Marine Epoxy??

galadduin

galadduin

Joined
Dec 25, 2004
Messages
1,363
I don't have the chance to find most known epoxies here, I've been trying different brands time to time, none of them good enough, most of them fast curing, some of them are very weak... So I decided ask the shipyard workers, what do they use mostly, I bought a gallon of it, it is quite pricey, not known brand, clear transparent, 1 to 3 mix, 24 hour curing time. I used it for my latest 4 knives.. Mostly I'm satisfied about the results, the tests I ran shows it is stronger than all of these popular ones. The only down side is it is too thin that it flows like crazy before curing. So I mix it at least 10 mins then I wait 2-3 hour and mix it again, finally I apply 4 hour later when it is not so thin...
I want to ask, do any one use/used that kind of product? Is there a method to make it thick enough just after mixing it ??
 
Emre,

I am by trade a boatbuilder, and use a marine epoxy (West System), which has similar characteristics. It is neccessary to mix in a thickener to the epoxy/hardener mix to make a glue. The un-thickened epoxy/hardener is used as a laminating resin for fiberglass. Colloidal Silica is an excellent thickener for your purposes.

John
 
John White said:
Emre,

I am by trade a boatbuilder, and use a marine epoxy (West System), which has similar characteristics. It is neccessary to mix in a thickener to the epoxy/hardener mix to make a glue. The un-thickened epoxy/hardener is used as a laminating resin for fiberglass. Colloidal Silica is an excellent thickener for your purposes.

John
Click to expand...
And West sells every possible "accessory" that you could ever need from fillers to mixing cups and syringes.:thumbup:
 
John White said:
Emre,

I am by trade a boatbuilder, and use a marine epoxy (West System), which has similar characteristics. It is neccessary to mix in a thickener to the epoxy/hardener mix to make a glue. The un-thickened epoxy/hardener is used as a laminating resin for fiberglass. Colloidal Silica is an excellent thickener for your purposes.

John
Click to expand...

Thank you John for this great info. I was struggling with that epoxy, I knew it has some great potential, let's see if they have some thickener for it...
 
I used to use something similar with good results. I used a fine chopped glass fiber powder as a thickener. I stopped using it when it got past its shelf date. It still setup fine, but eventually I noticed the bond wasn't as strong. I never got more because it was very spendy and I only ever used half of it.
 
Thanks friends, I found a dealer selling West Systems products, I am buying fiber powder (west systems 403) and 406 - colloidal silica, I'll test both and use one that passes my tests :)

I want to thank you again John, and also Nathan for fiber advise :thumbup:.
I'm not sure it is weak, the only thing that passed my strength tests was this product and JB weld. I use corby rivets mostly so frankly any epoxy will do but I want to be sure you know....
 
Emre did you ask them at West about their excelerator. I read somewhere that it is supposed to speed up the setting of the epoxy. I have never tried it yet but it may help you out. Good luck.
 
Emre,

You may find that the silica works better for knife use than the chopped cotton fibers. The fibers are used more for wood to wood contact, and can leave a more visible glue line. All epoxies require a "glue line" to form their strong bond. The epoxy mixture is "greasy" and excess clamping pressure can force too much glue out of the joint, leaving a "starved' joint, leading to failure of the glue-up.
Silica can be mixed into the epoxy/hardener in almost any proportion, from a thinner mixture for pouring into a handle, to a stiff, "peanut-butter" non-sag, for filling scale cavities.
No thinners should ever be used on high solids marine epoxies, and there is no "accellerant" for West Epoxy, though there are "fast" and "slow" hardeners.
Finally, all these structural epoxies must be mixed exactly in the specified proportions, as any excess resin or hardener remains un-linked in the mixture, and thorough mixing to blend the resin and hardener is essential.
This all sounds more complicated than it really is, but the better the materials used for any project, the more important it becomes to follow the carefully designed procedures for their use. (sounds like advice on heat-treating, doesn't it)

John
 
if anyone else is looking for a supplier,

Rockler (www.Rockler.com) is a woodworking supply chain throughout the US and they carry West Systems products.

not the "best" price but certainly reasonable
 
John White said:
Emre,

You may find that the silica works better for knife use than the chopped cotton fibers. The fibers are used more for wood to wood contact, and can leave a more visible glue line. All epoxies require a "glue line" to form their strong bond. The epoxy mixture is "greasy" and excess clamping pressure can force too much glue out of the joint, leaving a "starved' joint, leading to failure of the glue-up.
Silica can be mixed into the epoxy/hardener in almost any proportion, from a thinner mixture for pouring into a handle, to a stiff, "peanut-butter" non-sag, for filling scale cavities.
No thinners should ever be used on high solids marine epoxies, and there is no "accellerant" for West Epoxy, though there are "fast" and "slow" hardeners.
Finally, all these structural epoxies must be mixed exactly in the specified proportions, as any excess resin or hardener remains un-linked in the mixture, and thorough mixing to blend the resin and hardener is essential.
This all sounds more complicated than it really is, but the better the materials used for any project, the more important it becomes to follow the carefully designed procedures for their use. (sounds like advice on heat-treating, doesn't it)

