Glue chipping glue-mix questions

[Stan Hubbard]

Hello out there, I am getting started on my first glue chipping project and would like to ask a couple of questions before I begin. I am currently working from instructions in a book called The Art of Glue-Chipped Signs by Robert R. Mitchell. Naturally, I want to produce professional quality signs right from the start,(ha ha), so I want to have a clear understanding of the glue-mix calculations. In the "calculating the mix" section of the instructions it starts by suggesting that 4.5 oz. of glue mix is needed to cover one square foot of chip area. Then it goes through instructions as to the physical aspects of mixing the glue. Then the section ends by suggesting that one square foot requires 3.75 oz. of glue mix. I don't want to come up short at glue application time nor do I want to waste materials. Would some of you experienced chippers please share how you enterpret this section or share how you calculate the glue-mix per chip area?
Just one more and I'll go. Before I order a bolt of sand-blast mask, have any of you found any that is preferrable to the 3M #300 or are there reasons to have more than one type?
P.S.- I was the guy in your school classroom that asked all those questions that made you roll your eyes.
Thank you very much! Stan Hubbard

[Mike Jackson]

Stan,
Before you get too far, read all these pages:
http://www.theletterheads.com/lhparts/gluechip.html

Sounds like you have Bob M.i.t.c.h.e.l.l's book? I am not sure who Robert R-- is.

Normally, if covering a solid square foot, you use 1.5 oz of glue and 3 oz of water, totalling 4.5 oz per square foot.

In practice, if you use a small dixie cup of glue, the same cup filled with water gives you the 2 times water amount.

Still, you should read all the different pages on the link above. In many respects, this is easy. But, it takes some practice and a few dozen blown jobs. It works differently in the summer than in the winter.

[Larry White]

Hi Stan-
Seems there's a lot of different information on glue mix ratios. When I started, I too followed the Bob Mitche11 book's instructions. Rick Glawson simplified it a bit, measuring in volume, rather than weight. He had come up with the ratios of 1 - 3oz. Dixie cup of glue, to 1 1/2- 3oz. Dixie cups of water per square foot of glass. Whatever volume you're going to mix up, you can use that 1 to 1 1/2 ratio. When flowing (pouring) glue over the entire surface of the glass, I pour 6 fluid ounces of prepared glue per square foot. If you're doing the asphaltum method, applying the glue via a squeeze bottle, the glue will flow out to it's own level right up to the edge of the asphaltum. Just be sure to mix up enough for the job. Make sure you heat the glue until it is steaming hot. I like to let the glue dry to a clearish, rock hard state prior to subjecting it to chipping. That's what I do...seems to work. There's some pictures of these various processes in the La Azora Step-by-step thread.
Hope that helps.

[Mike Jackson]

There is a little "flex" in the amount of water added to the glue part. That flex has to do with the fact all the water you pour into the glue evaporates before the glue starts chipping. So whether you add 1.5 or 2 parts water to the mix would be based on how thin or viscous you want to the mixture to be as you pour it. You'd still have 1.5 oz of glue on the square foot piece of glass once the water disappears.

If you did a test "one square foot" piece of glass, you could get an idea how thick glue needs to be using that formula. Once you see that thickness, you'd want to apply the same thickness if you squirted glue out from a bottle using the asphaltum method.

Hope this helps,
Mike Jackson