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Author Topic: What happened to Pacer ZAP/CA  (Read 940 times)
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USch
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« on: May 17, 2017, 12:12:21 PM »

Hi all,
I am having since quite some time an issue  with the ZAP/CA from Pacer. I used this CA for many years and it was just fantastic on balsa.

Then, about 2-3 years ago, I got bottles which where no more crystal clear as before, but reddish like taken from a rusty container. And for gluing it was more or less useless not starting off after minutes. I had to bin all my surplus. Now I got a new sample which at least is again crystal clear but even putting a drop between my fingers it doesn't glue them together, let's alone on balsa or other material. At one time I thought it maybe because I use a lot of old balsa, but even licking the wood to dampen it doesn't help.

I searched the web to see if anybody else had the same result but nothing. As this is a builders forum I hope somebody has a different experience or knows that Pacer changed formula on there Ciano's.

Urs
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Starduster
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« Reply #1 on: May 17, 2017, 12:35:14 PM »

In a way, I'm glad to hear this. I thought I was the only one that was having issues with Zap.

I have same issues as you. I don't see any of the reddish tint, but it does not set for quite a while, and when it does, the bonding is terrible.

I stick with the Bob Smith Industries brand. This is your local hobby shop's "store brand" most of the time, the shop will put their own label on the bottle, but it's by Bob Smith.

A couple months ago I ran out of Ca, and I didn't really want to drive the extra 20 miles to my local hobby shop, so I just went to a local craft store. All they carry is Zap. A complete waste of money.

In a nutshell, yes, Zap sucks.
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Pops
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« Reply #2 on: May 19, 2017, 02:29:19 PM »

Hm, this is indeed strange, because I've always had the opposite experience with Zap! In fact I have two bottles on my desk now, thin and medium respectively, that's just working like a charm! Yes, I've also used other brands of CA and found them good - exept for the Great Planes CA, that hardened in the unopened bottle just a week after I bought it! (No, it was not stored with the kicker, and yes, it was still within the "best before" date!) The Bob Smith brand is also great, I've used it for years - but my LHS now focuses on Zap and like I said I always had good results with it.

Something really funny is going on if a drop of CA can't stick your fingers together! I would have taken the bottle back to the store and had it replaced.
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« Reply #3 on: May 20, 2017, 03:47:54 AM »

Quote from: Pops
Hm, this is indeed strange, because I've always had the opposite experience with Zap!
I like Zap because the thin stuff is really thin. You can probably achieve the same result by putting some acetone into regular CA, but maybe Zap! (Pacer) have a cleverer way than that.

There's no doubt; CA does have a very strange habit of failing to stick sometimes, and it's infuriating. And I have had rusty-tinted CA, and congealed CA.

The rusted stuff was clear to start with but became rusty during deep-freeze storage. Whether it became tinted because of deep-freezing I don't know. Anyway it wasn't just Zap CA, it happened to another brand at the same time. I used both bottles; the mechanical properties didn't seem reduced. I have used a brand which thickened in the bottle but only over months, and again it still seemed to do its job, so I used it where a thicker adhesive was an advantage.

The mystery of why CA fails to work sometimes has me beat. I'm sure it's not brand-related though. I've considered the temperature and humidity (both highly relevant to CA cure) and after experiencing 'non-stick' episodes in a variety of temps/RH, don't believe that's the cause.

I use thin CA dropped onto joints already in position, so the CA invades the joint by capillary action. So the accuracy of the mating faces could be an issue, but again I've seen the non-stick thing too many times to suspect the accuracy of my joinery as the only reason.

The following is from a commercial pdf I downloaded but didn't save a link to.

"Curing Mechanism

When confined in a thin film between two surfaces, cyanoacrylate adhesives cure rapidly at room temperature to form rigid thermoplastics with excellent adhesion to most substrates. Cyanoacrylates typically reach handling strength within one minute at room temperature and achieve full strength in 24 hours.

Cyanoacrylate adhesives undergo anionic polymerization in the presence of a weak base, such as water, and are stabilized through the addition of a weak acid. An essential function of the stabilizer is to prevent polymerization in the container, which is usually made of polyethylene.

When the adhesive contacts a slightly alkaline surface, trace amounts of adsorbed water or hydroxide ions (OH-) that are present on the substrate’s surface neutralize the acidic stabilizer in the adhesive, resulting in rapid polymerization. In general, ambient humidity in the air and on the bonding surface is sufficient to initiate curing within a few seconds. Therefore, parts must be joined quickly. The open time is dependent on the grade of adhesive, the ambient temperature and relative humidity, and the nature of the substrate surface (pH and amount of adsorbed water). Optimal bonding conditions are when the ambient relative humidity is between 40% and 60%. Lower humidity slows cure, high humidity accelerates it, but could lead to lower bond strength.

To achieve the fastest cure, a very thin bond line is desirable. The cyanoacrylate adhesive need only be applied to one surface. Without the application of a primer, acidic surfaces may delay or even prevent curing, whereas more alkaline or basic surfaces accelerate curing. Generally, the accelerator is applied to one surface while the adhesive is applied to the mating surface. Exposed liquid adhesive can be cured within seconds with activators. In those cases the activator is sprayed directly on the liquid cyanoacrylate."


