T88 cure time

[Painfullyslow]

Brand new to segmenting and attempting my first go at it. I've done some digging and kept seeing T88 coming up as a preferred option so I picked some up then cut and set up my first segmented blank...and then read the package for cure time. Nothing. Ok, off to the website where after a bit of digging came up with...72 hours!

Patience, like most virtues, is not something that I possess in any great quantity.

Since this is my first shot I am not attempting anything particularly challenging; just a few simple bands of aluminum/ebony/aluminum.

So I have two questions for you all:

Do you all really wait 3 days for this to cure before turning?

Is there an acceptable alternative with a faster cure time that can be used with simpler segmentations?

 

[KenB259]

I usually build blanks on weekends and don't get back to them until the next weekend, so yes, I wait that long. Your first attempt at segmenting though is not going to be as unchallenging as you might think. It's problematic gluing ebony and aluminum, not saying you can't but ebony being pretty oily doesn't glue easily to aluminum. You need to wipe both down with acetone prior to gluing and also before that you'll want to rough up the mating surfaces. Also, drill types matter, I would never use a brad point on any segments that include any metals and watch for heat. I know your post was only questing epoxy wait times, but since this is your first segmenting attempt, I thought I'd throw in a few tips. To your last question, I would stick with epoxy for segments that have metal in them.

 

[Painfullyslow]

I usually build blanks on weekends and don't get back to them until the next weekend, so yes, I wait that long. Your first attempt at segmenting though is not going to be as unchallenging as you might think. It's problematic gluing ebony and aluminum, not saying you can't but ebony being pretty oily doesn't glue easily to aluminum. You need to wipe both down with acetone prior to gluing and also before that you'll want to rough up the mating surfaces. Also, drill types matter, I would never use a brad point on any segments that include any metals and watch for heat. I know your post was only questing epoxy wait times, but since this is your first segmenting attempt, I thought I'd throw in a few tips. To your last question, I would stick with epoxy for segments that have metal in them.

Thank you for your response @KenB259 and I am absolutely open to any and all advice offered.

I had some some reading at least and so I was sure to scuff up the ebony and aluminum with 120 grit paper and then used denatured alcohol to clean both before using the epoxy.

I also appreciate the tip on the drill bit. I will be sure to use a new jobber bit when attempting to drill this. I was also considering using CA to affix 1/4" plywood to all 4 sides before drilling and simply removing it after a (hopefully) successful drilling attempt.

I will stick with epoxy as you recommended, I just wasn't sure if using a shorter set-time option was viable.

 

[jrista]

The cure time is temperature dependent. I also picked up T88 recently, due to some segmentation failures with the JB Weld and CA I had tried before. The T88 cure time in colder weather is days to a week (can cure as cold as 35 degrees). But under normal conditions, its much less time than that. Strait from the data sheet:

"At 70°F, T-88 will harden in 6-8 hours and will reach functional strength in 24 hours. T-88 has been specifically formulated to cure as low as 35°F without reduction in strength; this cure will require approximately one week. At 150°F, T-88 will set within 30 minutes and develop maximum bond strength and impact resistance after 2 hours. If excessive flow-out occurs, allow 2-4 hours at room temperature before heat cure."

So, at room temperature, its hard in 6-8 hours, full strength in a day.

I heat my epoxies, and the parts I'm epoxying, a bit before I glue them. I then try to keep them as warm as I can while they are clamped for curing. I've turned some segmented blanks the same day (probably 6-8 hours after gluing) after keeping the blanks heated after gluing, and did not have any problems with the segments separating. I haven't yet tested with metal layers yet, and that was where I had the most problems...but, I'll be doing the same thing, heating to get the best cure.

There is another reason to heat, beyond just speeding up the cure time. I'll have to see if I can find the article again, but, letting epoxies cure under cold weather is not a good idea in general regardless, as it leads to a weaker bond (T88 says it can cure to full strength as low as 35C, but it would take a week to test that...and I haven't wanted to try... ALL other epoxies I've cured at colder temps, in my garage, are weaker than anything cured at ~70 degrees or warmer indoors.) Epoxies cross-link/cross-polymerize, and they do that a LOT better if they can flow while curing. The ability to flow ensures maximum cross polymerization, which maximizes the bond. So curing your epoxy under higher temps than room temp (for T88, its 150 degrees, but don't go over 160 as that's the max functional temp...most epoxies are in the range of 120 to around 180 degrees I think) will be beneficial to the quality and strength of the bond. That is really the primary reason to heat everything...the faster curing time is really just the cherry on top.

