Carbon fiber - Kevlar sheath

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So you want to fill the empty space between the mould and the wooden handle with resin and fibers , then vacuum it and then the finished product to be wooden handle encased with fiber and the surface finish to be nice and smooth without the need of sanding? Very hard task . I will ask a friend that makes carbon fiber wings for radio controled gliders. He might give me a tip :)
 
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So you want to fill the empty space between the mould and the wooden handle with resin and fibers , then vacuum it and then the finished product to be wooden handle encased with fiber and the surface finish to be nice and smooth without the need of sanding? Very hard task . I will ask a friend that makes carbon fiber wings for radio controled gliders. He might give me a tip :)
No , wooden handle would be removed after I make and split mold . .Then that empty space in shape of handle inside mold would be filled around tang with Kevlar. Other part of mold/not in pictures / which i have made will hold blade and tang and seal that side in right position to future Kevlar handle , if it is clear what I mean ?
Sanding Kevlar is out of question , impossible task .I try everything and nothing works , you get wool on the surface :)
 
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You could use a sleeve and heat shrink tubing.
I have some of that in carbon . It is more easy to do that way and i would do that on some knife .I hope that in my last post is clear what i want to do ? All handle from Kevlar , marble Kevlar ...I hope ?
I thought of doing it in two steps, first one half of mold then the other. But it will be difficult to keep blade and tang to be 100% centered with handle
 
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Taz

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Are you trying to make a kevlar sheath or handle?? You can sand Kevlar and carbon fiber (basically like fiberglass). It gets very fuzzy at lower grits and then cleans up and smooths out as you go up in grits, usually past 120 or 220 or higher. Same with home made micarta. I would just make a solid block of kevlar/epoxy and shape the handle out of that, or do scales and do a frame handle, or do scales, cut out discs and stack up. Belt sanders work very well on carbon fiber, I know others have used the carbon fiber/kevlar mix before as well. Carbon fiber sands as easily as G10/fiberglass and easier than Micarta. Don't try to use a wood saw blade to cut the kevlar or CF, its like fiberglass and will kill regular saw blades quickly. Use a blade made for cutting metal.

This is using carbon fiber for the handle and M3 composite material for the ferrule:
WhFmazc.jpg


I found I got less bubbles/air voids in my carbon fiber material by using less pressure and squeezing less epoxy out and letting it soak into the material longer. I get better results with regular fabrics and more pressure, though. You should be able to get a decently solid piece of kevlar/epoxy by using regular c clamps. I use a 2 ton jack in my press and don't max it out pressure wise. I found Burlap material also likes less pressure as well to keep more of the epoxy in the fabric fibers. There will be tiny air bubbles and voids, so I use super glue to fill those after I get the handle pretty much to shape and finish.

People do vacuum infusion and bagging of carbon fiber and get a smooth finish from their process. You should be able to build up a super glue finish on the handle to get it glossier as well?
 

FredyCro

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Hi Natlek, i think you will need to split your mold, no? You could then do threads and close the mold with bolts? I would then sand the wood on the inside to 600-800 and seal it with something like PU lacquer. I know there are special release agents for releasing carbon, but a thin coat of oil or vaseline should work as well, no?
 
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Are you trying to make a kevlar sheath or handle?? You can sand Kevlar and carbon fiber (basically like fiberglass). It gets very fuzzy at lower grits and then cleans up and smooths out as you go up in grits, usually past 120 or 220 or higher. Same with home made micarta. I would just make a solid block of kevlar/epoxy and shape the handle out of that, or do scales and do a frame handle, or do scales, cut out discs and stack up. Belt sanders work very well on carbon fiber, I know others have used the carbon fiber/kevlar mix before as well. Carbon fiber sands as easily as G10/fiberglass and easier than Micarta. Don't try to use a wood saw blade to cut the kevlar or CF, its like fiberglass and will kill regular saw blades quickly. Use a blade made for cutting metal.

This is using carbon fiber for the handle and M3 composite material for the ferrule:
WhFmazc.jpg


I found I got less bubbles/air voids in my carbon fiber material by using less pressure and squeezing less epoxy out and letting it soak into the material longer. I get better results with regular fabrics and more pressure, though. You should be able to get a decently solid piece of kevlar/epoxy by using regular c clamps. I use a 2 ton jack in my press and don't max it out pressure wise. I found Burlap material also likes less pressure as well to keep more of the epoxy in the fabric fibers. There will be tiny air bubbles and voids, so I use super glue to fill those after I get the handle pretty much to shape and finish.

