Heat Packs in shipping problem

[ReeferMac]

Like a lot of folks here, I ship corals out for sale/trade at different times throughout the year. I live in Western NY, USA, and it gets mighty cold here during the winter, so I usually don't ship from November to about April/May. When it does get cold and I am shipping (Sept., Oct., May, June some years... :rolleyes: ), I put a heatpack in the cooler.

Like everyone else, they're the iron based heat packs/hand warmers, they work via rapid oxidation of Iron Oxide of some sort (I _think_.. not 100% on the chemistry there, but you get the idea).

Anyways, my problem (and everyone elses):

The heat packs work on oxygen. The shipping coolers are sealed and insulated very well... So once the heat pack consumes the O2 in the cooler (should be very little if you're packing things right), the chemical reaction that provides the heat we desperately want, stops.
When the cooler gets to it's destination, you open the case, let fresh air at the heat pack, the damned thing heats up!

Well, so far, I've figured I could punch some holes in the cooler on the side that I place the heat-pack... only this might let out as much heat as it generates by allowing air in. I've thought about making tiny tiny holes to minimize heat transfer.. but figure I'll be letting in very little air if I do that as well. I'm honestly wondering if that's an affective solution to the problem (or does the heat that escapes, negate the benefits)?

Anyone got some thoughts on the matter? I hate shutting down trades for the winter, but.. I've lost too many corals.

Thanks for the idea's.

- Mac

[coralsandbar]

Hi Reefermac,

I have some insulated containers that are octagonal that fit in a square box. In the areas between the angle of the styrofoam container and the box i put the heatpacks there figuring they will get oxygen through the tiny holes in the corner of the box and you don't sacrifice the intregity of the box.

With regular square boxes, I usually place on the top of the styro prior to taping down the cardboard box on top of it.

I figure if it somewhat helps the ambiant temperature outside of the box, it should help stablize the insides.

I guess it wouldn't hurt to put 1-2 inside and 1-2 outside on top & bottom of styro.

I haven't heard any complaints using this method lately, but your right when it gets really cold it's hard keep everything warm.

I asked a buddy of mine and when it gets really cold they use 4-5 heatpacks, and only 1-2 now for the 40-50's we experience now.

I'm going to try 2 in box and 2 outside above styro.

If you are shipping 2-4 frags you could always use 2 thermos then pack box with packing material and put heat packs around the thermos, that way heat packs are still exposed to air inside the box and through the tiny holes in corners (that naturally occur from box folds).

HTH,
Rob

[ReeferMac]

Thanks Rob.
That sounds like a good idea w/ the external one's (besides, they all end up in those plastic bins the shipping companie's use anyways..

- Mac

[coralsandbar]

true....food for thought....I would also like to hear what others say. Sometimes provides some new insight.

I'm going to try some new packaging techniques on sps this weekend.

Rob

[JB NY]

Interesting. I've used those heat packs before. I've never had any problems so I was assuming they were working fine.

I do use the heat packs all the time when visiting people and getting frags. I've always noticed that the heat packs seem to be working. They are always warm and the water in the bags and the cooler itself seems to stay nice and cozy warm too.

[coralsandbar]

I use the 24 hour heat packs that are used to ship fish, lizards, etc. I forget the name of them at the moment.

[Zephrant]

Best thing to do is to pack it up like you are going to ship, then put outside for 24 hours. Check the temperature when you open it up again and adjust as needed.

Zeph

[coralsandbar]

the heat packs I use are heat factory.

rob

[billsreef]

You've got to watch out for putting too many in, they will rapidly consume the O2 and cool off. Generally no more than 2 in a large box is best, along with extra insulation. Thicker boxes or multiple layers of newspaper works well ;)

[ReeferMac]

Originally posted by billsreef
You've got to watch out for putting too many in, they will rapidly consume the O2 and cool off.

That's exactly my point, Bill. I ship in pretty tight coolers (don't like the frags bouncing around in 'extra space', so I even fill empty bags w/ air to make it all a tight fit), as small as possible for a given a shipment. There's very little air-space left over. Even one heat pack, IME (using my coolers, etc.), rapidly consumes all the air. The inside of the box is cold by the time the recipient gets it (in the winter months), but 15 minutes after it's been sitting there opened, the heat pack starts to get warm again! The most reasonably assumption is the reaction starves itself of oxygen.

Unfortunately, putting holes in the cooler to allow in extra air has the counter-productive feature of letting heat out as well. Packing things in an extra large cooler not only (IMO) puts the livestock at risk (as tumbling around through the handling equipment will be more hazardous), but also increases shipping costs significantly.

