MyKarta? Fiberglass resin VS Epoxy

R

RHankins

Joined
Jul 14, 2007
Messages
190
Which is better? What results have you obtained?

Before spending a bunch of $$$ on press and material could use some advice!
 
Well, the press and material will serve you well no matter what you use to bond them. Truthfully though, you don't need a press. A couple wood worker's clamps, or several c-clamps and a 2x6 will work fine, just get one that's flat. I've used both epoxy and fiberglass resin, they both have advantages and disadvantages.

Boat builder's epoxy gives you more work time and is often available in a low-blush formula. This will allow you to keep your scales closer to the original colour of the material. The boat builder's epoxy is also usually rated for UV exposure, salt water and often tested with various chemicals and is possibly more resistant to the elements.

Fiberglass resin is cheap and available locally. The boat builder's epoxy is a larger up-front investment and many folks will have to order it. The resin goes on much thicker than the epoxy (as well as setting much faster), this makes it harder to work with initially, but I find that it's easier to press it between the fibers because it doesn't move around and push out the sides as easily. The resin also seems to be a bit denser and harder than epoxy. There is a fairly high blush with fiberglass resin, so if you use light colours, they will take a tan hue. Stark white cloth will become a nice cream colour, for example.
 
Thanks for the input.
What are your thoughts on using the fillers like CaboSil and chopped fiberglass fibers?
Would using a mold and some penetrating Epoxy Not require the use of a press?
 
just a little clarification. Epoxy, such as the West System product, is one of the three common fiberglass resins used in the marine industry. The other two are polyester and vinylester. I am told that most of the time, boat builders use the other two on less stressed components because epoxy is quite pricey. But in your application, it shouldn't be an issue. With that said, my understanding is that real Micarta uses yet another phenolic based resin.
 
jdm61 said:
just a little clarification. Epoxy, such as the West System product, is one of the three common fiberglass resins used in the marine industry. The other two are polyester and vinylester. I am told that most of the time, boat builders use the other two on less stressed components because epoxy is quite pricey. But in your application, it shouldn't be an issue. With that said, my understanding is that real Micarta uses yet another phenolic based resin.
Click to expand...

yes and a heated cure for it also
 
Yes, reinforcing what JDM said. what people often refer to as boatbuilding fibreglass resin is often polyester resin. cheap and basic... Epoxy resins are also used for fibreglass for boat construction and is essentially an advancement to improve on the shortcomings of polyester resin, such as UV sensitivity, water absorption and delamination. For handles you are looking at small volumes of resin so probably epoxy would be a good route anyway.

The usual objective of composites manufacture is to get a high 'fibre volume fraction', and using a press or a vacuum will help you get there, and help eliminate ugly voids
 
langchop said:
Yes, reinforcing what JDM said. what people often refer to as boatbuilding fibreglass resin is often polyester resin. cheap and basic... Epoxy resins are also used for fibreglass for boat construction and is essentially an advancement to improve on the shortcomings of polyester resin, such as UV sensitivity, water absorption and delamination. For handles you are looking at small volumes of resin so probably epoxy would be a good route anyway.

The usual objective of composites manufacture is to get a high 'fibre volume fraction', and using a press or a vacuum will help you get there, and help eliminate ugly voids
Click to expand...

Epoxy based FRP also has higher strength than polyester or vinylester. Most of the builders of larger sportfishing boats tend to restrict the use of anythingother than epoxy to no stress bearing parts like the deck surface. The stringers and hulls tend to be epoxy. The cold molded wooden boat builders use big vacuum bagging setups to impreganate the wood hulls with epoxy and then they usually throw layers two of cloth and epoxy on the surface.
 
You can likely get away with just using clamps, but I wouldn't try just soaking the material in epoxy. Depending on the weave of the material, you may have a hard time getting it soaked through well. Also, as mentioned previously, you may end up with voids/inclusions. Don't know about using the vacuum bag, I'd like to hear anyone's experience with that.

Didn't know the details about the boat builder's epoxy, just know that it costs about 5 times as much in my research. When I say fiberglass resin, I mean the bondo you buy at wal-mart. It takes about 1/3 of a can of the bondo to make enough for two sets of scales, give or take depending on thickness and scale size. It seems to take a bit less epoxy, but you have to buy more up front.
 
you can also figger for about a 32oz can per inch in a box 6x10
not that i know ;) this is also dependent on the fabric
 
I did a varsity project based on composites and we had a little composites facility which I was gratefully able to access. for bigger items in fibreglass they would measure the correct weight of fibre against the correct weight of resin and use a roller to force it in... If you dont measure, one tends to use way too much resin. I never did the actual operation, but the quality of the vacuum formed components were far superior to manually 'wetted' resin, both in terms of strength and void formation. Something else you could look into is pre-preg cloth, which is already wetted in good proportion
 
Resins are one thing, but I would hesitate to use glass cloth in any application where you are going to be making a handle of any kind. You would have to either gel coat or paint the surface. The great thing about the paper or cloth used in making micarta is that the raw material will not poke you with tiny sharp fibers either when you make it or when it starts to wear on the surface.
 
Hi Joe - I'm pondering this issue and I'm wondering if we're on the same page. The fiberlgass cloth that I've worked with in modeling is not sharp or pokey in any way. As a child and teenager I worked with it extensively without any gloves or even a respirator (not that I recommend this). From what I understand of G10, it's fiberglass cloth and melamine resin. Is the concern that when the fiberglass resin wears with use that you'll be left with stiff glass splinters on the handle?
 
I have a question that I have been meaning to ask for a long time. Why do people want to make their own micatra? It can't be the cost. Is real micarta inferior to home made? I have not used any since the late eighties.
 
LRB said:
I have a question that I have been meaning to ask for a long time. Why do people want to make their own micatra? It can't be the cost. Is real micarta inferior to home made? I have not used any since the late eighties.
Click to expand...

The same reason that we make homemade knives (for many of the hobbyists here). It looks like a fun project - if it can be done at home, it will be done at home! I imagine there's also a certain 'wow factor' if showing to friends (or customers).
 
LRB said:
I have a question that I have been meaning to ask for a long time. Why do people want to make their own micatra? It can't be the cost. Is real micarta inferior to home made? I have not used any since the late eighties.
Click to expand...
Also because Westinghouse et al. never saw fit to make weird things like camo pattern Micarta:D
 
AcridSaint said:
Hi Joe - I'm pondering this issue and I'm wondering if we're on the same page. The fiberlgass cloth that I've worked with in modeling is not sharp or pokey in any way. As a child and teenager I worked with it extensively without any gloves or even a respirator (not that I recommend this). From what I understand of G10, it's fiberglass cloth and melamine resin. Is the concern that when the fiberglass resin wears with use that you'll be left with stiff glass splinters on the handle?
Click to expand...
They don't have to be still. I had a very unpleasant experience with a fiberglass radio antenna on our boat that had the gel coat worn off by salt spray, etc. VERY ouchy:D
 
Another reason, you can make micarta that you can't buy and can also get cool patterns and colors.
 
yep its all about makeing something cool
that you cant get any place
 

Attachments

  • DSC04205sm.jpg
    DSC04205sm.jpg
    96.1 KB · Views: 109
You must log in or register to reply here.
Back
Top