Accelerators-Compromised Strength Of Bond???

[69NovaYenko]

I was engaged in a casual conversation at my LHS and one of the parties commented that they felt accelerators may quickly set CA glue but, the rapid curing compromised the strength of the bond.  He said his observation was  that glued parts, when allowed to cure slowly, bonded together with more strength. The glued joint had a higher degree of structural integrity. Just wanted to get others take on this subject..

Edited April 5, 2016 by 69NovaYenko

[Impalow]

I believe I have experienced this..  especially with the BSI gold non-fogging stuff.  

I know that it is true with some other catalyzed chemicals... also curious to hear others opinions.

[Mike Chernecki]

I have no idea, but how about a test. Remember the old Krazy Glue commerical where a guy Krazy glued his hard hat to a steel girder on some tall building somewhere. Lets find an idiot willing to do the same test, do two tests with and without accelerator. If he falls then I guess it weakens the bond.

[cobraman]

Funny you mentioned that. I have wondered for a long time about that. I believe in some cases it does but that is just my opinion, no proof.

[Lunajammer]

Pretty easy to test. Glue your fore-finger and your middle finger to your thumb. Use accelerator on one and see which one comes off easier. Pics please.

[Foxer]

I should dredge up my old Strength of Materials Lab handbook and devise a test, but you guys ..

[SfanGoch]

I have no idea, but how about a test. Remember the old Krazy Glue commercial where a guy Krazy glued his hard hat to a steel girder on some tall building somewhere. Lets find an idiot willing to do the same test, do two tests with and without accelerator. If he falls then I guess it weakens the bond.

My friends and I tried that when I was stationed in Germany. I was the unit armorer at the time and I had quart bottles of CA in the arms room, which was used to repair or replace the hard foam pads on Dragon Missile trackers, attaching velcro for MILES equipment onto vehicles, glueing drunk roommates' hands and feet to their bunks, etc. Well, a couple of us were sitting around talking and somebody brought up the Crazy Glue commercial. There was a lot of discussion whether the commercial was rigged or not. One thing led to another and I suggested that we try it. Word got around the company and there were bets made (800 bucks' worth  ). We got a mechanic in our motor pool to attach a 5" square steel plate to the top of an M1 helmet and make another one with an eyebolt attached.  We looped a length of cable through the eyebolt and clamped it. Then, we made our way to our company's M578 recovery vehicle and hung the looped cable on the boom hook. I applied the CA on the helmet mounted plate (along all four sides and an "X" from corner to corner) and attached it to the one on the hook. The motor pool sergeant, Kevin De Salle, volunteered, for a piece of the action, to be the guinea pig. He secured the chin strap, held on to the steel pot and the boom was raised slowly until Kevin was about 5 feet off the ground. He was suspended for about two minutes and guess what? It worked as advertised!

[Art Anderson]

I believe I have experienced this..  especially with the BSI gold non-fogging stuff.  

I know that it is true with some other catalyzed chemicals... also curious to hear others opinions.

It may, or it may not.   However, I've been using gap-filling CA's for now 30-years, with BSI's accelerator, and have yet to have a single model car built thus come unglued.  That also includes dozens of fabricated masters used in resin-casting, which had to withstand sometimes incredible stresses when removed from their inner "core" mold sections (those that broke apart tended to suffer breakage of un-bothered styrene sections at a frequency equal to or even greater than, CA glued joints.

Art

[Belugawrx]

I was pleasantly surprised with this duo..

Rock solid

[SfanGoch]

Good choice. I never had any problems with that combo. 

[Quick GMC]

I don't buy it for one second. I use CA a TON for filling chips in the face of granite slabs. It can't be used in direct UV light or wet areas, but for what we use it for it is perfect. It can be shaved flush with a razor, polished, color tinted, etc. 

Since CA is an anaerobic sealer and cures instantly with the absence of oxygen, we have to use an accelerator to fill open pits. It will sit in a cup for 20 minutes and not dry. I have never experienced accelerated deterioration or any less integrity with these repairs. 

If it does make a difference, it is so minimal, it's a non issue. 

[Harry Joy]

CAs don't bond, whether you use an accelerator or not. They stick parts together. Accelerators speed that up.

If you want a bond, use solvent glues.

For what it's worth, I use CA and an accelerator for almost all purposes in every kit I build. The stock I have of solvents should last me the rest of my life. The long-term durability of the accelerated CA glues has not been a factor yet, as I don't toss around my models overmuch.

[Harry Joy]

Pretty easy to test. Glue your fore-finger and your middle finger to your thumb. Use accelerator on one and see which one comes off easier. Pics please.

Shear brilliance.

(Pun.)

I've never tried that. I have tried the reverse though, using a debonder to separate one finger whilst using teeth and force to free the other.

 

Edited April 6, 2016 by Harry Joy

[BubbaBrown]

In my observations I agree that a natural cure has a stronger bond. With that being said , maybe I use the accelerator on stuff which should have a better fit

[kenb]

Sometimes I felt accelerator might have compromised a bond, but that was on one of my r/c planes. As far as my model car building I use it quite a lot, but there is no real stressing in my model car construction. So the way I look at it, it could weaken a bond on your model car but would it matter. It's a static model.  Unless you intend to stand on it.  Ken

[Jantrix]

Pretty easy to test. Glue your fore-finger and your middle finger to your thumb. Use accelerator on one and see which one comes off easier. Pics please.

I'm sure (pertty sure) Mike was kidding when he posted this. DO NOT TRY THIS. The chemical reaction of the accelerator on the CA glue creates a very intense amount of heat. A friend in my model club has the scars to prove this. You WILL hurt yourself.

Based upon my experiences the accelerated bond is considerable weaker. This might be because of the chemical reaction but also because you might apply the accelerator before the CA has had time to flow into the joint completely.

[peteski]

I am also big fan of BSI CA glue and accelerator. I hava lso used about half a dozen of other brand CAs and accelerators.  In my experience using accelerator does affect the properties of the cured CA glue.  I don't think it affects the actual bond between the glued surface and the adhesive but it makes the adhesive more brittle.  The viscosity of the CA also makes a difference in the amount of brittleness. The thinner the accelerated CA is, the more brittle it will get when fully cured.

But none of this has ever caused any of my models to come unglued.  So, I wouldn't worry about it.

[69NovaYenko]

I am also big fan of BSI CA glue and accelerator. I hava lso used about half a dozen of other brand CAs and accelerators.  In my experience using accelerator does affect the properties of the cured CA glue.  I don't think it affects the actual bond between the glued surface and the adhesive but it makes the adhesive more brittle.  The viscosity of the CA also makes a difference in the amount of brittleness. The thinner the accelerated CA is, the more brittle it will get when fully cured.

But none of this has ever caused any of my models to come unglued.  So, I wouldn't worry about it.

I have used several CA glue brands but now primarily use  BSI CA glue.  I have been using "Zapp" accelerator instead of BSI accelerator. What I have experienced is the Zapp appears to makes the adhesive more brittle or weaker. I have been considering switching to the BSI accelerator in hopes of getting around this issue. Also, Jantrix may be on to something....I might be applying the accelerator before the CA glue has had time to flow into the joint and chemically bond the parts.