Adjusting g-flex ratio when using dye

Matt Rochester

Matt Rochester

Joined
Nov 28, 2014
Messages
1,864
I have noticed when I dye g-flex, or any epoxy, it seems to become runny. Do I need to add hardener or resin to thicken it up? I use the smallest drop I can and it's from USA knifemaker.
 
The hardener/resin ratio is very exact. It is best to do it by weight. Don't change that for any reason. Color is best added with dry pigment epoxy dyes. K&G sells good ones. I am not a fan of liquid dyes.
 
Read the instructions on how to mix your epoxy. Not all epoxies are best measured by weight, as many are expected to be measured by volume.

I had absolutely no luck with dry dye. Much more consistent results with liquid. Buy some and try some, I guess.
 
I mix it 1:1 like on the bottle. It just gets thin with the smallest drop of dye. I just want to make sure it isnt affecting the strength. I never used it with the devcon because it is clear. The g-flex is Amber and shows up a little more.
 
Yeah, that's what I do, as well, with G-Flex, as that's what their customer service tech said to do when I called them asking for specifics. I actually called to find out if there was a way to thicken it, as you can do that with their other compounds. I have no love for G-Flex because of its thin viscosity. Far too messy. It works well, but there's other strong contenders. I'm currently testing some of the new BladeBond formulas, and so far I'd say there's a good chance they'll be a candidate...
 
I also don't like the long wait time. I would like to find something that sets in 20 mins or so. The devcon was too fast. You could barely get the knife together, but I was grinding 20 mins later. The g-flex takes way too long. I have to wait til the next day to start grinding. Anyway, I will give the powder a try and see which I like better. Thanks.
 
Thanks, Chuck, I have seen that. Fact is, I usually use a far better aerospace adhesive for my knives, but I needed to order a bunch of G-Flex as it's what I need to patch my Kevlar canoe with.:) Figured I'd at least try it on a knife or two, as lots of folks here seem to really like it.

My destruction tests proved that it is certainly an adequate performer, requiring me to destroy the handle material on the full tang knife I tested it on, and finally grinding off where it was still adhered to the tang. The grain of the wood failed before the bond in almost every spot on the tang - not much more can be asked for, I don't think. Still, it was easier to induce failure than with my secret weapon, but the expense of it is literally fifteen times more...

Back to my comment on reading instructions. As Stacy pointed out, many epoxies don't use volume as a measuring/dispensing method. The rest of the West Systems lineup does, but G-Flex is done by volume. RTFM!!!

Very few guys do surface prep properly, too. A word of advice... Don't listen to other knifemakers. They likely got their opinion from... Other knifemakers. This doesn't make them bad guys, mind you, but who's to say the first guy was doing it right? ASK THE VENDOR. Most epoxy companies will tell you best practice is surface abrasion (likely sandblasting), and NOT to use solvents to clean the surfaces before assembly.

Perhaps the epoxy company will tell you what the best practice is for dye, too. West System sells liquid dye, you know...
 
I like g/flex a lot. I've done a lot of my own research including talking to the people at West Systems and I am a huge fan of the forgiving nature of the product. You can pretty much tint it with anything as long as it comprises less than 5% of the total volume. I tint with artist oil based pigments and can match any color I want. Mixing ratios are not strict either. It is supposed to be mixed 1:1 by volume but, being off a little one way or the other will have a negligible effect due to the slow cure time. And long term durability, I doubt you're going to find anything much better. That flex is the key to its' strength and shock resistance. Sure, it can get pretty thin in a hot shop and the cure time is long but, for me the benefits out weigh those things.

One thing I don't think it is appropriate for is doing epoxy filling around file work. It doesn't harden enough to take a good polish.

Bob
 
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