People do vacuum infusion and bagging of carbon fiber and get a smooth finish from their process. You should be able to build up a super glue finish on the handle to get it glossier as well?
Both :) Last post is about making handle . Working with carbon fiber is easy , Kevlar is something else . I would like to see what kind of handle you make with Kevlar ? I m talking on sanding pure Kevlar ? This is not first try for me to make scale/handle from Kevlar . I tried many times everything and that thing can t be sanded to get some nice finish , at least this ballistic Kevlar I use ? You can make\grind flat scale to fit tang , but to shape flat part of that scale is impossible .Drilling a nice pin hole is also impossible.
You can get some kind of acceptable finish on spine side of scale/grind - CA glue , grind -CA glue / but don t even try to shape from face side ....
67MyYlm.jpg

kOOikec.jpg

QLsj8Zl.jpg

look at this ...........
B81USLG.jpg
 
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Hi Natlek, i think you will need to split your mold, no? You could then do threads and close the mold with bolts? I would then sand the wood on the inside to 600-800 and seal it with something like PU lacquer. I know there are special release agents for releasing carbon, but a thin coat of oil or vaseline should work as well, no?
Fredy , I have bolts and alignment pins in mold .I don t know how to split mold after epoxy cure .I can t pull out that wooden handle because of shape .Probably i need to use thin saw to split it and than to add something between two parts to compensate thickness which I lose from cutting it so i can keep shape and dimension of handle ? I don't need the handle which is inside mold , I'm free to damage it ?
 
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:thumbsup:I have used Hornady One Shot and other spray lubricants that dry as a release agent. Some may impart a texture to the surface though?
Thanks for trying to help with this :thumbsup: I have everything i need to try this , i have release agent that they use in factory which make some military staff. I have Kevlar already prepared with special phenolic resin with which they make some ballistic equipment ....I have carbon fiber already mixed with phenolic resin in it which can after finishing can withstand very high temperature...
What I want to do is to make handle which will be finished when it come out of mold ?
 
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Taz

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Messages
1,557
I haven't worked the kevlar type like you have, but I do have some hybrid carbon fiber/kevlar fabric to laminate, just haven't gotten around to it. I know they sell knifemaking handle scales in carbon fiber/kevlar mix, so I know it is possible to use it?
Some info here:

Homemade handle materials like this will not typically take a high polish like commercially produced micarta/g10. I have taken my handle material with regular fabric up to 2000 grit wet sanding and it still feels almost the same as a 600 or 800 grit finish and isn't glossy at all. Even G Carta doesn't get glossy at high finishes, either and it is thoroughly wetted out and put in a vaccuum for several hours to fully saturate the fabric. The phenolic resin you are using I would think would do a better job to get more glossy? I am using a epoxy resin designed for laminating wood and fiberglass boat parts and cures pretty hard.

The Kevlar you have looks like it's from a ballistic vest? It may be an extremely tight weave in each of the tows (strands you see), so epoxy may not soak into the fabric as easily? They also have other fabrics in there as well usually that may be hard to laminate. You may need to use vacuum or pressure pot to force the epoxy into the weave, but it still may not soak fully into the fibers, which is where the fuzziness comes from I think from my experience with the home made fabric handles. I found that with the carbon fiber and epoxy I am using, some areas seem "dry" and may need a longer soak time or vacuum/pressure pot to fully wet out the fabric. If the kevlar is treated to be waterproof, the epoxy may not be able to penetrate into the fiber. I try to use natural materials, like cotton, jute, denim, linen, etc and not polyester fabrics for my handles. The carbon fiber fabric was different for me and I think the key is getting the epoxy around the fibers, not soaked into them maybe? Does the handle material you made with it feel hard/firm or soft? I am wondering if they epoxy is laminating the layers of fabric together, but not fully penetrating them? So when you sand them, there is little epoxy in the kevlar, which is why its fuzzier? When I sand my home made fabric handles, it is fluffy extremely fine dust, not looking like a cotton ball like yours does, which makes me think that there is more fabric and less epoxy inside the fabric material itself. Fabric handles feel softer and fuzzy until you get above 220 grit and start to feel firmer/hard and smoother, but still have the overall texture of the fabric to them. The kevlar is a much more coarse weave, similar to burlap. Kevlar is very strong, but can still be cut/abraded, but if there isn't epoxy in between the individual fibers/tow/strands, it will be like sanding fabric instead of sanding a composite.
 

Taz

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Natlek, there is a "carbon fiber fabricators" group on FB that you should join. These guys make high end car parts in CF and their products out of the mold look awesome, fully finished. Lots of guys in Europe and over seas, too, they should be able to give you a lot of help with getting a finished product out of the mold, release agents, vacuum bagging, etc! I am in the group and am playing with vacuum to get the epoxy more fully into the fabric to make my carbon fiber handle materials. I find the same tips help with dealing with burlap handle material as well, which is similar to CF and Kevlar in that it is comprised of extremely fine individual strands to make up the larger, coarser strands that we see. CF and Kevlar both have a stupidly fine individual weave of material that is made into thicker strands called tow (for carbon fiber) and then those are woven together. There may be 3000 individual strands in a 1/8" wide strip of CF tow, so there isn't much space in there for epoxies to fill in like a more open regular fabric and with being a glass fiber, epoxies don't soak in as well.

