I contracted a wallpaper hanger to cover sections of a painted contruction hoarding with custom manufactured graphics. He then applied a coat of acrylic varnish to seal the graphics. Looked fine while wet, but two days later the varnish is severely yellowed and shows massive streak marks throughout the finish. Anybody have an idea of what has happened to cause this? graphics were applied on a bright sunny day and were allowed to dry overnite, plywood (graphics only cover a small portion of the hoarding; so the painted surface is visible as well) was prepainted several weeks before, varnished next day, again sunny day no rain or excessive humidity
Any help would be appreciated
Thanks
Robert
Replies
might want to ask this over at Knots, where the gurus of finish drink their tea with their pinkys pointed out....
I do enjoy tea, but in a mug (ha!)
Varnish always has an amber tone when dry.Only water-based finish or nitro lacquer offers super-clear finish. IMO, it was a bad idea to apply varnish to custom graphics or wallpaper cuz most digital printers these days,including production ones, come with a protective satin or gloss finish for this purpose.
What's "hoarding"? I thought it was a typo but then you used the word twice. My definition of hoarding involves "To gather or accumulate a hoard, a cache"
Aside from that we also apply an acrylic finish to protect stenciled walls or walls which will be exposed to abuse. Oil finish always ambers. Most of the time we test it for material compatibility first. I know that doesn't help you now.
There may have been a reaction with the adhesive used to apply the hoarding(?). If wallpaper adhesive was used, I am guessing that the paper hanger applied adhesive to the wall and the decal and then applied it to the wall. How was the excess cleaned off? If ALL of it was not removed, the action of brushing or even rolling would have been enough to dissolve the excess adhesive and react with or color the acrylic finish.
The other possibility is that some of the color from the decals dissolved into the finish.
Ya know, I'm lost. I just reread your post to be sure I addressed everything I could. You write regarding hoarding and plywood and graphics... I need more/ clearer info.
F.
Hoarding is also fencing, barrier, screen, etc that surrounds a project... such as plywood boards/fence that surround the exterior renovation of a building in a pedestrian traffic area.
Acrylic is very clear. Basically plexiglass in either solvent or a water-based binder. Not good so far as long-term exterior durability, but one of the clearest. I've never known it to yellow. Did it yellow over the paint or just over the graphic? I'd suspect that it soaked into the paper (the graphic is on paper?) and made it transparent enough to reveal the glue and surface underneath. There isn't any fix that I know about. When I do varnish over paper, I spray a couple very light coats first. Seal the surface without enough to soak in. Once it is well sealed, then I apply a heavier coat for protection.
hoard
hoard [hawrd] intransitive and transitive verb (past hoard·ed, past participle hoard·ed, present participle hoard·ing, 3rd person present singular hoards)
store a supply of something: to collect and store, often secretly, a large quantity of something such as food or money for use in the future
noun (plural hoards)
secret store: a store of something such as food or money that has been hidden for use in the future
[Old English hord . Ultimately from an Indo-European word that is also the ancestor of English hide and obscure .]
WORD KEY: SYNONYMS
See Synonyms at collect
What are you talking about?
Webster's 1913 Dictionary Definition: Hoard"ing, n. [From OF. hourd, hourt, barrier,palisade, of German or Dutch origin; cf. D. horde hurdle,fence, G. horde, h["u]rde; akin to E. hurdle. [root]16. See{Hurdle}.]1. (Arch.) A screen of boards inclosing a house and materialswhile builders are at work. [Eng.]Posted on every dead wall and hoarding. --LondonGraphic.2. A fence, barrier, or cover, inclosing, surrounding, orconcealing something.
My software is inadequate, and my education has not done well at making up for it.Les Barrett Quality Construction
Don't feel bad. Did you notice Webster's 1913 Dictionary ?
You are just not old enough.
I learned that term about a year ago from an archy; at first I thought it was a typo, boarding instead of hoarding.