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Painting machines. What process?

Spud

Diamond
Joined
Jan 12, 2006
Location
Brookfield, Wisconsin
How do the various machine tool manufacturers paint machines, both CNC and manual? Brands such as: Haas, Mori-Seki / DMG, Weiler, Mazak, Makino, Taiwanese makers of Bridgeport clones, Moore, Amada , Trumpf, Hyd-Mech, DoAll.

I just completed my automotive collision repair and refinishing program at trade school. Most of our time was spent on the painting process. Most vehicles receive Primer, Base and then Clearcoat, using HVLP gravity feed guns.

Do machine tool manufacturers use HVLP sprayers ? Or powder coating? What about machine tool rebuilders , are they using the same methods as an auto collision repair and restoration shop ?
 
I have a warner swasey that left the factory naked. No paint. Still runs great. No rust. Point is with old stuff that used real cutting oil the paint doesnt matter.
 
I'll bet you $5 that they don't use base /clear ! Most likely a pressure pot/remote gun for production painting. Base/clear is a car makers rip off ,goes to shit in a few years . Cheaper to buy a new car than a quailty re-finish.
 
I'll bet you $5 that they don't use base /clear ! Most likely a pressure pot/remote gun for production painting. Base/clear is a car makers rip off ,goes to shit in a few years . Cheaper to buy a new car than a quailty re-finish.


With the pressure pot set-up, are they using HVLP?

No Airless or Air assisted airless ?

Solvent or Waterborne paint?

Given a choice between Solvent and Waterborne I would pick the later, it lays down nicer and is easier to blend to existing painted panels.
 
Personally I think a base and clear would be fine for most machine tools. That clear can be pretty tough.

Cash posted about painting his machinery here a year or two ago, try searching for his post.

Charles
 
A few years back I had some industrial equipment painted by a local automotive shop. They used a procedure where you first paint a base coat then overspray it at very high pressure and low paint so it leaves a textured surface. This looks good on industrial cabinets and hides the lack of body work. Then used a matt clear and they looked great and didnt show fingerprints. I have not had the need to have this tested on a machine tool.

Charles
 
A 2k polyurethane or acrylic gives a very tough coat But so does alkyd resin. They both need time to develop their maximum hardness and it's a matter of weeks/months rather than days. In days of yore, the primer/filler was the major part of the process, but manufacturers aren't bothered about the swooping curves of the Monarch/Hardinge/Myford on grey iron castings era any more, so the filler isn't as large a part of the process. I'm not sure that any machine manufacturers have gone to the point of powder coating, but I wouldn't be surprised if they had.
 
Well you got the first part down. How to spray a finish. That's a great start, and you'll need it.

I've built and repainted many machine tools over the years. Here's some of what I've learned for whatever it's worth.

Of course it depends on what you're dealing with and what your plans are with it. Personally I would not go through this much work for anything other then something I was keeping for use by myself.

The heavy cast iron stuff:


Parts like the main castings that you don't trust others to handle properly or doubt they have the equipment to do so is where your skills are needed. Keep it in house and spray it both with a good primer and I suggest a two part urethane. They're bullet proof against any and everything you throw at or on a machine tool. Sure there are isocyanates to deal with. An air supplied hood is technically what you need, but if you're not in business and using it all the time you'll be fine. Just keep the concentrations down. You'll find these paints at industrial paint supply stores. And yes I use a standard air compressor type HVLP but you'll need biggish tips.

Prepping cast iron for paint can come in many forms. Mostly in the way of elbow grease. There is a place for solvents and plain ole hot soapy water. (Meaning Dawn dish soap.) Fabulous Cleaner at the Dollar Store is good and cheap to use also. I'll always finish with hot Dawn water as my last clean before paint. (Even back in the day before rebuilding automotive engines.) Dry it off quick and don't get too worried about the small bit of flash rust. Even after heavy cleaning most cast iron will likely leach oil. You'll see wet spots in your primer after a day or two of sitting. There's very little you can do about it unless you want to bake it all out in an oven. I also use Acryl Clean (PPG?) after primer as a last wipe off before paint. I also like spraying sealers over old paints.

The sheet metal:

A full on CNC enclosure is best done by sending it all out to have the paint burnt off. No pre-cleaning necessary. It does a great job, and believe it or not is totally environmentally friendly. The after wash they use sets the panels up perfectly for what you should do next. Powder coating. Again Urethane. For what you end up with, I find the costs to be totally worth the tons of work it saves. Plus you get a finish that is very difficult to match at home both in look and reliability. Do all the bodywork before you send it out. The great thing about this process is it is little work with perfect, near bullet proof long lasting results.

