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View Full Version : Technical Translation needed, please!



Dee Gallo
10-13-2009, 7:36 PM
I am looking into buying some delrin but I know nothing about it. Can someone please translate this geek-speak into dumb-newbie for me?

Interstate Plastics offers both homopolymer and copolymer grades of acetal including enhanced bearing grade materials.

I was thinking about using it for making a chocolate mold. I might be completely off base here, but it sounded like a good idea.

Thank you from the tech-disabled, dee

Brian Robison
10-13-2009, 7:42 PM
Dee, if all you need to know is if it's OK, then it's OK.
Homo polymers and Co polymers has to do with the molecular length and type of the polymer chains and pertains to the strength of the plastic.

Dee Gallo
10-13-2009, 7:46 PM
Thanks, Brian, but which one do I buy? Does it matter?

Brian Robison
10-13-2009, 7:52 PM
Not going to matter for your job, co polymer is a little stronger. Be aware, Delrin stinks when heated to the melting point.

Scott Shepherd
10-13-2009, 8:07 PM
My plastic supplier gave me a scrap of delrin and informed me at the time that it gives formaldehyde when it's burned. That could be the complete wrong thing it gives off when it burns, but I do recall when he said it, it made a mental note in my head that something was bad about burning it.

I know I've seen people burning it on the forum, but I do recall him being a bit shocked that I took the scrap after he told me that.

Anyone care to expand on that? Someone with a clue about it, rather than a conversation I had 2 years ago with a sales guy at the plastics place?

Dee Gallo
10-13-2009, 8:15 PM
Okay, that's enough to make me ask: is there a good material to use for a shallow chocolate mold?

:eek: dee

Steve Clarkson
10-13-2009, 8:31 PM
Dee, I tested for the chocolate mold thing and could never find anything acceptable.....so I gave up. The biggest hurdle was finding a "food safe" material....let alone one that could endure hot chocolate and then freezing temps. Good luck....I hope you can find something workable.

Bill Cunningham
10-13-2009, 8:41 PM
Most chocolate molds are made from vacuum formed plastic.. A friend of mine had a chocolate factory in Toronto, and I built his cooling tunnel for him, as well as some vacuum mold masters we cast from silicone rubber molds. His Swiss Chef used to come up with some interesting ideas, and the man was a artist. It's amazing what can be made from chocolate..

Dan Hintz
10-13-2009, 8:50 PM
Fastest? Use stamp mold rubber and do a 3D cut (we all know you're a master at those types of engravings by now, Dee). The stamp rubber is not listed as being unsafe for food, though I'm sure they never considered that as a typical use, so I probably wouldn't trust it.

Most appropriate? 3D cuts again out of acrylic to make a positive mold, followed be a negative mold made out of silicone poured over the top of the acrylic. This probably won't be time- or cost-effective unless you can get a high-paying client.

You could go with straight acrylic negative molds, but again, processing time may be an issue unless the run is for a large number of chocolates.

Dennis McGarry
10-13-2009, 8:52 PM
Nevermind... covered already

Darren Null
10-13-2009, 8:59 PM
I've had results from acrylic. The files were on my nicked laptop, but the basic premise was this:

1) Build the mold from layers of acrylic; but make sure that each layer is a little larger than the one below it, so you end up with an 'upside-down ziggurat' look when viewing from the side. If you make the holes all the same size, it's difficult to get the chocolate out.

2) The bottom-most layer has your logo (mirrored)

3) In all the layers, drill holes in the same place for shaped pegs, to keep the layers together and in position (2 in opposite corners does it)
===================================

Method:

Assemble your mold layers, put the pegs in. Clothes pegs or bulldog clips are recommended to keep the layers tightly together.

Melt chocolate. Pour into mold. Lick spoon. Forward-thinking Creekers would have melted at least twice the amount needed 'just in case'. :D

Leave at room temp for a couple of hours. Then fridge for same. Let it cool slowly.

Disassemble your mold when ready, 1 layer at a time. Et voila! Chocolate!

=======================================
It worked for us, but it's time-consuming to do it properly. Nobody here wanted enough of them to make it economic for us.

