Author Topic: Glue up temps (Read 2226 times)

Autumnarcher · « **on:** February 03, 2020, 08:50:46 PM »

Tomorrow Im gonna be cutting out my pieces and glueing up my risesr block. What temp should I bake it at, and then what temp should I do the full glue up after that is ready? Should complete bow be cooked a lil lower than the inital riser backe temp? What temp should I start at and how much difference if any for the bow in its entirety?
I warned y'all Im a flat out rookie when it comes to the particulars, but I sincerely appreciate the help along the way.
Ain't had this much fun since a bear started climbin up my tree steps.

Flem · « **Reply #1 on:** February 03, 2020, 10:15:23 PM »

I cook at 160, so it only takes an hour at temp. Personally I don't worry about reaching the heat distortion temp when cooking pieces that have been previously glued. If they are under pressure/wraps, nothing is going to come apart and they always seem to be solid when cooled. First time, you might want to be more conservative and follow the directions that came with your epoxy. Assuming you are using epoxy.

EvilDogBeast · « **Reply #2 on:** February 03, 2020, 10:36:22 PM »

If you are using Smooth On EA-40 here is the technical data sheet with instructions. I have always done the 24 hour ambient temperature cure (~75 degrees) and haven't been let down yet.

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

Crooked Stic · « **Reply #3 on:** February 04, 2020, 06:49:39 AM »

If it is a one piece then the heat when you do the whole bow glueup will be fine. I have several TD risers out that had no heat cure and are fine. Mostly heat is used to speed the curing time.

kennym · « **Reply #4 on:** February 04, 2020, 08:13:21 AM »

I used to put a pc of plywood over riser area on bow glue up when I had a glued up riser but not anymore.

You could reduce heat 15-20 degrees if you want on second glue up but I haven't had a fail from cooking riser again...

Forwardhandle · « **Reply #5 on:** February 04, 2020, 08:51:08 AM »

I have done bows from no heat 24 hr cure to 170 Deg & have seen no difference I setteld on 135 Deg for 8 hrs because its easier for my heat blanket to maintain !

kennym · « **Reply #6 on:** February 04, 2020, 09:10:29 AM »

True, the bow I have hunted with the last 3 years was room temp cured cause I heard it could be done . Another test...(sigh)

Flem · « **Reply #7 on:** February 04, 2020, 09:55:06 AM »

Most epoxy's will cure at room temp, but for every 18deg increase in temperature, the cure time is cut in half. And the higher the cure temp will give a higher heat deflection temp. Which is a good thing if you are planning on leaving your bow in the car while scouting for Camels in the Sahara.

Crooked Stic · « **Reply #8 on:** February 04, 2020, 11:07:22 AM »

I dont think you need to cook a long time. once the form reachs temp should be good. now it may take your setup awhile to get that hot.

buddyb · « **Reply #9 on:** February 04, 2020, 01:11:50 PM »

Has anyone had a problem with recurve bows being cured at room temperature or are these all longbows? I'd like to not make a hot box if I don't need to.

I did make one takedown longbow by curing EA-40 at room temp a couple of years ago and its still ok but it isn't shot much.

Forwardhandle · « **Reply #10 on:** February 04, 2020, 01:44:07 PM »

I would suspect you would be fine ,the bows I mentioned where pretty curvy hybrids with no issues ,I dont have much room for a hot box in a town home size house so I picked up a couple electric blankets from Good Will & use those they will run 135 Deg on there own & if I want more I add clip on shop lights , but my own opinion is I dont think any of these bows approch the break down strength of EA-40 room cured I have a friend thats been making composit short horn bows for years using EA-40 to adhire the horn at room temp and never had a failure those are pretty high stressed bows !

buddyb · « **Reply #11 on:** February 04, 2020, 01:50:26 PM »

thanks forwardhandle

monterey · « **Reply #12 on:** February 04, 2020, 02:47:14 PM »

I have done a few by laying a blanket over the form with a small opening at each end. A very small space heater blowing through from one end takes it to about 130. The heater is backed off from the opening for safety.

Sure beats dragging the "coffin" out of the shed.

pditto613 · « **Reply #13 on:** February 12, 2020, 02:27:35 AM »

I did a test glue up once with 3/4” strips of maple. Six pieces glued with smooth on edge to edge. One set at room temp and one set at 170 for 4 hours. When clamped in a vise the room temp broke at the glue line. The heated set broke in the wood with glue line intact. I was using a 24” pipe wrench for leverage and it took a lot off force. I believe smooth on cures fine at room temp, but soaks into the wood better with a little heat. Especially on woods that aren’t as porous like maple or cherry

Crooked Stic · « **Reply #14 on:** February 12, 2020, 07:04:48 AM »

Patrick was youglue mix 50/50 or 2/1 resin to hardener. Several guys have done test strips with 50/50 and 2/1. The 2/1 always shows better adhesion. maybe something for room temp curing.

Carpdaddy · « **Reply #15 on:** February 12, 2020, 07:30:25 AM »

Am I the only one to use the back of their SUV in the summertime?

KenH · « **Reply #16 on:** February 12, 2020, 07:48:32 AM »

Like EvilDogBeast, I just use ambient temperature. Of course I live in South Florida so there are only an handful of days each year when I don't have 70+ temperatures for 24 hours at a stretch.

Crooked Stic · « **Reply #17 on:** February 12, 2020, 09:03:07 AM »

Hot SUV will cook them and un cook them

buddyb · « **Reply #18 on:** February 12, 2020, 12:18:50 PM »

I'm one of those guys that mix 2/1

monterey · « **Reply #19 on:** February 12, 2020, 12:58:58 PM »

Quote from: Carpdaddy on February 12, 2020, 07:30:25 AM

Am I the only one to use the back of their SUV in the summertime?

Nope!

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Author Topic: Glue up temps (Read 2226 times)

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