Integra Adhesives

[lensmith]

We're having problems with our normally dependable Integra Adhesives today. I would chalk it up to the weather, but it's not curing in spots....one entire edge will be completely cured, and there will be a 4 inch segment of edge that takes 2 to 3 hours to cure. There are also patches that yellow as it is trying to cure.


Any ideas on what is causing this? (We go through several cartridges per day, and the problem seems recently to be on the upswing.) Maybe one bad batch of glue?

[lensmith]

D'oh! I found out we were using an outmoded dispenser. We're running another batch with a new dispenser, will let you know how that came out. Very possible that our gluing troubles were self inflicted. More to follow.

[Jason]

We have had the same problems when we used ACS, we switched to Integra and the problem seemed to go away; several months later we start having the same problem, the rep for Integra said we are squeezing it out to fast, I haven't had a chance to try the test he suggested, I'll let you know after I try it.

[lensmith]

Well, we switched guns, slowed down the flow, and we're still having portions of seams that just won't dry. We had one top that we glued up yesterday at 1 pm, and didn't cure until around 9:30 this a.m. It's not the entire seam, it's just a random section about 4 inches long here and there. And they're not from the beginning of a new cartridge either.

Integra has had us run some tests, and Ray has been really on top of this, for which I'm thankful. I'm sure they'll find out what the problem is. For the moment, we've switched to Corian glue, which is drying somewhere between 35 and 45 minutes.

[al]

I'm hesitant to offer this advice, knowing of your experience, but as there are no stupid questions, I am hoping there are no stupid answers.

Well, I catch it every time we hire an experienced fabricator for doing this, but it will help stop your problem. I was trained by avonite. They recomend running two lines and using a popsicle stick to quickly twirl or mix it. It takes mabe a half minute to a minute on a long run and it will elimate soft spots. Make sure when you get to the end of a run to go back to the starting point to run the second line.

Most of the experienced help we hire will scoff, some have quit over my insistance to use the method. I have had glue not set up quickly maybe three times in six years, in all cases the tube of glue had evidence of leakage of the catalyst or hardner or whatever is in the smaller of the two tubes. Like you mentioned, it will set up eventually, maybe the next day.
I hope this helps.

[lensmith]

You're right Al, there are no stupid questions or answers here! That's a good tip.

Len

[lensmith]

Just a follow up to our gluing problems. Integra sent us a new batch of glue, which we have used without any curing problems whatsoever. It appears that the batch we originally received may have taken a shipping detour, and been left out in the heat too long before arriving at it's intended destination.

Anyway, we're a happy customer.

[jkbrand]

I'll second Al's technique. In fact, I teach it in monthly fabrication classes as standard fare.

I'm convinced that in the manufacturing proces--as with latex and silicone tubes--air pockets are inevitable. Not always, but occasionally. Such voids are not so much a problem in the glue as in the catalyst. Thus, a quick spreading of the glue as mentioned ensures a much better chance that a single squeeze that didn't contain sufficient (or any) catalyst will find its way to an adjacent area with catalyst.

As an experiment, Len, you might want to take some of those suspect cartridges and squeeze a few shots into a paper cup; mix it up and apply it to a scrap piece. Check back in 30-40 minutes, and if it's not cured, then the compound is bad. More likely, though, it will be cured because it was wholly mixed. If the cartridge is suspect, you're probably not going to use it on a real job anyway, so nothing's lost, and useful information can be gained.

We never have had a single problem when we dispense (short runs, of course) from a cup in which we've hand mixed. Any cure problems, on the other hand, have always been from the mixing auger when we'd not run the popsicle stick.

Finally, I don't understand the Integra rep's attribution for squeezing too fast. What difference could that possibly make? The mechanics of the gun wont allow one piston to travel more quickly than the other, and the auger doesn't care what's coming down the pipe, fast or slow. I'd say he was grasping at straws.

