How to make a cheap funnel for heat ducting pipe?

GervisLooper

I am talking about the stuff like this. I want to make a funnel so that I can transfer the heat from the aperture of a heater to another space. I don't want it there all the time though as it usually heats the space where it is but I want to try that so I can push to another part for drying things. So want to be able to dismantle it. No I can't just move the things I want to dry to the heater, well that isn't my first choice anyway due to space constraints.

The aperture is of an odd size though so want to make something I could mold to be wide enough to catch most of what the heater puts out and taper to the smaller circumference of the duct pipe.

What sort of stuff would be good for the job?

Either find something that fits perfectly (unlikely) or use something that I could make a wire frame and mould something over the top. The shape is a flat rectangle about 20-30cm wide and maybe 10cm high. I do not expect to capture it all as it won't be sealed but the heater expels the warm air out of around that space via a fan and a funnel could capture a decent proportion. That is the idea anyway.

Perhaps chicken wire to shape and then what would be good to mould over it that would also be somewhat heat resistant? Not going to be extreme heat, probably 25c or so max.

Just trying to jog my memory back to school and papier mache. Would simply using diluted pva glue and newspaper do the job?

teaselMay

odd size rather than shape? if the outlet is round or oval pipe as you've linked with a metal jubilee clip to hold in place

sorry missed the rest about it being rectangular

teaselMay

having read the rest of it I'd still use that piping, cut a piece length ways to make the reciprocal shape to your outlet and then fashion a join in the middle of that with an intact piece. It's relatively pliable if you're gentle with it whilst fashioning it

DullGreyGuy

Does the heat come out of the aperture by convection or is there a fan or similar?

Where are you trying to get the heat to using this apparatus relative to the heat source? What distance? What are the temps of the spaces it'll be moving through?

The linked to piping is designed to moist warm air and with an impeller move it outside the building its not really about preserving the heat or for air moving passively.

GervisLooper

teaselMay said:

having read the rest of it I'd still use that piping, cut a piece length ways to make the reciprocal shape to your outlet and then fashion a join in the middle of that with an intact piece. It's relatively pliable if you're gentle with it whilst fashioning it

Not sure I follow, what are you suggesting I use to make the rectangular piece that is to funnel to the circular one?

GervisLooper

DullGreyGuy said:

Does the heat come out of the aperture by convection or is there a fan or similar?

Where are you trying to get the heat to using this apparatus relative to the heat source? What distance? What are the temps of the spaces it'll be moving through?

The linked to piping is designed to moist warm air and with an impeller move it outside the building its not really about preserving the heat or for air moving passively.

I said in the OP it is coming out by fan. It is a diesel fueled heater, though not the same as the common circular aperture ones you will see that you see online as it is also a cooktop hob with a lid which closes and blows heat out, hence the wanting the odd shape, and a distance to go about 2.5 meters.

I am in a small van and I want to blow heat to the front of the van where I hang clothes sometimes as, even though I have active venting with a couple of computer fans, the airs still seems to be rather stagnant there and the heater heat is not reaching, much, to the front I don't think. So I would like to be able to concentrate heat up front when I have wet clothes to dry.

teaselMay

GervisLooper said:

teaselMay said:

having read the rest of it I'd still use that piping, cut a piece length ways to make the reciprocal shape to your outlet and then fashion a join in the middle of that with an intact piece. It's relatively pliable if you're gentle with it whilst fashioning it

Not sure I follow, what are you suggesting I use to make the rectangular piece that is to funnel to the circular one?

I'd make  a slightly larger rectangle out of the ducting cut along it's length, opened out slightly and then bent to the shape of the rectangle, so that it will sit around the rectangular outlet. I'd then make a hole in the centre, or wherever is convenient, and connect the intact ducting to that, either using a proper connector or by splaying out the end and sealing, if it's not going to get particularly hot an appropriate tape or glue would work for that (make sure it's appropriate to the heat you're going to expose it to) or you could use a diesel heater wall outlet connector through the hole, which is what I'd do.

GervisLooper

teaselMay said:

I'd make  a slightly larger rectangle out of the ducting cut along it's length, opened out slightly and then bent to the shape of the rectangle, so that it will sit around the rectangular outlet. I'd then make a hole in the centre, or wherever is convenient, and connect the intact ducting to that, either using a proper connector or by splaying out the end and sealing, if it's not going to get particularly hot an appropriate tape or glue would work for that (make sure it's appropriate to the heat you're going to expose it to) or you could use a diesel heater wall outlet connector through the hole, which is what I'd do.

The width is about 3x the size of the diameter of the duct though so not sure how you envision it could be bent that far?

Duct is about 10cm across, from rough memory, and the width of the gap is about 30cim and would probably want a bit over to give greater capture.

EDIT: Oh right I just re-read and noticed the 'cut along its length' makes more sense now. I actually did something similar with a 5 litre empty water bottle and put tinfoil inside it. Kind of worked but seemed a lot of loss with that as didn't feel much coming out the other end but didn't experiment extensively and gave up at the time.

Using the ducting itself might be worth a try and have over in length anyway some a good bit to spare.

GervisLooper

I thought of an easier way to make the funnel...some fire retardant cloth. I could tape it down at first to test it but could then use velcro after that around the sides if it worked well. Could also add insulation layer/s too.

This has a big added advantage of being able to store flat when not in use which is something I had been considering due to the very tight space limitations I described above.