70 degrees fahrenheit for Bob Smith (BSI) epoxy? But it's cold here in new england

I wanted to try using epoxy to attach a motor mount. Bob Smith's web site has a video that cautions against working below 70 degrees and stressed the need for good ventilation. I have access to a seasonal porch that gets enough sunlight to bring the temperature close to 70, but if I open a window to get some air circulation the temperatures quickly drop into the mid 50's. Is there a solution to
the predicament that I find myself in?

I have a heat lamp that I sit my epoxy next to in the winter. That warms it up enough to flow well.

I put mine in a tub of hot water for a few minutes, works great.
ventilation?? whats that??

I have an old microwave I heat the bottles up before mixing.

Can I just warm the epoxy (set the bottles in a warm bath of water) and still use them if the ambient air temperature is 59 F? I could warm the items beforehand on a radiator, the air temp would still be 59F during application and curing.

Work inside and crack a window. The smell is annoying but not toxic.

Yes, you can just heat them in a water bath. The hotter you get them the faster they will cure.

I never seemed to have a problem with cold air temps (never even thought about it before) epoxy drys and fins stay on.

I use a harbor freight FDA Laser food temperature device $20 to check epoxy cure temps among data sheets for expensive stuff like Cotronics 4700 which required preheating from near a stove eye or other heat source beyond thermostat range for mixing within a specified temperature range then an oven cure for final activation temperature and bonding. Spotlights, hair dryers, and heat guns with temperature monitoring have worked for rocketpoxy. I have never used BSI, but I would suggest not to get the epoxy too hot as it could lose strength. Paint respirators with N-95 filter and open windows helped for Cotronics and we used it in a rental house against most common sense or advice, so I'd hope BSI isn't as bad. For rocketpoxy the hair dryers had ample convection heat to 140 F even in a cold concrete lab on campus that was in forties F with no heat system. The spotlights also gave out about 120F for long static exposure no convection, it'll depend how long you want to babysit epoxy drying. If you have the luxury of a heated workspace that may help.

JJSR said:

I never seemed to have a problem with cold air temps (never even thought about it before) epoxy drys and fins stay on.

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I've had simple guerrilla glue fail to cure when cold for non rocket problems. Some epoxies won't cure outside of a certain temp range.

Could you put a box fan in front of a radiator to continually warm the epoxy while its drying and it will evacuate the fumes out of the open window faster? Don't know how bad BSI stinks.

I will use a heat gun to warm the epoxy in place. It guarantees a good cure and speeds up the process quite a bit. It also will help to smooth out the surface of the epoxy.

1. warmed two bottles to body temp (90's) inside​
2. went out onto the enclosed porch (59F) ​
3. opened the bottles and mixed equal blobs (by sight) with a wooden coffee stirring stick. ​
4. closed up the bottles​
5. applied the fillets to the motor mount joints (previous spot glued with super glue). ​
6. Warmed the epoxied motor mount for 5 minutes with a hair dryer​
7. Brought the epoxied motor mount inside and set it near the steam radiator. ​

Now I'm just hoping for the best. There was no smell at all. I did get a headache and feel a little light headed but that might not be related. I have to say, the BSI provides no instructions on the packaging.

Been about an hour. With a lamp above the temp is staying at 72 (F). Still a little tacky.

22 hrs later - Everything dried and the epoxy is no longer sticky. Hope this looks correct (was enough epoxy used?) Next time I might be tempted to work on only one side of each centering ring at a time (and let gravity level things).

Next up: epoxy this motor mount into the main body tube. Not sure how to epoxy the forward end of the motor mount in the tube (Madcow Mozzie) because I cannot reach in that far. (I watched an Apogee video on installing the motor tube with yellow glue). Maybe I could drip the epoxy down into the forward end of the body tube or find a longer coffee stirring stick. I found this helpful video:

https://www.youtube.com/watch?v=Xtr3758PvzA
Very exciting.

bamboo skewers are fairly cheap, usually come in a 100 pack, and are 12" (or longer) are your friend . apply some epoxy about 4" forward of the aft end of the body tube (a smooth strip around the tube), then simply insert the motor mount assembly and slide it forward to the proper location. you will know when the forward ring slides through the epoxy. then let stand for 20 minutes or so mount end down until the epoxy starts tacking up, and 'ta-dah' forward ring has a nice filet .
Rex

I’m in New England too. I just used some JB Weld to do a little redneck auto repair in my driveway this weekend. I mixed the two parts outside yesterday, and the stuff was so viscous it was hard to squeeze out if the tube. Left it to sit overnight, and today it seems to have set up nicely even though it was pretty cold last night.