Jeff

[chad t]

One of the most common misconceptions regarding 10 to 1 adhesives is that all dispensers provide similar performance. In order to give our customers the right information, we have done extensive testing on the dispensers in the market and our results showed marked differences in cure consistency. Specifically, the lower cost, all metal dispensers we tested have a very high mechanical advantage. This can result in off ratio mixing of the two components if the user pulls too hard on the trigger.

To explain it another way, excessive pressure on the cartridge, due to a high mechanical advantage in combination with operator strength, will actually bulge the cartridge slightly. When the cartridge returns to its original size after the trigger is released, the adhesive component (large side), will continue to flow out of the cartridge, while the activator component (small side), will not as it does not bulge. This results in an area of the bead that the 10 to 1 ratio is off and the adhesive bead will have

[Dani]

I would like to say as a fabricator that having the problem of cold spots in the adhesive was extremely rare with the old style tip. Since the new style tip has come out the problem is on going not only for me but many other fabricators. All the manual guns will put about 470 lbs on the cartridge and yes it is possible to get over 500 lbs on the metal guns, but at that point your fingers are hurting from squeezing so hard. Tell me this I use my pneumatic gun, the pressure force on the cartage is set at 350 lbs and I sill have the problem with cold spots in my adhesive lines with the new style tip. All this talk about placing blame on the applicator, what about the cartridge design? All I know is I did not have this same problem with the old style cartridge.

Dani Homrich

[chad t]

Dani,

Are you having cure issues the new MFX tip or the Integra quadro?

Chad Thomas
Integra Adhesives

[Dani]

Chad,

I have used both
No problem with the quadro.
I do believe there is a design flaw in the MFX tip. The old MCX had a tapered mixing station to blend the adhesive and catalyst together before they reached the stirring blades, the new MFX tip does not have a tapered mixing station only a flat collar. I think that catalyst is backing up in this area causing uneven flow rate giving fabricators hot and cold spots. Fluids do not flow accurately with this type of design. This is only my opinion and have not done any testing on this matter, although I am mad at the problems that the MFX tip has caused in the fabrication of my tops, more fixing than needed.

Dani

[chad t]

Dani,

When we were approached with the new MFX tip over a year ago, we did a fair amount of testing for performance. With our adhesive products, we found it to perform adequately. The main reason we decided to go with the Quadro tip was the cost savings for the fabricator as it wastes as much as 30% less material due to its small size.

Viscosity of the two components is an important factor when we look at the performance of a static mixer. As I said, the MFX performed well with our adhesives, but I can not speak for the other products on the market as we have not test any other adhesives with the new MFX tip.

I find your idea regarding the pooling of activator in the flat collar area interesting. It may be that this factor, in conjunction with "A" and "B" components of less than optimum viscosities, is producing the results you are seeing in your fabrication.

As always, the only way to really nail down the reason is hands on testing. If you would like our lab to look at this, please give me a call.

Chad
888.862.6665

[Joe Corlett]

All:

There are several disadvantages to using the cup/stick method. First, it is very slow and a real profit-sucker for production shops. Second, the chance for contamination between the dispenser, cup and stick is great. Thirdly, it is wasteful. Fourth, there is too much adhesive air time.

If you've got a job that absolutely, positively has to have sound bonding, remove the old tip from the gun, wipe off any crud, stick the gun in the corner of a gallon-size clear plastic Ziplock bag. Pump in as much as you need, you'll be surprised at how accurate you get at this. You are positive you have catalyst, as you've seen it with your own eyes. Air bubbles? Who cares? Remove the gun, twist the bag and mix by hand. Don't knot the bag, you can use the other corner later. Pinch the bag tip between your thumb and forefinger and pull until it streches and breaks, creating a perfect dispensing nipple.

Fast. Minimal chance of contamination. Positive mix. Minimal waste. No excessive air time.

(30) gallon bags are $3.69 at the grocery store. That's twelve cents apiece but you're getting two squirts from each bag so thats six cents a dispensation. If you buy a boatload at a time, you might get a tip for .60 each. Sixty minus six is a fifty-four cent savings each time you run a bead of glue and that's not counting all the wasted adhesive left in the tip.