Raw Kevlar may work better than ballistic kevlar because I believe that is usually treated with something to make it water proof. I know sweat, heat and moisture degrade ballistic vests over time, so they are usually coated/sealed to provide better ballistic protection. You may need to look into non coated Kevlar? Burlap will give you a similar look with the strands, too.

This is some blue and white burlap that I pulled apart into strands and pressed with epoxy:
wJ1buWB.jpg
 

FredyCro

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Fredy , I have bolts and alignment pins in mold .I don t know how to split mold after epoxy cure .I can t pull out that wooden handle because of shape .Probably i need to use thin saw to split it and than to add something between two parts to compensate thickness which I lose from cutting it so i can keep shape and dimension of handle ? I don't need the handle which is inside mold , I'm free to damage it ?

Yeah, split the mold with a table saw (ca 2 mm), add some 2mm shims to keep the exact shape. But I dont understand, how you cant split mold after cure? Just unbolt it and if you used a release agent the handle shouldnt stick to the mold?
 
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This is what I need to split /cut , Fredy . Only that part of cured epoxy , that two set of wood from mold would be protected with with release agent so no problem .
XKMnqpc.jpg
 
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Yeah, split the mold with a table saw (ca 2 mm), add some 2mm shims to keep the exact shape. But I dont understand, how you cant split mold after cure? Just unbolt it and if you used a release agent the handle shouldnt stick to the mold?
Ok , now will be clear what i want to do and how that mold would look complete .
Part with number 1 is bottom part , will close mold from that side and will hold blade with tang in prefect position , I mean aligned with inside cavity / which is future handle / when I fill mold from top side with Kevlar .After I finish , just split mold and pull knife out from that bottom part and if I have some lucky I will have nice Kevlar handle on prefect centered blade ?
how assembled mold will look like from above , imagine that wooden handle is not there , just cavity and tang inside ?
WSaR9Em.jpg

here is bottom part which will hold blade , blade goes thru that steel ,there is big hole
ff2vFSn.jpg

5VYYPrp.jpg

UkTSyhq.jpg

assembled and viewed from the side
PoIhvA3.jpg

All this is just for one handle , if that work I will make mold from aluminium
I hope it is clear now ?
 
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Natlek, there is a "carbon fiber fabricators" group on FB that you should join. These guys make high end car parts in CF and their products out of the mold look awesome, fully finished. Lots of guys in Europe and over seas, too, they should be able to give you a lot of help with getting a finished product out of the mold, release agents, vacuum bagging, etc! I am in the group and am playing with vacuum to get the epoxy more fully into the fabric to make my carbon fiber handle materials. I find the same tips help with dealing with burlap handle material as well, which is similar to CF and Kevlar in that it is comprised of extremely fine individual strands to make up the larger, coarser strands that we see. CF and Kevlar both have a stupidly fine individual weave of material that is made into thicker strands called tow (for carbon fiber) and then those are woven together. There may be 3000 individual strands in a 1/8" wide strip of CF tow, so there isn't much space in there for epoxies to fill in like a more open regular fabric and with being a glass fiber, epoxies don't soak in as well.

Raw Kevlar may work better than ballistic kevlar because I believe that is usually treated with something to make it water proof. I know sweat, heat and moisture degrade ballistic vests over time, so they are usually coated/sealed to provide better ballistic protection. You may need to look into non coated Kevlar? Burlap will give you a similar look with the strands, too.

This is some blue and white burlap that I pulled apart into strands and pressed with epoxy:
wJ1buWB.jpg
Thanks my friend . I just mention Kevlar and carbon fiber with phenolic resin .I don t use that to mold carbon fiber handles and in this case with Kevlar .What you see is pure clean Kevlar in that bag and that scale are made with right epoxy .Believe me when i say that you can not sand that thing if you want at the end handle in shape like on bowie knife for example .Ask your self why you don t see handles from Kevlar , I m not the first one who thought of this ? I use special epoxy which was made just for this kind of work with carbon and Kevlar .It is from Germany and it is approved by the competent German institution for use in aircraft parts construction , so that is that what i need .I use that epoxy for years and have never have problem with soaking ..... I use carbon for many years , not knife related so i know how to work with composites . Look , close friend of me is owner of this Company on video clip , you can see what they are doing ...Just one note about that company .There are only three machine/robots on this world ......... very , very advanced technology for making parts from composite material .Two of them are in USA and the third is a mile away from me. No other country has such a machine at the moment . I know every engineer employed in that company so i have no problem asking and get right answer........Whenever i go there on coffee i get bag full with carbon :)
Some Hi-Tech from Macedonia .............they make and sell that robots or whatever they are ,they make parts for all around the world , like for Airbus.......
 