 

[Painfullyslow]

The cure time is temperature dependent. I also picked up T88 recently, due to some segmentation failures with the JB Weld and CA I had tried before. The T88 cure time in colder weather is days to a week (can cure as cold as 35 degrees). But under normal conditions, its much less time than that. Strait from the data sheet:



So, at room temperature, its hard in 6-8 hours, full strength in a day.

I heat my epoxies, and the parts I'm epoxying, a bit before I glue them. I then try to keep them as warm as I can while they are clamped for curing. I've turned some segmented blanks the same day (probably 6-8 hours after gluing) after keeping the blanks heated after gluing, and did not have any problems with the segments separating. I haven't yet tested with metal layers yet, and that was where I had the most problems...but, I'll be doing the same thing, heating to get the best cure.

There is another reason to heat, beyond just speeding up the cure time. I'll have to see if I can find the article again, but, letting epoxies cure under cold weather is not a good idea in general regardless, as it leads to a weaker bond (T88 says it can cure to full strength as low as 35C, but it would take a week to test that...and I haven't wanted to try... ALL other epoxies I've cured at colder temps, in my garage, are weaker than anything cured at ~70 degrees or warmer indoors.) Epoxies cross-link/cross-polymerize, and they do that a LOT better if they can flow while curing. The ability to flow ensures maximum cross polymerization, which maximizes the bond. So curing your epoxy under higher temps than room temp (for T88, its 150 degrees, but don't go over 160 as that's the max functional temp...most epoxies are in the range of 120 to around 180 degrees I think) will be beneficial to the quality and strength of the bond. That is really the primary reason to heat everything...the faster curing time is really just the cherry on top.

Thank you @jrista for your reply. I have done quite a bit of laminating epoxy work so I am somewhat familiar with epoxy and have a heat-lamp setup for curing carbon fiber which I put my segmented blank under so it has been sitting at around ~100 degrees for 23 hours. The only information I could find on the cure time was from the S3 website under physical properties:

This is what I was basing my information off of.

In any case, I appreciate your comments and based on that I unclamped and trued up the blank a bit. So far, so good!

24 hours is about the limit of my patience so I can work with that =)

Again, I appreciate the feedback and information!

My first blank, so far: spalted tamarind, aluminum, gaboon ebony.

Fingers crossed that it drills and turns ok!

 

[KenB259]

Thank you @jrista for your reply. I have done quite a bit of laminating epoxy work so I am somewhat familiar with epoxy and have a heat-lamp setup for curing carbon fiber which I put my segmented blank under so it has been sitting at around ~100 degrees for 23 hours. The only information I could find on the cure time was from the S3 website under physical properties:

View attachment 330812
This is what I was basing my information off of.

In any case, I appreciate your comments and based on that I unclamped and trued up the blank a bit. So far, so good!

24 hours is about the limit of my patience so I can work with that =)

Again, I appreciate the feedback and information!

My first blank, so far: spalted tamarind, aluminum, gaboon ebony.

Fingers crossed that it drills and turns ok!

View attachment 330813

It is nice looking blank for sure.

 

[wolf creek knives]

I let mine cure for 24 hours. I've never had a problem with pen vs. blank splitting or coming unglued. I also use a 50/50 ratio on the glue. A line of Part A with an equal line of Part B.

 

[jttheclockman]

May I make a suggestion? When doing a simple segmented blank like that with only flat surfaces. It is better to drill the pieces before you build on the tube. Just be sure to use something to hold the metal pieces. I would drill the wood blank on the lathe using a pen chuck or some other chuck that can support the blank. Find center of the blank by making a cross from corner to opposite corner. Now use an awl and make an indent. Use a pointed live center in the tailstock and line the point with the indent and lock the headstock chuck down. Now replace the tailstock with a drill mandrel and use a starter bit and switch to the size bit needed for tube. Then cut the blank accurately to sizes needed and when build allow about 1/32" on each end for trueing ends later. Sounds harder that it really is. But it will save you angst when drill all in one. Just a suggestion. That is the way I do those type blanks.

 

[jrista]

Thank you @jrista for your reply. I have done quite a bit of laminating epoxy work so I am somewhat familiar with epoxy and have a heat-lamp setup for curing carbon fiber which I put my segmented blank under so it has been sitting at around ~100 degrees for 23 hours. The only information I could find on the cure time was from the S3 website under physical properties:

This is what I was basing my information off of.

This is the data sheet I was using:

http://simplexaero.com/wp-content/uploads/2011/02/T-88_TDS.pdf#:~:text=cure%20as%20low%20as%2035°F%20without%20reduction%20in,heat%20cure.%20BONDING%20WOOD%20WHITE%20OAK%20AND%20TEAK

In any case, I appreciate your comments and based on that I unclamped and trued up the blank a bit. So far, so good!

