Home Forums The Learning Center Studio Tips and Framing does alcohol absorb water from the air?

Viewing 15 posts - 1 through 15 (of 15 total)
  • Author
    Posts
  • #984428
    colin
    Default

        I was having a lot of trouble with bloom in shellac and finally figured out the can of alcohol i was using to make it with was contaminated with
        water .

        Does anyone know if alcohol will absorb water from the air — my shop is really humid — or did i just get a bad can ? Should i stop buying the big, cheaper half gallon cans of alc. ?

        thanks,
        Colin

        Littlefield Gallery, Winter Harbor, ME[/url]

        Colin Barclay Blogspot[/url]

        #1035491
        dcorc
        Default

            Yes, alcohol does absorb water from the air – it’s very hygroscopic – anhydrous copper suphate (for example) may be used to remove water from it.

            Dave

            #1035490
            JamieWG
            Default

                Colin, alcohol is commonly diluted with water. The alcohol I bought in the pharmacy states that it is 91% isopropyl alcohol; the remainder is water. Perhaps there is some way you can obtain 100% alcohol.

                Jamie

                Hudson Valley Painter[/url]
                Hudson Valley Sketches -- Reviews/Lightfastness Tests/Art Materials
                [/url]
                One year from now, you'll wish you had started today.

                #1035483
                colin
                Default

                    Thanks Dave ,
                    I dont suppose anhydrous copper sulfate is a readily available thing ? Is this the same as copper sulfate in Blue Vitrol — what they used to use for killing algea on farm ponds ? My dad used it too in toolmaking for putting a thin copper coating on press-fit machine parts to make em
                    tighter .

                    Hi Jamie,
                    Isopropyl is a different animal –im talking about denatured alcohol from the hardware store –grain alcohol wih wood alcohol added so’s ya cant drink it or make bathtub gin from it . ( at least not without going blind ! )

                    Its not sposed to have ANY water in it, since its used for cutting shellac and water makes the shellac cloudy or even opaque white ( bloom ) . You could also use pure grain alcohol like Everclear from the liquor store but thats a pretty pricey way to go …

                    Littlefield Gallery, Winter Harbor, ME[/url]

                    Colin Barclay Blogspot[/url]

                    #1035492
                    dcorc
                    Default

                        Thanks Dave ,
                        I dont suppose anhydrous copper sulfate is a readily available thing ? Is this the same as copper sulfate in Blue Vitrol

                        Blue copper sulphate pentahydrate crystals can be dehydrated to the anhydrous form (which is off-white) by heating – you could put a tray of it in a low oven.

                        Dave

                        #1035496
                        CarlyHardy
                        Default

                            I use denatured alcohol in painting with my pastels, but have never noticed any water problem with it, but I keep it tightly sealed in its metal can except when pouring out a bit into a glass jar for use.

                            Is it possible that your container was wet inside before you added the alcohol or perhaps your brush was wet?

                            carly

                            #1035488
                            Arsinoé
                            Default

                                It is not possible to have a 100% alcohol in normal room conditions.
                                Commonly sold is 90% and 70% alcohol, the rest of the percentage being water.
                                The 70% one is about stable, the 90% one will go to 70% as soon as the can is opened and there is some humidity in the air.
                                Do you really need a more than 70% alcohol?
                                It seems surprising that is should be required as these characteristics are well known by every chemical manufacturer.

                                http://www.annaigart.blogspot.com
                                It is a very sad thing that nowadays there is so little useless information. - Oscar Wilde

                                #1035493
                                Enchanted
                                Default

                                    You could also use pure grain alcohol like Everclear from the liquor store but thats a pretty pricey way to go …

                                    I don’t think that “100 proof” is the same thing as “100 percent.” :rolleyes:

                                    #1035484
                                    colin
                                    Default

                                        Hi Arsinoe,
                                        I just want shellac thats transparent … i guess ill just buy small cans
                                        of it .
                                        Jaxas – everclear is 200 proof which would be 100% ( theoretically ! ) alcohol . God knows why anyone would actually try and drink the stuff — i guess the answer would be in an AA forum.

