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View Full Version : Can I powder coat a lathe?



Pinresto
02-20-2015, 08:30 AM
I'm looking at lathes now and I'll likely buy an older used lathe. Something ugly but still somehow beautiful. I love restoration work and the lathe will likely get the full treatment in time. Last year I built a powder coating oven. I prefer it over paint whenever possible. I'm not sure what, if any effect the cure will have on precision equipment. My gut says 400 degrees for 20min will not hurt it but I'd like to know for sure. Will putting the compound tool rest or bed ways in the oven for 20 hurt them? Will it make them brittle or warped? Damage them in any way? Has anyone done this and what were your results?
No powder or paint on working surfaces of course.

Thanks, Tony

J Tiers
02-20-2015, 08:45 AM
Lotta iron in a lathe, might take a lot longer to get up to temp. I see adhesion issues unless you do that well. No issues with sheet metal, it's up and down in temp very fast.

Pinresto
02-20-2015, 09:16 AM
I've done a few cast items with high mass. As long as a preheat the part and preheat the oven to 500 and drop it back down to 400 when I put the part in I've been ok. Just need to get the part up to temp as fast as possible. I'm more worried about effecting the precision.

Davek0974
02-20-2015, 10:33 AM
I can see issues with oil leeching out of the cast and ruining the coat.

Personally I would opt for a quality brush or spray job.

shoeboxpaul
02-20-2015, 12:02 PM
I am in agreement with Davek. I restored a doctors bathroom scale, the stand on type with the slide weights and the height measurement gauge. The base and the beam castings are cast iron. Twice I tried powder painting the upper casting (white). First, I cleaned it with Purple Power, figuring it was good to go. Wrong. Apparently the good doctor lubircated the moving parts he could get to and the oil bled through the baked powder, leaving a couple big brown spots in a nice smooth white finish. Back to the blast cabinet. After removing all the baked-on powder, I baked the casting at 500 degrees for at least an hour and re-cleaned again with purple power, then acetone. Second attempt was another failure - more brown spots. The spots were in an area of high visibility. I blasted off the powder a second time and completed the restoration using white Rustoleum aerosol paint. An old lathe would get oiled every time it was used. I know of no professional powder coater that will guarantee the finish on any casting and if they do it twice, they will charge accordingly.

macona
02-20-2015, 01:14 PM
Alkyd Enamel with hardener is the way to go.

Mike Amick
02-20-2015, 01:50 PM
Pinresto, your enthusiasm make's me smile. I can remember what it was like
getting ready to buy my first lathe. Your mind is going all crazy thinking about
things you want to do to make it look nice, and work good.

Don't loose it, it makes life rich ... good for you

Rich Carlstedt
02-20-2015, 01:55 PM
Alkyd Enamel with hardener is the way to go.

1 +

Rich

Doc Nickel
02-20-2015, 02:36 PM
"Hardener" as in an actual catalyst, or do you mean Japan drier to help it dry faster?

Doc.

Tundra Twin Track
02-20-2015, 07:42 PM
I powder coated my Doall Bandsaw and had oil residue seep through in a few spots where main body was welded to 5/8" thick base plate.He cooked it twice to try to avoid this before coating but still happy how it turned out.You can look at 1950 Doall thread if you would like to ,in the 2nd pic.

Forrest Addy
02-20-2015, 09:19 PM
First of all, remember it's a machine tool, not fine furniture or a custom car. A machine shop operates under an entirely different esthetic: the only things that count are good parts within spec, nade of the right material, on time, and within budget. Everyting else is a distant second and that includes paint, texture, Fung Zhue, political correctness, ideological purity, and the power of crystals.

That said, powder coat is a sensible finish for machine tool castings. It's hard, durable, color fast, and resistant to coolants and oil. OTH iron castings are massy and slow to heat. Much longer heat time may be required to flow the powder into a continuous film. Also the casting will have to be clean, free of films and infiltrated liquids. Finshed surfaces may need to be masked and the surfaces to be coated media blasted to give the casting tooth. All this equates to some surgical risk avoided by simple brush painting over a good paint prep.

