Delrin OEM Coloring

jmclfrsh

jmclfrsh

Joined
Dec 1, 2012
Messages
1,379
Does anyone know the process that Schrade used to make certain parts of a Delrin scale darker than other portions?

I've heard of the scales melting from a heat source as small as from buffing the nearby blade, which would preclude me using a flame source itself to make certain parts darker than others if I wanted to do so on an existing knife.

I guess what I'm trying to ask is, how did Schrade achieve the brown/tan color discoloration dispersion effect on a sawn Delrin handle?

Anyone know?
 
They used heated dye. Raw molded parts were submerged in a dye vat, stirred, timed, then removed, rinsed and dried. The two-tone Old Timer handles used only a bown dye bath. The Uncle Henry Staglon handles used a brown bath, rinsed, and then a black bath. Buffing the handles after assembly revealed the underlying lighter colors around tangs in fixed blades and next to bolsters on folders. The base Delrin material varied somewhat in color over the years from light cream to tan.

10s8561.jpg

Here is one of my knives which has not been reduced showing only the black top dye.
r94qqa.jpg
 
I forgot to add: I've never redyed a Old Timer handle but I have done so with an Uncle Henry. I used Feibings leather shoe sole dye. I brushed it on with the applicator and let it dry, then buffed it back down with an old t-shirt, then let it cure. It looked good and was fairly durable. I did not use heat, but if you want to redye a user, you might do so, heat the Delrin (hot water bath) and the dye slightly. That will not melt the Delrin but might help the mordant in the dye set in the Delrin better.
 
Thanks for bringing that foreward Frank. Honestly, I was just too lazy to do it myself! And as one can see on that thread, initially some of that Delrin molding was done out of house, then later done in-house, then again outsourced. Having worked as production engineer in plastics molding I can tell you that it is an entirely different industry from cutlery making.

Injection molding machines evolve with technology as do plastics, so keeping up is an expensive proposition. The molding machines themselves can be updated, added to, improved by inhouse engineers and molding machine manufacturing engineers can do only so much before an entirely new updated machine is required, the goal to increase speed and efficient use of raw material, reduce rejects due to short shots, sink and splay.

To be cost effective in today's manufacturing environment, it just makes sense for plastics molding to be done by a company completely dedicated to that process. And evidently Imperial Schrade was moving even further in that direction by having the die-cutting/punching and dyeing done via outsourcing, freeing up plant manufacturing space and manpower for cutlery making and packaging. The same evolution was occuring in their sheath making from what I gather.
 
Thank you gentlemen, I read the entire thread and what a wealth of information.

What prompted my question is the handle color of my BNIB Old Timer Mustang's Delrin handle color was a little more tan in appearance near the bolsters than some other knives are, and it is an original Made in USA unit.

Codger, is soaking the entire knife in 303 protectant or mineral oil a few days a way to try to darken the Delrin without risking using leather dye on it and completely messing it up?

If not, and I use leather dye, can it be applied carefully with a rag just at room temperature on the areas I wish to darken? Is the Delrin somewhat porous at room temperature, or is heat needed to open the pores?

THANK YOU again for this information.

BTW, I'm becoming a Gold Member tomorrow, tried once a few months ago but somehow it did not work out, the payment process. Will try again tomorrow as mentioned.
 
jmclfrsh said:
Thank you gentlemen, I read the entire thread and what a wealth of information.

What prompted my question is the handle color of my BNIB Old Timer Mustang's Delrin handle color was a little more tan in appearance near the bolsters than some other knives are, and it is an original Made in USA unit.

Codger, is soaking the entire knife in 303 protectant or mineral oil a few days a way to try to darken the Delrin without risking using leather dye on it and completely messing it up?

If not, and I use leather dye, can it be applied carefully with a rag just at room temperature on the areas I wish to darken? Is the Delrin somewhat porous at room temperature, or is heat needed to open the pores?

THANK YOU again for this information.

BTW, I'm becoming a Gold Member tomorrow, tried once a few months ago but somehow it did not work out, the payment process. Will try again tomorrow as mentioned.
Click to expand...

The heat is not to "open pores" in the plastic, IMHO, but to increase the action of the mordant and to a degree soften the surface of the Delrin. Like vinegar in Easter egg dye. 303 is a wipe on/wipe off affair. I'd apply it with a q-tip rather than soak. Same for the dye if you use that. I would not submerge the knife in either. But it sounds like you are talking about the base Delrin color which was changed intermittently from cream to shades of tan. If that is the case, you won't likely affect it much unless it is chalked/dried like the Buck shown. Some variation over a long period of production is just normal due to changes in materials and processes.
 
There is quite a bit of variation in the original two-tone Old Timer handle colors. I wouldn't worry at all about one knife being more tan, more reddish, or lighter/darker than others.
 
Good point. Think I'll just use it the way it is. Sure cleaned up good with Simichrome, looks fantastic.

I'll take some pics with a better camera, my iPhone did not do it justice.

Thanks again for the info, guys. Much appreciated!
 
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