Posted by Mike Jackson on March 12, 2004
Jeff Lang called today with a question worth discussing here.
In many of the previous posts about glue chipping, we have talked about spreading the glue on the glass evenly and quickly. I noticed the other day my glue wanted to immediately start gelling when it hit the glass. Not much time to spread it evenly!
I've noticed that glass exagerates ambient room temperatures. If there is the least bit of a chill in the room, glass seems cool to the touch. In the summer, if it is warm outside and in the room, the glass can feel almost warm. Of course, if it is exposed to sunlight, it can get quite hot. So, I suggest putting your glass on a light table or warmed table top before applying the glue. It is probably best to add a little more water to the glue, too.
Danny Baronian and I have talked about the issue of the glue/sq. ft ratio a few times over the phone. The normal ratio is 1.5 oz (by weight) of glue and 3 oz. (by weight) for a full square foot of coverage. That also translates to one bathroom dixie cup of glue to one dixie cup of water since the water weighs twice as much as the glue. In my opinion, the amount of water is flexible in this formula. You can add less water to make it thick if needed, or add more water to make it flow easier. The water ALL evaporates, no matter how much was added, leaving only the layer of glue.
Of course, you have to make allowances for extra water and build up the glue thicker when you pour it on the glass. Still, in the end, you need roughly 1.5 oz of glue per square foot of coverage. To understand what that looks like, an easy test is to frost a 12" x 12" piece of glass, mix up 1.5 oz of glue and 3 oz of water, heat it an pour ALL of it on the sandblasted glass. THAT is the thickness you should be aiming at, even if you only squeegee areas of glue on a particular glass job. If you did another test piece, you could mix 1.5 oz of glue and 4.5 oz of water, then pour ALL of it on a 1 foot square piece of glass. You would then be able to analyze, for future projects, the thickness required with both formulas.
If you view the pics above, you can see I "domed" the glue on the glass much thicker than you might have imagined. The glue was mixed thinner to go through the squirt bottle, so I had to adjust.
Hope this helps!
If others have suggestions, please post them!
Mike
Vance Galliher
Jeff Langit's great to have so many of you interested in glue chipping ....and i appreciate the sharing of the "how i do its"........i've been chasing the perfert chip since i read bob's book back in the early 80's....i remember when i first started,... i thought i needed to buy a triplebeam scale to insure proper mixture....this was science !...and i would spend countless hours trying to figure out the correct ratio between dry/liquid weight......then i met rick....and he said "1:1".....(and a whole lot more...ahhhhhh and i miss not hearing that anymore)....funny how simple that was !....but in doing larger arears i kept having flow problems..gelling to fast.........but found that just by adding a little more water made all the difference......i really like the explosives chips.......the true drama of fractured glass!....and gilding it really makes it pop !!...... but soft is nice to .....ahhhh ..to predict the outcome...perhaps that is the quest .....but there is something about not knowing....seeing something new.........must be a wordy night for me..........i'll try the prewarmed glass on the next one.....may your chips always fall in the right place ..........
Mike Jackson - Other Glue Spreading ToolsMike,
When you talked about the glue gelling so quickly on the glass because it was cold, it got me thinking. I decided to warm the glass by getting a towel soaking wet with very warm water. Then placed the glass on to it on a level surface. I thought the combination of warmer surface & a moist environment would help. The result was the glue did not gel as quickly & allowed a little more time for the glue to flow out. I would have liked it to flow out a little more before gelling. I decided to try spreading it on, & I used a scrap piece of glass with a polished edge that was wider than the piece I was coating. I poured the glue on one end & dragged the glue across the panel like wiping a silk screen. It seemed to work pretty good, the coat was fairly consistant. I have more test pieces going so I'll report the results.
Jeff
Here's some more goodies. I am a sucker for gadgets and usually buy small tools "just because". These three didn't even have a power cable! I bought these from Rick as Esoteric over the years, and I suspect they still sell them at Esoteric2.
The two with the white rollers are supposed to work as spreaders. I tried them and didn't think they worked that well, and they are a pain in the rear to clean. I haven't seen it, but I hear Pat Mackle uses a pair of tracks or spacers that are roughly 1/16" thicker than his glass. He puts one on each side of the glass, then uses a long glass rod to roll across the glass once he pours a large bead of glue at one end. The spacers keep the glass rod off the surface the desired amount. Sounds like it would work but I never tried it.
The tool in the middle is used on a glue chipped panel when the glue has lightly gelled, but not to the leather stage. The idea is to create small craters in the glue so the glue with develop more of a controlled patter, with chips originating from the divit. I think it might work better on larger areas than anything I tried. On a related note, Jeff Lang told me today he shook his squirt bottle of glue (not really on purpose) and got a bunch of bubbles that didn't pop before the glue gelled. I suggested it might create a similar effect to the nail wheel.
Looks like we all have new experiments ahead of us. Hopefully people will share their results.
