Heated cat pad idea

Tx for the tip about these micro-waves heated disc, and the link too.

 

This will surely solve many problems for many of our rescuers and caretakers with outside kitties and none possibilities for electrical heating.

 

Probably some humans will also have use for this.  :).

 

 

Tx again!   *vibes*

I use the SnuggleSafe too - inside of a small dog house. I like it so much I ordered another.

Thanks SO much for that idea. I never knew about SnuggleSafe Pads before. Good to know for sure that you can still heat your feral's house without electricity
Edited by Feralvr - 12/14/11 at 4:53pm

I have a heating pad and two snuggle safe heating discs that I put in her igloo.It stays warm all night long. I think it is better than the heating pad:wavey:

Just talked with another feral caretaker friend today, by chance, at the vet's office She said she uses those micro heating discs too and said they work incredibly well, hold up a long time too.

I can also recommend the Snugglesafe heated pads, long lasting heat and can be placed into existing bedding. No wiring and virtually chew proof :)

At the recommendation of this site, I have bought two micro heating disks and will be using them for the first time when I TNR in a few days.  I may leave one trap out all night (without checking it), maybe that way I'll get the ever elusive feral kitten. 

I also may use the disks in the trap, both ends open, on a night(s) when it is bitterly cold.  Last year they had access to an unused utility closest that had a furnace inside; this year, nothing.   (Though I had a trap stolen last month so have to think twice about this.)

As I type this, my snuggle safe disk is in the microwave heating up for Barney who lives in my husbands workshop.  I absol love it.  I plan to get two more next week for the two feral barn kitties.

Good news bad news.

The snuggle safe disks didn't stay warm as long as the label said it would.  Next time I'll adjut the heating time.  And maybe warm one up to see if Ritz likes it.

But the good news is that I trapped two cats, one an adult cat I'd never seen before and the kitten I'd been hoping to trap.

Good news outweighs the bad...

Heat keeping ability is almost linear to how much they weight, so get something that weights most and it will stay warmer longer, some rock (rock is of course hard, but silicone, wool, cotton etc stuffed inside fabric cover/pillow would be needed on top of that) is probably best, but to get most of it it should be insulated with rockwool, expanding foam etc so that there is only one surface giving heat off.

Heat conductivity plays part too I think, but it also works so that heating object will be slower if it gives heat off slower.

Also temperature difference affects quite a lot to how long object will stay warm.

Also object should be as dry as possible, even rock can have quite bit of water in it, if one has sauna putting anything there during warm up period will dry and heat object nicely.

There is really no short cuts in thermodynamics, but knowing some basics will help to evaluate if some product is going to work or not, neat trick is however to put little bit of insulation to top so that object can be heated bit more without feeling too hot and also it will prolong the time object will stay warm as it reduces heat transfer to surrounding air.

To stop heat escaping to wrong direction is thing that requires quite thick insulation, best practical insulation material is expanding foam and one will need more than two inches of that to stop heat escaping, less is quite ineffective, that means that heating pad would become quite bit larger than what surface of heating pad will be, however there really is not much better materials out there, of course there is vacuum insulation, but it is rather badly working for things with sharp claws and habit of clawing things they like.

With these realities limiting possibilities it is quite safe to say that any product that will really keep heat well will be quite difficult to sell because of bulkiness.

Here is basics of what these stone discs are based off which can help to understand science behind it and if one will have good math head it should be possible to calculate how much mass one would need to have enough heat for full day, house building and specifically insulation planning is area where one can find formulas to work out what amount of insulation would make enough of limit to heat escaping so that mass can be reduced to sensible level.
http://en.wikipedia.org/wiki/Thermal_mass

Soapstone is best rock that you can get for such purpose, I believe that those snuggle discs might use that, but never I have seen such so it can be about anything. Soapstone's good thing is that it is giving heat off rather slowly and weights quite a bit per volume unit, so one can get away with smaller disc than otherwise.

Easiest way to build such would probably be to get washbasin of desired size and shape, get stone of same shape that is smaller than washbasin, so that there is space for insulation, rockwool is easiest to work with and is quite good insulation so putting that to bottom and sides of washbasin and putting stone to middle would make good base, then pillow or cat bed to top of stone and attach that to washbasin with string, some hole drilling required to make holes to edge of washbasin for string that would be sewed to pillow and some stone shop needed to get desired stone made, but that would be better than anything one can buy, surely it would be large, rather heavy too, but one can always adjust this to smaller scale, it will not be as good as retaining heat but maybe sufficient.

