Coro-plast Mold Liners

[DWinMadison]

Clarice asked me about a reference I made in another post to lining molds with Coro-plast sheets (plastic sign material from Lowe’s or other big-box hardware stores). This may be old news, but it might help someone. Here’s the concept: You cut half way through the sheets using an Exact-O, then flip it over and fold the flaps up to make sides. Duck Tape closes the corners. It’s smooth, sturdy, and reusable.

 

[Jenniffer]

Do you line it with freezer paper or do you pour right into it?

 

[DWinMadison]

I’ve done both, but since the sides fold down, it’s easy to remove without the freezer paper. You’ll note in the photo, I tried to cut divider holders in the sides and made plexiglass dividers. Didn’t work out so well, but as a slab mold liner this is top-notch. You do have to build the mold to accommodate for the thickness of the coro-plast.. just shy of 1/4” all around and on the bottom.

 

[jcandleattic]

You’ll note in the photo, I tried to cut divider holders in the sides

When I made my coroplast mold, I didn't cut all the way through, I just scored then folded the ends. When I get home I'll try to pull up a pic. However, doing it my way you can't use it as a liner, just a stand alone mold. I also don't line my coroplast with freezer paper and never had a leak. I love it. It works so great. And the best part about it is it's cheap, customizable (you can literally make almost any sized loaf or slab mold with it) and easily accessible. (any hardware store has it - at least where I am they do)

 

[dixiedragon]

or get it free the day after elections.

 

[jcandleattic]

or get it free the day after elections.

haha yes!! I've always used white though, I'm wondering if the coloring would come off on the soap due to the high pH? That can't be good if it does that!
(I have some from a roofing advertiser that asked us to put their sign in our yard for a couple weeks after they repaired our roof. I kept it, but haven't been brave enough to use it yet for the very reason I don't want the coloring to bleed onto my soap!)

 

[SunRiseArts]

Once I used a piece of cereal box cardboard to divde a batch, and some color did bleed.

 

[Misschief]

haha yes!! I've always used white though, I'm wondering if the coloring would come off on the soap due to the high pH? That can't be good if it does that!
(I have some from a roofing advertiser that asked us to put their sign in our yard for a couple weeks after they repaired our roof. I kept it, but haven't been brave enough to use it yet for the very reason I don't want the coloring to bleed onto my soap!)

Once I used a piece of cereal box cardboard to divde a batch, and some color did bleed.

The coroplast (corrugated plastic) shouldn't bleed. I have a sheet of black that I've used as dividers in the past and some that I've made a mold with and nothing discoloured. Keep in mind that with the coroplast, the entire batch of plastic is coloured before the manufacturing process. With a cereal box, the cardboard/paper is printed, an entirely different process.

 

[Jeboz]

This shows how to use this stuff (we call it corflute) to make a folding mold/liner which is held together with binder clips on the edges so you can open it out and peel off your soap. I have seen a link to here before. If you make it, think about the way the channels run if you want to use her coat hanger strengthening method to stop your mold from bowing at the sides.

 

[jcandleattic]

the entire batch of plastic is coloured before the manufacturing process.

Not the kind I'm talking about. The election signs and yard signs are plastic but the whole plastic is not colored. Just the logo/slogan is colored. In severe weather, it takes a while, but the color does wear and eventually fades and comes off. That's why I'm worried about the pH taking the color off and transferring it to the soap batter.

 

[Misschief]

Not the kind I'm talking about. The election signs and yard signs are plastic but the whole plastic is not colored. Just the logo/slogan is colored. In severe weather, it takes a while, but the color does wear and eventually fades and comes off. That's why I'm worried about the pH taking the color off and transferring it to the soap batter.

In that case, yes. I work at a print/sign shop; those are usually done with vinyl adhesive. Sometimes, the media is white, other times, coloured. In that case, yes, the colour could come off.

 

[DWinMadison]

The coroplast (corrugated plastic) shouldn't bleed. I have a sheet of black that I've used as dividers in the past and some that I've made a mold with and nothing discoloured. Keep in mind that with the coroplast, the entire batch of plastic is coloured before the manufacturing process. With a cereal box, the cardboard/paper is printed, an entirely different process.

I think they were talked no about the white ones with political stuff printed on them. I believe that’s a silk-screening process. Oops ignore this. Mischief had already responsed.

 

[Carolyne Thrasher]

How many uses do you figure you get out out of one of these?

 

[DWinMadison]

How many uses do you figure you get out out of one of these?

That’s a great question. I only use them to line my slab mold, which historically I don’t use very often. Maybe others can offer some better experience. They are actually quite sturdy if cut correctly, so with care I cannot imagine why they would not last indefinitely. For me, the only wear-and-tear occurs at the corners where I Duck tape them closed.

 

[Obsidian]

I made small molds out of coro plast just like in the video, they work well and are easy to unmold.

 

[DWinMadison]

Love this! Had not seen the video. If you designed a peg-board base with moveable pegs to support the sides, you could theoretically expand this to any size.

 

[jcandleattic]

How many uses do you figure you get out out of one of these?

I've had mine for about 4 years. I don't use it exclusively, but I have made soap in it at least 20+ times and it's still is like new.

 

[penelopejane]

Not the kind I'm talking about. The election signs and yard signs are plastic but the whole plastic is not colored. Just the logo/slogan is colored. In severe weather, it takes a while, but the color does wear and eventually fades and comes off. That's why I'm worried about the pH taking the color off and transferring it to the soap batter.

I’ve used it for dividers that have been printed on one side and it bleeds right off in soap. You can clean it off with alcohol but it takes effort and a lot of alcohol.

It does bow.