Pyrography criteria to justify changing tools with different woods?

Question

I have been using a binding-post interchangeable-tip pen (as seen in the third image here https://www.razertip.com/pyrography-pens.htm) from The Razertip® Wood Burning Systems for over 10 years now with minimal complaints.

In a discussion with a fellow pyrographer, it came up that their system of choice was a simple soldering iron (never tinned or used for anything other than wood however), and unlike so much of the literature and instructions out there, they claimed with this type of pen, they NEVER have to touch hot pen to wood. Thus shading in their work is exceptional. I have enjoyed making my own tips, but the relatively small gauge wire (even the thick gauges feel like they cool in the air so rapidly they can't burn from a distance).

I am considering out a iron-pen system, like the one shown here (specifically because it has a few interchangeable tips, and I feel this would still be a plus over a soldering iron dedicated for wood burning) http://www.leevalley.com/en/wood/page.aspx?p=31041&cat=1,41115 but I am not sure whether it would make shading of heavily grained hard woods any easier...

Long story short, I would like to ask for some advice or brief stories of your experience regarding a few observations and determining whether different equipment would help improve this:

1. With the thin wires of the razertip system, the pen requires contact with the hardwood with smooth deliberate motion (technique and reading of the wood is vital here and requires time, patience, concentration, and focus as if the pen isn't lifted in time the grain can ignite (with a flash) leaving a blob.) This is common and there is lots of material out there about techniques and better woods to use to avoid this, but I would like to focus on whether an iron-style pen which is not in contact with the wood will make the wood less sensitive to this problem.
2. I have been told, iron style pens (without touching the wood) generate faster, more even burns to a larger surface area compared to pens with thin wires. Is this true, or have our discussions not given enough credit to the wood we are using? Based on photographs of my friends work, I know for sure we aren't likely using comparable woods as there is never a discernible grain on their work. I tend to burn on a lot of pine, poplar, maple, and red oak. The grain and changing density/wetness on red oak can be a real pain!, but all the more satisfying with a well done end product.

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No affiliations to Razertip, Lee Valley, or Veritas. Just trying to provide as much relevant information as possible to get the best advice from the pros and gurus out there.

Answer 1

Pyrography depends in part on the ignition point of the species. Which you seem not to want to discuss. To answer your question, thermal conductivity as defined here: https://physics.stackexchange.com/questions/76509/what-is-the-units-for-thermal-conductivity is what you are concerned with, plus the ignition point of the wood.

Ignition point has several dimensions. First the moisture content of the wood. Next is the species in terms of extractives with low ignition points. Extractives example: pine sap. Dry wood with no extractive factors and zero moisture has approximately the same ignition point given a specific density of the wood. More dense species, e.g., Lignum vitae (guiacum species), have higher ignition points than Ochroma pyramidale, Balsa.

So it matters, in my opinion, what wood you use. As much or maybe more than the conductivity and specific heat ( what you are asking really) of the tip. Jenka hardness also enters into the equation here. Really hard woods - which are generally more dense, require greater energy input to 'caramelize' ( my own term)

My opinions only. I've never used iron tipped burners, but my pyrography is, um, mostly not high quality. I am pretty good with Wood Science, however. For more on the properties of wood try Bruce Hoadley's book - which I would strongly recommend to anyone doing much of anything with wood: 'Understanding Wood' http://www.amazon.com/UNDERSTANDING-WOOD-2nd-EDITION-Hoadley/dp/B000UQH160