Demolding blanks from Vertical clear tube casting

[Russianwolf]

I've had a couple questions about the casting using clear vertical molds. and specifically the demolding. One person asked how I got them so clear as his tubes bonded completely with the PR, Another asked when he was turning one and the tube (which I hadn't removed) came flying apart and off.

So her we go, in depth and with pics.

Remember that I am using West Systems Epoxy and not PR so things WILL be different if you use PR.

1) Cast tube as it comes out of the pot.
2) Obvious I know, but remove the pigtail wire.
3) I use a utility knife to score the tube from top to bottom (the portion at the top without resin I cut all the way through) (you may wind up with a score line on the outside of the blank, but it turns away).
4) I literally just peal the tube off with my hand. I do have a pair of glass Chasing pliers that I sometime use if they are stubborn to get a grip on.)
5) You can now see the discarded tube in the background. These are disposable and cost is just a few cents.
6) pull the plugs from the top and bottom of the tube and you are done.

Label a snack sized ziplock and drop in and I'm done. They are ready to be turned into beautiful pens.

 

[djncas]

I don't understand why you are using the type of molds you are using, seems like a lot of extra work.

 

[seamus7227]

I don't understand why you are using the type of molds you are using, seems like a lot of extra work.

Mike,I think he has a suggestion to make, I'm all ears!

 

[Russianwolf]

Seamus, as an aside, the crazing on the surface seems to have disappeared since I switched to the smaller diameter tubes. Even on the long clicks with the amount of resin that they take.

 

[Russianwolf]

I don't understand why you are using the type of molds you are using, seems like a lot of extra work.

Hey Carl,

This mold process allows you to see the entire blank as you pour resin, so eliminates the chances for hidden bubbles and other problems that can hide on the bottom side of a horizontal mold.

I've used several types of resin saver molds in the past, and while I love then (and they are great for certain types of castings, they do have their cons as well. One big one I was getting was resin leaking into the blanks.

The demolding process that I pictured above really takes less time than it took to take the pictures. I can demold a blank in about 30 seconds. In fact I spend more time inspecting them for flaws than anything (which thankfully are a rarity now).

 

[teamtexas]

I like this and I think I would like to try casting my clear items this way. Where can I get some of the clear tubing. Are you using the t8 tubes made to protect fluorescent lamps? What is the purple base?

Dan

 

[JohnU]

Plus it reduces the area for air bubbled to accumulate since they will rise to the top, towards the plug and not along the length of a tube on its side, and yes if you use PR and remove the plastic sleeve you will be polishing all of your blanks to get them transparent. Not to mention risking a flying object, from a spinning buffing wheel, in the shop that will hit a wall and break. Don't ask me how I know this...

 

[Russianwolf]

I like this and I think I would like to try casting my clear items this way. Where can I get some of the clear tubing. Are you using the t8 tubes made to protect fluorescent lamps? What is the purple base?

Dan

I have used the T8 tube which are about 1.25" in diameter, so you'll "waste" a bit more resin. The tubes I got from Seamus are from Visipak and are about 1".

The purple plug is Castin' Craft Silicone Putty. (Same stuff I used in the "Make your own mold" video) I just cut a tube to about an inch tal, mix the putty and pack it in so that its about 1/2 inch deep. then press one of the silicone stoppers into it and let set up. If the stopper come loose, then I use a small nail to hold the two together for the next casting.

 

[lele]

dove si trovano i tappi in silicone per la coata? grazie

 

[steve worcester]

For the newbie in me, I have no reservations about showing my innocence/ignorance.

PR= Polyester Resin?

What is the wires for?

Casting under pressure with the molds, bubbles aren't my issue at all.

I read from this you are casting in epoxy, and since it doesn't have any UV inhibitors that I know of, do you have any yellowing problems over time?
What about the additional costs of epoxy over resins? Isn't it a lot more expensive?

How does epoxy turn vs resin?

 

[Pitoon]

dove si trovano i tappi in silicone per la coata? grazie

puoi fare da solo con silicone.

Pitoon

 

[volozhin]

I don't know if this belongs here but I need help with this problem. I cast a blank in a 3/4" PVC pipe. Turns out it's a epoxy resin. How do I demold it? I can't knock the blank out from the pipe. Help!

 

[wyone]

well if you cannot knock it out with a dowel of the appropriate size then I would say the mold is lost and just put it between centers and turn the PVC pipe off if it. DAMHIK

 

[volozhin]

Thanks. Good advice.

 

[79spitfire]

OK, I'll have to admit it took me a few moments to figure out what your doing, but now it makes sense.

Have you tried this with 'troublesome' materials such as Carbon fiber? If so how did it work? I may have to try this.

I will also be using PR.

 

[VE5MDH]

Volozhin, next time don't forget to use some PAM from the kitchen. Cheapest to use for demolding, I hear.

Michael

 

[volozhin]

I finally knocked it out. I think it wasn't fully cured when I first tried to knock it out. Thank to all for your responses.