The Framers Forum

I'm repairing a pair of very old gilded frames, where the gold has been darkened with bitumen, (a favorite with the victorians I think). I've tried matching it in without success, so I need to make up some bitumen glaze. I assume it's a mixture of bitumen paint and french polish, but I don't actually know for sure. Anyone know about this?
Cheers,
Mark

This any good???



(Edit) Hmmmm maybe not! Maybe a good frame filler though! Must check it out - screwfix probably!

We call the material Asphaltium (asphalt) on this side of the pond.

Powdered form can be found in shops catering to print makers (Intaglio) It is the same stuff that is used to tar roofs and pave roads.

Or get some (liquid) from a home center.

simply thin with mineral spirits (paint thinner)

Jerome

When I've used bitumen in the past, and just diluted it with white spirit, it didn't
stay fixed very well after the spirit evaporated.
Any suggestions for another further additive to stop it coming off?

Paul Hardy

Yes, the material is soft.

I do not have any real answer other than an overglaze of polyurathane or equiv. I do not like the way the overglazes look - my top coats are generally paste wax or shellac.

My hand made frames always have a caution - "do not clean with anything wet - dust with a duster only"

My expectation, not from experience, is that oil based paints and glazes thinned with white spirit are not likely to successfully adhere to gold. This is why I assume french polish or shellac is likely to the media to which a much smaller quantity of bitumen is added.

I don't know whether we are talking about real bitumen or a bitumen coloured paint. I do know that bitumen, was at one time available as an oil paint colour as some of the pre-raphaelites used it. I don't whether there still is such a paint, but when I get the chance I will check it out.
Cheers,
Mark

many years ago I worked as an artist in a gravure repro company - the etchers used to paint out the gravure cylinders with bitumen paint. I think it was thinned with Toluene - A chemical that i suspect is now banned for its carcinogenic tendencies. If it wasnt Toluene then it was probably acetone. The paint could be thinned down to a very watery consistency and wouldnt wash off easily.

oil based glazes such as asphalt and japan colors will adhere to gold.

Problem solved! I tried various things which didn't work, but I remembered I had an old tin of Liberon black patinating wax tucked away in a cupboard somewhere. It took a long time to locate it, but it was worth the effort. I mixed this wax about 50/50 with black bison dark oak wax and got a perfect colour match. Looks o.k. now! Thanks to all.

BTW, I have since discovered that bitumen glaze does has not usually contained bitumen for a long time, according to a retired framer friend, who informs me that in the 1950's it was made with Van Dyck brown and lamp black pigments and applied over gold suspended in a mixture of traditional varnish (blackfriars is the nearest modern equivalent) and shellac. Apparently, it is not very easy to use and needs to practice and skill to get the right result.
Cheers,
Mark

Now you've found your black patinating wax Mark, use it more.

Try a black spirit based stain on ash and finish with black patinating wax.

Glad you got your job done ok Mark.

My finisher uses bitumous black from the hardware store, a small tub, putty like consistancy, goes a loooonnng way.

Dilute a small blob with methylated spirits (I think) to whatever consistancy you like.

It really makes a pale-ish gold go very much richer looking colour.

Pic here . . .



We go over this with a 70% gloss clear lacquer to protect.
This coating is heavier than we'd use to say give a new finish an old look (along with crackling / wax techniques etc).

Yes, most times you could get the same effect with dark wax, especially if your frame has some 'character' to it.

Hi Les,

I think yours in the answer I was looking for. The frame in question not only has the brown colouring, but in some places it is thicker and looks almost black. It's hard to explain what it looks like, but it looks seriously old, which is what the customer wants to be kept. I will try out your technique on something else in the not to distant future.
Cheers,
Mark

Yep, looks good by itself, but when combined with a crackle medium, clear, and dark wax. well . . .
Looks absolutely aged !

John (robo) with his art / craft knowledge probably knows / supplies the sort of crackling I'm talking about.

Taking pics today of the latest frame we are turning out, large chunky traditional style. Aged gold paint, and antiqued silver convex mirror fitted, looks 100+ years old !