Blocking Chile forge rear opening

[Adodero]

I've seen a few folks blocking the rear opening of their Chile forge with firebrick or insulation. Has anyone done this and found if it causes any issues with the forge or burners?

[Jealdi]

I believe Chile recommends against blocking either end of their forges on their website.

[Grouser]

That is the factory recommendation to never block either opening. But I see people do it on other gas forges all the time,,,,,, who's right and who's wrong?? has to be a logical reason or none at all

[Glenn]

Contact the forge manufacturer and ask WHY to never block the opening.  They will know the reason as it is their forge and their design.

[Grouser]

This is a quote from their website

"If I add doors to the forge will it get hotter?
No. Adding doors to these forges is dangerous. Closing the openings
can introduce unburned propane into the forge chamber, which under
certain conditions may explode. The forge openings give the spent exhaust
gasses, which expand 7x during combustion, an escape path."

if this is true then it shouldn't just apply to chili forges. All gas forges should be warning people against this. But you see it done all the time even on the famous forged in fire show. In search of the truth

[George N. M.]

I use a modified sandia forge which has doors on both ends.  I usually just open the front door enough to insert and remove the work piece.  However, the sandia forge has a chimney for exhaust gases.  That may be the difference.  The exhaust gases have to go somewhere.  If there is a chimney for escape then it is OK to close in the ends.  If the forge is a simple open ended cylinder or box then there has to be someplace for the exhaust gases to go.  Also, doors cut down on dragon's breath which is uncomfortable and possibly dangerous.

"By hammer and hand all arts do stand."

[Grouser]

If a forge has a set of doors and exhaust from the factory, then I would assume it's built to be used in a closed door fashion. Just want everyone that doesn't have those features to be aware of the danger of blocking the openings off

 

[Irondragon Forge ClayWorks]

The forge openings are not totally blocked with the "doors", but the open area is reduced with enough open space to allow for exhaust and stock pass through.

[Buzzkill]

12 hours ago, Grouser said:

No. Adding doors to these forges is dangerous. Closing the openings
can introduce unburned propane into the forge chamber, which under
certain conditions may explode.

This doesn't really make any sense.  Unburned propane simply cannot be introduced into the forge chamber just by adding doors.  Propane, whether burned or unburned, is introduced by the burner, not the openings or the doors.   Before a forge is lit there is certainly the possibility of trapping air and unburned propane together in the forge chamber which could result in a small explosion when ignited.  However, if a burner is functioning properly it should be pretty much impossible to accumulate unburned propane and air inside the forge chamber in quantities great enough to cause an explosion after initial ignition.   Even if a burner is running extremely rich the result would be flames extending from the openings and combusting in the open air, not an explosion inside the forge chamber.    This strikes me as a statement designed to cover their own behinds rather than to impart correct information.

Having said all that, what I said is my opinion based on my experience and understanding of propane forges.  Take that for what it's worth.

[Irondragon Forge ClayWorks]

I agree with Buzzkill, here is a set of doors that are adjustable both front & back.

[Frosty]

Grouser: You asked too open a question, "If I add doors to the forge will it get hotter?

They couldn't answer anything but NO for solid liability reasons.

I have to disagree Buzz, if you block the openings back pressure will prevent the burners from inducing combustion air so the ONLY thing the jet can do is squirt raw unburned propane into the chamber and make a very real explosion hazard. 

We've seen too many inexperienced guys take a good suggestion to ridiculous extremes and tell us it was a bad suggestion. A person MUST have knowledge and experience to have a good chance of altering designs successfully.

Grouser didn't specify anything about doors. How many times have we had to help trouble shoot forges that had the openings closed too much, sometimes completely. Think of it like your 16yro driver with his brand new driver's license and he asks if the family car will go 100mph.

Would you say, yes in a twitter message? You MIGHT if you were face to face and you could explain and lay down the law. Even then a kid might give it a try, hopefully in a "careful" way. I

know I did, at 2am on a deserted freeway and YES a 1970 Nova with a straight 6 would hit 124mph. before handling got too scary to threaten the engine further. Red line? Mother's Nova didn't have a tach.

One last word Grouser. Asking good questions is an acquired skill set, just like everything. I doubt the manufacturer would've said yes no matter how you worded it. Try your forge door baffles outdoors until you find out what and how much works. Listen to the burner, it'll tell you when back pressure starts inhibiting the flame.

Frosty The Lucky.

[Buzzkill]

45 minutes ago, Frosty said:

I have to disagree Buzz, if you block the openings back pressure will prevent the burners from inducing combustion air so the ONLY thing the jet can do is squirt raw unburned propane into the chamber and make a very real explosion hazard. 

And I disagree right back 

Let's say your burner is already lit and you completely close off the openings which would significantly reduce or eliminate the ability of the NA burner to pull in air.  In that case all available oxygen will be consumed and combined with the propane until there is no more oxygen available.  At that point the forge chamber is saturated with unburned propane, which *can't* explode.  All that could happen is burning of the propane any place it leaks out into the open air.  Along with unburned propane, oxygen is a *requirement* for an explosion.  Maybe it's possible to create that scenario in a forge with the burner still functioning, but I'm having a hard time seeing how that could happen.