Mike Jackson
John Parker
Many of you are way ahead of me on glue chipping glass but now that I have sold the sign business to my son, I hope to do some catching up and that I can obtain the skills to produce pieces as fine as the ones being displayed on this site.
I have been finding and reading old books regarding the procedures involved in glass docoration whether it be gilding, etching, carving or glue chipping. I recently read a couple of paragraphs in the International Library of Technology #90, 1921 (Sign and Banner Making-Practical Design and Ornament) that stated the use of hydrofluric acid and equal amounts of water to etch the glasss as opposed to the use of "emery powder", allowing it to stand for twenty minutes, stating the acid will give more satisfactory results. (I assume they had yet to start sandblasting glass), In the section describing the application of the glue, the procedure was to use soap and water to clean the acid from the glass and to rinse thouroughly with clean water. (now the part that I have not seen mentioned before) "before applying the glue, the surface of the glass should be moistened with water, using a clean sponge for this purpose".
Is this a common practice, or is it an unecessay step? How could this affect the process?
I would apprciate any input.
John Parker
Robare M. Novou
Danny BaronianI made a post a while back about acid etching on a piece that I was also going to glue chip.
The deal was to sandblast both the etching area along with the chipping area. Then pour the acid onto the selected etching areas using a 2 parts water to one part acid, wait twenty minutes, and hose off.....well I did, but the acid leaked under the glue dam onto the area I had sandblasted for the chipping. I thought I had ruined it.
After hosing it off I noticed that the acid had not turned the blasted areas clear...instead they were a smoother frost. Okay, I thought, no big deal, the glue should still stick? Well the glue DID NOT chip those acid leaked on areas...I tried it twice... the glue would just harden and peel off, no chipping. Finally I resandblasted those stubborn smooth frosted areas...and they chipped fine.
Now if I had used a one to one ratio for the acid, I would have gotten a rougher etch (which I did on some earlier work). And that may have provided the necessary tooth for the glue.
I would rather sandblast for chipping than acid etch...much safer!!!
When using those polyurethane glues for signfoam, the directions state to get the edges wet with water before applying the glue...the best I can figure is "capillary action", the water helps to draw the glue into the tiny pores that the glue would otherwise lay across and thereby not get a deeper grip. Those ICS wetting instructions seem to have merit.
RMN
I just reread this post and the last sentence sunk in. It's not capillary action.
Pollyurethane glues are basically the same, the most recoginized being Gorilla glue. The purpose of misting the glue or it's mating surface is an excelerator. Glue two pieces together without the glue and it takes a long time to dry. Spritz with water, clamp up and almost immediately you'll see the glue expand.
Same principal used in water borne contact adhesives, except those use salt water.
Danny
Robare M. Novou
Jeff LangOk, that makes sense of why one would wet the surfaces for gluing up signfoam.
So then, why would one wet the glass prior to the application of the chipping glue?
Would that be accelaration also?
Im still thinking that it would be penetration. Or perhaps Lubrication for the glue as its being applied.
RMN
Mike Jackson - Photo of Pouring GlueJohn,
The glass is not porous, so I assume the water would just sit on top. When the glue would be applied, the one thing I suppose it would effect would be the consistancy of the glue. Sounds logical, I do rinse off the residue & dust from blasting, but have always dried the glass. I'll have to try it that way.
Jeff
Danny BaronianHere's a shot me pouring and spreading glue from a recent project. The glue gelled up quicker than I wanted (and remembered), but then it was early February and generally chilly even with the heaters going.
As I said earlie, I'd probably go to the office and put the glass over the light table for a while prior to pouring.
Mike
Here's another trick I ran into by accident.
I thought I'd try a jar like Rick did of the 1 gallon jar I posted. In looking for the right glue ration, I found it to be 1:1 for pouring on, but it has to be applied fast because it starts cooling quickly. My first run was 1 cup of glue to 1/2 of water, but brushing in on was was streaky so I washed it off. I then mixed it 1-1, zapped the glue in the microwave several times to the point of below boiling, and poured it on as I rotated the jar, like coating a candy apple. Worked very well.
By heating the glue up to it's max before boiling, the glue goes on so hot, it dries very fast in part because of the heat, partly because there's less water. Let it sit overnight, put it outside at 10 am today, and by 3 it was almost completely chipped.
I'm sure there's not a lot of practical applications for what I've described, but it was interesting to see how well it chipped and how fast the glue dried. Besides, it was fun to see how it worked. I think many times Rick had fun doing the same things on projects we never saw. He'd told me he brushed the glue on the 1 gallon jar, but from my limited tries, I think Rick spent a lot of time achieving the final result. No one can say Rick didn't enjoy the journey!
Chipping goes a lot better in warmer weather too. Today it's about 75, couple of weeks ago we were in the low 60's with humidity in the high 70's.
Danny
Denver Chapter of the Letterheads