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Author Topic: What additives can be used to make SiC slurry more sticky?  (Read 1128 times)

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R.U. Sirius

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I've cut some preforms that I want to fit neatly together, intarsia style. I like the idea of letting the two pieces grind against each other through vertical oscillations to wear down any slight imperfections and mismatches in shape, so I am setting up an old engraver to hold one piece on a dop stick.

My plan is to rely on a few (tens of?) drops of silicon carbide slurry to do the work, and was wondering if there were any additives that are typically used with bare wire saws or other slurry-based systems that help slurry coat surfaces more effectively than plain water.

Or is this really not a problem?
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vitzitziltecpatl

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Re: What additives can be used to make SiC slurry more sticky?
« Reply #1 on: May 18, 2022, 07:29:07 AM »

That's a good question. For your application a heavier mineral oil might work.

R.U. Sirius

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Re: What additives can be used to make SiC slurry more sticky?
« Reply #2 on: May 18, 2022, 10:04:04 AM »

That's a good question. For your application a heavier mineral oil might work.

I considered it, but would prefer to keep the preforms oil-free to avoid problems with gluing them together in the end.

I will just go ahead with plain water and maybe a bit of soap to improve surface coverage, and will revisit this question if the simple approach turns out to be inefficient. Apparently there are additives used with herbicides or with power-washing solutions that help it all cling onto surfaces...

Will be traveling for the next few weeks, so this will be a nice summer project!
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lithicbeads

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Re: What additives can be used to make SiC slurry more sticky?
« Reply #3 on: May 18, 2022, 06:35:35 PM »

Siccatives like you are talking about are just water soluble gums like gum arabic.Those machines were popular a number of years ago and a few drops of grit were not enough. People sat by the machine with a brush or used a pump and or grit slide like ultrasonic drills use.
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R.U. Sirius

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Re: What additives can be used to make SiC slurry more sticky?
« Reply #4 on: May 18, 2022, 08:26:50 PM »

Few drops not being enough makes perfect sense now that you pointed it out... not sure what I was thinking.

I'll do whatever it takes... if one hand is holding the dop stick stuck on a vibrator, another hand will be brushing on the slurry, and for good measure I'll just stick a camera onto my forehead and whistle La Marseillaise.

I've prepared several pairs of pieces, so there is some room for error and learning.
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lithicbeads

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Re: What additives can be used to make SiC slurry more sticky?
« Reply #5 on: May 19, 2022, 10:50:49 AM »

You want to minimize vibrations to your hands it is really bad for them.
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R.U. Sirius

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Re: What additives can be used to make SiC slurry more sticky?
« Reply #6 on: August 24, 2022, 01:08:05 PM »

Just an update in case anyone was wondering... I mounted a dop stick with the stone onto the small engraver, and gave it a try with just 220 grit slurry in water. Sharpie marks were halfway gone within minutes, and the hand-cut preforms were now mating much more nicely. Then, mysteriously, the grinding stopped - the markings on the top half of the perimeter were just staying there, and the inner piece was not getting any deeper.

It turns the culprit was this bit of dop wax that was overhanging and covering part of the girdle. I ground that off, and just as I restarted the messy work, the stone popped off. I blame it on cold water I used to clean up the mess after the first round.

So I decided to try with CA gel adhesive on aluminum 10-32 "Chicago" screw (the barrel part) that fits nicely onto the engraver pin with a heat-shring tubing sleeve. The screw head was slightly domed, so had to grind it flat first.

This time I added a few drops of dishwasher rinse aid to the SiC slurry, seemed to help keeping it dispersed. Really the main issue when it comes to slurry was drying out soon after I would brush it onto the stones, and I guess some glycerol or another humifectant would be helpful.

Another improvement was placing a ribbed plastic liner under the outer stone to allow for used slurry to drain away.

Again, it was going great for a minute or so, the inner stone was working its way in, when it popped off AGAIN.

Of all the issues I was expecting when planning this character-building project, adhering stone to a stick was not on the Top 10 list.

I am only a millimeter away from calling this "good enough," but really getting sick and tired of cleaning up and trying yet another adhesive. Epoxy? Gorilla urethane? Not looking forward to it at all.

Once it's all nested in as I was hoping, I will epoxy the two pieces together, and finish making the cab. I get to enjoy this hobby project an hour here and an hour there, so might be a few weeks before I show the final result.
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lithicbeads

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Re: What additives can be used to make SiC slurry more sticky?
« Reply #7 on: August 24, 2022, 03:46:52 PM »

Wax is sort of a joke at this point. Extremely clean cab and dops and either superglue or epoxy is the trick but they must be allowed to mature or use an accelerant if super glue. The correct superglue matters and it needs to be fresh or out of the freezer. Acetone is a safe cleaner after using soap and water.
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