On 05/02/2020 09:55, polygonum_on_google wrote:
On Wednesday, 5 February 2020 08:49:17 UTC, harry wrote:

The Hammerite is rubber based. I'd put the varnish on first.

The MSDS for brushable Hammerite says nothing about any relation to
rubber.

The product description is: Styrenated oil modified alkyd containing
organic, inorganic pigment, aliphatic and aromatic solvents.

https://www.farnell.com/datasheets/45976.pdf

It is a cross linked cure on setting as it dries polymer formulation
that once fully cured is probably impervious to most solvents as far as
being dissolved again but it will swell up with organic solvents.

There is a warning to recoat inside the cure window when it will still
bond to itself or waiting until after allowing a full cure. Repainting
in the interim period tends to be disastrous with the under layer
deforming and swelling up through absorbing solvent from the next coat.
In cold weather you need to allow a lot more time for a full cure.

I would have expected any rubber-based product to mention the fact in
the MSDS due to the issues of latex allergy.
There may be a plasticiser in the mix but nothing like a rubber latex.

--
Regards,
Martin Brown