Slow heating will have little effect on casting stability although there may be metallurgical changes lurking within the metal. It's the rate of heating and the inequality of heat distribution that causes localized expansion and, if excessive, permanent distortion. I suggest you heat the work starting from a cold oven, remove it piece by piece for the powder, then after coating increase the heat on the whole load to cure it. I know little of powder coating but much about protecting precision castings from heat distortion. This is the point where a powder coat process expert should weigh in, review these suggestions and reccommend a suitable process.

Returning to my earlier remarks about esthetics, I suggest you put off fancy paintwork until you get a chance to assess your lathe's condition and invest some TLC, accomplish remedial work, whatever. It's the precision of the machine that counts not its appearance. I suggest you spend your first hundred hours cleaning, repairing what needs to be repaired, acquiring tooling, attachments, and equipment, and accumulating the skills and resources oi takes to put your new machine tool to work.

If your circle of friends downcheck you for owning an ugly machine tool that is otherwise in good condition that performs accurately, efficiently, and predictably, you need another set of friends.

If the bedraggled appearance of your machine really does drive you nuts, strip the machine to basics, clean, prep, and prime, and brush paint a standard color of an alkyd industrial coating. A good two coat paint job on a well prepped surface is almost indistinguishable from a spray-paint job and, because it does not have to be masked and the shop draped to form a paint booth, the job takes half the time.

Another point, paint jobs on machine tools are subject to chip wash and small dings from wrenches and fumbled work, staining. Powder coat and calylized paint is difficult to touch up - it always looks patchy and then here is adhesion. Alkyd paint requires only prep sanding and a dab of paint. Touch it up on Friday close of business and the machine is ready for production on Monday morning.

J Harp
02-20-2015, 09:34 PM
I'll raise the question of the effect of 400 degrees on heat treated parts such as hardened ways, and rolling element bearings. I don't know, so I'll look for comments by those more knowledgeable and experienced.

Edit,

Forrest covered it, found his post later.

macona
02-20-2015, 10:01 PM
"Hardener" as in an actual catalyst, or do you mean Japan drier to help it dry faster?

Doc.

Catalyst. When I was going through the 10EE I made the mistake of not using it. Even after a week it was quite tacky. Doing some reading it will take alkyd enamel up to 2 years to fully cure without the catalyst. I ended up having to restrip the lathe and start over. But the stuff holds up real well.

Pinresto
02-20-2015, 11:28 PM
I'll raise the question of the effect of 400 degrees on heat treated parts such as hardened ways, and rolling element bearings. I don't know, so I'll look for comments by those more knowledgeable and experienced.

This is what I'm concerned about.

Pinresto
02-20-2015, 11:32 PM
First of all, remember it's a machine tool, not fine furniture or a custom car. A machine shop operates under an entirely different esthetic: the only things that count are good parts within spec, nade of the right material, on time, and within budget. Everyting else is a distant second and that includes paint, texture, Fung Zhue, political correctness, ideological purity, and the power of crystals.

That said, powder coat is a sensible finish for machine tool castings. It's hard, durable, color fast, and resistant to coolants and oil. OTH iron castings are massy and slow to heat. Much longer heat time may be required to flow the powder into a continuous film. Also the casting will have to be clean, free of films and infiltrated liquids. Finshed surfaces may need to be masked and the surfaces to be coated media blasted to give the casting tooth. All this equates to some surgical risk avoided by simple brush painting over a good paint prep.

Slow heating will have little effect on casting stability although there may be metallurgical changes lurking within the metal. It's the rate of heating and the inequality of heat distribution that causes localized expansion and, if excessive, permanent distortion. I suggest you heat the work starting from a cold oven, remove it piece by piece for the powder, then after coating increase the heat on the whole load to cure it. I know little of powder coating but much about protecting precision castings from heat distortion. This is the point where a powder coat process expert should weigh in, review these suggestions and reccommend a suitable process.

Returning to my earlier remarks about esthetics, I suggest you put off fancy paintwork until you get a chance to assess your lathe's condition and invest some TLC, accomplish remedial work, whatever. It's the precision of the machine that counts not its appearance. I suggest you spend your first hundred hours cleaning, repairing what needs to be repaired, acquiring tooling, attachments, and equipment, and accumulating the skills and resources oi takes to put your new machine tool to work.

If your circle of friends downcheck you for owning an ugly machine tool that is otherwise in good condition that performs accurately, efficiently, and predictably, you need another set of friends.

