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Discussion Starter · #1 ·
How much weaker or worse is the G5 (West System) 5 minute epoxy than the standard West System 105/205 epoxy?

With such a cold winter, I haven't completed as much epoxy work as I was hoping to and I'm getting backed into a corner to get some things done. I am thinking of doing a job which consists of:

1. applying thickened epoxy to fill in gelcoat scratches/gouges
2. Let that cure then finish sand and wash off amine blush
3. Wetting out and applying one layer of fiberglass to reinforce the area
4. Apply remaining 2 - 3 coats of epoxy

If I use 5 minute epoxy I can do this whole job in one day at 55 degrees and maybe even get a coat of pre-kote primer on. This would take a lot more time with the regular epoxy.

Is this a bad idea or this G5 stuff pretty decent?
 

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I would use standard 105/205. You won't have time to thicken the G5 before it sets. It isn't as strong either. Great for holding parts together before using 105 to coat or fillet etc.
 

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The instructions also state:

Not recommended for long-term bonds subject to high loads or moisture.
It's kind of for quick, temporary repairs. I found the fully cured consistency to be a little rubbery compared to G/Flex or the standard epoxy.
 

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Discussion Starter · #6 ·
I would use standard 105/205. You won't have time to thicken the G5 before it sets. It isn't as strong either. Great for holding parts together before using 105 to coat or fillet etc.
I should'v mentioned that the area is small, about 3" wide by 6" long. So at about 55 degrees I would definitely have time to thicken and apply it. When we say it isn't as strong (which is exactly what I've heard before) does anyone have any idea by how much?

If it were say 70% - 80% the strength of normal West system, well that would probably be ok..if it were only 30%-40% as strong, well that probably would not be worth it.

Also, does anyone know if the 5-min epoxy will chemically bond to normal west system? Maybe I could do the first 2 coats with G5, and then finish off with the normal stuff?
 

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Discussion Starter · #7 ·
The instructions also state:

It's kind of for quick, temporary repairs. I found the fully cured consistency to be a little rubbery compared to G/Flex or the standard epoxy.
Ok, given that - I think I'll just use G5 for fairing in the surface flaws and use the regular stuff for the glasswork and surface coats.

Thanks all!
 

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West has free technical support if you can call them.

They'll tell you the exact strengths, differences, best choice of materials to use.
 

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Just re-read your orig. post. Those must be some hellacious dings/gouges if you feel you need to put a layer of fiberglass on to strengthen the repair.

How about some pics so we can see what you're working with?
 

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Discussion Starter · #11 ·
Just re-read your orig. post. Those must be some hellacious dings/gouges if you feel you need to put a layer of fiberglass on to strengthen the repair.

How about some pics so we can see what you're working with?
Sorry I don't have pics! This is the area surrounding the backstay chainplate deck penetration. I need to get this done quickly so the chainplate can be re-installed and ready for the rig to be put back together.

The dings aren't really that bad - I just wanted to reinforce the area after some repairs I've made.
 

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Instead of fighting weather all winter and early spring, take a few days in the summer and just knock it out! You will get a better job and the work will go 4 times faster. If you can't take it inside, just wait until the weather turns.
 

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The repair from the description should not need fiberglass cloth, just thickened epoxy and paint afterwards.
 
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