Back up paint for mirroring

[Roderick Treece]

I am trying to come up with a list of back up paint for mirroring.Here the list so far.Some are from Sara King and some are from me.

1. Sericol by itself is fine. Sericol with One Shot Hardener added destroys Copper and Galena mirrors. Ok for Silver and Gold.
2. Shellac is the same – it oxides copper and galena ok for silver and gold. Very bad if you are going to cut the glass after mirroring since it peels off (too bendy)

3. Gray and Black Roll Coat are made by a mirror paint manufacturer and the only ones on your list that are Official
4. Asphaltum – ok for all mirror types. As we all know, it does not ever really dry hard.
5. Rick’s Back-up Black, I have been told, is Sericol. I don’t know if Rick added the Hardener.
6. I think that Bruce Jackson in Australia uses Nazdar screen printing ink with some success.
7. I have a customer who uses blackboard paint on silver. I’m going to investigate this further but I haven’t yet.
8. Also Permalac (clear and black) works very well. All of my blown glass customers use Permalac because it is thin and can be poured into the blown glass.

Roderick

[DAVE SMITH]

I think the best paint to use Roderick is the Italian Mirror backing formula from Fenzi.
They do have a works in Canada so it may be worth you checking it out.
The paint is expensive and has only a shelf life of around a year I think.
You may want to buy this paint as a group purchase to keep the cost down.
This paint which is grey has the copper in it already.Trust me once you use this nothing else is close.
its a minimum order for this product,if you order it yourself you would need to be manufacturing mirrors day and night.
I bet Larry and a few others would be interested. I buy mine from a mirror manufacturer here who sells me a smaller amount of this paint.
Check there website out
http://www.fenzigroup.com/inglese/internaz.asp
Hope this helps
Dave

[Roderick Treece]

Thanks Dave,
I will contact them Monday.Tell us a bit more about this paint.

What type of solvent does it use?

Application,brush,roller,screen print,Bright lining,?

Consistancy from the factory?

Can you use it over a mask?

Roderick

[DAVE SMITH]

The solvent to be used is Xylenes thinners This backing paint is a traditional product. I was using this same paint back when I started in 1990 and buying it from Kemira coatings in Wales the company has since closed, the only difference with this paint is that it contains the copper and is grey.
You can use it over mask and it peels beautifully.Roller is what I use not sure on screening but spraying probably fine and brushing also.
Factory consitency very good.

good luck!
Dave

[Danny Baronian]

Rod,

the gray back up paint sounds like what Sarah sells, and sounds like what Dave describes.

Needed to back up a mirror one night, had the paint from Sarah and discovered it needed.... xylene to thin which I didn't have - after the stores were closed. The paint's on the thick side. Using a roller to apply over a mask, it dried quickly, mask came off clean and seems very durable.

Danny

[Roderick Treece]

Yes it does sound like the same thing.That is what I use when rolling ut larger areas and over masking.

What would be concidered a good back up when doing

1)bright lines with a fine sign painting brush
2) screen printing

Back up paint using Xylenes are way to HOT to use for screen printing it would seem.

Roderick

[Robert Schwieger]

Hello. I have a question regarding the backing paint described above. "What solvent/remover is needed to remove this backing after it has dried and cured?"

Thank you for the great information provided on this sight. Bob

[Roderick Treece]

Robert,

I use acetone or laquer thinner for everything EXCEPT new commercial mirrors.For those I would use any paint striper.

Question,
Starting with a commercial new mirror,masking a design on the back,stripping off the backing right up to the masked design leaving a clean edge.
What type of mask and stripper will work together?

Right now I am looking for a stripper that will work on commercial mirrors but will not melt a mask off with it.All the strippers I have tried eat what ever mask I have off so I have not been able to strip the backing off right up to a masked design.


Roderick

[Danny Baronian]

Rod,

to answer... or confirm your question / thought.... xylene will reactive any type of paint it touches, unless a shellac barrier has been applied. The gray back up paint is too thick to screen and dries too fast.

As far as finding a mask that will hold up with stripper, I don't think one exists, unless Pat makes one up .... in his next lifetime. Jasco paint and epoxy stripper works well.

The best you'll be able to do is either strip the backing off the mirror completely, or selectively. Once the back up paint is removed, apply the mask and use silver strip to remove the silver, which will not degrade the mask. I thought sandblast resist would work well, but the weakness is in the adhesive; stripper will attack the adhesive.

Danny

[Patrick Mackle]

How about the Peacock brand product for mirror backup? I don't know what their current product is like, but I have 2 sacred gallons of their backup from the early 60's.
It is THICK with heavy solids and medium gray in color and the solvent odor will knock your socks off and seat your arse at the Mad Hatter's tea party if you work too closely with it. Combined with the orange shellac- a guaranteed euphoric mirroring session!
This early Peacock paint is super tough. It contains xylene and toluene. I wonder if the current paint being sold is at all the same.
Pat

[Patrick Mackle]

Rod,

to answer... or confirm your question / thought.... xylene will reactive any type of paint it touches, unless a shellac barrier has been applied. The gray back up paint is too thick to screen and dries too fast.

As far as finding a mask that will hold up with stripper, I don't think one exists, unless Pat makes one up .... in his next lifetime. Jasco paint and epoxy stripper works well.

The best you'll be able to do is either strip the backing off the mirror completely, or selectively. Once the back up paint is removed, apply the mask and use silver strip to remove the silver, which will not degrade the mask. I thought sandblast resist would work well, but the weakness is in the adhesive; stripper will attack the adhesive.

Danny

I might approach this selective stripping from a different angle. Take a block of beeswax and rub it like a crayon on the mirror paint area that you intend to strip. Allow it to build up to an even layer. Then apply your stencil mask sheet and burnish onto the wax. The beeswax will actually now be the material that adheres the mask to the mirror backing. Weed, or cut and weed out the stencil where the mirror will be removed. Then carefully take a cotton rag moistened (don't saturate) with petroleum thinner and wipe away the exposed wax where you intend to strip. The beeswax should withstand the stipper, even if the mask ripples up. The mask is really only intended to be the stencil for the beeswax resist.
Pat

[Danny Baronian]

Pat,

I think the gray back up is is all one and the same.

You need to wear respirator when you open the can, or hold it at arms length! Your right, it's got a potent smell.

Danny

[Roderick Treece]

Regarding what type of tape to use.New testing has shown that paper based tapes are working the best standing up to strippers.I did call my 3M rep and found a tape used for stripping paint off aircraft.Great I thought until I asked how much.
1 1/2" roll 66.00 each
21" 800.00 2 roll minimum

OHch!

They do make a solvent resistant 2040 so I might try that.

Roderick