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Bonding Cellulose Acetate help!!

Bonding Cellulose Acetate help!!

Bonding Cellulose Acetate help!!

I am trying to figure out how to bond numerous chunks of cellulose acetate into one solid "brick". These chunks are of the same color and do contain some sort of dye or pigment which I do not know exactly what it is.

It is absolutely important that the final "brick" not show any signs that it was fused together from smaller chunks, so the "fusion" must be very good.

I read that it is possible to dissolve cellulose acetate in chloroform, then evaporate the chloroform and this should leave behind a bonded form of cellulose acetate. My concern is that since I will be performing this at home, I do not want to handle chloroform as i do not have a fume hood or the PPE necessary to handle it. Additionally, I am unaware if this method will not show signs that it was built from smaller chunks especially considering that it contains a dye/pigment.

My question is regarding what is the safest, best, simplest, cheapest way I could bond many small chunks of cellulose acetate (which contain a dye/pigment) into one large chunk?

Thank you very much for your help.

RE: Bonding Cellulose Acetate help!!

Solvent bonding and diffusion bonding require equipment and process control that you clearly don't have.

Start with a big chunk, and cut off what you don't need.

Mike Halloran
Pembroke Pines, FL, USA

RE: Bonding Cellulose Acetate help!!

would simply melting them by bringing the material to its melting point work? It's approximately 170-260 Celsius which I could do safely with a toaster oven in the backyard. If the material is melted and I give it time to set, wouldn't that produce the same results? The chunks are about a centimeter wide while I would like the block to be about 1x1x6 inches. Any other ideas or ideas of how I could achieve this at home would be greatly appreciated.

RE: Bonding Cellulose Acetate help!!

Sorry there was a typo in the last post and I can't see where I can go back and edit it.

The last sentence should read: "Any other ideas or tips of how I could achieve this at home would be greatly appreciated."

RE: Bonding Cellulose Acetate help!!

The editing system here works like this: You Red Flag the message to be edited.
In the resulting dialog box, you leave instructions for the site operator, who will do a reasonable amount of editing as a courtesy. Be very specific and very polite and do not abuse the operator's courtesy.

I misunderstood that you were trying to join a number of prefabricated pieces of specific shapes into a larger whole of a specific shape, as in bonding Legos without glue lines.

If all you want to do is form an ingot from a cup of scraps, your apparatus could be as simple as a metal funnel suspended by bent steel wire over a small ice cube tray sort of thing, also made of metal.

A toaster oven would probably burn the material nearest the heating elements.

A convection oven might work. You will need patience. Set it to the lowest end of the melting point range, and give it a _lot_ of time, like maybe upwards of 12 hours.

If the material burns or discolors, use a lower temperature and more time.

If the ingots crack, cool them more slowly. Plastics do not conduct heat well, so slowly means crank the temperature down a few degrees per hour, so you spread the solidification and cooling over at least a day.

Do it outdoors of course, and beware of hot/molten plastic; it can give you a really nasty and really painful burn.

Mike Halloran
Pembroke Pines, FL, USA

RE: Bonding Cellulose Acetate help!!

Yes! That's a perfect description of what I am trying to do - forming an ingot from scraps. Thank you very much for your tips.

For my purposes I am only interested in making a single ingot at a time, so would an overhead funnel not be necessary? Could I simply lay the material inside of the tray? I am unfamiliar if there is anything special to consider (like using a funnel) to accommodate for the thermodynamics of cellulose acetate at high temperatures. It is important to me that the end product (the ingot) be very uniform since the material is moderately transparent.

Thank you very much for your help. If ANY additional tips come to your mind that may help me in this process I would greatly appreciate it no matter how trivial it may seem.

RE: Bonding Cellulose Acetate help!!

Yes, you could just put scraps in the ingot tray, but it will have to be extra deep, how much depending on the packing fraction you can achieve with the scraps.

It should also have tapered sides so you can get the ingot out, or be made so that it can be disassembled.

Mike Halloran
Pembroke Pines, FL, USA

RE: Bonding Cellulose Acetate help!!

I'll probably CNC a tray that can be split in half. Thanks again. :)

RE: Bonding Cellulose Acetate help!!

NFSs (Materials)
If you are melting Cellulose acetate,pre heat it for several hours to drive off the moisture or bring the temperature up slowly for at least a couple of hours. The material absorbs moisture, and if you heat it too quickly, the moisture will produce voids in your plastic.

You are judged not by what you know, but by what you can do.

RE: Bonding Cellulose Acetate help!!

Solvent bonding is an immensely easier process. Acetone is more commonly used than chloroform. The block must fit together with no gaps. If you have gaps to fill then you need a adhesive which is solvent with the polymer already dissolved.

RE: Bonding Cellulose Acetate help!!

As mentioned, acetone (or probably other nail polish remover products) should work and are safer than chloroform.

Technically, cellulose acetate doesn't melt as it's not crystalline. It softens and flows though.

To make a glue, dissolve some of your scrap in solvent (e.g. 20 weight% )and apply that.

Chris DeArmitt - PhD FRSC

Plastics & Materials Consulting

Plastic Training Seminars

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