Heating of stone would be done at oven, heating time would be something to experiment with, but it should be possible to calculate too.

It is not really difficult to make heat pad that will keep the heat for 24 hours, but challenge is how to make it enough small, with current technology in this world it can't be really small.

If stone sounds bit too difficult to obtain, one can use same type of design with any water container that can be sealed reliably, for example those reservoirs of cold bags that you put freezer, put hot water in there, one can buy even gel type that can be heated at microwave, putting those inside of 'insulated bowl' will keep them warm whole day if there is just enough insulation and mass of heated objects, more insulation less mass is needed.

Reason I favour self made versions is that I find often those shop products to be more of pretty and selling than working in task that they were meant to, sadly quite often true with pet accessories, even somehow working ones can be improved vastly with little effort.

Cost is very small, rock wool from hardware store is not going to cost much, free if one knows constructor, there is always some waste bits that they can give free or pennies to spend, most expensive is object that will store the heat, but should be less than a 10 dollars or euros.

One thing to remember is also styrofoam and alike, even expanding foam is available at sheets, those are nice in such that they will reflect body heat back, or more of wont allow body heat to escape, which makes nice warm feel, try and sit on styrofoam, in seconds there is warm feeling.

Now of course stuff available will vary a bit from country to country, but I have found that hardware stores and specifically house building sections are best for any heat or heating related shopping, with 1 hour work one can get lot better heat pad with half price than there is commercially available. Well here is my kind of approach to issue, might help some, I hope

Thanks.  I'm going to experiment with the micro heating discs I have, vary the time I put in the microwave, test it that way.

Good point about size of animal.  The cat that stayed in the trap overnight was a large male, I'd never seen him before.

And the other cat was female; of the 25+ cats I've TNRd since November 2010, only five are female.

I don't think cat weight has much to do with it, but more of disc weight, that is something around 2lbs I guess? It can't store very much of heat energy, but you can improve time it stays hot by simply putting rockwool under it. My ferals did love such simple as piece of rockwool put on the shelf of warehouse, they did stay warm in that, also dry which is very important too.

That is interesting thing how trapped ones seem to be males here too, is it that females are too cautious or is it that there is more males born? Mysteries of life which makes world around us so interesting.

JTBO´s   physic´s  remarks are interesting and surely correct.

 

I want to add another insulation:  wrapping in something silvery, with the silvery towards the heating pad. 

Like many emergency towels the ambulance people and mountain savers do have - here it is the human to be saved who gets wrapped.

 

Say, you want to make the warmth is going upwards. Perhaps the pad under the trap, warming up the floor.  No point of the warmth going into the ground under the trap.  Wrap it in silver foil, the silver around the pad, reflecting back the vaves of warmth.  and of course, preferably a thick isolating layer á la Jtbo under the pad, between the pad and the ground.

 

Something like that.   :)

Tinfoil is good, one must just take care not to make heat conductor instead of heat reflector, typical computer heat sinks are same material as tinfoil, just thicker and not shiny, also tinfoil has typically two sides, shiny and not shiny, shiny one towards heat source, ie. what one like to keep from cooling, it just gets bit funny for my brain when you have heating pad and heat producing cat, when there is no cat it would make sense to reflect heat towards pad and when there is cat it should be reflecting heat towards to cat. However to keep disc from cooling too quick shiny side should be towards the disc as Stefan writes about. I must say that I have still my doubts of it's practical effects on here, but it is so cheap and easy to do and it really can't make much harm that it is worth to test.

Heat loss itself is related to surface area, so if tinfoil layer is larger than disc, then it would increase surface area and act as heat dispencer, well kind of, but probably those are quite minor effects in this size and application, however it is always better to know and understand more, that is ever going process really, but it really saves lot of trouble when basics are known, it is easy to improve existing design then to meet ones preferences.

Surface area, mass, temperature difference, these are basics that affect how pad cools, with insulation one can then limit effect of temperature difference, but larger temperature difference and faster pad cools, less mass makes it also cool faster as well as more surface area makes it cool faster, no need to really get much more complicated than that, tin foil can work to some degree, however how much effect it has I have never really found out, it is not huge effect, not with these small temp differences, but it is rather easy to apply so it probably will be beneficial.

