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Mill repaint - paint of don't paint mating surfaces?

Paul G

Plastic
Joined
Apr 16, 2013
Location
USA
I'm painting a CNC mill after dissassembly and cleanup.

The question i have is to weather to paint the mating surfaces (machined surfaces) or not to.

These are parts like servo motor mounting adapters that bolt to the bed and servo, or ball srew bearing housing parts.

So essentially it looks like the machine was originally all put together dry (no coating) and then primered and painted in assembled condition.

But when piece mealing the machined back together it makes more sense to paint the parts first then bolt together as i can't deal with the entire machine at once.

I know the concern is painting mating surfaces will lead to a change in parallelness when assembled (different paint uniformity).

On the other hand it makes it easier to paint the entire object rather than tape of the interface.

Any thoughts on this - what do most people do when repainting a machine?

Thx

Paul
 
I'm painting a CNC mill after dissassembly and cleanup.

The question i have is to weather to paint the mating surfaces (machined surfaces) or not to.

These are parts like servo motor mounting adapters that bolt to the bed and servo, or ball srew bearing housing parts.

So essentially it looks like the machine was originally all put together dry (no coating) and then primered and painted in assembled condition.

But when piece mealing the machined back together it makes more sense to paint the parts first then bolt together as i can't deal with the entire machine at once.

I know the concern is painting mating surfaces will lead to a change in parallelness when assembled (different paint uniformity).

On the other hand it makes it easier to paint the entire object rather than tape of the interface.

Any thoughts on this - what do most people do when repainting a machine?

Thx

Paul

No

Apply a light coat of lithium grease and assemble. Other's may have a better suggestion of what grease or rust inhibitor to use. Google [Fluid Film]
 
No

Apply a light coat of lithium grease and assemble. Other's may have a better suggestion of what grease or rust inhibitor to use. Google [Fluid Film]

This.
Those surfaces rely on being clean for precision.
Would you paint your tool holders before sticking them in the spindle?

As he says, everyone has their magic lube rust preventer.
I like marine bearing grease.
 
:skep: we really need a *forehead smack* smiley.

Or a "newbie" filter. :eek: We were all newbies once and I, for one, don't mind answering questions and helping
others out but I think that someone who intends to get into machining should display at least some level of
common sense before plunging in. When assembling any machine making sure that mating surfaces are free of
burrs, chips and paint is very basic knowledge. I suspect that this "rebuild" is only cosmetic in nature without any
real thought as to function...
 
On the other hand it makes it easier to paint the entire object rather than tape of the interface.

Any thoughts on this - what do most people do when repainting a machine?

Thx

Paul

It's easier yet to just scrap it and not have to even BUY the paint, let alone USE it.

WHEN we see a machine where surfaces not MEANT to be painted WERE painted?

No one with any sense will buy it. It's proof an opportunistic FUCKWIT had his hands on it, therefore NOTHING ABOUT IT can any longer be trusted. All we do is JOKE about it! Examples are all OVER PM.

There might be rust, steel wool and glue, chicken-wire & Bondo, Devcon plastic, soft-solder, or even ignorant Plaster-of-Paris under that paint.

You want to be tarred with the same brush - spray-painted with the same rattle-can - as an opportunistic Fuckwit?

Don't bother masking, and you are a member of that tribe, automagically, no effort required.

The pride of doing even SIMPLE shit correctly? That requires at least a smidgen of actual EFFORT.

Your life. Your parts. YOUR choice which tribe to join. Craftsman. Or fuckwit.

Can't be helped. Just Deal With That.

Capiche?
 
Last edited:
MODERATOR PLEASE DELETE THREAD:

REQUEST IS FOR A MODERATOR TO DELETE THIS THREAD COMPLETELY. I DO APPRECIATE THOSE THAT HAD A HEPFULL REPLY - I'll stop at this point.

Best eyes,

PAUL
 
MODERATOR PLEASE DELETE THREAD:

REQUEST IS FOR A MODERATOR TO DELETE THIS THREAD COMPLETELY. I DO APPRECIATE THOSE THAT HAD A HEPFULL REPLY - I'll stop at this point.

Best eyes,

PAUL

You have had a face full and now want to pull back the shades? Weak!

Paint is Not a useful interface material between precision components.
 
Its ok to paint if you use precision paint on those precision surfaces, any machine dealer should have it in spray cans or gallon buckets.
 
Heh.

This is like the time they painted the Moore jig borer at work. Including all the way surfaces.

Never saw a modelmaker curse like that before.
 
Not to hijack the thread (which I guess doesn't matter at this point anyway) but what about bolting painted machine parts on areas that aren't high precision? Do they tend to be impossible to disassemble if they are bolted together with a lot of force?
 
Not to hijack the thread (which I guess doesn't matter at this point anyway) but what about bolting painted machine parts on areas that aren't high precision? Do they tend to be impossible to disassemble if they are bolted together with a lot of force?

World is full of "non precision" stuff done that way. Some asembled still gummy, some bone-dry. Paint "skins" linseed-oil era were intentionally used as sealants, pre-loctite days.

Surely you've seen it where some of the paint sticks to one surface, some to the other?

Raggedy appearance, but no significant adhesive effect - not on "flats".

Tubes or shafts or posts in hole, yah, PITA maybe. Even so, better than RUST, (it expands..) same joint

Force usually shears right in the paint line. Weakest component, usually.

Plastics? Roll yer dice... Paints ARE a form of plastics, mostly. Not impossible to have one that polymerizes AKA "cross links" to stronger than the plastic it was applied to.
 








 
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