If the bedraggled appearance of your machine really does drive you nuts, strip the machine to basics, clean, prep, and prime, and brush paint a standard color of an alkyd industrial coating. A good two coat paint job on a well prepped surface is almost indistinguishable from a spray-paint job and, because it does not have to be masked and the shop draped to form a paint booth, the job takes half the time.

Another point, paint jobs on machine tools are subject to chip wash and small dings from wrenches and fumbled work, staining. Powder coat and calylized paint is difficult to touch up - it always looks patchy and then here is adhesion. Alkyd paint requires only prep sanding and a dab of paint. Touch it up on Friday close of business and the machine is ready for production on Monday morning.


I understand what your saying but were not all running machine shops. I don't care about time lines and budgets. I'm not going to start stripping it for powder coating the second I get it. I was just wondering if it was an option. As far a someone looking down on me for having an ugly lathe......lol.

thaiguzzi
02-23-2015, 05:03 AM
+1 on what Forrest said.

Doc Nickel
02-23-2015, 05:49 AM
Catalyst. When I was going through the 10EE I made the mistake of not using it. Even after a week it was quite tacky. Doing some reading it will take alkyd enamel up to 2 years to fully cure without the catalyst. I ended up having to restrip the lathe and start over. But the stuff holds up real well.

-What catalyst? I was told by several people (varying degrees of 'expert') that there's no catalyst for an alkyd enamel, apart from the aforementioned Japan drier.

As for the "tackiness", I can indeed attest to it taking a while to dry. Generally my parts are safe to handle within 24 hours, but the coating is still soft enough that if you set something on it, it'd slowly form an impression. Seems it remains like that for several days.

I don't believe "two years" though- it's not a reaction like epoxy, it's just drying solvents. I suppose I can see there still being faint traces of VOCs after perhaps even several months, depending on conditions, but unless it's being refrigerated, I doubt there's more than a few parts per billion of solvents left after less than six months.

Doc.

Deus Machina
02-23-2015, 06:21 AM
Rehashing, I'm only worried about 400 being about at the line where treatment and any internal stresses may come into play. Not so worried about the stress on a good lathe, but you never know.
Aside from that iron's fine, but it's the other things. Oil's pretty much impossible to get out, and some tools are going to have this Bondo-like filler in places that heat won't do any good. I know I haven't bought an import tool without it, but age and origin will have a factor.
For ease and variety, get some paint. Two-part if you can. Get fancy with it if you want.
For what it's worth, petty much everything I do gets a coat of Rustoleum 'professional' primer, then the matching enamel on the top unless I'm color-matching with some the more basic Rustoleum. Dry it overnight, then toss it in a 200 degree oven for a couple hours and I have yet to damage any of it.
You might not even have to do that, but Florida's constant 90% humidity sucks for rattlecans.

bborr01
02-23-2015, 03:19 PM
I wouldn't likely powder coat a machine tool even if it wouldn't harm it. With that said, I have read that there are businesses who will come in and powder coat appliances. They use infrared lights to heat the powder coating. At least that is what I recall reading many years ago. I don't know if a casting would have to get up to 400 degrees all the way through or if the powder and surface of the metal is enough.

Brian

philbur
02-23-2015, 05:12 PM
I understand what your saying but were not all running machine shops. I don't care about time lines and budgets. I'm not going to start stripping it for powder coating the second I get it. I was just wondering if it was an option. As far a someone looking down on me for having an ugly lathe......lol.

Forrest is universally recognized on this and other machinist forums as having unrivalled knowledge regarding all things related to machining and machine tools. He has made it clear that there is a risk of none uniform heating causing stress induced deformation. It would be to your advantage to take careful note of the comments that should concern you and ignore the parts that do not apply.

On most machinist forums you can anticipate short shrift for having a nicely painted lathe that performs like crap. They tend to be under-impressed by pigs with lipstick.

Phil:)

oldtiffie
02-23-2015, 08:15 PM
Why powder coating?

Why not dismantle the machine and have a good professional shop/factory sand (garnet/bead?) blast it and paint it? No heating required, preparation is easier and no worries about heat distortion/problems either as well as easy "masking"?

