Kydex pressing foam question

NeverMore1701

NeverMore1701

Joined
Jan 29, 2008
Messages
3,445
I made several sheaths with some old foam I had lying around, worked spectacularly. After a dozen or so sheaths it was pretty worn out, so I chunked it and ordered some from knifekits. It's a lot firmer, which is great, but when I pull the sheath out after pressing, there's a border eaten into the foam around where the kydex was. I reduced the heat I was warming the kydex in from 350 to 275*, and it does it a little less, but it still happens. Do I need to reduce the heat even more, or is there something else I should be doing?


Thanks!
 
In this post The Count links to some great kydex how to's... you can see in these vids that there are some serious marks on his foam, he's heating to just about the same temps you are. Without seeing pics of your foam it's hard to compare... give those a watch as he makes a living at doing kydex holsters it may be that what you're seeing is normal...

Oh, and I see the same thing on my foam, but I don't have a press proper, I just got a couple of pieces of wood that I sit on for a while... In a couple of weeks I'll have a press built, we'll see if I have the same results.
 
I don't have an actual press, just foam, plywood, and a bench vice. I dug the old flat foam out of the trash and put it directly on the kydex, with the new foam outside of that, and then the pywood. I'm getting results like I was originally, much better than with just the new knifekits foam. I'll definitely give those videos a watch, thanks!
 
I believe the "borders" you refer to are unavoidable but In my experience have not noticed them affecting any of my work and Ive used it LOTS. :thumbup: (I dont exceed 300 degrees for what its worth)

securedownload-1967.jpg


old well used but still functional knifekits foam with a new piece, stuff rocks
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@dericdesmond: thanks for the photos. Is that the knifekits CCK press? and do you preheat your foam?

I'm on the fence right now on buying or after watching those vids, making a press.
 
dericdesmond said:
I believe the "borders" you refer to are unavoidable but In my experience have not noticed them affecting any of my work and Ive used it LOTS. :thumbup: (I dont exceed 300 degrees for what its worth)

securedownload-1967.jpg


old well used but still functional knifekits foam with a new piece, stuff rocks
securedownload-1338.jpg
Click to expand...

Mine actually break the surface of the foam by a good 3-5mm. Can't exactly tell by your pics, but it looks like the surface isn't broken? I'll try to grab a pic.
 
That don`t look good at all...never had this happen even on my 1/2" thick foam i was using..
 
theHobbyist said:
@dericdesmond: thanks for the photos. Is that the knifekits CCK press? and do you preheat your foam?

I'm on the fence right now on buying or after watching those vids, making a press.
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Yes it is. I am looking to buy a 2nd. Lots of people talk of making there own but for the $100 or a little less I prefer to have an ideal product and be done with it. And no, never heard of preheating foam until you just asked.
NeverMore1701 said:
IMG_8997.JPG


IMG_8998.JPG
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YOWZA! How much weight are you putting on top of your press? I go 300 dregrees and stack 3 35lbs hex dumb-bells, maybe a 4th 25lb on top of those if I want an extra tight mold.
 
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Was the kydex rough on the edges before pressing? Was it really limp or distorted when you pressed it? Looks like a rough edges, a lot of pressure or maybe too hot.

I used to bandsaw my kydex before molding and would get something like that but switched to scoring it and bending to cut instead. It is easier and faster that way.

I use the blue foam and go through a decent bit of it, I think it lasts for 30-40 knives then I toss it. I have 5 presses I keep going so I use a lot of foam.

I have tried all sorts of things and I think the key to good kydex is to get it molded fast and tightly. I don't think the impressions will do much to hurt a sheath but after a while it will get pressed down and wear out.
 
dericdesmond said:
Yes it is. I am looking to buy a 2nd. Lots of people talk of making there own but for the $100 or a little less I prefer to have an ideal product and be done with it. And no, never heard of preheating foam until you just asked.

YOWZA! How much weight are you putting on top of your press? I go 300 dregrees and stack 3 35lbs hex dumb-bells, maybe a 4th 25lb on top of those if I want an extra tight mold.
Click to expand...

never heard of it either till i stumbled on a gun holster kydex forum alot of gun holster guys do preheat the foam...gives more time to adjust the kydex if necessary i guess also after the pressing they hit the foam with the heat gun and it comes back up a bit..
also i don`t think it`s the weight his problem
 
The reason I'm not buying a press right off is that I live in Hawaii... shipping that thing is between ridiculous and WTF DID YOU JUST SAY?!?!?

In any case, is that the shiny side of the foam?
 
Tried it again today at 250, didn't mess up the foam quite as bad, but it was hardening up as I was getting the blade in there. Maybe I'm using too much pressure (bench vice)?
 
NeverMore1701 said:
Tried it again today at 250, didn't mess up the foam quite as bad, but it was hardening up as I was getting the blade in there. Maybe I'm using too much pressure (bench vice)?
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i am using a bench vice since i started a year and a half ago...i tighten it so hard i can hear the screws geeing ready to pop out never had this...there is something wrong with the foam
DSC01668.jpg

in this pic the press is not as tight as i usually have it
 
theHobbyist said:
@710 & NeverMore1701: I'm curious, how are you getting your temps?
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I noticed that anything higher than that burns it... besides if its not hot enough heat to make it playable, leave it in for an extra few seconds or minutes... once it gets to hot there is no trying to fix it, you just end up with a big giant piece of melted scrap or messed up foam pads. you can use what ever heat you desire but whats the rush on trying to use higher heat with less time.... take it slow and speed will come naturally. just like wood "measure twice, cut once" I dunno maybe it's the carpenter in me....
 
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