Glue Chipping & Mask Removal

Kelly Thorson · Post by **Kelly Thorson** » Sun Sep 04, 2005 7:20 pm

Okay guys, at the risk of getting my fingers slapped.....
How come the mask is removed before the glue chips?
Is it just to make sure no glue has seeped under the mask?
If you wish to do a double chip is it then permissable to leave it on?
I know that using ashphaltum will solve the problem, but my mind tells me that it would be far less intrusive to the gelled glue to leave the mask alone and just remove the excess glue. I'm sure that I have done that in the past without any problems when I have used a 3 mil vinyl mask.
I tried to do a search here for the answer but didn't come up with anything
Thanks in advance.

Doug Bernhardt · Post by **Doug Bernhardt** » Sun Sep 04, 2005 7:33 pm

Kelly....a good question with a single answer (and you are right about the asphaltum method too!) it will be a mess of plinks and oysters and have seen this in person. One of the first times i tried it I didn't realise how quickly the glue sets-up ready for cutting and thought to leave it to get ready over-night...yikkes!!

Russ McMullin · Post by **Russ McMullin** » Sun Sep 04, 2005 10:39 pm

So, even if you cut around the letters when the glue gels, there will still be problems if you don't peel up the mask and extra glue?

Russ

Keith Pettit · Post by **Keith Pettit** » Mon Sep 05, 2005 2:38 am

I have found if you do not remove the mask or at least run a knife around the edges. The tension of the glue acts on the vinyl and pulls that up from the glass, before the glue has hardened properly, which as a result, lifts the glue from around the edge of the blasted part. So you have a unchipped edge to your design. This has happened when I have have had my fire lit in the shop and the glue is probably tacking a little too quickly.
The other problem I have run into is run outs or a "plink" running into the clear glass.....very frustrating!

Russ McMullin · Post by **Russ McMullin** » Mon Sep 05, 2005 8:40 am

So, the question remains. Even Kelly wasn't suggesting a solid layer of uncut glue. What happens if you do cut around the letters, but you leave the mask on instead of removing it?

Russ

Doug Bernhardt · Post by **Doug Bernhardt** » Mon Sep 05, 2005 5:25 pm

Good question....and would love to know. If no-one has an answer will try that one out myself this winter (slow time)

Kelly Thorson · Post by **Kelly Thorson** » Mon Sep 05, 2005 8:57 pm

Thanks Russ for clarifying the question - I guess it helps to understand me if we have been discussing this.

In the past couple of years I have played with glue a bit and I'm pretty sure that I left the mask on. I find the "Lil Chisler" works really well for removing most of the the excess. I then let it set until it just started to get transparent, cut along the mask lines and peeled of the extra glue. When I try to remove the mask as well I find I don't get as crisp a line. Messing with the gooey combination of sticky gel and sticky mask seems to lend itself to pulling up corners of glue and also having glue "slump" onto areas that should be clean. The problem may be one of impatience - maybe I need the glue to gell more? The pieces I did with the mask on were all pretty basic though - on smaller lettering it might be a little tougher. If no one has any conclusive comments on why this won't or will work I'll give it a go an some more samples,and see if I eventually run into trouble.
Thanks for your input Doug.

Post by **Mike Jackson** » Mon Sep 05, 2005 10:46 pm

As with any process, there is the "standard" set of steps, passed on by craftsmpeople over the years, and then there are dozens of "might work" scenarios. Those might require you to do a series of test pieces to prove or disprove the alternatives.

I was taught originally (by Bob Mitchell, his book, and several early stained glass booklets) to peel the mask prior to the chipping process. That can be done as soon as the glue gels slightly...enough that it will remain firm, and prior to it rewelding. You might find you can cut and peel the excess within about 30 minutes if you are quick and careful. Once you do it a few times, you realize the hard, crisp edge is more relative to the frosted etch than how neat the glue is on the glass before chipping.

You seldom have chips that bridge across clear glass with the "peel" method, but part of that is relative to the power of your glue and the thickness left along the edges. It is not a step I try to eliminate.

Good luck,
Mike Jackson

Raymond Chapman · Post by **Raymond Chapman** » Tue Sep 06, 2005 8:14 am

Recently we did a glue chip piece and failed to get to it in time to cut around the mask. There were several places where the glass chipped across or into the bright areas.

I don't have an answer to the question of cutting around the pattern and then leaving the mask on while it chips. It would make a good experiment.

Larry White · Post by **Larry White** » Tue Sep 06, 2005 9:33 am

John Yarnell asked me the same questions. I told him the edges would plink if you left the mask on. He did a sample of all the various methods. The ones with the mask left on had plinked edges. The one with the mask removed had only minor edge defects.

The mask is removed because it's the right way to do it.

