Question before my 3rd attempt at a watch pen

[Ulises Victoria]

Hello all.
I am determined to make a pen with watch parts cast in acrylic, to enter a crafts contest at the end of this month.
I already have a bunch of watch parts and gears I got at amazon.com.
My doubt is about the gluing of the parts.
In my 2 previous and failed attempts, I painted the tubes black and then glued the watch parts with minute amounts of CA. My concern now is that the resin gets extremely hot when curing, and heat is the worst enemy of CA... or so I've heard. So there is a chance that the parts unglue and end getting loose in the resin. What are other alternatives? Epoxy reacts to heat the same as CA, no?
Any information will be most appreciated.

 

[sbell111]

Two thoughts:

1. I'm not sure that PR gets so hot during curing that it will break the CA. If so, I'm thinking that you need to cut down your use of catalyst considerably.
2. There is no such thing as things being 'loose' in the resin. Once the resin has cured, what's in there is in there.

 

[Jim Burr]

You may want to consider Alumilite as an alternative...not nearly as hot.
The main issue with PR is the paint on the tubes...C&C changed their formula so a lot of paint bubbles. CA can over heat and get cloudy. Think there are better products for this application out there!

 

[Ulises Victoria]

Two thoughts:

1. I'm not sure that PR gets so hot during curing that it will break the CA. If so, I'm thinking that you need to cut down your use of catalyst considerably.
2. There is no such thing as things being 'loose' in the resin. Once the resin has cured, what's in there is in there.

Thanks for your thoughts.
*Can you explain the catalyst thing? How does the catalyst/resin ratio affects the end result? I am using a 10% ratio with excellent results, according to the sellers' instructions. My last failed attempt at casting this pen was due to me using too little catalyst. The resin never hardened.
* Sorry I didn't explain myself correctly. I didn't mean things being loose, but that due the heat melting the CA, parts may become unglued and end up "floating" in the resin cast.

 

[Kenny Durrant]

I Haven't used watch parts but I've cast coins, feathers,stamps, and a few other things and I use elmers white glue. I also use pr resin with 3 drops per ounce. Good luck.

 

[sbell111]

Two thoughts:

1. I'm not sure that PR gets so hot during curing that it will break the CA. If so, I'm thinking that you need to cut down your use of catalyst considerably.
2. There is no such thing as things being 'loose' in the resin. Once the resin has cured, what's in there is in there.

Thanks for your thoughts.
*Can you explain the catalyst thing? How does the catalyst/resin ratio affects the end result? I am using a 10% ratio with excellent results, according to the sellers' instructions. My last failed attempt at casting this pen was due to me using too little catalyst. The resin never hardened.
* Sorry I didn't explain myself correctly. I didn't mean things being loose, but that due the heat melting the CA, parts may become unglued and end up "floating" in the resin cast.

As I understand it, the more catalyst that you use, the higher the 'kick' temp will be and the more brittle your final product will be. The suggested catalyst ratio is for very thin pours. The much thicker pours used to make blanks do not require nearly as much catalyst. I am currently using around 4 drops per ounce.

Also, as I understand it, a number of factors play into whether the resin will cure. These include age of the resin and catalyst, ambient temperature, humidity(?), colorant, etc.

Finally, I doubt that the cure temp of the resin is enough to cause CA to fail. I suppose that it might be theoretically possible if someone used a lot of catalyst and perhaps heated the resin, but I doubt it. I did a quick google search to try to find some sort of information about this. I couldn't find a CA failure temperature. In fact, what I found were manufacturer claims that CA didn't fail due to heat. I did find an article that warned against excessive amounts of MEKP. It stated that using too much could push the reaction as HoH as 300 degrees and result in the resin cracking n the mold.

So basically, you want to find the amount of catalyst that causes the resin to kick, but doesn't result in excessive heat. You will find that it is far less than the amount suggested on the can.

 

[Ulises Victoria]

Thanks so much, Kenny and Steve.
Time to go and do some testing before making the final attempt. :highfive:

 

[Ulises Victoria]

Well the info given to me above has been a real eye opener!!!:RockOn:
After doing some test, here is what I've learned and maybe this will be of help to somebody else.

1.- Casting using a 10% ratio catalyst/resin:
Starts hardening at around 10-11 minutes.
Generates so much heat that I could not hold the mold in my hand for more than 2 seconds.
Hardens really fast and really hard. This hardness may indicate it's more brittle.


2.- Casting using a ratio of 3 to 4 drops per ounce.
Starts hardening at around 10-11 minutes.
Does not generate that much heat. Or at least I didn't notice.
Takes longer to fully harden. About 5 hours to safely release from mold, which doesn't mean it can be cut or turned at this stage. I'll wait till tomorrow for safety.

I appreciate the information given in the previous threads. I love it when I feel I learned something new. cheers. :drink:

 

[sbell111]

Well the info given to me above has been a real eye opener!!!:RockOn:
After doing some test, here is what I've learned and maybe this will be of help to somebody else.

1.- Casting using a 10% ratio catalyst/resin:
Starts hardening at around 10-11 minutes.
Generates so much heat that I could not hold the mold in my hand for more than 2 seconds.
Hardens really fast and really hard. This hardness may indicate it's more brittle.


2.- Casting using a ratio of 3 to 4 drops per ounce.
Starts hardening at around 10-11 minutes.
Does not generate that much heat. Or at least I didn't notice.
Takes longer to fully harden. About 5 hours to safely release from mold, which doesn't mean it can be cut or turned at this stage. I'll wait till tomorrow for safety.

I appreciate the information given in the previous threads. I love it when I feel I learned something new. cheers. :drink:

You may find tomorrow that it is hard, but tacky. This tackiness is a feature, not a problem as it allows good adhesion when making multi-layered pours. Regardless, the tackiness will go away in a day or so. Some people expedite this by putting the blanks in a warm box (light bulb in a box equals warm box) for a while. Personally, I just let my blanks sit for a couple days. If I want to turn a blank that is still tacky, I go ahead and cut/drill/glue/turn as normal. It's only tacky on the outside, after all.

 

[Ulises Victoria]

Another useful piece of information. Thanks!

 

[Kenny Durrant]

The set up time is delayed quite a bit but you will find the blanks will be easier to turn because they are less brittle. As far as being tacky when I keep them pressurized at laest 10 hours , most of thr time overnight, take them out of the molds and let set for the rest of the day which I'm mostly at work. That afternoon I'll turn them down to a good workable size. I use a vertical mold I made myself with thin plastic that I can unwrap the blank and let set and cure. With what little I know it sounds like your on the wright track. Thank you for letting us know how it's going for you so I might pick up some tips.

 

[Ulises Victoria]

Absolutely, Kenny. The first mold I cast (about 3"x 5") using 4 drops per ounce, came out really solid. I took it out of the mold after 5 hours and it was a bit tacky. After maybe 5 hours more, tackiness disappeared. I feel it's ready to cut and turn (Now it's 24 hrs. since I poured it.)
I will post some more info later and maybe a photo or two. :wink:

Thank you for your comment.

 

[Ulises Victoria]

Watch pen makers haven

I got this from Amazon.com for 22.dlls. It's 1 oz (two .5 oz bags for 11 dlls. each) of assorted gears, wheels and miscellaneous watch parts. Just in case anyone is interested.
Amazon.com: Lisa Pavelka 1/2-Ounce Watch Parts for Crafting, Silver, Brass, Copper, Black and Steam Punk: Arts, Crafts & Sewing