I glued up another bow today using the heat strip system and every thing ran as smooth as silk to the locking up stage of all of the components and applying the air hose pressure.
Heat was applied in a similar manner to the first glue up.
Ambient temperature [as pointed out in the instruction sheet] has an effect on the heat strip system.
The first bow was glued up around midday whereas the second bow was not glued up until late afternoon and the heat was applied around 5.30pm.
Unlike a hot box where the temperature can be maintained in a closed environment the heat strips are at the mercy of the prevailing temperature and breezes flowing through the workshop i.e. heat loss.
The above is not a criticism as such of the heat strip system but more so things to be aware of.
Thermostat settings were about 25% higher than the settings used for the first bow. A loose covering such as an off-cut from an old blanket or a thermal blanket placed over the form would probably help to maintain a more consistent environment in certain conditions and allow for a lower setting on the thermostat.
Do I like the heat strip system? Yes; I should have been using it years ago.
Daryl.
Heat Strip Update;
Moderator: Moderators
Heat Strip Update;
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken. [Ascham]
“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]
I am old enough to make my own decisions....Just not young enough to remember what I decided!....
For a good bow twice paid for, is better than an ill bow once broken. [Ascham]
“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]
I am old enough to make my own decisions....Just not young enough to remember what I decided!....
-
Gringa Bows
- Posts: 6331
- Joined: Thu Aug 30, 2007 7:09 pm
- Location: Bundaberg QLD
Re: Heat Strip Update;
Sounds like the go Daryl,i'll to save up my pennies and get one over. 
-
stringnstik
- Posts: 1106
- Joined: Tue Oct 21, 2008 12:09 pm
- Location: Cranbourne
Re: Heat Strip Update;
Great to hear Daryl.
Do you think the main problem is the control system?
yo mention it has a thermostat and that you are setting it to such n such %. which infers to me that its a power setting not a temperature setpoint.
A power setting (simple to achieve) is indeed at the mercy of its surroundings where as a temperature control (slightly more expensive and complex) would compensate and adjust as needed.
Is it worth pursuing a temperature control mod?
Do you think the main problem is the control system?
yo mention it has a thermostat and that you are setting it to such n such %. which infers to me that its a power setting not a temperature setpoint.
A power setting (simple to achieve) is indeed at the mercy of its surroundings where as a temperature control (slightly more expensive and complex) would compensate and adjust as needed.
Is it worth pursuing a temperature control mod?
"I am the arrow..the arrow is me...together as one...I fly to thee"
"the stick maybe crooked and the string hath no form,
then married by bowyer, transforms when first drawn"
"twang....thud"
"the stick maybe crooked and the string hath no form,
then married by bowyer, transforms when first drawn"
"twang....thud"
Re: Heat Strip Update;
Gidday Daryl,
Good to hear the system is working for you.
Maybe putting the form into a box (like a bow oven) would shield the whole process from variables such as wind etc and allow it to come to a stable temperature quicker. You loose the advantage of space saving but still get the advantage of time saving.
As stringnstik said, maybe a method of thermostat control would be preferable to the dash pot that comes with the system. Of course this requires some feedback from a sensor (thermocouple or such) and a controller to respond to the signal.
The cheapest thought I could come up with is to switch on/off the power via a surface mount thermostat (like in a water heater) that is attached to the excess heat strip outside the form and suitably insulated to simulate the temperature inside the form. Only problem is the deadband is likely to be 7 to 10 degrees lower than the set point. This may be too much fluctuation?
Cheers.... Rod
Good to hear the system is working for you.
Maybe putting the form into a box (like a bow oven) would shield the whole process from variables such as wind etc and allow it to come to a stable temperature quicker. You loose the advantage of space saving but still get the advantage of time saving.
As stringnstik said, maybe a method of thermostat control would be preferable to the dash pot that comes with the system. Of course this requires some feedback from a sensor (thermocouple or such) and a controller to respond to the signal.
The cheapest thought I could come up with is to switch on/off the power via a surface mount thermostat (like in a water heater) that is attached to the excess heat strip outside the form and suitably insulated to simulate the temperature inside the form. Only problem is the deadband is likely to be 7 to 10 degrees lower than the set point. This may be too much fluctuation?
Cheers.... Rod
Re: Heat Strip Update;
Hi, Mark and Rod,
Thermostat was the wrong choice of words on my part; the only wording on the unit is [calibrate low speed] which is next to a small hole on the side of the unit.
I think a blanket draped over the form should be sufficient to maintain a relatively constant temperature in adverse conditions and does away with the need for extra electronic gadgetry.
Daryl.
Thermostat was the wrong choice of words on my part; the only wording on the unit is [calibrate low speed] which is next to a small hole on the side of the unit.
I think a blanket draped over the form should be sufficient to maintain a relatively constant temperature in adverse conditions and does away with the need for extra electronic gadgetry.
Daryl.
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken. [Ascham]
“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]
I am old enough to make my own decisions....Just not young enough to remember what I decided!....
For a good bow twice paid for, is better than an ill bow once broken. [Ascham]
“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]
I am old enough to make my own decisions....Just not young enough to remember what I decided!....