If you're going to double chip, use the asphaltum method. After the first chip, you can touch up the asphaltum and re-apply the glue.

...perhaps you will see things more clearly..

Russ McMullin · Post by **Russ McMullin** » Tue Sep 06, 2005 11:42 am

Thanks Larry! Oh, and thanks too for sending me my notes from the meet!

Russ

John Studden · Post by **John Studden** » Tue Sep 06, 2005 12:07 pm

I have found when using the Asphaltun method that leaving the mask on or taking it off makes no difference, it just acts as another resist & made the job easier.....this was using the sqeeze bottle method & making sure there was no bridging of the different areas. John

Post by **Mike Jackson** » Tue Sep 06, 2005 12:15 pm

Just to underscore John's comment....you can't simply cover the entire design with glue and call it good, even if using asphaltum. The squirt bottle is used to squirt glue only onto the open frosted glass. If a little overlaps, it normally won't have anything to grip and will not negatively affect the chipped edge.

Pat Mackle mentions a term called "breaking the glue's back", and that might be a secret for anyone trying to leave the stencil on. To do it, you must cut the glue along the stencil at just the right time. If you wait too long, it will get very hard. If you cut too soon, the glue will reweld to itself. Again, I never liked the odds, figuring it is easier to pull the stencil than redo the entire panel if too many plinks occur.

For the large panels with large ornaments and elements, the cut and peel method is quicker, easier, and less messy than the asphaltum method. The Asphaltum method, using squirt bottle, can give you a much better chip on small, complicated designs.

Mike Jackson

Kelly Thorson · Post by **Kelly Thorson** » Tue Sep 06, 2005 2:06 pm

Thanks guys, lots of good replies. I appreciate the help.

I have 4 pieces chipping as we speak. The humidity is high here and I suspect I was a bit in a rush to get the mask and glue off. I thought they would be ready to go by 8:00 pm, (about 4 hrs after the first was poured) but I was still at it at 1:30 AM. Normally Saskatchewan is so dry it only takes a day to chip, and it has been 2 days already and the glue is only now finally starting to pull.

Do you usually leave the glue until it is getting "leathery" before cutting or do you do it when it has gelled enough that it will hold its shape - or somewhere in between?

Post by **Mike Jackson** » Tue Sep 06, 2005 2:50 pm

We slice and peel the glue/mask as soon as it will cut and allow us to peel it. That can be as soon as 30 minutes. You can easily cut and peel it until it passes that leathery stage and starts getting hard and dry feeling.

Mike

BruceJackson · Post by **BruceJackson** » Sat Sep 10, 2005 7:33 am

The last job I did a few months ago, I tried some minor variations. Normally I have mainly used the asphaltum resist and syringed glue method.

This time I left the thick sand blast mask in place and after washing out the residual blast powder, rolled on some asphaltum with a hard rubber roller. It was only marginally successful as it didn't bridge the wider areas to be chipped, but it still did help keep the syringed glue off the mask. On the rest of it (after giving up on the roller) I just cut around the mask at gel stage. I found that peeling the soft glue off the mask was easy and the mask could stay in place without affecting the result.

One thing I prefer, as Mike has stated, the cut edge is thicker than a syringed edge and doesn't leave as much un-chipped sand-blasted glass at the edges.

Bill Masters · Post by **Bill Masters** » Sun Sep 11, 2005 9:35 pm

I haven't used the asphaltum method in a long time.What I do is clean glass and apply avery paint mask with design and glo lines cut, peel areas to chip, sandblast, wash blasting residue from glass, apply glue(squeeze bottle method) when glue gells cut around design,when the glue chips it lifts the thin vinyl glo line with it and leaves a clear glo line and seldom bridges.The background vinyl is still on the glass so I guess you could silver then back up and I haven't tried this part yet but will this winter.

Kelly Thorson · Post by **Kelly Thorson** » Mon Sep 12, 2005 12:17 am

All four pieces chipped beautifully. After three days of no action I moved them onto boards and set them outside in the sunlight. Within an hour they were almost all fully chipped. Only one had a few small plinks in one area where I had blasted slightly deeper. Are you more likely to get a stray chip on areas that are blasted deeper and if so is it because the glue can get a grip on the vertical edge of the glass? Perhaps it was just a coincidence.....another test project.
Thanks again for all the replies. This place is an incredible resource.

Larry White · Post by **Larry White** » Mon Sep 12, 2005 8:33 am

All you want to do is frost the glass when sandblasting. And yes, if you depth carve the glass there will be a "vertical" edge where the glue will grap and cause the edges to plink. ...glue chipping depth carved glass doesn't work, truth be told...

Glue Chipping & Mask Removal

Glue Chipping & Mask Removal

Test pieces...