HOW LONG SHOULD I PUT THE BOW IN FOR AT 150 TO 180 DEGREES????? THANKS FOR YOUR HELP EVERONE.
I WAS TOLD 6 HRS. IS ENOUGHT TIME BUT LET IT COOL TO ROOM TEMP ???
When the glue that has squeezed out the sides of the lams are rock hard then shut the oven off. At the temps mentioned that would be about 3-4 hours I would guess. Let cool to room temp and build the bow. Alot of guys cook the bows long after the glue is hard (6-8 hours)I never understood the long cook time. I think they are afraid to open the oven to check the glue during the process for some reason and think they need the longer cook time.
Once the epoxy is hard it is cure, plain and simple. If you can cure a bow in an hour with heat tapes then it shouldn't take 6-8 hours in a hot box at 150-180 degrees.
Chad
I normally cook for four hours at around 140-160. I've heard of folks doing only one hour at 180.
cool, thanks Chad and Evith
I cook 5 hours when I use a box.
I glue up my bows in the evening so I use a good 15 amp timer (about $18- $20) and I usually set timer between 4 and 5 hours my oven temp with 4 100watt bulbs runs up to 165 degrees ..when I get up to go to work the next morning I open the oven and check air hose pressure, If I have time and form is cool I will pull bow out of form and grind the smooth on buggers off of bow blank, then go to my paying job..but all I can think about is whats under the masking tape on that blank.
It will also cure at room temp in 24 hours if a box isn't available.
Trevor
24 hours....I have a hard enough time waiting the 9 hours for the 5 hour cook time and 4 hour cool down times..I use the firehose method and already have trouble getting to sleep worrying about loosing pressure during the first 2 hours of cooking at 160+...I always check pressure about 15 minutes after putting form in oven so far so good, I know I lose a pound or two checking pressure but I just have to know it is not leaking. Binghams suggests 60 psi but I have been pumping hose up between 65-70psi
I cook for 5 hours and let it cool down some before taking it out. Interested in the hose comments. I just bought a hose setup and I'm really dreading it. This is an idea I just don't trust. I like my clamps, but I'm reaching a point where i can't lift a clamped form any more. I'm thinking about building a workbench height oven with an opening end and putting the form on a trolley.
Look into getting heat strips. I bought two 32"x1.5" strips for $57. 45 minutes at 160 degrees and I can pop my limbs right out if I want. I can glue up a set of limbs in 2.5 hours including glue up and a bit of cool down.
Trevor
I was told on here I think that the 5 hr cook time was to allow enough time for the riser/ limbs (in a press) to get fully up to temperature and time at that temperature for the curing process. The heat strips are supposed to get the limbs up to temp in 15 minutes and cook for 45 min so with heat strips its 1 hr.
Terry
I have the same concern as T Folts. The hot box is radiation or convective heat tranfer at best while the strips are purely conductive which is faster. It takes a while to radiantly heat up a form and the core of a riser. The tips not so much but the fades maybe need a little longer than an hour in a hot box. Three hours seems safe to me if it is a slim riser. A thicker riser section will take longer to heat up due to the cooler core sinking the heat away form the glue lines for at least a couple hours. It takes my small brisket hours to get to over 160 in the core and it has a high water content. Imagine a drier wood which is an insulator type material.
I use a metal pressure strip..I wonder how much the galvanized pressure strip I use helps to transfer heat to the limb? Mr DW, I have only used the firehose method and can say it has worked for me.. Pat D says he keeps an air hose attached to firehose when in the oven and he has his regulator set to 60 or 65 psi? maybe he will share a pic or two of his oven/compressor set up.
4 hours with a timer. The wait time has never been a big deal. I'll spend most of the day cutting, grinding, sanding, ect...than glue up everything towards the end of the day. The timer shuts itself off after 4 hours, so everything is good to go by morning. A timer is a must...saves you from having to get up in the middle of the night to shut off the oven :mad:
I also made my oven 2'x2'x8' so I could fit lots of stuff in at the same time.
I check my air hoses(water bucket)every 8-10 bows and have never had a problem. 65-70 psi
Metal pressure strip in direct contact with glass should speed it up I would think. I have a rubber stip between my metal strip and the glass so it probably insulates from any advantage that could provide. I'm all for making this process shorter but with an oven I just think it should take longer than an hour or two. That's why all the real deal bowyers use the heat strips, because the box takes longer and they know that.
THANKS TO YOU ALL .SORRY I DIDNT ANSWER BACK SOONER BUT I WENT TO THE P&Y MUSEUM MON.& TUES.JUST GLUED UP MY OTHER LIMB WILL TAKE OUT AT 11:00 PM NEXT IS THE RISER I AM GOING TO TRY TO SHAPE IT AFTER THE 1959 PALOMINO.IN 1959 THIS BOW BROKE 22 RECORDS AROUND THE WORLD.
I copy/pasted this information right off of the Smooth on EA-40 data sheet - you can find it at smooth on's website.
"Apply to prepared surface and let cure for 24 hours. Applying mild heat will cure EA-40® faster – 150°F/65°C for 6 hours."
"Post Curing – After EA-40® has cured at room temperature (this was 24hrs), heating the epoxy to 150° F (65° C) for 4 to 8 hours will increase physical properties and performance. Let cool to room temp. before moving bonded substrates, machining, etc."
That being said I put my bows in my oven at 150 degrees for 6 hours and haven't had a problem. I always let them cool down before I work on them also.