FAQ Which Adhesive Best For Glass On Glass

From Mosaic And Stained Glass

Contributed by Linlee

I made a GOG test using GEII, Weldbond & MacGlue. The test was started last Thursday. This was the setup:

Fresh GEII:

Fresh Weldbond:

Fresh MAC:

After the glues finally dried I plunged the test into water for a total of 3 days.

The SiliconeII looked the same coming out as it did going in...kinda murky with bubbles. It was removable using a blade. Also note that this is the only one of the three that can be used for leveling.

The Weldbond slid off of the glass at about 3 hours into the water bath. But note that when it actually dried it was very clear.

The Mac dried fast and clear. That milky haze eventually went away. At the 3 hour mark the edges of the glue that were squished out of the test piece did start to get a milky edge. At this point it was really easy to pull this overflow off with my finger nail. But even after the 3 day mark I couldn't pry it off without fear of shattering the test plate.

These photo's were taken mere minutes ago.

The GEII is completely dry and quite opaque compared to the MAC. The Weldbond is still not drying so it's clearness compared to the MAC is yet to be seen. GEII:

Weldbond

MAC:

The MAC does indeed look crystal clear with exception of some minor bubbles. But turned slightly into the sun there can still be seen a milky haze. This may go away in time...I'll let you know.

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More info:
I paid:
Mac - $25.50 for 2 8oz. bottles from the Mac site. ($10 per 8oz)
Weldbond - $4.99 for 8oz. @ Local store
GEII - $3.44 for 2.8oz @ Local Big Box Store

GEII Pro's:
The silicone has leveling ability
Easy to use
Holds very well and fairly quickly to vertical surfaces
Easy to remove already stuck pieces
Easy cleanup with a blade
Can be used for outdoor pieces
Can be purchased locally
You feel really good after about an hour in a closed room

GEII Con's:
Fairly pricey because of the amount you use
Does not dry crystal clear
Tends to change color after awhile
You need denatured alcohol to really clean off residue
Possible loss of brain cells in an enclosed room

Weldbond Pro's:
Not too pricey
No real learning curve as it applies just like Elmer's,
Cleans up with water
Very good hold

Weldbond Con's:
Not as easy to find locally
Shouldn't be used for outdoor projects
No immediate vertical hold
Drying can take a very long time

Mac Pro's:
Dry/hold time is fairly quick tho not as fast as GEII
Strong hold
Clear on application
Edges cleaned up well with exacto knife
At this point it looks to be the clearest (Jury's still out on this)
Cost effective as very little adhesive is used as it is just a tad thicker than water.
The Mac site states that the glue is "water resistant"...which usually means that it will eventually break down if wet. However the bottle itself clearly states "waterproof." The site also says that Mac is a marine adhesive and can be used to bond carpets in boats.

Mac Con's:
Internet sales only at this time.
No immediate vertical hold
Indoor pieces only
Posted by mosaicwench1:
Here's a CON of Mac not listed. Once it's dry, it's almost impossible to get off - of ANYTHING. It's not like Weldbond where it can be re-wetted and removed, or in some cases just scraped off. It's ON - for good.
If you're a tidy mosaicer, not a problem. If you're like me and have glue all over, its a BIG con. I made some coasters with scraps and Mac glue and I'm impressed by the clarity. I don't know that I would use it on my glass-on-glass windows, though. Even with it's superior clarity the "not being able to rub it off" is a drawback for me. I tend to squirt glue into an area on which I'm working and then place the glass. If I don't or can't place all the glass before the glue dries, I want to be able to easily remove the dried glue and begin again where I left off. Not being able to do that makes MAC iffy for me in a GOG circumstance

Mac can be considered pricey, however if it does turn out to be the best GOG adhesive the price would be inconsequential as you use so very little of it compared to the quantities used of GEII.
Oz per oz...
GEII ends up being $1.23 per oz.
Mac ends up being $1.25 per oz.
You will use more GEII on 1 piece of glass than you will Mac. So the Mac, if you so choose, is actually a more cost effective product.