CA finish issues

[Marc]

Over the past several months, several of us have experienced issues with the CA finish crackling as it cured. Lots of us speculated various reasons for this, but there have been few definitive answers.
I work in a brick and mortar woodworking shop and asked our CA vendor about this issue and I wanted to share the response, hopefully there is an answer or two that might help us understand this issue.

"Two things cause the cracking:

One = putting on too thick of coats.

Two = old CA Finish – which also leads into item #1. Batch numbers: the first number represents the year 3 = 2013 and the next three number is the batch. This past year we had less than 400 total batches so you can get a quick idea of when… the smaller that number the closer to the beginning of the year. I tried to get the batch numbering system changed to a date but ISO 9000 does not allow that… I will try again to see if the rules have changed.

The problem is that the coat is not curing all the way through before putting on the next coat… when it eventually cures it shrinks slightly creating cracking under the final coat.

The older the CA Finish, the slower it cures – which is why the older material has problems.

This happens with older regular CA also but since we made the CA Finish slower to start with making it easier to apply the Finish becomes "Old" sooner – even though it looks ok. The Old CA Finish can still be used as an adhesive like CA but cures slower."

Hope this info helps.

Marc

 

[Jim15]

Thank you for the info.

 

[edstreet]

Sorry call me a skeptic but I am not buying the 'to thick' approach. Also what brand CA are were talking here as there are more than one. This also does not account for the often seen 2 day to 2+ year cracks.

 

[Dan Masshardt]

Once again, we should experiment to seek if we can make it happen on purpose.

This does thread does give us two interesting things to try.

Maybe somebody with some really old ca can try using it on a blank.

And somebody can try putting on several really thick coats and see what happens.

 

[lorbay]

This CA I used is 6 years old. Not sure that's old enough or not.
http://www.penturners.org/forum/f13/yellow-cedar-burl-kitless-116798/
Lin

 

[cal91666]

Dan, I like the idea of experimenting to try to find a cause/reasoning for this to happen and would gladly participate but wonder how we would control the multiple other variables that are possible causes for this. Type of wood, moisture content, surface area (eg...slimline versus cigar), room temp, humidity, age of CA batch, brand of CA, definition of "THICK" coat, etc., etc., etc. Again I like the idea of experimenting and would gladly participate if we could figure out a way to control the experiment.

 

[its_virgil]

Although I've never had a problem with CA cracking or even the often questioned cloudy and dull spots I have noticed my CA finishes are not as nice as they once were. I started out using the oldest and original Hot Stuff. Over time I migrated to other brands because of various reasons. Recently I purchased an order of Hot Stuff and my CA finishes quickly went back to the excellent finishes of "back in the day." I will now stay with Hot Stuff for my finishing needs. Just saying.
'Do a good turn daily!
Don

 

[Dan Masshardt]

Dan, I like the idea of experimenting to try to find a cause/reasoning for this to happen and would gladly participate but wonder how we would control the multiple other variables that are possible causes for this. Type of wood, moisture content, surface area (eg...slimline versus cigar), room temp, humidity, age of CA batch, brand of CA, definition of "THICK" coat, etc., etc., etc. Again I like the idea of experimenting and would gladly participate if we could figure out a way to control the experiment.

As frustrating as it might be, it might be best for someone who accidentally experiences a ca problem to embark on a couple other tests to see if it would be replicated under the same conditions.

I would love to see someone willing to repeat the same finishing process in the same type of wood under the same conditions. And see if it repeats.

 

[longbeard]

Thanks for the info Marc

 

[Tom T]

Great info. Thanks for helping us all.

 

[Boz]

We have a freezer in the basement just outside my pen workshop. I keep all my CA in the freezer all the time. When I need to use it just pull it out and put it in my pocket for a few minutes. When warmed up use it for gluing or finish. Just started doing finishes on some projects and I am going to say that the stuff in the freezer is at least 3 years old. Working for me but hey what do I know? Right.

 

[edstreet]

So on the 'to thick' issue, would 1/32" be 'to thick'??
http://www.penturners.org/forum/f56/dragon-sceptre;-gent-tube-conversion-114232/

That is how thick I put the CA on this project and to date there has been no cracking, chips, distortion or problems of the like.


I still say we should do some experiments and find out the truth of this matter.

 

[Holz Mechaniker]

Just remember, when you "Experiment" The difference between Science and Messing around is Writing it down.

