HT fail!!!

R

redd1981

Joined
Oct 4, 2011
Messages
251
This is really starting to get frustrating I recently made a HT oven from black stove pipe,kaowool and 2 propane torches and just could not get this 1/4 in steel to non magnetic. I had it in there it seemed like forever (15-20 mins) with both torches on full blast and it came out glowing but the magnet still stuck to it.:confused: so I quenched it anyway and of course it is still in a soft state.

soooooo..... should I switch to mapp gas? and if so how bad is it to use a regular propane benzo burner with mapp? (not recommended I know)

And also do I need to worry about grain growth since it never got to non-magnetic anyways?

Thanks

BTW I refuse to be "the guy who had to send out 1084 for HT" lol help me!!
 
how long did you give the oven to heat up before putting the steel in? how much insulation? some pics of the setup would help us figure it out.
 
This set up will get you to the temp you need easily...

weedburner.jpg
 
well crap I have no way of taking any pics at the moment but will post some a.s.a.p.

it is 1 inch kaowool and I think I may have only let it heat up for a minute or two.
 
Just build a simple venturi burner. It will cost you about $5. The propane hose and regulator can be purchased new for about $30, or scrounged up cheaper. A welding regulator and hoses will work fine with propane, BTW.

This will save you time, money, and frustration.
 
I cant really find any specific instructions on exactly how to build one or even how it works. grrrr any good plans out there?
 
Last edited:
Just a quick question on your current setup.

How much bigger than the torch head is the hole it goes in?

One mistake that's easy to make (well, I've made it), is to have the hole too tight.

Torches are usually designed to work in free air. Only some of the required combustion air is drawn in with the gas and this burns as the central cone of the flame. The remaining gas then mixes with air from the outside and burns as the outer, softer, part of the flame.

If you fit the torch closely into the forge, it can't get any of the air from outside and you'll only partially burn the gas, leading to a lower temperature.

Just to really louse things up, the natural tendency when things aren't getting hot enough, is to wind up the gas. If the problem is already too much gas/too little air, that ain't gonna help.

I'm with Bladsmth and strongly recommend you make or buy a good Venturi burner to a proven design. I'd also recommend buying a good thermocouple and a cheap readout for it.

A good Venturi burner allows fine adjustment of the fuel:air mixture, providing good temperature control. Some of the experts can judge temperature to within a few degrees by eye. For the rest of us, the thermocouple is a really useful tool.

The thermocouple I'd recommend is the KHXL-14G-RSC-24 from Omega.

http://www.omega.com/ppt/pptsc.asp?ref=KHXL_NHXL&Nav=tema06

Not cheap, but it will allow you to check any temperature up to the lower end of the welding range with a bit of care. it's 6mm (1/4") diameter and 600mm (2') long with a handle and a length of cable terminating in a miniature plug. It's rigid enough not to sag when you hold it in the forge for a while. It has a grounded junction, so responds fast and measures at the tip.

Any readout that takes a type K input, has a miniature socket (they pretty much all do) and reads to 1300 degC (2372 degF) will get the job done. I use a Chinese TM-902C bought from ebay. I have more expensive units, but the TM-902C agrees with them, so there's no point risking a pricy one in the shop. Unfortunately, the TM-902C only reads in degC. I was brought up on SI units so it suits me, but if your head only works in degF, you might be better getting something else.
 
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