Bill Cunningham
10-13-2009, 9:01 PM
The problem with 3d laser cutting, is you need a very smooth surface or the chocolate will never come out of the mold.. We would pour casting silicone in a frame over the part to be dupilcated, once cured, it was removed, and a casting acrylic was poured into the Silicone mold. When that cured, the bottom was flattened, and we made another, and another, and another. When we had enough, we sent the hard masters to the forming plant and they prepared the base and all the vacuum holes, and did the actual vacuum form sheet over the group of masters.. The one step that a lot of folks making their own miss, is after mixing the casting silicone, you have to put in under a vacuum dome, drop the pressure, and allow all the mixed in air to bubble out, or the silicone mold will look like a Nestle Aero Bar

Michael Hunter
10-14-2009, 4:33 AM
I would not worry particularly about lasering delrin - formaldehyde fumes are not any worse than the fumes from acrylic or even natural wood.

Epilog give engraving details for delrin - see "notary seal" in their sample club pages.

That said, I would expect that getting a deep enough engrave in delrin would need many passes and leave a rather unsatisfactory finish.

Keith Outten
10-14-2009, 5:43 AM
Dee,

You might consider Dupont Corian, it is food safe and the engraved areas can be polished easily to a mirror smooth surface. Scraps are available for free, I suggest you stick with solid colors.

On my 35 watt Epilog 6% speed and 100% power will produce an engraved area about 1/32" deep, multiple passes will get you just about any depth you need. Use a brush to clean the surface between engraving passes.

Corian won't soften until temperatures reach above 300 degrees F.
.

Dee Gallo
10-14-2009, 6:28 AM
Keith,

THANK YOU! That is brilliant and I happen to have a bunch of Corian 4" squares doing nothing, which I actually forgot about completely. Perfect.

Now on to the fun part of designing and making.

cheers, dee

Mike Null
10-14-2009, 7:14 AM
Dee

I have spent a large amount of time on this project without good results.

Acrylic is a good material as is PETG. Whatever you use it must have some flex to facilitate removing the chocolate.

You might give consideration to using the rubber stamp mode to give slant to the sides for easier release.

There is a company who does this as their only business but I can't find out the process nor the name of the company.

John J Wang
10-14-2009, 7:39 AM
I am looking into buying some delrin but I know nothing about it. Can someone please translate this geek-speak into dumb-newbie for me?

Interstate Plastics offers both homopolymer and copolymer grades of acetal including enhanced bearing grade materials.

I was thinking about using it for making a chocolate mold. I might be completely off base here, but it sounded like a good idea.

Thank you from the tech-disabled, dee

I think homopolymer means the plastic is made of a single type of molecule in a long chain. Copolymer means there that long chain is made of two or more different types of molecules, ie ABS is made up acrylonitrile + butadiene + styrene. You should probably ask the supplier for copies of the MSDS sheet to make sure there are no odd molecules in the copolymer grade material. Probably should ask the supplier if either material can be used for food preparation as well.

Steve Clarkson
10-14-2009, 7:50 AM
I considered the Corian.....but I don't think that you'll ever be able to polish the intricate details for a mold....be it text or shapes.

Dan Hintz
10-14-2009, 8:00 AM
I was wondering the same as Steve. A flame polisher <nudge nudge> would work well for smoothing out acrylic, but I do not know the effect on Corian... some day I'll go grab some scrap and start playing... some day :rolleyes:



Keith, haven't seen you post in here for quite a while... you're either hiding or busy (hoping for the latter).

Steve Clarkson
10-14-2009, 8:05 AM
OK Dan......this is the last time I'm going to offer......send me your flame polisher and I'll test it on Corian for you.

Cause if you don't atleast take it out of the box, the Mods are going to make you remove it from your signature info.......

Scott Shepherd
10-14-2009, 8:28 AM
I would not worry particularly about lasering delrin - formaldehyde fumes are not any worse than the fumes from acrylic or even natural wood.

Epilog give engraving details for delrin - see "notary seal" in their sample club pages.

Michael, I wasn't implying you cannot or should not laser Delrin. I was mentioning the formaldehyde because she was planning on using it in a food environment.

Belinda Barfield
10-14-2009, 9:00 AM
Dee,

I was going to suggest Corian, but Keith beat me to it! Are you going to try the built up layered technique, or go for engraving into a single thickness? With a single thickness you may be able to get enough flex to pop the chocolate out of your mold. Keep us posted.

Oh, and send samples for taste testing! :D