe with denatured alcohol before painting.

I used Sherwin Williams industrial alkyd enamel. It gives cure times of maybe 6 - 10 days depending on temperature. But that is based on a specified film thickness only achieved by proper spraying. I brushed and had a much thicker film so my complete cure time was probably several weeks.

I finished it last summer and so far everything looks good.

John