24 hours is about the limit of my patience so I can work with that =)

Again, I appreciate the feedback and information!

My first blank, so far: spalted tamarind, aluminum, gaboon ebony.

Fingers crossed that it drills and turns ok!

View attachment 330813

Nice looking blank!! Gonna be a beauty!

I am still a beginner with this kind of segmenting myself...but, to what John T said, I have found that drilling any segmented blank with metal layers is fraught with trouble. That is always where my segments separate, at the metal to wood or metal to resin bonds.

Given how beautiful this blank is, I recommend adding some external structural support, to maximize the chances of success once you drill. What I did the last couple, was to glue on some of those fat popsicle/craft sticks on the outside, so that there was some additional support holding all the segments in place. I thought about wrapping that with something else, but I ended up just drilling with the craft stick outer layer only. It worked, and I was able to drill without anything separating. I've only done that twice now, though, and I have more experimenting to do. I think, also, that so far all of the blanks have been resins and metals, no wood yet...

One thing I have not yet figured out how to do though, is drill the metal layers on their own. I always seem to have some kind of problem trying that. So far, I've been trying to glue down or clamp down the pre-cut squares on their own. I've tried gluing them on the flat surface of a sacrificial piece of wood, and that really didn't work. I tried gluing and clamping, which was a bit better, but I seem to get a rim on the back side of the hole, which then requires extra work to work that out. Even when I drill real slow. I currently have mostly bradpoint bits, and I think that is part of my problem, so next time I get into segmenting, I intend to buy another set of drill bits that are not bradpoints, and see how that goes with the metals.

One thing I did see in a thread a while back, was someone drew out all the metal segments they wanted on each piece of metal, then drilled first, then finally cut up each piece. That, to me, seemed like a much better way to go about it, as you would then have a lot more metal surface area to clamp down or do whatever you needed to do to hold it in place properly while drilling. Still would need that sacrificial piece of wood, but, I think it would work better than what I had tried before.

 

[Alan Morrison]

I agree with JT.
Far easier, when joining flat pieces, to pre-drill them and then assemble them all onto the tube.

Alan

 

[Painfullyslow]

This is the data sheet I was using:

http://simplexaero.com/wp-content/uploads/2011/02/T-88_TDS.pdf#:~:text=cure%20as%20low%20as%2035°F%20without%20reduction%20in,heat%20cure.%20BONDING%20WOOD%20WHITE%20OAK%20AND%20TEAK


Nice looking blank!! Gonna be a beauty!

I am still a beginner with this kind of segmenting myself...but, to what John T said, I have found that drilling any segmented blank with metal layers is fraught with trouble. That is always where my segments separate, at the metal to wood or metal to resin bonds.

Given how beautiful this blank is, I recommend adding some external structural support, to maximize the chances of success once you drill. What I did the last couple, was to glue on some of those fat popsicle/craft sticks on the outside, so that there was some additional support holding all the segments in place. I thought about wrapping that with something else, but I ended up just drilling with the craft stick outer layer only. It worked, and I was able to drill without anything separating. I've only done that twice now, though, and I have more experimenting to do. I think, also, that so far all of the blanks have been resins and metals, no wood yet...

One thing I have not yet figured out how to do though, is drill the metal layers on their own. I always seem to have some kind of problem trying that. So far, I've been trying to glue down or clamp down the pre-cut squares on their own. I've tried gluing them on the flat surface of a sacrificial piece of wood, and that really didn't work. I tried gluing and clamping, which was a bit better, but I seem to get a rim on the back side of the hole, which then requires extra work to work that out. Even when I drill real slow. I currently have mostly bradpoint bits, and I think that is part of my problem, so next time I get into segmenting, I intend to buy another set of drill bits that are not bradpoints, and see how that goes with the metals.

One thing I did see in a thread a while back, was someone drew out all the metal segments they wanted on each piece of metal, then drilled first, then finally cut up each piece. That, to me, seemed like a much better way to go about it, as you would then have a lot more metal surface area to clamp down or do whatever you needed to do to hold it in place properly while drilling. Still would need that sacrificial piece of wood, but, I think it would work better than what I had tried before.

Again, much appreciated info!

I ended up trusting myself and used three new jobber bits to drill while it was clamped tight in a blank vice on my drill press. I made three passes with the drill press: small, medium, and final diameter. I went slowly and backed out often. As soon as I felt the aluminum I made sure to apply constant but light pressure and I am happy to say that it went without a hitch.

I will post a separate thread for the pen but I have to say that I am kind of surprised that I was able to make something that looks like this does.

Again, HUGE thanks to all who offered advice here. It all contributed to my first successful segmented pen!