In a hurry? Take a heat gun to the mixed bag for four minutes maximum, clamp it and keep the material warm and your seam will be ready for sanding within twelve minutes.

Don't hate me glue-tip-selling-guys,

Joe

[jkbrand]

All:

There are several disadvantages to using the cup/stick method. First, it is very slow and a real profit-sucker for production shops. Second, the chance for contamination between the dispenser, cup and stick is great. Thirdly, it is wasteful. Fourth, there is too much adhesive air time.
Joe

Joe, just so there's no misunderstanding, you did notice in my post I referred to "short runs" for the cup method, right? For short runs, your list of disadvantages are debatable.

First, two or three squeezes into a cup (for a deck seam, e.g.) takes about 10 seconds to mix and about the same amount of time to apply. Second, only modest care is necessary to minimize contamination. We always wipe the tip of the cartridge whether we're dispensing through a new mixer or directly into a cup. Cups in the shop--and in the classroom--are in a dispenser; sticks are in a closed box. Third, not only isn't it wasteful; but as with your suggestion for using plastic baggies (a good one, by the way), it takes only a few examples to learn how much is enough; waste is minimal. Fourth, on short runs air-time exposure is minimal and of little or no consequence.


As far as mixing with Popsicle sticks goes, this is completely unnecessary if the adhesive is properly dispensed.


Chad, the "if" is a huge condition and begs the question. How does one know if it's being properly dispensed? That's the conundrum!

You cited tests that you've conducted specifically with the all-metal guns and their tendency to deform the glue's cylinder if squeezed too hard. How 'bout the ubiquitous all-plastic guns, which is what we use in our shop and in class? It seems virtually impossible to oversqueeze those. Are you saying that even plastic guns can be distort the cylinder?

Getting back to your comment above, however--and addressing the work-flow issues that Joe raised, I will say that one aspect of the Integra adhesive I enjoy over the other manufacturers is its lower viscosity. It is much more tolerant of air time than the others. Once we've laid down, say, 8 feet of seaming compound (through the tip, because we only advocate using the cup for short runs!), it takes about 5 seconds to run down the length of the bead to ensure no cold spots. Given that most manufacturers estimate about 40 - 50' of seaming from a cartridge (we get about 60'), we will have spent one extra minute of time spreading the adhesive for every two cartridges we consume. A small price to pay to minimize the chances of a cold spot.

[chad t]

Static Mixers:

Static mixers vary in mixing performance and pressure drop (back pressure) depending on the dimensions, number of elements and the mixer design.
Use a static mixer with an adequate number of mixer elements and the lowest backpressure to minimize off ratio dispensing. Talk to your adhesive supplier as mixer design requirements vary depending on the adhesive flow properties.
Partially blocked static mixers or cartridge outlets can also have a negative effect on the cure.
Check for crystallized or cured adhesive at the outlet before re-attaching a new tip to a previously used cartridge.

Dispensing guns:

Manual dispensing guns vary in mechanical advantage.
Higher mechanical advantage dispensers can produce more internal pressure and increase chance of off ratio dispensing. To minimize off ratio dispensing, use as little pressure as possible to dispense the adhesive and maintain a constant forward motion of the cartridge pistons.

Some dispensers have a non-drip feature that releases pressure at the end of each stroke. This is a useful feature but it can add to off ratio dispensing if the gun is pumped and then paused between strokes. Apply a technique of constant motion and a rapid re-grip of the trigger.

Damaged or worn dispensing gun:

Damage to the ratchet / brake mechanism and cracks or missing teeth on the plunger of a dispensing gun can cause uneven feeding of the pistons. Check the condition of the dispenser paying particular attention to the ratchet mechanism. Look for broken teeth, build up of adhesive or play in the dispensing mechanism. Also look for loose, bent or missing piston rod ends.

