Need help on repainting a PM935T, recomendations welcome

COMachinist

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Well I would like to get rid of the paint job, on my new 3 week old PM935t it looks like it is 3 years old. That white paint they use on the mill sucksbig time. I know they use body filler but this junk flakes off in hunks, they must have not cleaned the casting at all and plastered that stuff an 1/8th+ thick over the whole machine. Never gave it much thought, but white is not the color for a machine shop environment pro or hobby. Any way best way to start this job, plan do it this fall before winter sets in.
CH
 
@davidpbest did an excellent writeup on the paint job he did on his PM-1340GT that might be helpful to you.

 
@davidpbest did an excellent writeup on the paint job he did on his PM-1340GT that might be helpful to you.
I I I I number
Yep I saw that and he repainted his 935 as well. He did that in white, is which is a nonstarter. Just can't live with that. Was hopping to get paint brands and best that will stand up.
 
Yep I saw that and he repainted his 935 as well. He did that in white, is which is a nonstarter. Just can't live with that. Was hopping to get paint brands and best that will stand up.
Let me clarify my re-paint decisions a bit.

One of my biggest criticisms of the equipment from Asia (Taiwan included) is the crappy paint jobs. They slather the castings with a body filler that remains soft and chalky when it “hardens” and then the apply a paint that has zero elasticity. The end result is that any bump to the finish and it flakes off with a nasty bruise. But even areas where the paint isn't applied over filler, the paint will also chip if bumped. I’ve *****ed and *****ed at the resellers but it never improves.

In my case, my perfectionist side took over and I stripped the lathe and mill back to hard castings and ground the castings fair and smooth, then where necessary applied Bondo auto-body filler and sanded that fair and smooth, but none of the edges or corners are Bondo - they are ground cast iron. The two coats of DTM primer, then two top coats of Steel-it poly-enamel (lathe) or quality DTM Alkyd enamel (mill) paint applied. The lathe paint was applied with a combination of rattle-can and brush/roller, and the mill with air-assisted airless sprayer.

I chose to match the existing "whiteish" color on the mill because I didn't want to strip the J-head down far enough to repaint it. Like @COMachinist, I had my own mechanical failure issues with the machine which ultimately required a complete replacement of the J-head, so in retrospect, I'm glad I stuck with the white even though I would have preferred to go to some kind of darker grey color throughout like I did with my lathe. But to get a decent paint job on the J-head, it would have required tearing that unit down extensively, which I wasn't prepared to do. That head is a near identical clone of the Bridgeport original and is a marvel Rube Goldberg contraption with lots of selectors and teeter-totter mechanisms, and I just wasn't inclined to mess with it given the issues I had at the outset - hence the color choice.

The particular paint I used on the mill has been robust, but it does stain from the inevitable oil that pools on the mill base originating from the saddle and knee gib-ways. The Steel-it paint I used on the lathe (recommended to my by Tom Lipton) does not show stains and is more impervious to solvents like Naphtha, Acetone, MEK, etc. than the Sherwin Williams Alkyd enamel I used on the mill. I can highly recommend the Steel-it if you are ok with the color. For my lathe STAND, I used a Sherwin-Williams 2-part epoxy paint called Macropoxy which is commonly used to paint things like fuel storage tanks that sit outside for decades. It is nasty stuff, expensive, and requires a proprietary solvent to clean up, but is positively bomb proof and can be tinted to the color of your choice.
 
Thanks David for some great info on the paint. I thought about useing POR 15 direct to metal paint. It is very tough, and I used it on my under carage of my Jeep Xj when I restored it. It has held to some reel rough treatment. I'm not sure how to apply it. POR15 is very thick and I used a brush on the under carage. Did you spray your paint and primers and paint? That Sherwin-Williams Macropoxy sounds like some bullitt proof stuff as well. I have nothad very good response from Matt on my problems withmy machine. I bought 3 machines from PM and have not had real stellar post purchase service from them. Again thank you for you great help on this subject.
CH
 
Well I would like to get rid of the paint job, on my new 3 week old PM935t it looks like it is 3 years old. That white paint they use on the mill sucksbig time. I know they use body filler but this junk flakes off in hunks, they must have not cleaned the casting at all and plastered that stuff an 1/8th+ thick over the whole machine. Never gave it much thought, but white is not the color for a machine shop environment pro or hobby. Any way best way to start this job, plan do it this fall before winter sets in.
CH
I did a write-up on painting when I did the restoration on my Pratt & Whitney 12C. I’ve included a few pictures of it and of the 10EE that I restored as a couple of examples.

IMG_0469.jpg IMG_0473.jpg IMG_0472.jpg IMG_0471.jpg

IMG_0346.jpg IMG_0347.jpg IMG_0348.jpg IMG_0349.jpg

If interested in the details, here are the links to those posts. If I can help or answer any questions about my approach to painting, let me know.

https://www.practicalmachinist.com/...-12c-restoration-pictures.402002/post-3935165

https://www.practicalmachinist.com/...-12c-restoration-pictures.402002/post-3935167

https://www.practicalmachinist.com/...-12c-restoration-pictures.402002/post-3935168
 
Wow beautifully done. That one the nicest restored machine I have seen. Thanks for responding. Much appreciated.
CH
 
Did you spray your paint and primers and paint? That Sherwin-Williams Macropoxy sounds like some bullitt proof stuff as well.
CH
The lathe primer and Steel-it paint was applied with a combination of rattle-can and brush/roller mostly because of the small surface area. I didn’t want all the cleanup associated with my Greco Fine-Finish air-assisted airless sprayer.

On the mill, I first attempted to apply the finish with brush and roller. I was not at all happy with the finish, and ended up stripping it off again. Then I applied the Sherwin Williams DTM primer and Alkyd enamel with that Greco sprayer. Lots of detail on all this is in my PM-935 upgrade blog.

The Macropoxy I used on the lathe stand is very thick and viscose and would require dilution with the proprietary solvent to spray with any home sprayer, and is toxic requiring serious masking and ventilation. I ended up applying it with short nap roller which resulted in a pebble-like finish. That finish was fine for a stand but not what I would want on the machine itself.

If I were in your situation, I would recommend using this Greco sprayer using the 3M dosing containers. Sell it when you are finished if you don’t have additional need.

If you do disassemble the PM-935 to strip and paint it, consider sealing up the one-shot oil delivery system as I documented here.
 
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