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I haven't worked the kevlar type like you have, but I do have some hybrid carbon fiber/kevlar fabric to laminate, just haven't gotten around to it. I know they sell knifemaking handle scales in carbon fiber/kevlar mix, so I know it is possible to use it?
Some info here:

Homemade handle materials like this will not typically take a high polish like commercially produced micarta/g10. I have taken my handle material with regular fabric up to 2000 grit wet sanding and it still feels almost the same as a 600 or 800 grit finish and isn't glossy at all. Even G Carta doesn't get glossy at high finishes, either and it is thoroughly wetted out and put in a vaccuum for several hours to fully saturate the fabric. The phenolic resin you are using I would think would do a better job to get more glossy? I am using a epoxy resin designed for laminating wood and fiberglass boat parts and cures pretty hard.

The Kevlar you have looks like it's from a ballistic vest? It may be an extremely tight weave in each of the tows (strands you see), so epoxy may not soak into the fabric as easily? They also have other fabrics in there as well usually that may be hard to laminate. You may need to use vacuum or pressure pot to force the epoxy into the weave, but it still may not soak fully into the fibers, which is where the fuzziness comes from I think from my experience with the home made fabric handles. I found that with the carbon fiber and epoxy I am using, some areas seem "dry" and may need a longer soak time or vacuum/pressure pot to fully wet out the fabric. If the kevlar is treated to be waterproof, the epoxy may not be able to penetrate into the fiber. I try to use natural materials, like cotton, jute, denim, linen, etc and not polyester fabrics for my handles. The carbon fiber fabric was different for me and I think the key is getting the epoxy around the fibers, not soaked into them maybe? Does the handle material you made with it feel hard/firm or soft? I am wondering if they epoxy is laminating the layers of fabric together, but not fully penetrating them? So when you sand them, there is little epoxy in the kevlar, which is why its fuzzier? When I sand my home made fabric handles, it is fluffy extremely fine dust, not looking like a cotton ball like yours does, which makes me think that there is more fabric and less epoxy inside the fabric material itself. Fabric handles feel softer and fuzzy until you get above 220 grit and start to feel firmer/hard and smoother, but still have the overall texture of the fabric to them. The kevlar is a much more coarse weave, similar to burlap. Kevlar is very strong, but can still be cut/abraded, but if there isn't epoxy in between the individual fibers/tow/strands, it will be like sanding fabric instead of sanding a composite.
Look , I have no problem with soaking Kevlar . Look at that Kevlar sheath in first page, it was fully soaked 100 % , would you like to see what would look after i sand it little ? This is what is happening ...Kevlar is very abrasion resistance , and very hard to cut material .When you try to sand laminated Kevlar since it is very resistant to abrasion and in same time it is easy to sand epoxy you expose Kevlar strand and ..............fuzzi ?
 
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I try to sand leftover from sheath with new 800 grit SIC paper and here it is after sanding several minutes with my thumb ...........I get nowhere ?
3TwmCA8.jpg

Here it is how it look if you sand edge ...........fuzzi , but you can use lighter to burn them
C0r1IPc.jpg

9kYpPne.jpg

Here is how it look unwoven, individual fiber are extremely thin
cAXURXk.jpg


Now I get another idea ? If I can make that handle instead of wood from some soluble material after curing of mold I can easy break that two part and they will match perfect ? Some car engine piston rods are made that way?



There are lot of kind of Kevlar .............
  • Kevlar K-29 – in industrial applications, such as cables, asbestos replacement, tires, and brake linings.
  • Kevlar K49 – high modulus used in cable and rope products.
  • Kevlar K100 – colored version of Kevlar
  • Kevlar K119 – higher-elongation, flexible and more fatigue resistant
  • Kevlar K129 – higher tenacity for ballistic applications
  • Kevlar K149 – highest tenacity for ballistic, armor, and aerospace applications
  • Kevlar AP – 15% higher tensile strength than K-29
  • Kevlar XP – lighter weight resin and KM2 plus fiber combination
  • Kevlar KM2 – enhanced ballistic resistance for armor applications
 
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Natlek
it looks like you want to shape a finished Kevlar handle around a tang ? (correct)
i think only if you make a metal/Aluminum mold for the handle shape, and use a metal tang with release agent on it it should be easy.. solid handle shaped and done.
i would only recommend doing the 2 part aluminum "Female" mold on the sides . that way it should be very easy to open and remove the handle.
also this helps you keep the tang centered by using a block/spacer to hold the "Blade" straight as you are putting the 2 halves of the handle together. that way the "Blade would lay flat on its side"
it is a very interesting idea!!! why not if you have the gear to do it ..
 
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