epoxy question

[upstatenybowyer]

I noticed this chart on the packaging my epoxy comes in, which says that the best performance for hardwood is the "medium-cure" or "15 minute" variety.

From what I thought I understood, the longer the cure, the stronger the hold. The "30 minute" cure is rated for 4500 psi, so I thought that was the best to use for splicing and wood backings.

Am I missing something? What variety do you all use?

[Stick Bender]

Some epoxies have a high psi rating but are some what brittle for flexing of bow lams or backings ,static areas its probably not a concern , smooth on Ea-40 is probably king of the hill in bow making epoxy , the stuff is amazingly strong & flexible it takes 24 hr cure at room temp , I use it for every thing now I figure why risk it with all the work that goes into a bow especially laminates ! with epoxies prep work is key with a ruff surface at least 60 grit or 36 grit and the right amount of pressure to much pressure can starve a bond.

[upstatenybowyer]

Great info SB. I'm new to this lam thing so every little bit of knowledge is much appreciated. 

[youngbowyer33]

smooth on Ea-40 is probably king of the hill in bow making epoxy

I hear more about Unibond 800. What makes smooth-on better? More flexible? Stronger hold?

[PatM]

Glue doesn't really have to be flexible in a bowmaking application.

[bubby]

Smooth on and unibond are both made for bows, I've used both and prefer smooth on

[Stick Bender]

Unibond 800 is good glue to, but has a shorter shelf life , I had a can go bad in 8 months and smooth on has a longer open pot life , Pat ,maybe it doesent but smooth on  claims there glue was design around bending applications , Im sure there are other epoxys that work smooth on is just the most popular among lam bowyers for those reasons listed , Unibond 800 is cheaper and easier to get , flooring & furniture guys use it a lot , I have been making very high stressed designs lately and the glue has been flawless for me , & its user friendly ! Smooth on can be cured quick by hot box baking I just like it based on use, but all epoxys require good even clamp pressure with no voids  to achieve there full strength ! and Smooth on has a invisible glue line , I just use it like salt and pepper put it on any thing I can....lol

[PatM]

Smooth on definitely has the market cornered but many general epoxies have the same or even better numbers, particularly if you are just doing a room temperature cure.

 System three makes a couple with higher heat tolerance after just a room temperature cure.   Gel Magic in particular is a very good epoxy with a modification that prevents it from running all over the place.

[Dances with squirrels]

I'm a Smooth On fan. What's not to like?

I make a glass bow once in a while. How's Unibond for clear glass? Besides adhesion, it's not exactly transparent. I don't keep Unibond around anymore because Smooth On does what it will, and more. It's quite versatile and like Stick Bender, I use it on all sorts of things. No issues, so no reason to kick it to the curb to try a different one.

[Stick Bender]

Another up side for Smooth on it makes a really good grain filler for porous woods when mixed with acid tone it dries invisible but fills the grain !  Plus if your putting on tip overlays you can keep a rag and acid tone and clean up the squeeze out before it dries for a clean no glue line joint ! Plus if your doing multiple glue ups you can use the same method ! And if it's cool in your shop you have close to 2 hour open time so no rush with the stuff.

[bubby]

The west systems and resorcenal cost more than smooth on, and even though unibond costs less you get more glue ups out of smooth on so the price difference is negligible

[leonwood]

Mostly use titebond for my lams today but I am a fan of smooth on too: Relatively cheap, really easy to mix (I always use 50/50) really long working time, gap filling and cures perfectly at room temp without the need of a hotbox

[PatM]

For me it's just accessibility.  Wouldn't begin to know how to access some smooth on so it's easier just to go to any one of the several boat shops and get some other epoxy that does all the same things.

[bubby]

For me it's just accessibility.  Wouldn't begin to know how to access some smooth on so it's easier just to go to any one of the several boat shops and get some other epoxy that does all the same things.

I hear that, I order the smaller batch from 3rivers but if I needed a gallon I'd go straight to the manufacturer

[upstatenybowyer]

Lots of good info here. I just ordered some Smooth On from a sculptor's website. The had the lowest price w/shipping.