I wonder about the acidity thing in the article - perhaps only a tiny increase in acidity at the joint could cause the stuff not to cure for ages? I should say, I've never seen CA fail entirely to cure: it can just take a minute or more to do so. For me, these non-stick episodes happen with CA taken from the same bottle that worked fine yesterday, and worked fine the day after. Unless the CA in the bottle isn't entirely homogeneous (unlikely but not impossible, I suppose), then it's not the CA but the mechanical/environmental conditions that are the problem.

Maybe the CA that congeals in the bottle is a brand that uses less acidic stabilizer.

Stephen.



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USch
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« Reply #4 on: May 22, 2017, 05:12:42 PM »

Thank you Stephen for your excellent description about the mechanics of CA.

Maybe I was not clear in my first post, I am not talking about a strange behavior of one bottle of ZAP/CA, but the radical change the product had about 2 years back.
For at least 15 years ZAP/CA was considered the best and sort of standard for gluing balsa with CA. It had the following high points
   - extreme spreading power, one drop on a joint spread out a long way
   - non the less it set immediately without the use of accelerator

Indeed, as a friend had me noticing in the meantime, on the old label was written
Penetrating Action, Super Fast Cure, Best for Tacking Applications
On the new labels it just says thin CA  . No mention that it takes hours to set  Sad  Shocked  Cry

Urs

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« Reply #5 on: May 22, 2017, 05:18:55 PM »

Hi Urs,

I have had exactly the same experience with CA, as you describe.

Used to love it, now hate to use it. Or better, am dissappointed whenever I use it.

I need to find a replacement...

George
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SBlanchard
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« Reply #6 on: May 23, 2017, 11:21:47 AM »

I have been using CA adhesives for the last 15 years. I too realized that the only brand I can count on completely is Bob Smith products. I tried Zap once and found that Zap = Crap. Never waste my money again on it.

Steve
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Prosper
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« Reply #7 on: May 25, 2017, 05:26:33 AM »

Quote from: USch
Penetrating Action, Super Fast Cure, Best for Tacking Applications
Oh dear. I just looked at the bottle I'm using and it says  those words. Perhaps the next bottle I buy will be this new duff stuff.

Stephen.
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« Reply #8 on: May 25, 2017, 06:09:02 AM »

I've been using Loctite "Super Glue" for the last few years. It is available at both Lowes and Home Depot in the US. Unlike the hobby shop stuff, I have never seen a bottle of Loctite covered with dust. I'm assuming the big box stores have fast enough turnover that the stuff is fresh.

Loctite offers a variety of CAs, "Professional Liquid", Ultra Liquid Control" and their "gel" are the three I use. The gel has a fairly long open time and works well for applying carbon capstrips. Tmat has a thread on Hip Pocket about how to use Loctite gel for carbon caps.

For balsa-to-balsa construction I still prefer Titebond. For me, CA is a specialty adhesive, so the small bottles of Loctite make sense.

Louis
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fred
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« Reply #9 on: May 27, 2017, 01:04:07 PM »

As above NIX onna ZAP.
After decades of use I began to have Bad allergic reactions (Flu symptoms)
 Stopped using CA entirely.
 Finally got a Bob Smith bottle of Ca . Surprisingly it produced No allergies ! 
Plus the stuff is cheaper than Zap And lives much longer in the bottle.
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USch
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« Reply #10 on: May 27, 2017, 01:24:40 PM »

Thanks for the input.
Now Bob Smith will be hard to find here in Europe, but Loctite is, or at least was, a Dutch company and there products are widely used in the workshops.
I will try to find the Loctite CA for a try.

Urs

PS: B. Smith products are sold in some European country's, but not in Italy  Sad
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Konrad
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« Reply #11 on: May 27, 2017, 04:47:23 PM »

As above NIX onna ZAP.
After decades of use I began to have Bad allergic reactions (Flu symptoms)
 Stopped using CA entirely.
 Finally got a Bob Smith bottle of Ca . Surprisingly it produced No allergies ! 
Plus the stuff is cheaper than Zap And lives much longer in the bottle.

Please be aware that there may be an exposure threshold to trigger these allergies. Use in a well ventilated area regardless of brand.
YMMV, but my CA allergies were isolated to the accelerator.

All the best,
Konrad
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« Reply #12 on: May 31, 2017, 01:20:12 PM »

Yess of course, thank you.
 Mine is triggered  (mildly though) even by walking thru a room where (Zap) CA was used the previous day.

 Never Ever... even owned, let alone used Accelerator.. as aside.
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« Reply #13 on: June 17, 2017, 10:41:20 AM »

Back to topic:

Will wonders ever cease!?!? Looking at my bottle of thin Zap CA, it has now got a rusty tint to it, and the bottle of gap-filling CA has turned a wee bit yellow! :-o

The table where I've left them for a while now (approx. 5 weeks) is located by the window and the sun can shine in on it. Can it be the uv-rays that has triggered these colors and change in chemistry? The thin CA now refuses to harden instantly but the gap filling CA still cures like it did before. Both bottles are still as liquid as they should be.
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