Smooth on ratios

[Lee Lobbestael]

There seems to be a discrepancy concerning the ratio of part A to part B with smooth on. The cans I have had all say to mix at a ratio of 70:30 A to B by volume I believe. Most people I have talked to mix it 50:50 by volume but some said they mix it by weight and some said they use a different ratio. Whats the deal with this?

[Crooked Stic]

This is right out of the horses mouth
 web page

[macbow]

Mix ratio is 1:1 by volume. When mixed 2A:1B by volume, EA-40® will achieve greater heat resistance and improved physical properties.. "from web page"
So does anyone use the 2A : 1B  I use the equal by volume on my wood laminate bows.

[Al Dean]

I mix 1-1, but am not critical about it.  Close is completely good enough.

As a rule of thumb I always use a little more A than B...  If I use 40 grams of A I will use 35 grams of B...  That way I am always on the good side of things and there is less waste in the end...
  In your standard epoxies if you don't mix them exact it could have problems reaching it's full potential...  It's kinda like having more bolts than there are nuts for a project... If you have 10 holes, 10 bolts and only 7 nuts only 7 bolts will do the holding... Only the bolts with nuts will hold...
  So that is why I err to the good side...

[bigbob2]

for a 4 lam longbow, and I know this weight is in grams, not ounces but I use 72 g of A to 58 G of B. Works very well.

[jsweka]

Originally posted by Al Dean:
I mix 1-1, but am not critical about it.  Close is completely good enough.

Yup!  One dixie cup of each part is how I do it and never had a problem.

[bamboo]

2a--1b here---clearly harder--more peel resistance

[Crooked Stic]

I would tend to agree with you. Do we know anyone who sells it for the 2 to 1 mix?

[monterey]

I do 1:1 by volume and it seems to work fine.

Which one is A and which B?

[JamesV]

where can I buy half a can of B??????????

[kennym]

I can get quarts of  A only if you guys want it , then with a  quart kit and the extra quart  of A you are good to go .

Sorry , can't get pints of A only.

[Robertfishes]

Monterey, the cans are marked A or B. I mix 1:1 but I usually add a little extra part A. I always have about 8 oz in the B (blue quart) can when the A (yellow quart) can is empty.

[kennym]

Part A is yellow can.

If you use too much hardener, it won't set up properly.

So said a fellow who did to set it faster and called Smooth-on to ask. (not me this time but a customer who thought he got some bad glue.)

[kennym]

Oops , dbl post

[Crittergetter]

I've often wondered exactly what physical properties are supposed to be improved by mixing 2a to 1b. If it sits up harder is that necessarily a good thing for how a limb bends?

[mwosborn]

Originally posted by Crittergetter:
I've often wondered exactly what physical properties are supposed to be improved by mixing 2a to 1b. If it sits up harder is that necessarily a good thing for how a limb bends?

This is from their literature:

Heat Distortion Temperature:
At 1A:1B Mix Ratio*: 163°F (73°C)
At 2A:1B Mix Ratio*: 217° F (103 °C)

[Crittergetter]

Yes sir, I've read that before. I am just wondering if any other properties are affected. Flexibility, longevity, ect.....

[monterey]

Is there any difference in the pot life with the various ratios?

[bamboo]

one I found is peel resistance---

you would be amazed how easily you can peel the glass from a limb