Shellac Glue

[gordrob]

Does anyone have a recipe for making a shellac glue using shellac flakes and 99% isopropyl alcohol. I have taken the bezel off of a Mamiya Press Super23 and now need to reattach it. From information I have been able to find tells me that the metal bezel was originally attached to the body using Shellac glue. The one article I have found recommends 1 gram of shellac flakes to 4mm of denatured alcohol. I have tried this using 99% isopropyl alcohol instead of the denatured alcohol but I couldn't get it to work. Does anyone have a method of making a glue from the Shellac flakes. The reason I want to use the shellac glue instead of a hot glue or contact cement is to be able to remove again if I have to by using a heat gun.

 

[F4U]

If I'm not mistaken denatured alcohol is actually ethanol like gin or everclear liquor, with poison added to it so that it doesn't have to be taxed like liquor. That;s what you're supposed to use. Although I don't know what difference it makes. But obviously it does. And don't expect it to dissolve the shellac flakes right away. It can't NOT work.

 

[ags2mikon]

And whatever you do, DO NOT pour the denatured alcohol into old vodka bottles.

 

[bdial]

If you can get 190 proof vodka, it should work and avoid the denaturing agents in hardware store alcohol.
This would work too, but it’s pricey for 1 project, https://www.leevalley.com/en-ca/shop/tools/supplies/finishing/solvents/20107-shellac-lacquer-thinner

Hide glue should be a reasonable substitute, you can undo it with modest heat. It’s available pre-mixed in small bottles, most hardware stores should carry it, I’d expect that Lee Valley’s will certainly have it.

There are lots of different grades of shellac, for using it as a glue, I would think you would want blond or “super-blond” dewaxed flakes. The grade you’re using probably influences what solvents would work well.
I have a bag of shellac flakes for some wood finishing projects, but I’ve not actually used it yet. I bought a bottle of this stuff, https://fiddes-usa.com/shop/accessories/chemicals-solvents/thinners-acids-bleach/finishing-spirit/ which seems to be similar to the product Lee Valley sells, but I don’t know what the availability would be like in Canada.

 

[reddesert]

Shellac is used as a cement and a finish for various things. The uses that I'm familiar are related to musical instruments: it's used as a finish for wooden instruments, and it's used as a cement for gluing pads into woodwinds (saxophone, clarinet). In that use it is often melted rather than dissolved in alcohol. There's lots of information out there, google "shellac cement alchohol" for example. I think any reasonable denatured alchohol (ethyl alcohol) should work. You should just be able to put some shellac flakes into a jar and drip some ethyl alcohol in and mix it around, adding alcohol until you get the desired consistency. You can soften it with a heat gun or mild heat like an alcohol lamp.

There is no need to avoid the denaturing agents in hardware store ethyl alcohol. Those just make it impossibly bitter so you can't drink it and make moonshine without paying tax.

You should be able to use any color (blond, dark) as cement IMO. I suppose dewaxed is better although I thought the waxed vs dewaxed issue was more relevant for people using it as a finish.

Anyway, I might just glue the part on with a little bit of contact cement, but shellac is likely superior for removal and repositioning, that's why it's used on woodwind pads. It should work, so keep trying with the proper solvent.

 

[F4U]

I remember studying about shellac a year or 2 ago, and learned that it has an expiration time, where in raw form or mixed. It goes bad and just doesn't mix or dry. I'm familiar with this camera and still don't know what the OP mean by the term "bezel'. Exactly what part is being called the bezel?

 

[gordrob]

The bezel is the front metal piece above the name that act as a support for the focusing glass.

 

[F4U]

Ohhh.. I bet a wee dab of ordinary contact cement would be fine for that.

 

[Kodachromeguy]

I have used shellac on new wood used as house siding to seal knots. Then the oil or sap will not bleed through the paint over time. But oil based primer works almost as effectively.

 

[gordrob]

Ohhh.. I bet a wee dab of ordinary contact cement would be fine for that.

But will I be able to get the contact cement to release without damaging the bezel if I need to access viewing lenses again. That is why I am leaning towards the Shellac glue.

 

[Dan Daniel]

But will I be able to get the contact cement to release without damaging the bezel if I need to access viewing lenses again. That is why I am leaning towards the Shellac glue.

Elmers glue might be a good choice. It acts a bit like shellac in this kind of use, including dissolving in alcohol for removal.

 

[Ian Grant]

I use French polish quite a lot for vintage camera restorations, essentially I mix flake shellac with Isopropyl alcohol or Methylated Spirits (denatured alcohol)/ Usually I fill a small plastic bottle loosely full with flaked shellac the add the alcohol then screw on the top and place in hot water, until the shellac has dissolved. This is too thick and sticky to use as French polish. For use as a glue you want it slightly thicker than treacle. I use old acrylic paint bottles, the top lifts like a ketcup bottle top allowing small amounts to be poured at a time. I dilute into Fuji 35mm film cans for use as French polish.

Blonde shellac would be best, it has the least colour.

Ian

 

[ags2mikon]

You could use a few small dabs of rtv silicone and if you need to remove it later you can use fishing line to cut through it. I've done that for other things.