Epoxy failing to bond to acrylics

[johnnycnc]

Anyone having issues with their epoxy failing to stick to inside
of acrylics here lately?
I have reasonably fresh (4-6months) 2-part epoxy from wally world, same Devcon brand in 90 minute I've used several tubes of it over the last couple years.
Well, drilled up some acrylics from Beartooth woods and epoxied tubes in.
let cure a wek or more. The mixing pad was cured in an hour.
When trimming the ends square,just removing base plate wax, one tube just slid out.
Epoxy was all still bonded to tube.
It's as if the blank material was not in the mood for any association with the epoxy at all.
I don't drill wet or use funny lubricants when drilling blanks, so it can't be contamination.
I wound up CA gluing it right back in, epoxy on tubes and all, turned, finished,
no problems.Funny thing, the CA glue was a salvage from my flooded shop last June, the tip was glued closed, and it survived no water in it.This freakin CA is 1-1/2 years old or more, been in flood water, and still cures.
Starbond brand CA, I think it is pretty good stuff!

Anyway,
Any one else been here with some of the newer generation acrylics??
Epoxy or whatever not sticking to some acrylics??

Thanks in advance for any clues!

 

[Chasper]

I've had the same problem. I've been using 5 minute epoxy; 4 oz bottles of epoxy and hardener that I bought at Hobby Lobby. My wife had been gluing in some tubes for me and they wern't curing, some were pushed out when I used the end mill, some spun inside the blank when I tried to turn them. I thought she was not using a 50/50 mixture , so I started doing it myself.

Last week I glued up 24 tubes in batches of 6. I noticed that some of the were still wet, about half of them. I think that I didn't get a 50/50 mixture on the two batches that didn't cure. I may have been a little off on the mixture, but not much. I was thinking of using a jewelry scale to get the mixture even; is the specific gravity the same for the epoxy and hardener?

They did harden in the mixing tray. Was it not sticking to the arcylic or just still wet? Mine was wet. I had dyed the epoxy red and the inside of the tube was painted red, the tube was brass and had not been painted. When I pulled the tube out it was red, and it as the epoxy that was on the tube, not the paint from the inside of the tube. I'm usually pretty good as eyeball something like equal quantites of epoxy and hardener, but I thought possibly the measure was very critical and too difficult to get it accurate by eyballing it.

 

[johnnycnc]

Gerry,
The epoxy I am using is the syringe type 2-part it squirts out both a and b sides same time.
I'm pretty careful to keep them equal. Mine was all cured well, in the mixing tray, and on the tubes.Nothing wet or sticky.
It is like someone armor-all'ed the inside of blanks, it just did not stick.
I had no paint or dyes in my situation, so i can't point to that in any way.
I'm really wondering about this, perhaps the shelf life/storage conditions
got to my epoxy, we really don't know how old it is, even when buying at store.It's new to us, but could be a year old.
Shelf life expired is the only thought I have for what happened to me.

I've had the same problem. I've been using 5 minute epoxy; 4 oz bottles of epoxy and hardener that I bought at Hobby Lobby. My wife had been gluing in some tubes for me and they wern't curing, some were pushed out when I used the end mill, some spun inside the blank when I tried to turn them. I thought she was not using a 50/50 mixture , so I started doing it myself.

Last week I glued up 24 tubes in batches of 6. I noticed that some of the were still wet, about half of them. I think that I didn't get a 50/50 mixture on the two batches that didn't cure. I may have been a little off on the mixture, but not much. I was thinking of using a jewelry scale to get the mixture even; is the specific gravity the same for the epoxy and hardener?

They did harden in the mixing tray. Was it not sticking to the arcylic or just still wet? Mine was wet. I had dyed the epoxy red and the inside of the tube was painted red, the tube was brass and had not been painted. When I pulled the tube out it was red, and it as the epoxy that was on the tube, not the paint from the inside of the tube. I'm usually pretty good as eyeball something like equal quantites of epoxy and hardener, but I thought possibly the measure was very critical and too difficult to get it accurate by eyballing it.

 

[fernhills]

Hi, i had that problem 1st time last week, 1 hr epoxy from Lowes, two part eyeball amounts. Did six pens for a customer, all acrylic, went to clean ends of tubes and about three pens i had to re-glue with c/a. I had to use epoxy because i wanted to color the epoxy. I thought i must have done some thing wrong. Product was only about 3-4 months old. I am stumped. I like the 1 hour stuff, gives me more time to do mutiple pens.

 

[johnnycnc]

Thanks for relating your experience.
I'm kind of like you, thought I must have done something wrong.
I really like the 2part syringe epoxy, but am wondering if it's the epoxy,
or if it's a new acrylic blank formulation that may be causing this issue.
I'll probably have to try some other brand epoxy and try it on the same blank material.I'm not ready to go back to ca glue just yet.

