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
Smooth On cures fine at 70 degrees for 24 hours. I always use the 1 to 1 ratio.
70 degrees fahrenheit ?
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.
70 degrees fahrenheit ?
Yes.
The hotter it is the faster it dries. But 70 will do the job.
QuoteOriginally posted by Roy from Pa:
Smooth On cures fine at 70 degrees for 24 hours. I always use the 1 to 1 ratio.
X2
how do you successfully to adjust the ratio of 1:1, if you have an image to see it would be good
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!
Yup , thanks
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.
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.
If you use the higher temperature, say 158 degrees fahrenheit . How many hours standing in a heat chamber
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.
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.
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
4 hours ? Did you make charcoal (http://i853.photobucket.com/albums/ab99/tragomvuka/Capture.jpg) (http://s853.photobucket.com/user/tragomvuka/media/Capture.jpg.html)
That chart doesn't make sense. 4 hours will not hurt the bow.
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
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.
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.
Ah, I see that now.. Thanks Paul
I'll throw in my 2 cents just to be difficult :bigsmyl:
I use plastic cups to measure a 1:1 ratio, then the bow goes into the oven for 6 to 8 hours @ 172-176 degrees F.
Ok so here's my question. If it will cure in the over or at room temp is there an advantage to using the oven? I just recently built a form and oven for a glass bow and have been wondering about smooth on myself.
I like to cure the bow at the higher temp for better heat resistance, tho I have no test data to prove anything on that. Only what I've read on the Smooth-?on site that it makes it stronger. I haven't seen that it pertains to bows or electrical.
The overlays I don't worry about heating because they aren't stressed that much and if need be you could put them back on. I'd bet it would never be necessary tho.
I have been wondering the same thing as mjwhitby. Bickerstaff bows has a video series on YouTube where they glue up a longbow with rubber bands and no heat. They say theyve never had a bow delaminate. But they dont specify what glue they use.
I should add that even though I sometimes question why, I still believe in staying with whats tried and true! I will be doing mine with heat. I really dont want any sudden surprises!
These glass bow questions are tuff:)
I learned a little more about epoxid and do not be surprise if you do not glue it in the heat chamber. It is important that the surfaces are cleaned with alcohol. As for the explanation of the smooth-on website, the higher the temperature and the ratio of 2:1 increases static and temperature resistance. So a good clean and balanced pressure
QuoteOriginally posted by kennym:
I like to cure the bow at the higher temp for better heat resistance, tho I have no test data to prove anything on that. Only what I've read on the Smooth-?on site that it makes it stronger. I haven't seen that it pertains to bows or electrical.
The overlays I don't worry about heating because they aren't stressed that much and if need be you could put them back on. I'd bet it would never be necessary tho.
Exactly what my mentor taught me. Curing at room temperature is fine. Curing with heat offers more heat resistance with the finished product. Not a big deal unless you're prone to leaving your bow and/or children in the car on a hot summer day. Don't worry so much about curing temps. If the bow delaminates some day, you'll be just like those wood guys and their "kindling" :biglaugh:
Hey gooberboy, don't make me come out there:)
Another that always does 1:1 ratio and has never used a hot box, with 30+ glue ups under my belt.
Yup 1 : 1 and cure at 70 degrees is all I've ever done.
The 1:1 is a mainstay for me, cure, 5hrs @ 180 deg. NEVER remove from the form when it is still hot! Overlays, I use a lower temp (one heat lamp) and I like to put "socks" on the limbs, a couple of pieces of fire hose work well.
That's why I like this site so much. Never thought about using a bit of old fire hose to deflect the heat when 'cooking' tip overlays but have always been conscious of the need for lower heat , thanks Grizz for that tip, will become standard practice for me now.
Always 1:1 Ratio by volume
180F @4h for limbs!
Riser I cure in room temprrature for 24h
Last onepiece I cured in room temperature for 24h.
Just as nice gluelines and no sign of delamination.
what are the fume's like? I'm trying to figure out a place for glue-up,is a pilot lite on a furnace ok? or will I blow my house up :knothead: Burt
Should be good Burt, I have one in the oven 20ft. from the furnace and no issues at all. I had the same concerns. I can't even smell the thing cooking. I thought it would have some odor.
You can weigh the stuff at a 100:83 ratio resin to hardener and it comes in just like the 1:1
EA 40 will completely cure at 160 degrees in 20 minutes with heat strips applied to either side.
The hot box technique requires cooking your whole form to death at 180 degrees for 4-5 hours... again,,, and again... and again...
next thing you know your form starts twisting on you and these guys can't figure out how come the limbs are twisting? Good greif! you would be better off not using heat at all than a hot box. IMO.
I'll stick with my heat strips, thank you...
20 minutes with heat strips! Where would someone find these heat strips?
Kirk, from Bigfoot Bows, a nice gentleman that will help you out.
I do 1:1 and pretty much do it the way robertfishes does it.
Did anyone find out where to locate heat strips? Google doesn't seem familiar with them.
Aha, Google does know something of silicone heating strips...
Bigfoot bows sells heat strips for bow making..
They are no longer listed on Kirk's site.
I can still get heat strips. Might have some instock.
They are a little thicker and higher quality than the old ones.
After the Expo in Kzoo I will be placing an order.
Anybody interested just PM me what size you need
(length and width). and I will get a price.
Thanks Chuck! That sounds great. Do you use only one strip, or a strip on the bottom and one on the top of the stack in the form?
I have done it both ways, when I needed to. And it worked fine, but a tad slower. I don't try to push the speed factor during glue up though.
I use two strips in my everyday work.
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