Regardless, I've never seen anyone on here recommend completely closing off a forge chamber while it is in use.  If a door or other object that is used to block an opening has even a couple square inches of area to let out exhaust I can't see an explosion hazard forming.  It may or may not be enough for optimal burner performance, but I personally would have absolutely no concern about an explosion. 

I'd recommend opening the ends of the forge and tossing in a burning piece of paper or something like that before turning the gas on any time a forge is to be lit, but especially once the temperature inside exceeds the combustion temperature for the fuel air mix the risk is so minimal as to not be worth discussing, in my opinion.

[Frosty]

And when the guy puts his face down front and opens the door to see what happened? 

No, I don't think anybody here has recommended closing forge doors all the way here. Well, nobody I'd pay enough attention to to notice that is.

You don't need to explain the requirements to make fire, I knew the 3 legs of the stool before Cub Scouts. 

There's a BIG difference between the IFI gang explaining how to do a thing and the guy answering vague answers on a company web site. You and I don't bear any liability if someone misunderstands or is to dumb to understand and gets himself hurt botching our suggestions.

The company making a product that makes a recommendation of okays using it in a non-approved manner stands to lose big time in court. It could be a 10 YRO using big brother's forge asking who closes the doors, turns it on and lets it run for a while before remembering to light it. Don't scoff, I had a 16 YRO niece give her hair a nice trim trying to make TV dinners. She lit the gas stove with a match and it blew the match out. Remember those? She'd seen her mother light the oven but didn't know the fine points so she got up and got another match. 

It was only a few seconds but long enough to scare the crap out of her, cause a trip to the hair salon and give her a low level 1st. degree face. 

No company that wants to stay in business is going to give an okay for something that has ANY chance of going bad.

Frosty The Lucky.

[Mikey98118]

EXACTLY!!!

[OakAndIronStudios]

Mine has the optional half brick insert -

 

 

[Leather Bill]

If you ask AmeriGas if it's ok to transport newly filled bottles in the fashion 90% of us do,the answer would be no.  That's why most fill stations don't(non are supposed to) help customer load bottles in their car.   As for explosion resulting from closing forge doors,it could occur outside forge as well.  Considering past lawsuits where mfgrs were held liable for consumer mis-use and ignorance,propane is fertile ground for lawyers.  Blitz gas can lawsuits come's to mind.

[Frosty]

Welcome aboard Oak and Iron, glad to have you. Do you have a name, nick name, handle, etc. we may use to address you? Your login is pretty cumbersome for casual conversation. 

Frosty The Lucky.

[Buzzkill]

So again we're all saying the same thing.  The answer was designed to cover behinds, not impart accurate information. I get it.  Many times on here if I answer a question it will be what or how I would do something rather than recommend a specific action for someone else to do.  

In that vein, if I had a Chili forge I would be comfortable using fire bricks or other objects to block off most of the front and rear openings while in use.  I would have them completely open when lighting the forge, and I would always leave room for exhaust gases to escape while the forge was in use.  With that criteria I would not be concerned about an explosion. 

Other people should do their own research and do what they think is best.

 

[Frosty]

I strongly doubt the person who answered the question had any experience using the forge, any forge. What do you think your homeowners insurance adjuster would do if s/he found a home made propane burning appliance at or even near the site of a fire? You probably wouldn't be covered if it were commercially made if it wasn't UL approved. Is there ANY propane forge with a UL listing? 

So yes, butt covering rules much of the world.

I have the same advice for the current forge as I have made for ANY propane forge. Pay attention to the sound of the burner as you close the openings so you can leave enough opening for adequate exhaust.

You I and many here have something the company rep doesn't. We have experience making tuning and using propane burners and we have NO legal liability so long as we don't get stupid. Moral or ethical liability? Oh yes, I feel a strong responsibility to not give dangerous advice and not just to the person asking but for folks around the planet who may read it years from now.

Frosty The Lucky.

[Mikey98118]

When I burned the garage down, my insurance company's adjuster was on site before the fire department finished rolling up their hoses

Eighteen years later, my book was published. In the cash register line down at Safeway, there were four firemen. One of them turned to me with a wolfish grin, and said he 'd seen my book...long memories.

[George N. M.]

Mikey, can you please give a citation to your book, at least the title and your full name.

Thanks.

GNM

[ThomasPowers]

I assume it would be this one: Gas Burners for Forges, Furnaces, & Kilns" Michael Porter

[Mikey98118]

On 12/16/2021 at 5:56 PM, George N. M. said:

Mikey, can you please give a citation to your book, at least the title and your full name.

Gas Burner for Forges, Furnaces, & Kilns by Michael Porter 2004

However, this book has been out of print for two or three years. Fortunately, it was heavily pirated, which means that you can still probably download a digital copy

[Leather Bill]

 Mikey you and Frosty sure have attracted alot of people looking to gain credibility and profit from your efforts,.   At least you can still reccomend people buy it after pirates did what ever it was they did with it.   They have loused Frosty's up so bad even Frosty say's he wouldn't buy their versions much less reccomend it to others.   

s

[Mikey98118]

I'm no saint. When the book began being pirated I was boiling mad. Over time I realized that the effect on sales was both positive and negative; a wash. Years past and, like so many other authors, I found out that was not true of my publisher, nor the guy he sold out to. So, it is logical to feel more kindly about pirates, who did no actual harm, when two different publishers did plenty of it. Whoever, just as soon as become faultless, it might be time to reevaluate this