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Following some advice here, I built a makeshift "hot box" using a heating mat for seedlings, a cardboard box covered with a fleece blanket. The box raises temps enough that I should be able to put the rocket inside the box to cure down in my basement and stay above 70 (without the risk of a fire or bothersome odor) . Not sure how much air circulation epoxy needs to cure (there will be none). Going shopping for bamboo skewers.

Underdog said:

Following some advice here, I built a makeshift "hot box" using a heating mat for seedlings, a cardboard box covered with a fleece blanket. The box raises temps enough that I should be able to put the rocket inside the box to cure down in my basement and stay above 70 (without the risk of a fire or bothersome odor) . Not sure how much air circulation epoxy needs to cure (there will be none). Going shopping for bamboo skewers.

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Doesn't need ventilation to cure. It is a chemical reaction. I would guess that the volume of you basement will be plenty to disperse any fumes for the small amount you are using.

Hot box is a great idea, ought to get the job done. I have a garage, so my smelly work is done there, during favorable weather.

BSI recommends that modelers keep a large open ended cardboard box around for use during colder months. Place it over your project after the epoxy is applied with a small lamp inside (or heating pad as underdog used). This creates a mini-environment of about 85 degrees so that an entire room doesn't have to be heated. This also works for finishing with paints that cure better at higher temperatures. As mentioned, it is a good idea during colder weather to put the epoxy bottles (with the tops off) in a microwave oven for 10 seconds before mixing the components.

Heck. move to Florida.

Motor mount application looks fine. BSI is pretty easy to work with and is process forgiving.

Although I'll take a second to encourage trying wood glue for a future cardboard/plywood build
It's deceptively strong on materials where it can get into the fibers

Well, it's Spring, so this shouldn't be a problem too much longer. I've got a friend that does a lot of carbon/glass/wtf fiber layup in his unheated garage. His solutions are a small oil-filled radiator in a large cardboard box, or an electric blanket and thermal (loose-woven) blankets. The radiator has a thermostatic over-temp switch. The blanket has something similar, but is never set on a temp higher than "Med.". And ALWAYS ALWAYS ALWAYS have a smoke/fire detector/alarm and fire extinguisher nearby.

On a similar note - my friend Tim was mixing up a batch of epoxy to secure a motor mount. He was mixing it up in a plastic "medicine" cup. It was the middle of winter, so he was working in the kitchen. He made it out the back door (barely) before the mixture got hot enough to catch fire.

sooner.boomer said:

Well, it's Spring, so this shouldn't be a problem too much longer. I've got a friend that does a lot of carbon/glass/wtf fiber layup in his unheated garage. His solutions are a small oil-filled radiator in a large cardboard box, or an electric blanket and thermal (loose-woven) blankets. The radiator has a thermostatic over-temp switch. The blanket has something similar, but is never set on a temp higher than "Med.". And ALWAYS ALWAYS ALWAYS have a smoke/fire detector/alarm and fire extinguisher nearby.

On a similar note - my friend Tim was mixing up a batch of epoxy to secure a motor mount. He was mixing it up in a plastic "medicine" cup. It was the middle of winter, so he was working in the kitchen. He made it out the back door (barely) before the mixture got hot enough to catch fire.

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Cooking off can happen with almost any epoxy. It happens when the heat given off by the exothermic reaction causes the reaction to speed up greatly, resulting in even more heat like a chain reaction. Always mix shallow rather than deep and don’t ever mix deep in a meltable plastic container. I’ll mix medium amounts in a paper hot drink cup (never styrofoam) then pour it quickly into a shallow container like a paper bowl before it starts heating.