Hot filter media

I am thinking about hot filter, I know we talked about this. I was hoping for some updates, and ideas. I contacted a co. that builds ceramic filters for bio-gas, but… $2070.00 ouch. I been looking at wool blankets, wool blend not 100%. Ideas?


I believe several people are using fiberglass cloth, like a welding blanket. Gary in PA likes wool blankets. Kristijan is using terrycloth toweling but in a cooler location perhaps.

1 Like

Army surplus should have wool blankets. I forget what the temperature rating is said to be for wool, but it’s amazingly high.


I was thinking thin ceramic blanket, if not to dense. The company that I look at says their ceramic filters only pull 1’’ H20. I was hoping some one using the wool or weld blankets could post some pictures, and info.

Hi al you probley all ready know max gas man used a hot filter set up that i was going too try next myself because with out a dodge dakota v8 or the v10 the intake cleaning is too time effort consumming with out a good hot filter ! Max gasman reheats his gas after it has been run through the cooling rack and hay filter, I think he make box full of steel wool scrubbys that can be opened too clean easilly,after that he ran though a paper filter.But keeps the papper filter and canistor hot as can withstand or good and hot not sure the temp he has at the paper filter, probbly big as can fit.Any way this should be a good thread for hot filtering plans.


Ron Lemler uses fiberglass blankets on the left side of his International tractor before his cooling rack with good success.


I have seen some very light denim weave fiberglass that looks like it has good possibilities. My concern with it is so shinny that soot and water will travel through it better than any other fabric.TomC


And it should allso be clean’able materiel. Depending ware in line its located it seem anyway.?

1 Like

Curtain material used to often be made from fiberglass, might still be. That should offer a range of fabric weights and weaves. Curtains like that should be available in thrift shops.


Vesa Mikkonen from Finland uses Teflon-coated Nomex filter cloth for hot-filtering in his woodgas system.


Hi, Tilman!

The rest of us are trying out ALI-BABA micro mesh SS mesh, but no “baby” filters, grown-up people use 1m2 X 1 thousand rpm X liter displacement.


Dear Max,

this is a good approach and great idea.
How are the experiences with the micro mesh? Especially filtering ability and stability of the mesh?
How do you clean it? How do you fabricate any seams?
And how is the overall performance compared to fiberglass or Nomex cloth?

Sorry for so many questions.

Edit: Just have seen that you already answered some questions here:


Hi, Tilman!

To beginners I usually put the staring question:

How do you want to handle 8 gallons (~30 liters) of soot?

I do not question: How do you avoid handling 8 gallons of soot!

Starting point = reality.

Abrupt; I see you found my earlier writing. Please put it out in full length!

Well, the soot handling: In the twenties the best soot handling was split in 5 stages, now a decent cleaning system can be done with 3 or 4 stages.

Coaxial two-stage Thien cyclone
SS metal mesh tube filter
Washing-boiling + condensing cooler
Wet Open cell mattress filter (in a chest)

A smaller version:

A Thien two-stage coaxial cyclone
Washing + condensing cooler
Paper filter

The available space is a non-compromise factor in most mobile cases.


Hi Max,

thanks for your detailed answer.
My reference of your post in the other thread is a link and not a quote, you can expand it by clicking on the small arrow in the upper right corner.

I hope we are not moving too much away from filter media with this question, but I’m very interested in your opinion.
In his book, Vesa Mikkonen uses only a 2 stage setup: A large hot cloth filter (Nomex fabric) and a washing-condesing cooler. According to his book, this works very well for him.

My questions are:
Do you think, the micro mesh SS could be used in Vesa’s setup instead of the Nomex alone without a secondary paper filter?
And what are the drawbacks of Vesa’s design in your opinion, so that you go for more stages in cleaning?
I could imagine that a reason could be that Nomex is not cheap and his design tends to be large, so everything has to be installed on a trailer.



Hi, Til!

Then the 3-component build-up:


–Coaxial double Thien cyclone heating an outer peripheral paper filter

–washing-condensing cooler

Obvious gas-stream:
Gasifier to double coaxial cyclone to washing condenser, back to heated paper-filter around the cyclone.

Make it shorter! ???

Warm filtrated gas available with 3 components.

(Including the gasifier!)

1 Like

Hi Max,
your proposed setup sounds practical and relatively compact.

But may I ask again, as it is still not totally clear for me:

  • Do you think, the micro mesh SS could be used in Vesa Mikkonen’s filter instead of the Nomex alone without a secondary paper filter?

  • And what are the drawbacks of Vesa’s design in your opinion, so that you go for different gas cleaning?

Thanks again and sorry for still bothering you with my questions.


How do you buy from there?, read that you have to be careful who you buy from. Tips?

1 Like

Hi, Til!

You are Welcome! Hübsh und höflich!
Why not, with the same active area the weight will of course raise, that depends on what the current support weighs. (with Nomex)

Can, if you don’t strive for optimum quality. Good enough…But less safe. The paper filter has the role of safety filter, if something happens to the Nomex or SS mesh.

A big drum with insulation and extra metal accessories.

It drops totally away in the 3-komponent variety.


High, Al!

One guy buys a roll on internet; the minimum has been 10m on a roll, so others are sharing. That would become 2 good filters or 3 under-dimensioned ones for normal motor sizes.

The width varies for different qualities; 3 – 4 feet normally.


1 Like

That’s the million $ question, how that one guy buys on Alibaba