The other stuff:

Cabinet blast everything you can. (Walnut shell, glass bead, Black Beauty (Coal slag)) I never use sand anymore. Scares me more then the isocyanates. :-) The front clam shell opening cabinet types are best for dealing with large heavy pieces. Much easier to load parts in and out. I also powder coat everything I can except like I mentioned above. It's simply the best, and I've tried the rest. I use the same two part Urethane like on the other. Let's face it. Painting is a lot of hard and smelly work that can also disturb the neighbors, so why not use the best you can or at least best you can afford. Add Edit: Sometimes for small stuff I have used spray can Self Etching Primer with a top coat. Try to find Krylon over Rust-Oleum. I hate that stuff. Tips clog. And your newborn will be graduating high school before it fully drys. I've also had good luck painting gearbox and machine cabinet interiors with light colored Epoxy out of the can. Works well in that situation. Plus the light color helps see inside when you need to.

Misc:

A large tote completely sawed in half makes a great pallet jack-able wash tank with a cover for large parts and castings. A cow watering trough makes a great rinse tank. Both cheap to find on CL. Move your heavy stuff in and out with a hoist if you have or a cherry picker. The textured finishes mentioned limit your selection a little and are more prone to operator error then the plain types, yet those in the business should have experience with it. I've stuck with smooth gloss on everything. I painted a couple of my first machines with quart cans of enamel from Menards. Total crap paint jobs. Never did that again.

Final tip.


Don't waste your time blowing holes, threaded or otherwise, with the tip of any standard air gun. You're completely wasting your time. Get a cheap changeable tip air gun with the different length small tube tips that fit down inside the hole. I spent years blowing out holes with a standard gun thinking I was actually doing good. Ha-ha... what a joke. You'll realize the no-bull-here when you use what actually does work.

Here are some pictures of the wash tub, rinse tub with a tool changer casting, and the main castings of the last machine I rebuilt showing the main castings painted in house. What you can't see is the other half of the tote that fits perfectly over this one as a cover.

Final note. This tote with $300 worth of industrial water based cleaner in it is free for anyone near Saint Paul, MN. Even if you just want to pump it out into your own container. Looks dirty, but there is plenty of miles left in it, and any particulates are all settled out. The cow trough is for sale at 30 bucks. Decided that I've rebuilt my last machine tool so am looking to move them out. Haven't yet bothered advertising until I just thought of it now.

Hope at least part of this helps or gives you ideas. Good luck.

Dave

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Well you got the first part down. How to spray a finish. That's a great start, and you'll need it.

I've built and repainted many machine tools over the years. Here's some of what I've learned for whatever it's worth.

Of course it depends on what you're dealing with and what your plans are with it. Personally I would not go through this much work for anything other then something I was keeping for use by myself.

The heavy cast iron stuff:


Parts like the main castings that you don't trust others to handle properly or doubt they have the equipment to do so is where your skills are needed. Keep it in house and spray it both with a good primer and I suggest a two part urethane. They're bullet proof against any and everything you throw at or on a machine tool. Sure there are isocyanates to deal with. An air supplied hood is technically what you need, but if you're not in business and using it all the time you'll be fine. Just keep the concentrations down. You'll find these paints at industrial paint supply stores. And yes I use a standard air compressor type HVLP but you'll need biggish tips.

Prepping cast iron for paint can come in many forms. Mostly in the way of elbow grease. There is a place for solvents and plain ole hot soapy water. (Meaning Dawn dish soap.) Fabulous Cleaner at the Dollar Store is good and cheap to use also. I'll always finish with hot Dawn water as my last clean before paint. (Even back in the day before rebuilding automotive engines.) Dry it off quick and don't get too worried about the small bit of flash rust. Even after heavy cleaning most cast iron will likely leach oil. You'll see wet spots in your primer after a day or two of sitting. There's very little you can do about it unless you want to bake it all out in an oven. I also use Acryl Clean (PPG?) after primer as a last wipe off before paint. I also like spraying sealers over old paints.

The sheet metal:

A full on CNC enclosure is best done by sending it all out to have the paint burnt off. No pre-cleaning necessary. It does a great job, and believe it or not is totally environmentally friendly. The after wash they use sets the panels up perfectly for what you should do next. Powder coating. Again Urethane. For what you end up with, I find the costs to be totally worth the tons of work it saves. Plus you get a finish that is very difficult to match at home both in look and reliability. Do all the bodywork before you send it out. The great thing about this process is it is little work with perfect, near bullet proof long lasting results.

The other stuff:

Cabinet blast everything you can. (Walnut shell, glass bead, Black Beauty (Coal slag)) I never use sand anymore. Scares me more then the isocyanates. :-) The front clam shell opening cabinet types are best for dealing with large heavy pieces. Much easier to load parts in and out. I also powder coat everything I can except like I mentioned above. It's simply the best, and I've tried the rest. I use the same two part Urethane like on the other. Let's face it. Painting is a lot of hard and smelly work that can also disturb the neighbors, so why not use the best you can or at least best you can afford. Add Edit: Sometimes for small stuff I have used spray can Self Etching Primer with a top coat. Try to find Krylon over Rust-Oleum. I hate that stuff. Tips clog. And your newborn will be graduating high school before it fully drys. I've also had good luck painting gearbox and machine cabinet interiors with light colored Epoxy out of the can. Works well in that situation. Plus the light color helps see inside when you need to.