I have here expanding foam sheet with tinfoil applied on it at factory, then I have one without it, cats avoid tinfoil version as difference between two is such that with tinfoil there is delay of warm feeling, it is many seconds, more than 10, but without tinfoil and it is almost instant feel of warmth. Tinfoil at surface need to be warmed first, so it will take time until body heat is reflected, also tinfoil acts as heat spreader, so it does conduct body heat to total area of sheet and as sheet is larger than cat it actually increases surface area, it is different with those first aid blankets of reflective material as they usually are wrapped around the body so surface area is not increasing by much.
Of course that increase of surface area is not largest reason why cats dont use it, it is that it just feels cold at first, but there.

I would think that putting tinfoil so that cat is not touching (between ground and heating pad) would be best, also there is no harm wrapping disc to tinfoil and putting wrapped discs inside the cloth, it might stay warm bit longer, but I really miss any measurements of it's effect, might do some experiments myself some day when I get time.

Yesterday I trapped one cat, it was -5C at night, trap was on cold concrete floor at warehouse which is not any warmer than outdoors, not best possible way really, but he had cardboard flooring at the trap at least, did not complain when I brought him next to lit fireplace, of course so that he could not see the flames, animals don't like flames afaik. 1/2" thick (I'm thinking here 10mm, 1/2" is close of it) sheet of expanding foam or styrofoam would be also a lot better than nothing, I think, might go with styrofoam myself, it is really nice and warm stuff also when placed inside of trap it is protecting their claws a bit if they try to dig out of trap.

From my experience, if I put them something to rest after trapping they are not using it, so I guess I need to put styrofoam before arming the trap, maybe using zip ties to attach styrofoam to bottom of trap,

Campers have those carpets/mats that they keep on roll and unroll under the sleeping pad, I have covered window shelfs with that stuff, it might be also something worth to try, perhaps best to put under the disc.

There are many ways do it and almost any way is better than without anything.

Hopefully ramblings of mine makes some sense at least

Congrats on the trapping!

And VERY interesting discussion about the microwave discs/heating options.

We bought several of the discs for our inside cats. The front dash where they like to hang out gets REALLY cold in the winter, because of the big windshield. But none of them used them.... so I sent them on to someone who needed them for their outside cats.

GOOD FOR YOU Congratulations on the trapping's

Maybe it would take three years for your inside kitties to use those heating discs on the dash - like it took your outside kitties three years to use the Feral Villa's ...

p.s. I resorted to putting one bowl of wet food on the second level of the villa - Dixie is going up there now - I see her short black hair in the straw !!!!!

@JBTO:  it was explained to me by wiser and more experienced souls that male cats are more likely to be dumped because they spray nasty smelling urine when they are looking for female company.  And I think male cats are more ornery when they are looking for female company and cant' find any; female cats in heat are VERY affectionate.  (There is female cat in heat at the cat sanctuary where I volunteer who is very affectionate right now.  Because her health is compromised (FELK+), the sanctuary is reluctant to spade her.  All the other FELK+ males have been neutered.)

 

Possibly.  Although grown up, adult toms tend to wander away on their own.  Getting unpatient, Seeking females of course.

 

My eye opener was a couple of different forumites, living in rural conditions. Essentially cat friendly people around. Lots of cats around, and very few spayings /neutering.

 

They told the same story:  the toms tended to disappear at 1,5-2 years, very few older toms left... They wandered away.  As long as they were young, they could stand their male urges. But when they become fully adult, the urge become too strong, and thus, they tendered to wander away...

 

Of course, the from beginning no sprayers begans to spray at that time...  

 

Another may be the most dominant, strongest tom tended to chase the weaker, fully grown toms away.

 

So in reality it is probably a combination of at least these three factors
 

 

It is probably statistically meaningless, but here I have seen results of two female cats giving birth to 7 kittens in total, there was only one female with these kittens. First one had two kittens, but it might be that some of her kittens never did made from first month or two, only those two I have seen and both males, then other one had 5 kittens I did saw first when 3-4 months of age, those were all males except one being female, never did saw that mother cat actually, just her kittens.

So those that I know there has been more males born/surviving than those of females, which can of course be just random two events, to be any scientific meaning there should be data from preferably hundreds of queens and their litters as variability is probably so great that with just two cases there is no telling really if there are more males born and surviving to adulthood or not.