Are there any cheap battery powered heating elements that could be used? If it's going to cost me 10-bucks more in shipping to use a larger cooler, I can afford to spend that much in an alternative heat source.

- Mac

[coralsandbar]

true... but I figure with the extra heat packs between styro and cardboard box at least allow the heatpad to draw oxygen from outside the box versus inside. I figure if you cover inside and outside between styro and box your a little bit better off.

[ReeferMac]

Agreed... I'm curious to try an experiment like that (who want's a box of frags?).. Even w/ the expensive 36hr. heatpacks, you're only talking a couple of bucks... perhaps it might even pass some heat through the styrofoam (if it's a thin walled cooler).
A friend did an experiment w/ a data-logging Dive watch, but used a different type of cooler than what I typically ship in (and I can't bring myself to ask to borrow his fancy diving watch, in case something happens).

- Mac

[coralsandbar]

I sent a guy yesterday a test frag (sps frag of bird's nest)with his shipment. It was vacuum packed in just enough water to keep it wet, with papertowel at top to preven water from being sucked into vacuum. Sounds like it worked really well.

[ReeferMac]

Vacuum packed?!?!? Really? I would have suspected the corals needed _some_ air in there...

- Mac

[coralsandbar]

Yeah, I was thinking the same thing myself... I figured it was worth a try to see what happened.

[GreshamH]

I never have a problem with our heat packs (24 hour), but then again, our boxes are a bit larger then frag boxes so they contain more air to get used up. We never use more then 2 per Indo box, even if it's a $1,500 fish.

[coralsandbar]

yeah, the smaller frag boxed run out of air a lot quicker even if placed in between styro and box. Had one complaint of a cold shipment but most survived.

may have to go with the bigger boxes.

[Acro]

Not much help here. I've never had a problem either or at least thats how I see it. I've recieved frags in the winter months up here in Canada with out issue. Also have sent frags fine too. But what did intrest me was the 24hour heat packs. What kind of store are you guys grabbing those from?

Thanks

[coralsandbar]

heatfactory.com

[Acro]

Thanks Rob :)

[coralsandbar]

not a problem Jamie.

Rob

[serjuanca88]

Does the reaction use oxygen? or just air?

If it uses oxygen. could you somehow put pure oxygen into the container?

[ReeferMac]

I believe it's oxygen based, but not 100% certain. I don't have any O2 tanks, so it would be quite the PIA to achieve, but I like the idea. Wouldn't be an issue for a commercial shipper (or someone who happens to have an O2 bottle lying around - welding setup, etc.)

- Mac

[rsman]

thick plastic sealed like a bag, put the heat pack in there fill it to take up the space you get oxygen or air or whatever helps make it work. and your corals get cramed in there all nice and tight.

[billsreef]

Originally posted by serjuanca88
Does the reaction use oxygen? or just air?

If it uses oxygen. could you somehow put pure oxygen into the container?

It uses the O2 from the air. I recall someone talking about trying to super charge the box with pure O2 and finding it just caused the heat packs to overheat and burn out quicker. A good quality 24 hour heat pack should really have no problem, styro boxes aren't all that airtight ;)

[Gary Majchrzak]

Originally posted by billsreef
A good quality 24 hour heat pack should really have no problem, styro boxes aren't all that airtight ;)
I agree. And two heat packs per shipping box is the limit.

[niko5]

What if you poke a hole in the box then tape the heat pack over the hole so the heat pack and kind of pull the air through the hole and the tape will keep the air from just blowing through the box but the heat would come through the tape... just a thougt

[jaiden]

Yeah, I'd say some kind of non-airtight insulation on the "outside" of the heat pack, and then a hole to allow air in through to/through the insulation. maybe a piece of wool or other fiberous insulation.

[SeanT]

Originally posted by niko5
What if you poke a hole in the box then tape the heat pack over the hole so the heat pack and kind of pull the air through the hole and the tape will keep the air from just blowing through the box but the heat would come through the tape... just a thougt
Genius idea.

[bookfish]

Perhaps if the warmer is sandwiched between bags its free air flow is too restricted. Could you put it in a container so it got good air flow (soap bar container w/holes)?-J

[merlock116]

a shipment i got from an online store had a few holes punched in the styrofoam lid. The heatpack was taped to the bottom of the lid . Seemed to work pretty well.

[ReeferMac]

Thanks for the idea's. I think I might try popping a few small holes on the backside of the cooler lid, and taping the heat pack to that the next time I have to ship in the cold.

- Mac

[Flamehawk]

Hi, how about a heat pack inside a plastic fish bag filled with room air. room air is about 21% O2. Pack this "heat bag" next to the other bags. JOHNNY