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Help explain West Systems epoxy numbers

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Forum topic by yellowtruck75 posted 05-01-2015 07:18 PM 779 views 2 times favorited 7 replies Add to Favorites Watch
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yellowtruck75

464 posts in 2535 days


05-01-2015 07:18 PM

Can someone explain to me the different numbers for the West System epoxy. I am looking on Amazon and there is a 105 resin and a 205 hardener but then there are other numbers and I don’t understand which combo I need. I am looking to use epoxy to help fill voids in hardwood and use on table tops to help stabilize cracks.


7 replies so far

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JayT

4788 posts in 1679 days


#1 posted 05-01-2015 07:21 PM

See if this chart from the West System website helps

http://www.westsystem.com/ss/product-selection-chart/

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

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MrUnix

4247 posts in 1667 days


#2 posted 05-01-2015 07:47 PM

105 is the resin, and you get the hardener depending on application (temperature, cure time, clarity). 205 is the most common and has the widest temperature range. Here is the hardener guide: http://www.westsystem.com/ss/hardener-selection-guide/

I’d also recommend getting the pumps as they make it much easier to work with… and you can just leave them on and store the cans away without fuss. It has an almost infinite shelf life. I have some I purchased several years ago and it’s still just fine (although the hardener gets a bit more amber in color as it ages).

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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yellowtruck75

464 posts in 2535 days


#3 posted 05-01-2015 08:21 PM

Do they all dry clear?

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MrUnix

4247 posts in 1667 days


#4 posted 05-01-2015 08:24 PM

Do they all dry clear?

No. The standard stuff will have a slight amber color. And if you put in any filler additives, it will alter the color as well (like microfibers will make it whitish). If you want clear, then you need to get the 207 hardener. It is also quite common to mix in coffee grounds to get a dark brown color when filling voids. In some cases, it makes it look like natural spalting, and in others, it makes a unique contrasting feature that gives the wood some ‘character’ :)

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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garysharp

119 posts in 2948 days


#5 posted 05-01-2015 11:42 PM

I have been using the 105, 205 combination for about 10 years. The pumps are great but they start to lose accuracy after 6 or 7 years. To over come this problem I got a Harbor Freight electronic scale for $20 on sale. It works great because the mix ratio is 5 to 1 volume or weight. One word of caution cover the tops of the pumps withe zip lock bags because the fumes from the hardener WILL drift into the tip of the rosin and plug it up. It runs like water but you can seal the bottom of the crack with blue tape.
The best buy is the 1 gal. and 1 qt.
Gary

-- Garysharp "When sharpening woodworking tools, good enough,...isn't" “Your life’s complete only when your knowledge passes on”.

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MrUnix

4247 posts in 1667 days


#6 posted 05-02-2015 02:56 AM

+1 on the digital scale. I routinely make up small batches using those little 1oz plastic SOLO cups you get at the take out food places (I actually went and bought a bag of 100 from a resturant supplier for about $2). The pumps are designed to measure out in one full stroke, so you can’t easily do smaller batches unless you weigh it for the proper ratio.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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runswithscissors

2192 posts in 1493 days


#7 posted 05-03-2015 07:17 AM

Epoxy does have a long shelf life, but the resin can crystallize in cold weather (not the hardener). It’s an easy fix, though. Run a bucket of hot tap water, and immerse the resin until the crystals go away. Just like you do with honey.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

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