Mold Making-Quick & Dirty

[scotsman]

I have a client that wants a specific dimension to the soaps they are ordering from me so last night a slapped together a quick wooden loaf mold to accommodate this. From start to finish it only took me about 3 hours. My band saw needs some adjustments and I used cheap pine plywood so it's not my prettiest or best work. It will suit its intended purpose though and only cost me a total of about $17. Today I'm going to take the leftover wood and finally build a miter box since I can't cut soap freehand to save my life. The mold, according to calculations, should make just over an 8 pound batch of soap(5.5lbs of oils). I'll find out for sure this afternoon as I plan to make this mold's inaugural batch in a few hours. Keeping it simple for this one. 4 oils, light fragrance, and most likely no color except for a little TD. I think my next mold project will be a large slab mold with tall sides and removable dividers so I can make 3 or 4 loaves side by side. Here's a couple pics of this Frankenstein.


I'm really wanting to make a large acrylic or plexiglass mold but I can only find the material for sale in 4 foot by 8 foot sheets that are incredibly expensive. They have smaller sheets online but after the shipping costs I may as well go for the 4' x 8' sheet cuz it'll come out to almost the same price, lol! I have lots of experience working with wood and metal but no experience working with acrylic or plexiglass. Anybody on here ever work with the stuff? Is it more difficult than wood?

 

[navigator9]

Hey, that's no Frankenstein, you've got hardware on the ends to allow you to remove them. I'd say that's pretty nice. I just slapped together a couple of boxes for a some silicone liners that I had picked up on sale. Once in a while I've seen them at decent prices when purchased without the wooden box that they sit in. The box itself isn't hard to make, and makes the purchase of the silicone liner a bargain. If you haven't tried a silicone liner yet, you might want to consider doing that. I can't give you any info on plexi or acrylic, I've never used them. Enjoy your new mold!

 

[lsg]

Nice mold!

 

[scotsman]

Thanks. The only thing I'm really not digging about this mold is that I made it so only the ends fold down. It might prove to be a bit of a bugger to get the loaf out without damaging it. The next one I build I'm going to make it so all four sides fold down and use a more intricate and sturdy latch system to hold them all together. That or I may even try to make one of the completely collapsible ones where the end pieces and bottom fit into dado joints(grooves) cut into the end and side pieces and everything is held together by a couple long bolts with wing nuts. Only issue is that clean dado joints can be difficult to cut on a really good router, let alone my crappy freehand one, lol! I've toyed with the idea of using the silicone liners housed in a wooden frame but from everything I've read they can take much longer to unmold cleanly and I'm a very impatient person. I know of the freezer trick but I'm not big on sticking my soap in the freezer as I live in a very humid area and freezing it tends to make it start sweating badly after I take it out of the freezer. Also, freezer space is a problem too. I have two freezers and they're packed to the gills. I may try them at some point if I ever find them at a good sale price.

 

[summerflyy]

That's a really beautiful mold ! Good job done there !

 

[Susie]

That really is an awesome mold. I think you will be fine getting the loaf out if you line it with freezer paper. Just fold down the ends and push. Or leave enough paper at the top to grab and lift.

 

[scotsman]

That's a good point. I leave the ends of the liners a little long so I will have handles to pull it out if it's being stubborn. Still have to sand it down and put a coat of sealant on it cuz it's already given me a couple splinters but all-in-all not bad for $17 and a few hours of work. Having commercial woodworking machines in the garage does make it a bit less painful, lol! One of these days I want to make an aesthetically beautiful mold. Good quality hardwood, nice looking stain, maybe some relief carving or engraving or wood burning designs. Definitely lengthwise dividers and maybe an inset lid with a textured silicone liner on the underside to texture the top of the loaf while it insulates. Or maybe sandwich insulation between layers of wood to eliminate the need for towels or blankets. Ok, I really need to back away from the coffee for a little bit or my list of things to try will be ten pages longer by the end of the morning, lol! Off to get my honey-do list done so I can get to making some soap

 

[navigator9]

Scotsman, my first mold was a handmade one that I lined with freezer paper. I made it so that only the ends were removable, like yours, and I never had a problem removing the soap.

As for silicone liners, I make my soap and unmold the next day, with no problems. But... I always gel my soap. I don't gel to get it out of the silicone liners more easily, I gel because I just like gelled soap better. But if you do gel, the soap releases from the silicone like a dream, the next day, smooth as glass. I started using silicone because I hated lining my mold. Now, I wouldn't be without them. I preheat them in the oven, pour the soap, return them to the oven, turn it off, and they gel to the edges every time. This works for those of us who like to gel. But you're right, if you don't, you have to wait until saponification is finished to remove the soap.