                                        Littlefield Gallery, Winter Harbor, ME[/url]

                                        Colin Barclay Blogspot[/url]

                                        #1035486
                                        Patrick1
                                        Default
                                            #1035489
                                            Arsinoé
                                            Default

                                                And that’s a commercial indication, not a chemical one.
                                                Cherry liquor would be a good idea to use it ;).

                                                Now, what I said is what I learnt in chemistry.
                                                If someone sells you alcohol at 99.99%,perhaps it is really so, but in any case, you should open the can and use it immediately, then never use it again if you want it without water.
                                                Perhaps shellac stops the absorption of water by alcohol, and in the case of immediate use of this alcohol to dissolve it, it will stay clear?

                                                Did you try to let the diluted shellac stand for several days before using it?
                                                I’ve found a french site that recommend it.

                                                Another reason for lack of transparency would be the shellac quality.
                                                This page, in french, contains a photo of diluted shellac standard quality, for wood varnishing (troubled) , and a photo of diluted shellac artist quality, decolored and without wax (clear) :
                                                http://www.dotapea.com/gommelaque.htm#confusionschezlesauteursoccidentaux

                                                Hope that helps

                                                http://www.annaigart.blogspot.com
                                                It is a very sad thing that nowadays there is so little useless information. - Oscar Wilde

                                                #1035494
                                                Enchanted
                                                Default

                                                    Jaxas – everclear is 200 proof which would be 100% ( theoretically ! ) alcohol . God knows why anyone would actually try and drink the stuff — i guess the answer would be in an AA forum.

                                                    WOW! I’d never heard of “200 proof” anything. But I did have an experience once in Saudi Arabia (yep – you read it right) when I was invited to Thanksgiving dinner by an American couple who took pity on me, being as I was alone there on that typically American day. Before the meal I was served a couple of glasses of “wine” which is easily made from the German grape juices sold in Saudi grocery stores (at least at that time). When I went to stand up to go into the meal, I could hardly keep my balance and my head was swimming. My host advised me he “triple distilled” the wine after fermentation, raising the actual “proof” to something normal wines never achieve. My head is still swimming, just thinking about it… :p

                                                    #1035485
                                                    colin
                                                    Default

                                                        Yikes Jaxas! I hope that guy knew what he was doing — from what I gather its easy to screw up when distilling alcohol and you could end up blind ( or dead ) …

                                                        My only foray into that kinda thing involved a gallon of homemade hard cider and a wicked teenage hangover — the kind where you start personally appealing to yer favorite diety to just strike you dead on the spot and end your sufferings …

                                                        Littlefield Gallery, Winter Harbor, ME[/url]

                                                        Colin Barclay Blogspot[/url]

                                                        #1035495
                                                        Enchanted
                                                        Default

                                                            Yikes Jaxas! I hope that guy knew what he was doing — from what I gather its easy to screw up when distilling alcohol and you could end up blind ( or dead )

                                                            And some did! I’m speaking of my experiences “way back” in the 1970s when I traveled to the middle east Arab countries. One of the “worst kept secrets” in Saudi Arabia in those days was the fact that westerners brewed and distilled their own alcoholic beverages. I know of one oil company that had its own “compounds” and supplied both the blueprints and the stainless steel materials for constructing “clothes-closet stills” in private residences. And as you surmise, the problems arose when some wiseacre decided to double or triple distill the alcohol, ending up with a far more volatile product than what one normally thinks of as consumable.

                                                            As for making wine, there was a German brand of various fruit juices that was sold in glass bottles with re-sealable ‘corks’ that were hinged with metal hinges. All one needed to do was dump the contents into a crock, allow for the fermentation, and then re-bottle the “wine” that resulted using the same bottles the fruit juice was sold in. Again, the problem arose when this “wine” was subjected to further distillation.

                                                            #1035487
                                                            just dave
                                                            Default

                                                                Alcohol mixes easily with water.
                                                                Alcohol evaporates much more readily into the air than does water.

                                                                Dave...a student of the visual arts

                                                              Viewing 15 posts - 1 through 15 (of 15 total)
                                                              • You must be logged in to reply to this topic.