Heat Box question for 1st Bingham Bow build - also formica strip ?

kenboonejr · July 24, 2021, 04:07:33 PM

Quote from: Mad Max on July 24, 2021, 01:22:42 PM
It may take you until noon to get one in the hot box.
So A hot box let's you work on the bow the next Morning
And if you do over and underlays, striped riser and so on, you can cut day's off you curing.
That's the best thing about it.

Yea I didn't think about that aspect. I plan on doing a few accent stripes in the riser so I guess that needs to be tossed in the hot box too to cure.
Getting a lot of good info on this thread.

I am "hoping" to attempt gluing up my first limb tomorrow after church. We will see how it goes.

Shredd · July 24, 2021, 04:35:08 PM

Say your Prayers...

Shredd · July 24, 2021, 04:46:15 PM

Did you think about gassing out and wood shrinking and possibly cracking... Or wood shrinking and later on expanding and cracking the glass... In general, extreme changes in temperature is a no no in my book... Like I said, it's my 2 cents and there is more than one way to skin a cat and what ever works for you is good if you have success with it...

Flem · July 24, 2021, 06:53:27 PM

Can't say that I have Shredd. But then again it has not been brought to my attention before, as I have not experienced any problems first hand.

Crooked Stic · July 24, 2021, 10:06:41 PM

maybe over thinking

Shredd · July 25, 2021, 01:59:42 PM

Quote from: Crooked Stic on July 24, 2021, 10:06:41 PM
maybe over thinking

And they say, "Ignorance is Bliss'.... That is until you get bubbles under your glass...

A little common sense goes a long ways... Put any 6 foot length of wood you have in the sun on a hot day and see what happens... 6 feet will multiply the effect... Just because you use a 16" to 20" hunk of wood for your riser does not mean it's not moving... The more heat you add the more the stresses are between the surface of the wood and the core of the wood... Plus I have heard from multiple experienced bowyers say that heat can be hell on risers and the whole bow in general... That's why they say don't leave your bow in a hot vehicle...

Like I said, There is more than one way of skinning a cat and you can get by with your methods whether they are accepted to be right or wrong but I just choose to err on the side of caution...

Stic... Under-Thinkers are awesome...

Crooked Stic · July 25, 2021, 09:44:18 PM

Perfectly al I am saying is I been doing this for several years. I know what works for me.

Still learning about design tho.

kenboonejr · July 25, 2021, 09:55:22 PM

Well I got the first limb glued up today and tried out the heat box. The thermostat that came with the Bingham's kit said it will be in the range of 150 -180. I pre-heated the box up, glued up my first set of limbs, got them set in the form and put them in the heat box. I didn't see much of a temperature drop after putting the form in there.. Maybe a degree or so as the lid was off while I did that. It pretty much kept the temperature at 158 degrees the whole time based on my sensor's reading. The thermostat is a little bit closer to the lights than my sensor but still plenty far enough per the instructions so I figure this thermostat was turning off once it hit 160 degrees or so. Anyway, I didn't burn anything down

I turned it off and will let it cool down to room temp over night and pull it out tomorrow evening after I get home from work. I will say this. Getting the lams glued up and into the form is way more difficult than what they show in their video. In their video, the lams just simply lay into place, no issues with the lams sliding forward or over the 58" pin, etc.. It took a lot longer than what I thought to get them glued up, but I did make sure that I had epoxy on every part of the surface with no dry spots before I glued it up. So we will see what it looks like tomorrow night.

So a question - Would the one piece recurve be easier or harder to get setup in the form than the take down recurve limb? Just wondering.

Mad Max · July 25, 2021, 10:07:16 PM

NO
Make the butt end longer and use a 1/4" dowel threw all the glass and lams and butt wedge into the form.
Make sure and use some car wax in the dowel hole in the form and around the hole.

Shredd · July 26, 2021, 01:10:30 AM

Quote from: Crooked Stic on July 25, 2021, 09:44:18 PM
Perfectly al I am saying is I been doing this for several years. I know what works for me.

Still learning about design tho.

Flem · July 26, 2021, 08:51:36 AM

Shredd, I think you and I are 180deg on this(pun intended)........ Well because we are 180 deg apart, especially in climate. For perspective, where I live is essentially Desert. Less than 15" of precipitation per year. Summer is our humid time and it hovers around 20-30%.
[attachment=1]
Here is a piece of Teak I am using for a riser. It has been outside, under a shed roof in a bin for a few years. It's hard to see, but after a fresh cut the moisture meter reads <7%. Mine is not the best meter, but it's accurate to .5deg, so the wood is bone dry. Kiln dried wood or in this case Desert air dried wood is not going to check, crack, warp or twist at that MC. If you don't believe that, check out the USDA Wood Handbook or Dry Kiln Operators Manual. No hearsay or second hand anecdotes, just facts.
Something else to consider beyond the temperature, is the duration of heat exposure.
If you are cooking at 150deg for 5hrs, plus ramp up and cool down time, your degree hours of exposure is going to be in the range of 800-1000deg hrs. I might have 250-300deg hrs total with my program.
Conclusion? Both work fine. One is more optimized for efficiency.

Mad Max · July 26, 2021, 09:21:33 AM

Flem 88% humidity this morning at 8 AM

Longcruise · July 26, 2021, 09:33:45 AM

Where it's stored is another factor. Most of my wood is in the rafters of my uninsulated and unheated garage. It's hot and dry in the summer and cold and dry in winter. If a piece of wood is going to do crazy things, it happens quickly.

Flem · July 26, 2021, 09:44:13 AM

88%!!!!!! I'd wither and melt in that much moisture. I don't know how you guy's stand it. Conversely, I imagine if you plumped up moisture lovers came out here, you would desiccate and blow away.

kenboonejr · July 26, 2021, 10:15:43 AM

Quote from: Mad Max on July 25, 2021, 10:07:16 PM
NO
Make the butt end longer and use a 1/4" dowel threw all the glass and lams and butt wedge into the form.
Make sure and use some car wax in the dowel hole in the form and around the hole.

Yea I see how that would force the limbs to line up. That is a good idea. This is my first build and and am using the kit from Bingham's so the lams were already pre-cut. I did have to shorten there for my bow length, but not the wedge so I didn't have the option. - Nor did I know about it until now

And by the way the humidity in SC here is pretty bad too this time of year. Most of us do NOT love it! I left Florida to go to SC. Basically moved from 10 hot humid months in the year to 3 hot humid months.

Shredd · July 26, 2021, 01:18:09 PM

Flem... Valid points... After I dry my wood to about 5 to 8% I let it normalize and it goes up to about 12% if not a little more...

I cure at 110 to 120* for 5 hours... Considering about an hour to get up to temp. I am doing about 500 deg. hours... I guess that is about in the middle of both methods...

I am on Island time... Have been for a long time... Have never seen the need to rush anything... Slow and steady as she goes...(even slower now that I am older) But things get done and fewer mistakes are made... Sorta my Zen or philosophy That I go by...