Misc:

A large tote completely sawed in half makes a great pallet jack-able wash tank with a cover for large parts and castings. A cow watering trough makes a great rinse tank. Both cheap to find on CL. Move your heavy stuff in and out with a hoist if you have or a cherry picker. The textured finishes mentioned limit your selection a little and are more prone to operator error then the plain types, yet those in the business should have experience with it. I've stuck with smooth gloss on everything. I painted a couple of my first machines with quart cans of enamel from Menards. Total crap paint jobs. Never did that again.

Final tip.


Don't waste your time blowing holes, threaded or otherwise, with the tip of any standard air gun. You're completely wasting your time. Get a cheap changeable tip air gun with the different length small tube tips that fit down inside the hole. I spent years blowing out holes with a standard gun thinking I was actually doing good. Ha-ha... what a joke. You'll realize the no-bull-here when you use what actually does work.

Here are some pictures of the wash tub, rinse tub with a tool changer casting, and the main castings of the last machine I rebuilt showing the main castings painted in house. What you can't see is the other half of the tote that fits perfectly over this one as a cover.

Final note. This tote with $300 worth of industrial water based cleaner in it is free for anyone near Saint Paul, MN. Even if you just want to pump it out into your own container. Looks dirty, but there is plenty of miles left in it, and any particulates are all settled out. The cow trough is for sale at 30 bucks. Decided that I've rebuilt my last machine tool so am looking to move them out. Haven't yet bothered advertising until I just thought of it now.

Hope at least part of this helps or gives you ideas. Good luck.

Dave

View attachment 275243View attachment 275244View attachment 275245


Thanks for that write up.

At Tech school, we only used two part Primer Filler (aka Primer Surfacer) and two part Primer Sealer. Ratio of 4 parts Primer to 1 part Activator.
The Primer Filler/Surfacer is Nason 2K Urethane (made by Axalta , formerly Dupont) . It is a High Build primer.

I would prep and paint equipment with chipped paint using best practices, simply because it would be something I enjoy doing and I am Obssessive Compulsive about details. Anything I would paint in the future would be with an HVLP gravity feed spray gun in a proper downdraft booth. For the forseable future I don't have access to a booth.

Clearcoat was the only product that had isocynates in it. So we wore full body suit & hood with fresh air pumped into the hood. Our school was particular about following OSHA, EPA, NIOSH safety regulations and using best practices to repair/refinish vehicles.



Now regarding sheetmetal enclosure panels or sheetmetal machine bases : Do rebuilders typically powdercoat them?
 
Thanks for that write up.

At Tech school, we only used two part Primer Filler (aka Primer Surfacer) and two part Primer Sealer. Ratio of 4 parts Primer to 1 part Activator.
The Primer Filler/Surfacer is Nason 2K Urethane (made by Axalta , formerly Dupont) . It is a High Build primer.

I would prep and paint equipment with chipped paint using best practices, simply because it would be something I enjoy doing and I am Obssessive Compulsive about details. Anything I would paint in the future would be with an HVLP gravity feed spray gun in a proper downdraft booth. For the forseable future I don't have access to a booth.

Clearcoat was the only product that had isocynates in it. So we wore full body suit & hood with fresh air pumped into the hood. Our school was particular about following OSHA, EPA, NIOSH safety regulations and using best practices to repair/refinish vehicles.

Now regarding sheet metal enclosure panels or sheet metal machine bases : Do rebuilders typically powdercoat them?

Yes I love those high build primers too. That's what I used on the machine in the picture and others in the past.

The two part urethanes have isocyanates in the hardener.

The following refers mostly to semi-modern CNC and some manual equipment work, not antiques or manual hobby stuff.

I don't know if rebuilders working as a profession use powder coatings. I may be wrong, but I don't think they get into ground up rebuilds that include anything other then slap on paint jobs to make it look good to sell. Fix what's not working. At least the worst of it. Maybe redo the Turcite and scrape something in. Slap on some paint and stick a price on it. Seems most of the hard core rebuilds are people doing something for themselves.

I mentioned powder coating and paint burn off because in my experiences it is by far the best results for the least amount of work and money. Better then even the best planned and executed at home attempt. I say this from experience. You're not the only one who can be a little fussy. Besides these paints I speak of will cost you over a hundred bucks a gallon when you add in the hardener and solvents. The paint burn-off is dirt cheap and the powder coating totally reasonable. Why fight it? But it's great you got a handle on the skill set needed for painting the stuff that's tough to send out.

Dave
 








 
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