Sealing Oily Cast Iron for Painting
 

I am doing a rebuild on my lathe and I am having some trouble with
oily spots of the casting. I have tried heating and cleaning
repeatedly, but it wicks oil and the paint won't adhere. Can anyone
suggest a way to deal with this? I seem to recall a sealer of some
sort that would serve this purpose well, but can't find it from
google.

Also, as a side note, I had my lead screw reground and had new half
nuts and a new worm gear made by REMPCO for less than $700. I was
very pleased with all of my dealings with them and the quality of
their work. I am also replacing my compound screw and half-nuts with
a precision ball screw. I got it with oversize balls to reduce the
backlash to ~.001 and as I will be using a DRO, the .003 per foot
accumulated error in the screw was not a big deal to me. Just passing
this along as food for thought for others.

Sealing Oily Cast Iron for Painting
 

Joe wrote: (clip) Can anyone suggest a way to deal with this?
^^^^^^^^^^
I am pretty sure that shellac will solve your problem. There is also a
produce called "Bulls Eye", which is a white pigmented shellac based sealer
that ought to work.

Sealing Oily Cast Iron for Painting
 

You might try pressure washing the parts to remove the excess oil. Some of
our customers do this after they machine the castings. They probably use an
emulsifier in the water. When we have a local oil spot on a casting, we use
spray cans of degreasers. They are products manufactured for NDT work, to
remove red dye penetrants and/or UT coupling greases, etc.

I don't know how big the casting is, but if you could find a local service
that would vapor degrease the castings all the oil should be removed.
That's another process that would be a little more costly but more thorough.

You don't mention the type of paint you are using, but all the machine tool
manufacturers we have made castings for (Milacron, LeBlond (and Makino),
Hitachi, Okuma, Toyoda, Monarch, Mazak, Gleason, etc. ) want Polane type
coatings. These are the best for machine tools. They are also often used
on other industrial machinery for which we make castings.

Mark Fields


"Joe" wrote in message
om...
I am doing a rebuild on my lathe and I am having some trouble with
oily spots of the casting. I have tried heating and cleaning
repeatedly, but it wicks oil and the paint won't adhere. Can anyone
suggest a way to deal with this? I seem to recall a sealer of some
sort that would serve this purpose well, but can't find it from
google.

Also, as a side note, I had my lead screw reground and had new half
nuts and a new worm gear made by REMPCO for less than $700. I was
very pleased with all of my dealings with them and the quality of
their work. I am also replacing my compound screw and half-nuts with
a precision ball screw. I got it with oversize balls to reduce the
backlash to ~.001 and as I will be using a DRO, the .003 per foot
accumulated error in the screw was not a big deal to me. Just passing
this along as food for thought for others.