Hi, i had that problem 1st time last week, 1 hr epoxy from Lowes, two part eyeball amounts. Did six pens for a customer, all acrylic, went to clean ends of tubes and about three pens i had to re-glue with c/a. I had to use epoxy because i wanted to color the epoxy. I thought i must have done some thing wrong. Product was only about 3-4 months old. I am stumped. I like the 1 hour stuff, gives me more time to do mutiple pens.

 

[workinforwood]

I use loctite epoxy 30min and never had a problem with the epoxy. I've spun the occasional tube but it only happens if there is paint on the tube and the trimmer is a tight fit causing the tube to heat up. I don't know what your problem is. Maybe the hole was slightly enlarged from the bit getting hot or too much shavings in it which caused too much gap between the epoxy and the blank? There is a gorrilla glue now that dries clear and still expands like the old gorilla glue, and you can add some powder dye to it. I found a bottle at lowes recently. It dries faster then the original gorilla glue too, but when using it on acrylics it's best to give it 24 or more hours to dry. The difference between acrylics and wood is air penetration. Sometimes with acrylics, the gorrilla glue will dry on the outsides, but not so fast on the inside because as the outside dries it seals the inside from recieving any air, and thus the inside of the blank is uncured just like being in a bottle. So...solve one issue create a new one.

 

[mick]

Johnny this may sound silly but did you drill the blanks with a nice new sharp drill bit?
I'm wondering if you had such a smooth surface inside the blank that the glue couldn't get a grip?

 

[artistwood]

sharp drill bit, smooth holes........last time i had this problem, it was because the pen mill shaft had accumulated some brass. that was causing friction, which caused heat which caused the epoxy,and /or CA to soften. took a blow torch and a big pair of pliers to remove the tube from the mill. i started putting some blade lubricant from sloans scrollsaw shop on the pen mill shaft and haven't had the problem since.....bear

 

[workinforwood]

sharp drill bit, smooth holes........last time i had this problem, it was because the pen mill shaft had accumulated some brass. that was causing friction, which caused heat which caused the epoxy,and /or CA to soften. took a blow torch and a big pair of pliers to remove the tube from the mill. i started putting some blade lubricant from sloans scrollsaw shop on the pen mill shaft and haven't had the problem since.....bear

I second the lubrication. I am now spraying my mill with table saw slick and have not had the issues of spinning the tube loose from heat build up. It only takes a few seconds of that mill spinnning in the tube to heat the glue enough to soften it, and it only takes a few seconds for the softened glue to re-harden. Because of this, you could heat the tube, spin it out and by the time you finish scratching your head, the glue is hard again and you loose sight of the cause. Not saying you did do that, but it's possible. Took me a lot of spun tubes to figure it out. Usually it's specks of spray paint that get into the tube that cause the extra tight fit for me, but sometimes the tube is just tight.

 

[johnnycnc]

I use loctite epoxy 30min and never had a problem with the epoxy. I've spun the occasional tube but it only happens if there is paint on the tube and the trimmer is a tight fit causing the tube to heat up. I don't know what your problem is. Maybe the hole was slightly enlarged from the bit getting hot or too much shavings in it which caused too much gap between the epoxy and the blank? There is a gorrilla glue now that dries clear and still expands like the old gorilla glue, and you can add some powder dye to it. I found a bottle at lowes recently. It dries faster then the original gorilla glue too, but when using it on acrylics it's best to give it 24 or more hours to dry. The difference between acrylics and wood is air penetration. Sometimes with acrylics, the gorrilla glue will dry on the outsides, but not so fast on the inside because as the outside dries it seals the inside from recieving any air, and thus the inside of the blank is uncured just like being in a bottle. So...solve one issue create a new one.

Thanks, Jeff, the hole was pretty snug.
I retract to clear shavings very often.
I'm not real sure what was going on at this point.:biggrin:

 

[johnnycnc]

Johnny this may sound silly but did you drill the blanks with a nice new sharp drill bit?
I'm wondering if you had such a smooth surface inside the blank that the glue couldn't get a grip?

Thanks Mike, that is pretty much the case.It was a new bit.
Holes were real smooth now that I think back. Hmmm..

 

[johnnycnc]

sharp drill bit, smooth holes........last time i had this problem, it was because the pen mill shaft had accumulated some brass. that was causing friction, which caused heat which caused the epoxy,and /or CA to soften. took a blow torch and a big pair of pliers to remove the tube from the mill. i started putting some blade lubricant from sloans scrollsaw shop on the pen mill shaft and haven't had the problem since.....bear

Thanks, Bear, I have pretty much sworn off pen mills from early on, opting to use a jig on my disc sander. I go a little, and look to see where I'm at.
They usually stay pretty cool.
I had a pilot get stuck, early on, and 1/2" dewalt hammer drill would not dislodge it.I literally shredded the tube and blank to disassemble.
Needless to say that was not on my to-do list ever again. Thus, the disc sander.
I'll certainly agree that heat can be a major problem here!!:biggrin: