SMOOTH ON EA 40

[bowfanatik]

Hello guys i need help .I buy this epoxy .
Two ways, the first is the ratio of 1:1 the other is 2:1.
At the instruction manual explains that when we use the 2:1 ratio improves the temperature resistance and improves physical properties. All this I ask because   I bonding process performed at room temperature 24-48 hours .I have no current chamber higher temperature.  
 Basically this is a question for all bowyers who use this epoxy resin

[Roy from Pa]

Smooth On cures fine at 70 degrees for 24 hours. I always use the 1 to 1 ratio.

[bowfanatik]

70 degrees fahrenheit ?

[Bowjunkie]

I usually cure it with heat... up to 185-190 degrees, but have cured it at room temps. I mix it in a 1 to 1 ratio. Excellent glue.

[Roy from Pa]

70 degrees fahrenheit ?
Yes.
The hotter it is the faster it dries. But 70 will do the job.

[goobersan]

Originally posted by Roy from Pa:
Smooth On cures fine at 70 degrees for 24 hours. I always use the 1 to 1 ratio.

X2

[bowfanatik]

how do you successfully to adjust the ratio of 1:1, if you have an image to see it would be good

[tenbrook]

Most of us just eyeball it.  Meaning whatever looks correct.  You can do it by weight if ya' really want to get it perfect but I think that would be overkill.  If you do it by weight remember it a different ratio.  I forget what it is but its something like 83:100

Hope this helps!

[bowfanatik]

Yup , thanks

[Bob T.]

I have always mixed by 1:1. I was told to do this by John at OMC. I have a small gram/oz scale that I use for this. I use a dixie cup that I zero out on the scale. I put in part "A" check the weight, zero out the scale and put in the same weight of part "B" and mix. I keep track of how much I use for each bow for my future bows.

[Robertfishes]

I mix 1:1 by volume not weight. For a glue up I use 3 oz clear plastic bathroom cups to measure each part. I fill cups to top. I use plastic spoons to put each part in cup,then I mix the 2 parts on a plastic dinner plate. Throw all away when done. New cups, spoons and plates every build.

[bowfanatik]

If you use the higher temperature, say 158 degrees fahrenheit . How many hours standing in a heat chamber

[canopyboy]

4 hours will work fine a 160 degF.  I like to let it then sit in the heat chamber overnight and cool without removing it until the next day.  Have had fantastic results so far.

[Bivyhunter]

As Tenbrook says, it isn't a 1:1 ratio in weight. I weigh the white stuff first, then multiply by 1.8 to arrive at the total mixed weight for both part A and B.

[2treks]

This comes up often.


1:1 or 2:1 by weight.

   http://www.smooth-on.com/tb/files/EA40.pdf  


If you have no heat box and cure at room temp, just leave it set for at least 24 hours. but try to have at least 73*f/23*c(per data sheet)
If you are using a heat box, you need to allow time for the heat to reach the center of your glue up.
I always used 6-8hrs MINIMUM, when I used a heat box. I only went to about 100* - 120* though.
Longer is fine as well.

I have used Heat strips since around 2004.

It is not a "critical" mix ratio but it is easy to be accurate.
I had some wild stuff with gluing bows up in my early days and have never had a problem. I am always clean and accurate with my gluing process though. I have had form issues, heat issues and more but the bows always came out fine. Smooth-on is good stuff. Very user friendly.

mix it, clamp it, let it dry. Done

[bowfanatik]

4 hours ? Did you make charcoal    

[Roy from Pa]

That chart doesn't make sense. 4 hours will not hurt the bow.

[bowfanatik]

4 hours at 185 degrees will change the characteristics of the wood for sure, but why do you think it's reasonable instructions of the manufacturer of glue?
Like if we did not follow the manufacturer's instructions the drug and takes a double dose
This glue is new for me, but not wood. So I say, 4 hours ... not good

[bigbob2]

As was said, this has come up before, but re the ratio for a four lam HH style bow I use 70 grams of A to 50 grams of B. Right on the money.My oven is on for 8 hours at 150F and allowed to cool overnight.Also use 40 grit for the lams too. Whatever floats your boat I guess.

[Pheonixarcher]

That chart is a "step-cure schedule". Meaning the manufacturer recommends first 2 hours at 120*F, increase the heat to 150*F for another 2 hours, followed by another heat increase to 185*F for an additional 2 hours. That is a total of 6 hours oven time.