Rosco-P
02-23-2015, 10:01 PM
Personally, if I were moving to a tropical or sub-tropical region, I'd strip the machine down and send it to a plater to be yellow zinc (zinc chromate) plated. I can't imagine a finish, if the metal is properly prepped, that would be more durable and rust resistant.

LHC
02-25-2015, 10:39 AM
First of all, remember it's a machine tool, not fine furniture or a custom car. A machine shop operates under an entirely different esthetic: the only things that count are good parts within spec, nade of the right material, on time, and within budget. Everyting else is a distant second and that includes paint, texture, Fung Zhue, political correctness, ideological purity, and the power of crystals.

I don't know about the rest of you, but whenever I see a posting from Forrest I immediately set the coffee down, sit up straight and alert, open up the thread, and start reading. In my case it's more like a concentrated study session rather than simple reading. His depth of knowledge, willingness to assist those of us who don't realize how little we know, and the sheer entertainment of his classic rants and large helpings of reality, make this forum priceless. Please Forrest, don't ever stop posting on here - you sir, are indeed a treasure and very much appreciated.....

Cheers,
Lewis

thaiguzzi
02-26-2015, 11:42 PM
I don't know about the rest of you, but whenever I see a posting from Forrest I immediately set the coffee down, sit up straight and alert, open up the thread, and start reading. In my case it's more like a concentrated study session rather than simple reading. His depth of knowledge, willingness to assist those of us who don't realize how little we know, and the sheer entertainment of his classic rants and large helpings of reality, make this forum priceless. Please Forrest, don't ever stop posting on here - you sir, are indeed a treasure and very much appreciated.....

Cheers,
Lewis

Exactly !!

darryl
02-27-2015, 01:47 AM
Just my take on it- why risk anything happening to impair the accuracy of a machine tool by heating it to a temperature it hasn't seen since the day it came out of the forge-

It was good to consider the idea of powder coating it- now let that idea die and use a good paint. Many times I've used engine enamel and been entirely satisfied. Catalyzed paint seems to be good, though I haven't done that personally, just seen the results. Industrial paints- certainly can imagine that being a good way to go.

macona
02-27-2015, 02:23 AM
-What catalyst? I was told by several people (varying degrees of 'expert') that there's no catalyst for an alkyd enamel, apart from the aforementioned Japan drier.

As for the "tackiness", I can indeed attest to it taking a while to dry. Generally my parts are safe to handle within 24 hours, but the coating is still soft enough that if you set something on it, it'd slowly form an impression. Seems it remains like that for several days.

I don't believe "two years" though- it's not a reaction like epoxy, it's just drying solvents. I suppose I can see there still being faint traces of VOCs after perhaps even several months, depending on conditions, but unless it's being refrigerated, I doubt there's more than a few parts per billion of solvents left after less than six months.

Doc.

I used a hardener similar to this. http://www.tonzof.com/valspar-hp-oz-enamel-hardener/p/849080047185328?CAWELAID=120161430000051852&CAGPSPN=pla&catargetid=120161430001734195&cadevice=c&gclid=Cj0KEQiApbunBRDs0fba3dz484cBEiQAMsx-pxbhi_6zPLOytK7xOt60FYNtJCGHSorwSPiEvQE0FLoaAoOV8P 8HAQ

Don't know if it was a japan drier or not but it made all the difference.

After I shot the lathe was tacky for over a week, and this was in the summer. I could touch it and easily leave fingerprints. At that point I did some research and found that they recommend a hardener for it.

kevkeller
02-27-2015, 05:10 AM
Where do you normally buy the enamel paint and hardener? An auto paint store? Or would they have it at Home Depot?

MrFluffy
02-27-2015, 07:15 AM
Why powder coating?

Why not dismantle the machine and have a good professional shop/factory sand (garnet/bead?) blast it and paint it? No heating required, preparation is easier and no worries about heat distortion/problems either as well as easy "masking"?
You could go one further and have it pinstriped and flames airbrushed on while you were at it.

Never quite sure when your being entirely serious tiffie, suspect its less often than people generally give you credit for :)

Seastar
02-27-2015, 08:06 AM
To the OP
Let me sum up in a non gentle way------
Powder coating a lathe is probably a dumb idea because of the possibility of distortion of the castings and oil intrusion.
Painting is a good idea because it works, is safe and looks good.
Bill