Gold Leaf for an Exterior Door

Advice on prime coats and a top coat for gold leaf on a door. March 26, 2009

I am finishing some exterior doors with ML Campbell Euro X. It is my intention to stain and seal and then do a traditional gold leaf application which consists of a base coat of yellow enamel and then the slow dry sizing followed in 12 hours by the gold leaf, finally top coating with the 2 K polyurethane. What do you think? Do I have any chance of success? We have done gold leaf lots of time using varnish as a top coat but never this combination. Does anyone know of a resource that I can study? I was thinking to try to use the sealer to stick the gold down with.

Forum Responses
(Finishing Forum)
From contributor A:
Gold leaf doesn't have to be top coated.

From contributor R:
Like contributor A says it doesn't have to be top coated but if you want to bury it in the finish like an automotive application then you can do it. I haven't used the Euro X so I would suggest making a sample and then doing an adhesion test over the gold leaf. When doing interior work I use an isolante over the gold leaf before my build coats.

From contributor S:
Gold leaf doesn't have to be top coated but on an exterior environment it would be best to top coat. Also, unless you use at least a 23k, the gold will tarnish eventually unless you top coat it.

Technically, you should be able to use the sealer as your adhesive but I would guess it would be very tricky to get the leaf on at the correct drying time of the sealer as your sealer is not going to have anywhere near the same open time as a gold size. Any adhesive can be used to put down leaf, its success is dependent on the critical state of it being almost dry but still tacky (wet will ruin it).

As for adhesion, the leaf has about a gazillion micro holes in it, so your top coat should adhere to the sealer underneath. However depending on your sealer (catalyzed or not) you could have nothing but a mechanical bond once it is dry, which it will need to be before you rub down the gold and topcoat, so that is most likely to be a problem. Also, it would be tricky to catch it at the correct dry but tacky point as your sealer won't have the same open time as a gold size. I doubt there is any resource dealing specifically with the system/products you are looking to use.

I have never used a 2k over leaf or any catalyzed product, but I have used an acid cat adhesive (Hxtyl NYL-1) to put down leaf without any problems. Whatever you do, definitely do as contributor R stated and make a sample first.