 

[dixiedragon]

Will you be able to open the doors when the mold is full of soap? Will the edges of the doors dig into the soap?

 

[DeeAnna]

Don't get too fancy with your joinery, Scotsman, if I might offer a suggestion. Rabbets and dadoes and mortises and tenons ... oh my! ... may be more trouble than they're worth. Soap molds can get pretty messy -- and residues of soap and possible oozing of caustic liquids will seriously interfere with joint fit, so that loose tenon might not actually slip loose one day.

I enjoy making delicate jewelry boxes, fine furniture, and pretty lathe projects, but I just use basic carpentry for soap molds. It's really not worth the trouble to dress 'em up, IMO.

As far as acrylic, if you live in an urban area, look around. There may well be someone in town that uses or distributes large quantities of plastic sheet goods, and they may have an outlet where you can buy small quantities or even scrap. There was (maybe still is) a company in Kansas City, Missouri, like that. Fun place.

 

[scotsman]

Good point about the dadoes. Never even considered the residue sneaking past the liner and getting into the joints. I have a small HDPE mold that uses this kind of joinery and soap does regularly get into the joints. With that one I just wash it and never really gave it much though. Definitely don't want to wash a wood mold, lol! Thanks for the heads up. So no complex joinery for the wood molds. Now acrylic, if I can get hold of some, is an entirely different matter, lol! I've been looking locally for a company that deals in plastics but so far have only been able to find ones in Orlando, which is about a forty minute drive. I kinda live in the boonies so finding things close by can sometimes be difficult. I may have to suck it up and drive down there on a day off.

 

[cnm]

i made a mold similar to yours but the long sides fold down. if you get any kind of sticking an the short sides just use a bench knife or something to pop it of the loaf of soap. it is also so much easier to line with sheet pan parchment.

 

[CanaDawn]

beware. Acrylic does NOT like ethanol. I made a large acrylic display for one of the specimens at work, and didn't realise (the old one was glass, I hadn't stopped to think, in my pride at having it completed....) and filled it with 70% EtOH, only to have it crack impressively immediately and ruin. If you use ethanol on your soaps, you may very well crack and ruin the mold.

In my experience, acrylic is more brittle (and more expensive) than wood, and I would say you have to work it more like glass (etch with a blade a couple times and snap), and use chemical bonding solutions if you want to adhere the two pieces together (plastic welding), but it is pretty fun/frustrating.

Check home building stores and look for people who make display cases. It's likely worth trying to ask for offcuts.

 

[robosqu1d]

Here is one of our moulds (English spelling...)

Completely collapsible, no screws, no hinges - it just slots together firmly. It's made of 3mm plywood which is quite sturdy enough for the job, and the little pegs down the side are there to stop any bowing. We use a laser cutter so all the cuts are exact. The two sizes are 26x7x7 cm and 26x10x7 cm, which is the maximum we can do and still get into a flat-pack jiffy bag, which really reduces the postage costs. I always line with baking paper or clingfilm.

 

[DeeAnna]

"...Acrylic does NOT like ethanol...."

Yeah, I know what you mean, CanaDawn. I bet that was an exciting moment! :wtf:

Acrylic (Plexiglas) was seldom used in the chem lab or in my research work. We used polycarbonate (Lexan) for splash shelds, etc. Not to say polycarbonate doesn't have its weaknesses as far as chemical resistance, but it's better than acrylic and is much more impact resistant to boot.

 

[scotsman]

Tested the new mold out last night. It's holding up well so far. We will see how the unmolding goes. Built myself an quickie one bar at a time soap cutter. I'm in the process of designing the schematics for a really nice one though. Possibly making a planer/beveler tonight if I have time to pick up some new blades for my band saw and scroll saw.

 

[CanaDawn]

"...Acrylic does NOT like ethanol...."

Yeah, I know what you mean, CanaDawn. I bet that was an exciting moment! :wtf:

Acrylic (Plexiglas) was seldom used in the chem lab or in my research work. We used polycarbonate (Lexan) for splash shelds, etc. Not to say polycarbonate doesn't have its weaknesses as far as chemical resistance, but it's better than acrylic and is much more impact resistant to boot.

I was pretty bummed. It wasn't for a splash shield it was a biology specimen, and finding a large enough tube was the first challenge...it would have been much nicer if I could have just ordered something standard from a catalogue.

 

[eucalypta]

You did an awesome job, congrats!
I hardly use wooden moulds anymore, always (thick) silicone ones.
But if I would have a silicone liner, it would be another story.

 

[scotsman]

So I got bored and decided to make another mold. Not done with it yet. I still have to make the lid and a removable lexan liner, but this is what I have done so far. Not too shabby for two nights work, lol!

 

[Susie]

That looks awesome! Really!