Heat fluctuations in LWR

[snoozer]

After much research and planning, swim has decided to go to sleep and have his first dream.
He used a 1L RBF, Allihn condenser with condom on top and placed this in a sand bath in a saucepan on an electric hotplate.
He used the ratio 1:1.2:0.75:0.8    E:I:RP:H20. He first mixed the RP with the H20 then added the I and waited 20 min for the HI to be generated before adding 28g of E. The RP is MB and the E is from  pills, the I is LG. The condensor was put on and heat applied. The first thing swim noticed was upon adding the E it all dried out considerably, to the point that mixing was not possible. So when it reached 90c and nothing happened swim added 3ml of H20 with a syringe, this did the trick! It all started to liquify as described then bubble gently.
So all is going seemingly well so far? with white fog appearing now and then and the condom inflating and deflating occasionally.
Finally to my question!:
The only problem swim seems to have is controlling the heat source, it has 4 preset levels. Swim uses the lowest setting which still heats the sand slowly above 120c, so swim has to turn the power off when the thermometer in the sand reaches 100c because it still heats up to 120c before it starts to cool down and likewise he must turn the power on before it drops below 97c to stop it dropping below 90c.
The problem is with the slow heat reaction of the sand and trying to anticipate the fluctuations and even them out.
So swim is wondering if this would have any negative effects on the reaction? it does reach 120c occasionally but only for a few minutes before cooling down. He's more concerned with the temp swings and will this hurt it at all, not fully reduce?
Now swim knows 90-100c is preferred but sees no activity at this temp, not until 110-115c does he see any bubbling and condom inflating. Is 90-100c still OK even with no signs of activity or would 110-115c be better??
Swim thinks maybe he needs one of these to solve his problems, its basically a big light dimmer.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3803000540&category=42881

Swim is at the 36 hr mark with 12 more to go, any advice would be appreciated.

[SHORTY]

Taking the temp past 110 can cause the tweaky effects like jaw clenching so it is best to keep it at around 100 to be on the safe side.  However, some seem to like the tweaky effects so its up to the cook.

[wareami]

Visible Activity is not necessary.
The temp fluxuations are the result of the rxn being exothermic. Ibee thinks maybe eerything wasn't mixed intimately enough...but can't be sure as he's not there!
As long as that temp range has been consistant and not allowed to drop down past 70°C at any time it should be fine and completely reduced at the 48hr mark.
Time it to arrange the last two hours just at 115°C internal flask temp.

On the HI creation prior to adding E, always make sure heat is applied while capped off with condensor or attached to P/P to generate HI. Just letting it sit for 20min will not do it in Ibee's opinion.
Once those precursors are intimately mixed and HI generated properly, the addition of E should immediately go liquid on contact with quick stirring or even swirling.
Keep us posted!

[snoozer]

Yeah swim wants to avoid the dreaded "spacedope" at all costs, but thinks maybe 110c on the thermometer in the sand equates to 90-95c or thereabouts in the flask?
Swim thinks maybe the reactants weren't mixed together completely before the E was added, because the I was added directly from the container as large silvery flakes and not ground up before adding duh!

[CharlieBigpotato]

if the sand is soaked with water, the flask within won't get above 100 c unless the water has left, and the sand heats up beeyond water's boiling point. as long as water is maintained in the sand bath, it should bee an easy temp guide, w/ no thermometer needed. water lost can bee replaced with boiling water from a seperate pan, which shouldn't change the temp; whereas adding cold water would, and break the glass, too.

[snoozer]

That is something swim realized when he did a test run with water. He used damp sand by chance and noticed the thermometer didn't get above about 98c.
Good suggestion, thanks Charlie!

[popi]

Charlie is right about the sand .Watch that by a thermometer!As Geez has said oil will hold the temerature along time and it heats more even.Plus when the flask tips at some point in time you can recover your goods.Filtering sand is a lot harder! As Ware says 'Shtye Happens'.Don't let it go dry and add dh2o as soon as you saw it was not dissolving.

[geezmeister]

Spend a little cash and get a variable temperature, cool-touch deep fat fryer and modify it to accomodate your flask. Not only will you find the thermostat to have very little offset between on and off, you will find with the volume of oil that the heat stays very even.

There are disadvantages to heating oil, for sure. There are advantages. Being able to set this reaction up and let it mind itself is one. Water in sand is nice in a way, if you don't mind adding water for a day and a half.

The oil bath really made the LWR easy, life falling of a log, for me. Others don't like oil baths, but I find it a great tool for this reaction.

[snoozer]

Well I don't think swim is overly tight with cash but he saw a way to save money on retort stands etc by using a sand bath which will support the whole setup nicely, unlike an oil bath.
However after swims first LWR babysitting the reaction for 48 hours he thinks he'll splurge on a deep fryer! as it was a nightmare constantly twiddling heat settings for 2 days!

[CharlieBigpotato]

btw, swim definitely prefers oil and temp controls. beecause the veg. oil isn't going to evaporate at a mere 100C, it needn't bee babysat...assuming you have temp. controls.
if you don't, however, as in this curb-shot candle thingy, then there is no way to keep the oil from getting too hot and ruining the rxn.
swim would advise against oil bath w/ flame heat.
that's like asking for trouble.
water's non-flammability is nice for a beeginner, and the lucky fact that this rxn will manage fine, right at the boiling point of water. though, the flask temp. may vary slightly from bath temp...espcially outdoors in cold weather.