John
Click to expand...
My experience is that the normal West epoxy will harden into a VERY solid mass even without the filler. Just let some of it sit in a cup beyond the listed "pot time" and you will see what I mean! The chemical reaction generates a fair amount of heat too!!! However, I am mostly using it to pour down into handles, so I don't have the issue of using it for gluing slabs. I need to order some more, so I will try the silica filler this time.
 
galadduin said:
Thanks friends, I found a dealer selling West Systems products, I am buying fiber powder (west systems 403) and 406 - colloidal silica, I'll test both and use one that passes my tests :)

I want to thank you again John, and also Nathan for fiber advise :thumbup:.
I'm not sure it is weak, the only thing that passed my strength tests was this product and JB weld. I use corby rivets mostly so frankly any epoxy will do but I want to be sure you know....
Click to expand...
Another piece of advice that I read somewhere. Do NOT buy the "quick" JB Weld as it apparently lacks the strength of the regular longer curing stuff.
 
Joe,
The problem with "unfilled" west epoxy, besides the medium viscosity desirable for fiberglass laminating, is the brittle nature of the hardened, unfilled mass. It's plenty hard, but tends not to withstand shock loads like a filled mass.

John
 
That's what I've always heard , the 5 minute epoxys are not as strong.
John, do you mean "cotton" fibers or glass fibers ??
 
jdm61 said:
However, I am mostly using it to pour down into handles, so I don't have the issue of using it for gluing slabs. I need to order some more, so I will try the silica filler this time.
Click to expand...

If you're just filling, you can probably get away with polyester resin with filler instead of epoxy. It will be a lot cheaper.
 
Mete,

The fibers sold by West are chopped cotton, the cellulose and epoxy approximates the characteristics of the boatbuilding woods commonly glued. We also often use "wood dough", or the sanding dust from the actual wood glued. The "System" in West System now refers to the ability to use many different additives, and techniques, to tailor the epoxy to specific tasks.
Silica is a higher strength, but lower flexibility additive. Knives don't flex like boat masts,and don't need the higher flexibility, but can use the higher strength bond for wood to metal bonding.
Probably best not to encourage an old boatbuilder on epoxy usage, we're literally "full of it".

John
 
artmichalek said:
If you're just filling, you can probably get away with polyester resin with filler instead of epoxy. It will be a lot cheaper.
Click to expand...
With the small amounts that I use, I am okay spending extra money for the epoxy. Plus the polyester and vinylester resins have a particular smell that I don't like. They smell like cheap bass boats:D
 
John White said:
Mete,

The fibers sold by West are chopped cotton, the cellulose and epoxy approximates the characteristics of the boatbuilding woods commonly glued. We also often use "wood dough", or the sanding dust from the actual wood glued. The "System" in West System now refers to the ability to use many different additives, and techniques, to tailor the epoxy to specific tasks.
Silica is a higher strength, but lower flexibility additive. Knives don't flex like boat masts,and don't need the higher flexibility, but can use the higher strength bond for wood to metal bonding.
Probably best not to encourage an old boatbuilder on epoxy usage, we're literally "full of it".

John
Click to expand...
John.....what kind of fillers, if any, do shops like Rybovich and Whiticar use with the epoxy for "cold molding" their wood hulls?
 
Joe,

I don't have specific info on Rybo or Whiticar, but cold molding with West, MAS, System Three or equivalent, will always use a filler tailored to the grain strength of the wood. Its a two stage process, rolling on un-filled epoxy to soak into the wood grain, followed by the gap-filling , filled mixture.Since epoxy weight gets to be a factor, woods like red cedar are laminated with low density fillers such as micro-balloons stiffened with low amounts of silica, mahogany at the other end of the scale would use a high strength like cellulose,( cotton or wood dust.)

The purposes of a filler are to gap-fill,and to retard glue soak-up to prevent glue-starved joints, as well as to reduce the brittleness of the cured epoxy. For our purposes, using silica lets us stiffen the epoxy as needed to prevent run-out, and add some resistance to shock load,ie dropping the knife handle-first...

John
 
You must log in or register to reply here.
Back
Top