# Holding the item in the center of the mold



## kweinert (Jul 3, 2017)

This has probably been answered but I couldn't find it - guess I just didn't have the right search terms.

So I now have my mold built from the HDPE stock but what I'm casting is very light and full of holes.

So how do you keep something like this centered in the mold? Do you do the pour in stages?

Any hints or pointers to where this has already been discussed will be greatly appreciated.


----------



## sleevecc (Jul 3, 2017)

Does it try to float or try to sink?


----------



## Tony (Jul 3, 2017)

@rocky1


----------



## sleevecc (Jul 3, 2017)

find something to hold/suspend the object in the air cloth pins, paper clips,, ,, and pour resin to it,,, let it set for awhile pour again. This concept only works well with using clear,, if using different colors it will leave a half way line.

Reactions: Thank You! 1


----------



## kweinert (Jul 3, 2017)

sleevecc said:


> Does it try to float or try to sink?



At the moment I'm going to say float - I haven't actually tried it yet. 

I presume float because it's a small loofa that's been soaked in colored cactus juice and then dried - it's very light. What I'm trying to do is to encase it in clear and then use it for probably a bottle stopper.


----------



## kweinert (Jul 3, 2017)

sleevecc said:


> find something to hold/suspend the object in the air cloth pins, paper clips,, ,, and pour resin to it,,, let it set for awhile pour again. This concept only works well with using clear,, if using different colors it will leave a half way line.



So essentially stick it down and then finish it off :) Do you just let it air cure for a bit, finish the pour, then put it under pressure? And clear is what I'm doing right now so that would work.


----------



## sleevecc (Jul 3, 2017)

kweinert said:


> At the moment I'm going to say float - I haven't actually tried it yet.
> 
> I presume float because it's a small loofa that's been soaked in colored cactus juice and then dried - it's very light. What I'm trying to do is to encase it in clear and then use it for probably a bottle stopper.


It very well might set where you want it too have to try and see,, the resin might keep it in place just fine. the thicker the resin is the better the chances,, move it around with a tooth pick. likely wont have any problems,, suspending is usually for things that sink... if it float just let the resin thicken a little more

Reactions: Thank You! 1


----------



## sleevecc (Jul 3, 2017)

kweinert said:


> So essentially stick it down and then finish it off :) Do you just let it air cure for a bit, finish the pour, then put it under pressure? And clear is what I'm doing right now so that would work.


I have not used a fast cure resin for this only slow cure. but concept should be the same, I think if you try it probably will not float,,only a guess though,, if its so thin to float then wait a minute until it stops moving and then get in POt as fast as possible,,

Reactions: Thank You! 1


----------



## sleevecc (Jul 3, 2017)

Floating would mean it would have to push the resin off the top of itself,, the thicker the resin the least likely this can happen, it weights itself down . Bouyance or however ya spell it with resin and water are totally different and it changes second by second


----------



## rocky1 (Jul 3, 2017)

I assume you're trying to center it in the pour, so you can turn around it, without having to fill spots with CA where it tears out? Which that may be impossible. That'll depend largely on style you choose on the stopper, but if you got it to stabilize and take color, it may not be as bad about tearing out either. While the piece I tried did take some color, it wasn't purty after I baked it! I was thinking maybe DNA and dye to color it, then possibly stabilize with clear cactus juice. If it worked for you ! 

My thoughts on the loofa for bottle stoppers was to pour it in a PVC mold... 1 1/2" - 2" PVC pipe, dependent on size of the loofa, Gorilla Tape on the bottom, stuff the loofa in there, cut it a little long, and run tape over the top to hold it in place, if necessary. You could tape a peg in the bottom to center it in the pipe, turn it out, or finish it. 

On a square HDPE mold you could cut it a little long and stick it in the middle of your mold. BUT... it's going to be subject to flex and bend if you get too long, laying on its side.

Other options you may consider... 

-- Drill a hole in the ends of your mold to center it, and run a small skewer/dowel through it. That will likely show up in the middle of your cast, however if dyed a contrasting color, it might not be a bad deal. 

-- Drill a hole in the ends of your mold and use a drinking straw to center it. You should be able to pull it out after it cures, leaving a perfectly centered hole in your cast, that you could pour in a contrasting color or clear. 

OR... Simply cut a thin piece of loofa to space it off the bottom and top, to center it, taping the piece over the top to hold it in place. But... that's going to leave pieces on the sides that are going to tear out and have to be filled with CA.

And, it may not float Ken, the moss blanks, I haven't had anything try to float out, and that stuff wasn't stabilized. By the same respect however, I doubt seriously it will suspend. 

When you pour it, pour from one end/side/spot in the middle, allowing the level to rise up through the loofa, to help reduce trapped air in the pour. You don't want to pour randomly over the top, as you run a chance of trapping air in the pouring process.


----------



## rocky1 (Jul 3, 2017)

sleevecc said:


> Floating would mean it would have to push the resin off the top of itself,, the thicker the resin the least likely this can happen, it weights itself down . Bouyance or however ya spell it with resin and water are totally different and it changes second by second



The last time I tried casting the cholla blanks for Barry's pen, that I haven't forgot... The blank sat there perfectly in the mold for 30 - 45 minutes on the saw, with the saw running to try and vibrate any air in the mold up and out of the pour. When the resin started to kick, started thickening, I put the molds in the pressure pot, and ran pressure up to allow it to finish curing, and the SOB floated up a 1/4" in the mold under pressure.

While the buoyancy of water and resin is definitely different, I won't argue that at all, when you put it all under pressure, the whole equation changes. Probably wouldn't be as big an issue on loofa as it was on the cholla, but I wouldn't assume it isn't going to move, simply because it hasn't moved up to the point you put it under pressure.


----------



## DKMD (Jul 3, 2017)

How about using a dab of hot melt glue/epoxy/thick CA? I have no experience casting anything, so it may be a terrible idea for a reason I don't understand.


----------



## kweinert (Jul 5, 2017)

DKMD said:


> How about using a dab of hot melt glue/epoxy/thick CA? I have no experience casting anything, so it may be a terrible idea for a reason I don't understand.



Well, in my case it's because the intent is that the final turned item will have this small loofa sponge (colored either blue or green) floating in the middle of a clear surround. In the case where you're casting wood cutoffs and expect to turn some of it away during processing that would be a viable option.

Reactions: Like 1


----------



## rocky1 (Jul 5, 2017)

How big is the mold? What about a swizzle stick through the center, then pull and fill?


----------



## Tony (Jul 5, 2017)

rocky1 said:


> How big is the mold? What about a swizzle stick through the center, then pull and fill?



Or a wooden skewer?


----------



## Schroedc (Jul 5, 2017)

How about using monofilament line? the clear stuff almost completely disappears when resin is poured around it. if it wants to float, run a piece up to the bottom, tack to the bottom of the line to the mold. pour the resin, and then turn away the bottom.

Reactions: Agree 1


----------

