Casting?????

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jttheclockman

jttheclockman

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Feb 22, 2005
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I have casted blanks for pens before but want to start some bottlestoppers. I did a couple with two different layers but when I did this I waited just long enough for the first layer to start getting hard. My question is I want to cast the first layer and let it cure completely because of the drilling I want to do in it later. Then I want to cast a seond layer on top of this. My question is will the second layer adhere to the first layer without any problems or will this become a weak link.??? Thanks. If anyone has any photos of things where you did doing this process it would be appreciated.
 
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Weak link.

I have not tried mixing the exact proportion and adding it later after the first cast is cured. I have, however, added a second layer twice and without success. There is always a line where the two meet. One had a different consistancy, it was like rubber. I am sure that was my fault.

But now that you have opened this door of thought, I am going to try it myself.

I have a habit of collecting left over pours into a cup and have made medallions out of the left overs. I do not remember lines in them but I also add gold, silver, labels and stuff between layers.

You may be on to something.
 
John, it really depends what you are casting with. I didn't see what materials you are using. From what I have read here most people are using polyester resin of one kind or another. In most cases, in the quanties that are normally purchased, this is known as pre-promoted resin which means all the chemicals need to make it cure at room temperature have all ready been add. All you have to add is MEKP. If this is what you are using, most of them have a parifin based wax which rises to the surface during the cure period to make the surface finish non-tackey. If this is the finish you are getting you should sand it before placing another coat on top. If you don't, it may stick but will be a weak point and may cause delamination at some point in the future. I hope this helps.
JJ
 
JJturns said:
John, it really depends what you are casting with. I didn't see what materials you are using. From what I have read here most people are using polyester resin of one kind or another. In most cases, in the quanties that are normally purchased, this is known as pre-promoted resin which means all the chemicals need to make it cure at room temperature have all ready been add. All you have to add is MEKP. If this is what you are using, most of them have a parifin based wax which rises to the surface during the cure period to make the surface finish non-tackey. If this is the finish you are getting you should sand it before placing another coat on top. If you don't, it may stick but will be a weak point and may cause delamination at some point in the future. I hope this helps.
JJ
Click to expand...

JJ .. (and John) I've read what you both wrote, and JJ is correct in that
some resins have the wax added to give a cured finish.

BUT...

I haven't read of anyone here using those resins. Most everything I've seen
people using here (for PR) has been laminating resins, which DO NOT
contain the waxes, this is why you'll see people asking about 'post cure'
Post curing is necessary for a laminating resin because it comes out tacky
on the top. This is perfect for pouring another layer of resin because they
will bond. Air will inhibit the cure, so the surface (touching the air) will
remain sticky. If the wax is added, this blocks the air, so the resin cures
on the surface. Or you can put it in an oven to cure the surface.

SO .. John, if you're using the PR's that we're reading about here .. such
as the Silmar 41, Cast'n Craft etc. then pour, cure and then pour again.
They will bond. If you do a 'post cure' (such as putting the cured resin
in a toaster oven so it isn't tacky anymore) then it may de-laminate.
 
NewLondon88 said:
JJ .. (and John) I've read what you both wrote, and JJ is correct in that
some resins have the wax added to give a cured finish.

BUT...

I haven't read of anyone here using those resins. Most everything I've seen
people using here (for PR) has been laminating resins, which DO NOT
contain the waxes, this is why you'll see people asking about 'post cure'
Post curing is necessary for a laminating resin because it comes out tacky
on the top. This is perfect for pouring another layer of resin because they
will bond. Air will inhibit the cure, so the surface (touching the air) will
remain sticky. If the wax is added, this blocks the air, so the resin cures
on the surface. Or you can put it in an oven to cure the surface.

SO .. John, if you're using the PR's that we're reading about here .. such
as the Silmar 41, Cast'n Craft etc. then pour, cure and then pour again.
They will bond. If you do a 'post cure' (such as putting the cured resin
in a toaster oven so it isn't tacky anymore) then it may de-laminate.
Click to expand...


Thanks and that was the answer I was looking for. Took some time but I had faith. Thanks. I am using either similar 41 or Cast-n-craft. Haven't made up my mind yet. The part about not putting in the oven is key. Thanks again.
 
John, I use Silmar 41 and do this process frequently. In fact, sometimes i don't add the second layer till the next day and they still adhere with no problems. I have only tried this with pendant blanks so far, but i dont think you will have any problems.
 
For the ones that do the process I am wanting to do is there a noticable line between the 2 layers??? Thanks for the replys.
 
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