Posted by Robert Beverly on November 23, 2002
Mike JacksonHeads
What have y'all considered easier to use on glass and whay?
I am trying to get myself to start using asphaltum but seem to drift back to using mask because I must etch the area for chipping first and then I wind up leaving it on.
What is y'alls take on it?
Robert BeverlyRobert,
Are you having good luck leaving the stencil on, and still chipping? The traditional "wisdom" on the stencil method is that you still need to cut around the soft glue with an exacto knife and remove the stencil from the glass, leaving only glue in the areas that will chip. Normally, leaving the stencil on the glass with the glue will give you less than satisfactory results, often causing the chips to bridge over fine areas and plink under the stencil in places.
Mike Jackson
Kent SmithMike
I have tried it both ways and don't have enough consistency to continue doing it!...it has worked well on occasion but when it does go bad, it is not worth the risk therefore I have gone back to trimming....before putting it into the chip booth. I just was curious in terms of many peices done at the same time if the asphaltum is better!
Boy you sure get around!...LOL
Mike JacksonI certainly prefer the asphaltum and get superior results without plinks. When the glue rolls back from the asphaltum, I get a good clean edge and chips seem to progress inward from the edge which adds a little sparkle to the chip. I hate recutting, or redoing for that matter. What would Yogi Berra say?
Robert,
If I were doing large, simple, geometric patterns in large glass, I would use the stencil and re-cut method. I'd say 3' x 4' and larger would qualify, and even some of the smaller ones at times. All small and intricate panels and designs get the asphaltum treatment here.
The trade offs are how long it takes to double cut (plus having to be there at the precise time to get to double cut before the glue gets too hard), and having to deal with the extra mess of the asphaltum. The asphaltum method requires that you coat the entire piece of glass and let that dry before applying stencil, where the other way does not. Applying all the glue with small squirt bottles can take a while...and maybe even longer than double cutting the stencil, but in the end, the asphaltum method will usually hold the detailing in the fine corners and you hardly ever get a plink. We used to use Anchor sandblast stencil on the large panels (the version made for glass). After pouring the glue and spreading it out, you often get a ridge along the edge of the glue after you cut the stencil away. That ridge has more power due to the extra thickness and it can be part of the culprit that causes the plinks into the clear glass.
We did a series of test pieces here on a 100 lb bag of glue chip glue. Without modification, our glue usually plinked edges when we did the stencil/cut method. We created a test piece with no glycerin, one with five drops of glycerin per square foot of glue, one with 10 drops/sq ft., and one with 15 drops, and lastly one piece with 20 drops per square foot. It seems that 15 was our magic number, though 10 drops worked fine. The catch here, is that we knew we could rely on this to work for the rest of the 100 lbs of glue. We ordered some extra glue for the Boise meeting when we did the seminar and found out that some of the new glue acted differently than our old glue, so the formula would need to be adjusted.
Hope this additional information helps!
Mike Jackson
Robert Beverly
Mike Jackson - Glycerin and AsphaltumMike, Kent
Thanks for the suggestions...
I figured that you might say that about the asphaltum!
So how many layers of material(asphaltum) do you suggest laying down?
I also now have a term to the chippin outside of where it is suppose to!...PLINK!..LOL
I will have to bug Rick about the glycerin in February if he is unable to get to it here!
Again THANKS!!!
Robert,
You can buy glycerin at any drug store. It is fairly cheap and a $2 bottle will last you a long time.
We usually only appied one coat of asphaltum, using a 4" foam roller or 2" foam brush. It just takes a layer to protect the water based glue from the glass. It is self dissolving, so trying to apply too much asphaltum is actually difficult. The asphaltum requirements for glue chipping is completely differnt than for acid etching.
Good luck,
Mike Jackson
Robert BeverlyMike
Thanks
Rick SacksI am creating some pieces where the asphaltum will come in handy!....I appreciate the insight!!!
Mike, I never heard of adding the glycerin. Please tell me what this does? I remember the old guys adding it to the show card color too, and thought it might cause an increase in flowability.
Mike Jackson - glycerin
Hi Rick,
I suspect Glawson told us about it, but I don't exactly recall. It might have been in one of the old sign books such as the Ashmund Kelley book. Anyway, if the glue is too aggressive, you can add glycerin to relax it. No one could tell me how much to add, so I did the series of tests as described earlier. Now, I never had the problem, but I "heard" you could add alum to the glue to make it more aggressive. If I remember correctly, we purchased 100 lbs of 5x glue a long time ago. That was supposed to be the aggressive stuff. When I was speaking with Rick a few years later, he told me there was some confusion related to the 3x-5x coding. I am not sure if I understood the issue when he was explaining it, or if I wasn't really paying attention since I had a bunch of the 5x left.
I have personally invited Rick Glawson to post on this site numerous times. I keep hoping he will take the time to write once in a while, though I know he reads the posts. Maybe this question will be a good one for him to break the ice and make a response! His information on this topic would be very helpful to all of us.
Mike Jackson
Denver Chapter of the Letterheads