Ed Huntress wrote:
On Wed, 25 Apr 2018 10:03:37 -0500, shiggins1
wrote:

On 4/25/2018 8:24 AM, Ed Huntress wrote:
On Wed, 25 Apr 2018 13:06:04 +0000 (UTC), David Lesher
wrote:

" writes:


The citrus based solvent has its uses. Does not evaporate
quickly so good on dried grease, old paint etc. But not great
for cleaning before gluing.
Dan

I use starting fluid (OUTDOORS..) for cleaning that leaves no residue.
I don't know what the different brands may contain (I use straight
ether for starting), but avoid anything that contains acetone.

Pure acetone is great for adhesive prepping, but getting your hands on
pure acetone is not easy. The stuff they sell in cans in hardware
stores is almost always recycled from industrial users, and it usually
contains some oil. It has been the source of many bonding failures by
home boat builders.

After reading your post Ed, I looked at the can of acetone that I have.
It does not have an ingredients list, insinuating "pure" acetone.
There's no statement of purity either.
I've had some paint failures that I blamed on poor prep techniques.
Using acetone for prep often allows me to wipe the old coat of paint
away without scratching the part. I've gone back to using alcohol to
wipe the part down before painting. Oil in acetone could explain it.
I'm going to contact the manufacturer on the can for comment since I
bought it at the Borg. Stay tuned...

Steve

Here's an interesting claim from TAP plastics -- "Our Acetone is
virgin acetone and is not made from recycled acetone. It does not
contain any residual waxes or oils."

https://www.tapplastics.com/product/...tap_acetone/11

Acetone sold in hardware stores is almost always "industrial grade,"
which is the stuff that contains small amounts of contaminants.

Apparently there are ways to recycle it to remove all of the
non-volatiles, but it's pretty well known in the boatbuilding business
that hardware-store acetone is corrupted with non-volatiles,
especially lubricating oils, and that it can't be used to prep cured
polyester resins for laminating. When surfacing polyester cures (and
all of the resin sold in hardware stores is surfacing resin) a waxy
layer rises to the surface to seal it from the air, and that gets into
acetone, too, when you wipe the layer down to laminate on top of it.

(There's no need for it with epoxy prep; just wash with warm water and
detergent, like real TSP.)

It's too bad, because acetone is a great cleaning solvent, and safer
than a lot of others. It's just that the common grade can present
problems when you need a really clean surface.


Paint shop I worked at ran a "still" that was designed to reclaim the
acetone we used during production. Worked OK but you never got 100%
acetone out of the system. It worked OK for thinning and such but you
could tell it was a blend.

--
Steve W.