 

[Bad Habit]

being new I don't have the experience others have...my CA finishes have been fracturing as well, eliminated moisture and temp changes, allowed blanks to cool completely before applying CA. I also stayed with more thin adhes then using any med.adhes..
still have the fracturing issue..usually shows up within 24 hrs.

its possible I'm applying too many thin coats of thin..10-15.
wood doesn't seem to be the quanitive, soft wood or hard wood.
Only Constant (besides myself) is CA. Except for changing that up, I don't know what else to check...??????

 

[Rodnall]

For those of you using accelerator with problems, could you be using too much? I don't put any accelerator the first two coats because they dry so fast. After putting it on after the second coat & spraying from a distance I put on the 3rd through 5th coats before I spray again. The accelerator seems to help the next couple of coats dry fast. without adding any additional. After the accelerator the coats also seem to go on thicker. 8 coats of thin ca with 2 applications of accelerator and then start with 400 grit seems to work for me without any problems.

 

[Mike Powell]

I lay my CA on pretty thick. The only problem I ever have is ripples in it that I MM out.
I put on my CA turn the lathe down to lowest RPM setting and let rotate for a few, then off with a lamp on it for about 5 minutes. Then another coat or two the same way. Worst thing to happen to me so far is a zip lock sticking to it because I didnt let it dry long enough.

 

[steve worcester]

This CA I used is 6 years old. Not sure that's old enough or not.
http://www.penturners.org/forum/f13/yellow-cedar-burl-kitless-116798/
Lin

CA is usually considered old after a year. It has a definite shelf life and the fridge only helps if you are in a real hot environment. Humidity is as big of a factor as heat and generally the fridge makes it worse humidity-wise.

 

[TwoCatsPens]

Do you think storing CA in a sealed container like a big food storage container with a couple of packs of the silica desiccant (the 'do not eat' bags) might help. I understand that CA pulls moisture from the air to help cure, that might help?

Steve

 

[Bad Habit]

appears to be a shelf life issue...I had fracturing issue with lot 2122 and none with 3262...

 

[jyreene]

Thanks for the info Dad. Still won't use CA for a finish though!

 

[ed4copies]

So on the 'to thick' issue, would 1/32" be 'to thick'??
http://www.penturners.org/forum/f56/dragon-sceptre;-gent-tube-conversion-114232/

That is how thick I put the CA on this project and to date there has been no cracking, chips, distortion or problems of the like.


I still say we should do some experiments and find out the truth of this matter.

There is a problem, Ed. Experimentation would require listing the variables, and controlling all but one or two to see the results.

AGE of CA
Temperature and humidity it was stored at,
Open for how long
species of wood
oily? quantify
moisture content
How was CA applied
Brand of CA
Viscosity of each coat?
BLO?
Accelerator?
Sanding regimen?
Heat generated during sanding? Quantify?
Wet or dry?
OK, now on to the "climate and wood conditions" that happened between the time the pen was made and the surface started showing a problem.
How many days above 70 degrees (or should this be 72? 74?? 94??)
How many days with humidity above/below 50, or is it 60, or 40, or is 42.35 the critical number?? percent?
This is just starting----you see the problem??

Ed

 

[reiddog1]

I have a ritual that I do when I don't like the finish on a pen. I leave it out in the garage for a week in Northern FL. Yep, that's it. Weather here is 5 min at a time. Wet, dry, cold, and hot are a matter of a week. The change in weather will crack the finish until it looks like a broken mirror. Then, back to the lathe it goes for a date with the skew. This process makes it much easier to take the finish off. Yes, this story has a point!! Changing enviromental conditions makes the wood move, but not the finish, so the finish will crack like crazy due to the change. The more movement of the wood, the more cracks. Hope this helps in some crazy way.

Dave

 

[thebillofwrites]

This CA I used is 6 years old. Not sure that's old enough or not.
http://www.penturners.org/forum/f13/yellow-cedar-burl-kitless-116798/
Lin

CA is usually considered old after a year. It has a definite shelf life and the fridge only helps if you are in a real hot environment. Humidity is as big of a factor as heat and generally the fridge makes it worse humidity-wise.

Hi Steve, can you go in to more detail here. I'm not sure I get the meaning of your post.
It has always been my understanding that the inside of a refrigerator is relatively dry.

Bill

 

[thebillofwrites]

Do you think storing CA in a sealed container like a big food storage container with a couple of packs of the silica desiccant (the 'do not eat' bags) might help. I understand that CA pulls moisture from the air to help cure, that might help?

Steve

Hi Steve,

Yes, storing CA bottles in a container along with desiccants can help extend shelf life. Especially if your shop area is often humid. But keep in mind that many plastics are slightly permeable.

Bill