Leaking cartridge pistons:

Check the condition of the dispenser. Look for excessive play in the piston rods or loose piston rod ends. Check cartridge position in the dispenser and ensure that it sits parallel to the piston rods. For pneumatic systems, ensure there is a regulator on the dispenser providing controlled pressure. Adjust pressure to provide adequate flow without overpowering the system. If leaking occurs, your supplier may wish to inspect the molded part for defects or damage as part of their quality control program.


Operators trigger action:

Some shops find that off ratio dispensing appears to be a random event and may occur more often with some individual operators. The triggering action used with manual dispensers is an important technique to ensure an even cure.
Purge adhesive (1 tablespoon) immediately start to dispense adhesive. Apply smooth even strokes; maintain constant feed and pressure using the full stroke of the trigger. Do not stop and let adhesive drool out of the tip between strokes, quickly re-trigger the gun and continue until dispensing is completed. To minimize off ratio dispensing, use as little pressure as possible to dispense the adhesive and maintain a constant forward motion of the cartridge pistons.

Cold Adhesive:

Adhesive stored in the fridge or a cold shop, should be allowed to return to room temperature before use. Some adhesive components become thicker at low temperatures and may not mix as well. Thickened material creates higher pressure in the cartridge and tip. Higher pressure will flex the cartridge wall and can throw off mix ratio. If you re-warm adhesive, make sure the cartridge plug is in place. A previously used mixing tip left on the cartridge can allow expanding adhesive to back flow into the activator chamber and result in a plugged cartridge.
To avoid activator damaged, never warm adhesive above 110 degrees f.

Cold Sheet material:

Bonding sheet goods that have been stored below normal room temperature will cause the adhesive to cure slowly in the joint. Fabricating with cold sheet goods may prevent a full cure from developing in areas with lower than optimum activator levels.
Warm room air will cause the adhesive on the surface to cure much faster than the adhesive in the joint where the cold substrate will absorb much of the energy from the chemical reaction. This can cause joints to have low strength. For best results, allow product being joined to reach a room temperature of 60 f before assembly.

Disturbing adhesive prior to cure:

Disturbing the exposed adhesive at the joint line prior to the surface curing can cause the adhesive to remain sticky and under cured at the surface.
Let the adhesive cure undisturbed until the surface dulls and becomes hard. Do not handle the project until there is sufficient bond strength. A rough estimate for handling time (materials that are at room temperature when bonded) is 2 X working time. I.e. 15 minute to set up; allow 30 minutes before applying stress to the joint.

Storage:

For optimum shelf life and performance, store adhesive upright away from direct sunlight in a cool area or fridge.
It is possible that an air bubble could be trapped in the activator or adhesive, gases can also form in the activator if it is subjected to high temperatures during storage or shipping.
In the event that a gas or air bubble was trapped in the cartridge, upright storage should allow it to reach the top (outlet) of cartridge to be eliminated during the initial purge.

Activator failure:

Activator exposed to high temperatures during transport or storage will start to break down and loose strength, this will generally show up as a slower cure.
High temperature decomposition of the activator can also release gasses into the activator component.
Bubbles may appear in the dispensed product and the compressibility of the gases may act like a spring compressing with each pull of the trigger, producing fluctuations in the dispensing rate, off ratio cure and drooling at the tip.
Our tests revealed that some manufacturer

[lensmith]

Here's the mark of a very good company (in my book, anyway.) After our recent problems with curing, Ray Aleksic of Integra Adhesives came to our shop and worked with our glue-up guy. Ray asked about his techniques, and recommended a couple of simple changes. Since then we've had no further issues.

It appears that the original batch I posted about may have had some issues, but it also appears that our application technique was the culprit for a couple of subsequent slow cures.

Thank you Ray, and Integra for coming out to our facility and helping us with this!

Len

[Ray Aleksic]

Len,

I am glad it all worked out, if you need anything else do not hesitate to contact us.
Great new shop BTW.

Ray