Thinning diamond paste (extra high concentration)

huntyukon

huntyukon

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Howdy guys,

I have some oil based diamond paste in an extra high concentration from Poltava. Their extra high concentration means 40ct for 40 grams of compound. By my calculations that’s 20%, which I find to be a higher concentration than necessary.

I’d like to thin the paste to a 10% concentration, approximately. My reason for thinning it is that I use flinthard felt strops and I think a thinner compound would embed a bit more into the felt.

My question is as follows;
what would youse recommend to be the best thinning agent for this here oil based paste?
I’d obviously have to mix it well so that the diamonds are mixed evenly. Is there anything else of note to know before mixing?

Has anyone else used them rock hard, or even flinthard, strops? Your pros and cons to them strops in general would be much appreciated.

I use the ones called flinthard, which are a bit harder than the rock hard ones.
I actually sand those down a bit with 1500 grit paper, just until it’s a smoother stropping surface and until only very short fibres/hair are exposed. Maybe a more experienced sharpener who used felt strops could chime in on the usefulness, or uselessness of my sanding method.

As always, thanks in advance for any responses I get.
 
I have no experience with oil-based diamond paste, but since no one else has replied: are you aware of "extender fluid" or "lubricating fluid" sold specifically for the purpose of thinning diamond paste?
 
I think water based diamond stropping compound is typically 5 carats of diamond per ounce of water so 5.6 grams of carrier to 1 carat vs 1 to 1 for your paste. While I use that ratio myself I think it is still too concentrated.

Do you know what the oil used in the paste is? If not maybe try mixing a little paste with some petroleum jelly or mineral oil to see how well it dissolves.
 
Thanks for the response M Mr.Wizard and D Diemaker and sorry about the late response. I don’t know what type of oil they use. It just says it’s soluble in organic solvents. I will try some petroleum jelly and see how that works and otherwise might look into some “lubricating fluid”.

Sounds like even a 10% concentration, which would be 20ct for 1.4 ounces, is still pretty high. I’ll play around with it and go from there.
 
Diemaker said:
I think water based diamond stropping compound is typically 5 carats of diamond per ounce of water so 5.6 grams of carrier to 1 carat vs 1 to 1 for your paste. While I use that ratio myself I think it is still too concentrated.

Do you know what the oil used in the paste is? If not maybe try mixing a little paste with some petroleum jelly or mineral oil to see how well it dissolves.
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I would go with mineral oil.
 
Blade Lab said:
I would go with mineral oil.
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Thanks B Blade Lab . I’ll try that later on today. A 20% concentration is just too much, imo. That’s 40ct. to 1.4oz…..

The other reason for thinning it, is that a slightly more fluid compound should penetrate my felt strops just a bit better. At least that’s what I hope.
 
Lighter fluid, turpentine, or mineral spirits thin oil bases well, think paint thinner.
 
BJE said:
Lighter fluid, turpentine, or mineral spirits thin oil bases well, think paint thinner.
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Thanks BJE BJE . As a matter of fact I just tried paint thinner, since I had some sitting around. I obviously just tried a small amount but I gotta say it looks promising and it applies relatively well to the strop.

That said, if I used something like isopropyl alcohol it would theoretically mix just as well as turpentine etc but evaporate fairly quickly once applied to the strop?

I will play around with that a bit. Although, I’m unsure if there’s an advantage to the paste drying like that vs leaving it a little bit pliable, like with turpentine. Any opinion on that?

I realize that I’m asking questions to which I can probably find the answer myself, just by experimenting with it. That said I do believe in not “trying to reinvent the wheel” and rather ask around first.

Thanks again for the response. I definitely appreciate the knowledge I can learn from you guys
 
huntyukon said:
I realize that I’m asking questions to which I can probably find the answer myself, just by experimenting with it. That said I do believe in not “trying to reinvent the wheel” and rather ask around first.
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“Only a fool learns from his own mistakes. The wise man learns from the mistakes of others.”
- Otto von Bismarck
 
huntyukon said:
That said, if I used something like isopropyl alcohol it would theoretically mix just as well as turpentine etc but evaporate fairly quickly once applied to the strop?
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That's what I use, but I buy "universal" compounds that call out oil/water/alcohol soluble.
 
Mr.Wizard said:
That's what I use, but I buy "universal" compounds that call out oil/water/alcohol soluble.
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I tried turpentine and isopropyl so far and both worked. With isopropyl the compound got relatively hard. Works well though. Have you ever made your own emulsion or suspension with diamond/cbn powder, by any chance? Thank you!
 
huntyukon said:
Have you ever made your own emulsion or suspension with diamond/cbn powder, by any chance?
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Yes, and I like demineralized water as the carrier, but that was when I used leather. If you make your own then you have way more choices for abrasives, which is nice. I haven't noticed any signs of clumping even down to .1 microns so question how much of an issue it is for knives. The only issue I have had is sprayers plugging up fast above 5 to 10 microns so I am playing with different dispensing methods.
 
Diemaker said:
Yes, and I like demineralized water as the carrier, but that was when I used leather. If you make your own then you have way more choices for abrasives, which is nice. I haven't noticed any signs of clumping even down to .1 microns so question how much of an issue it is for knives. The only issue I have had is sprayers plugging up fast above 5 to 10 microns so I am playing with different dispensing methods.
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Very interesting D Diemaker . I can get my hands on all kinds of diamond powders at the moment; Mono as well as poly. I’m thinking of picking up some and try my hand at making my own. Of course as a guy that’s just a hobby sharpener and relatively new to it I appreciate any advice from experienced sharpeners, such as yourself.

I’d be very grateful if I could pick your brain in the future, when I’m in the process of making my own emulsions. Would that be alright?

By the way, I’m very happy with your stones. They perform extremely well!
 
huntyukon said:
Very interesting D Diemaker .I’d be very grateful if I could pick your brain in the future, when I’m in the process of making my own emulsions. Would that be alright?
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I don't have any secrets regarding making stropping emulsions. For my first attempt, I put 5 grams of diamond in 2 oz bottles of water and it was way too concentrated, so I did a little research and found most were using 1 gram per oz of water and did that. I think this is the most concentrated you will want and maybe half that is the good middle ground. All of my experience agrees with less is more when stropping, too much diamond makes your strop way too aggressive. The only time you will want a little more diamond on your strop is if you are using it to sharpen ceramic knives, which I find is the best or only way depending on the ceramic. As with most things in knife sharpening the right answer depends on the details of what you want to do. I have played with using Alox instead of diamond and so far haven't found a reason to do so.
 
Thank you D Diemaker . I hear a lot about polycrystalline and the advantages of it when it comes to emulsions.

Polycrystalline powders are 3 to 5 times more expensive than monocrystalline. So, in your experience is there much of a difference between poly vs monocrystalline when it comes to stropping?
 
From what I understand you want mono for polishing steels. This is what the lead engineer from one of the places I buy diamonds told me. I don't think we want the diamond crystals to break down into smaller sizes, and probably the pressures needed to break poly down are never achieved when stropping anyway.
 
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