Sandy Mathieu

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since Feb 22, 2013
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Recent posts by Sandy Mathieu

Why we are selling
We are selling our Dragon Heaters business because it not a good fit for us. We have 2 businesses and we do not have the shop space or attention for both. We are women over 60 and the physical effort of mixing refractory and packing orders is just too difficult for us. Our other business,, consists of small, lightweight parts and is better fit. We love the rocket heater world and are reluctant to walk away from the years of effort we put into Dragon Heaters, but we cannot do both businesses.

What is included
Included is all the inventory, molds, website, domain names, documentation, packing boxes, and equipment including a professional vibrating table. In addition, we will provide suppliers lists, detailed specifications for all products, including CAD models, packing requirements, and pricing data. We will also teach you how to make successful castings and pass along our long list of hard lessons learned. We believe we are the only organization to have solved many of the technical challenges of producing a commercial product. We want the new owner to be successful so will do everything we can to make that so.

What will be required in addition to the purchase price?
A week of training time here in Houston, Texas for hands on mixing and packing.
You will need significant storage space at your location, approximately 3 pallet racks, plus bulk storage for things like the portable heater metal boxes and the metal tops for the barrel builds.
You will be responsible for loading and transporting all inventory and equipment. 
If you are interested, please contact us at

6 months ago

Inclusion of a P-channel, and a trip wire in the burn tube would be very easy to do regardless of mold material type.

One problem with this, is that these design points are covered by a patent filed. Any commercial attempt to duplicate these design features would be pursued.
4 years ago
Just a quick FYI. The $350 price for Dragon Heaters includes the fabricated steel feed tube and heat riser. If someone wanted to buy just the burn tunnel, the price would only be $140. The steel feed tube which is cooled by 2ndary air prevents a secondary chimney from forming.
4 years ago
The rocket heater world desperately needs testing protocols that both the epa and the various states, most particularly WA will approve. Then official testing and approval can be done. But detailed protocols must be developed by an independent lab. Both the EPA and the state of washington are eager, and have positive attitudes about working towards these protocols. The issue is that money is needed to pay the lab. We put in a Kickstarter project at the beginning of the year to try to raise money for this, but kickstarter turned us down. said it was not a "creative" endeavor.

We would certainly aid and contribute to any ones endeavor to get these testing protocols written. This is the only way rocket heaters can be assured of a regulation, trouble free future. They plan on removing the current exemptions on rocket heaters. So this is an important and urgent issue. It would be fabulous if everyone could get behind some sort of effort to write these protocols.
4 years ago
The biggest reason was that they changed the rules without notifying us until the last minute. Our plan was to show the batch box with some enhancements in a masonry heater type installation, similar to our castle builds. This setup weighted over 3000 lbs. but we could put it together in a day.

They told us less than a month away that we would not be allowed to do any on-site construction. The unit needed to arrive on a pallet ready to go. In order to transport this 7 ft, 2 ton monsters we tried and considered everything. We purchased special vibration pads, built a custom pallet, and even assembled the unit without mortar.. In the end we ran out of time to solve the problem. We most bitterly were forced to withdraw.

The organizers did acknowledge that they had made a mistake. They informed the other 4 masonry stove people but did not send out the rules to all contestants and thus we were never informed, because they assumed we were not doing a masonry style heater.

We did have a fair amount of difficulty with the batch box. It is a sensitive thing. Changing something can send the box into a nose dive, so trying to get the exact box parameters along with the crazy requirement to show up 3000 miles away with our masonry stove all prebuilt was a bridge too far. In retrospect I wish I would have argued my case to bring the castle build, the other entry we submitted, since they messed up on the notice. But we were so bummed and exhausted about it all, we were not thinking clear enough. The j-tube castle was smaller and easier to deal with.

We worked 12/14 hour days for weeks on it, so, disappointment doesn't begin to cover it.
4 years ago
Just my 2 cents on the batch box. I have built and test several variations of the box and heat capture bells, barrels etc. We wanted to offer the casting for sale at Dragon Heaters. But alas after LOTS of time and money down this rabbit hole here are my thoughts.

1) They are not only more tricky to build and cast they are particularly more tricky for heat capture. Just ask Matt Walker. We both had lots of hair pulling with units that would run fine under one circumstance and then just crash and turn into a dog when the configuration was changed in a seemingly harmless way . The technology has promise and appeal and it will be there in the future, but in my experience, the design is not the stable work horse a rocket heater is. So we have tabled it for the moment. There are designs that work with this firebox, but many that also do not work well. The heat capture design is critical.

2) The fire is designed to burn from the "back" towards the glass door. The result is your looking at your pile of wood, seeing little flickers of light from the back for quite some time. You look and wonder, has my fire gone out... no there it is. Then at long last the fire comes forward enough you see a fire for a short period of time and then coals, and lots more ash than from the same wood burned in a rocket J-Tube.

3) Both the horizontal feed and the J-Tube have to be reloaded at the same interval. So the main advantage lies in its larger capacity and the ability to accept larger wood. It will burn about 30% more fuel per load.

I do agree, with satamax, nix the barrels.

4 years ago

Dale Hodgins wrote:They look nice, don't they. ? A tour of the website fails to explain anything to my satisfaction. Numerous products are offered. A little 4" core is $350 and $90 shipping. That's $440 in total. If I needed a 4 inch core, I'd spend $30 on supplies and build one.

Okay, don't buy. Our materials alone cost us many times more than your target $30, not to mention labor, cost of molds, cost of kilning, overhead etc.

Why the hostility? We are a small company trying to bring rocket heater concepts and technology to the larger public. We don't have excessive mark ups, it's just expensive to produce a quality core, as considerable dialog on this forum under other topics has shown. We produce quality, tested, ready to use products, for those people who just want to build a heater quickly, that will last and have it work right the 1st time.

How are these products unique ? What makes them better than one built at home ?

This question is answered in detail here...

Including a link to the development of the design (by Peter van den Berg) vs. a standard rocket heater.

We have also published extensive data logs on temperatures, efficiency, and emissions on the blog site here. Data which is largely missing from the rocket heater world, but which we publish in the clear.

There was also a review of the core done by Donkey some months ago published on this forum.

4 years ago
The kaowool with the rigidizer might hold up, only time will tell. The cinder blocks however may not really the best option. Based on the size of the barrel he is using and the channel the question, the issue is, what is the temperature entering the cinder block area? It should be less than 400F, Since his barrel is small, it is likely his heat is higher than the 400F. Long term this will result in the cinder blocks failing. The other issue is that cinder block is not very good at thermal mass. See the chart posted at this blog. If you are going to make the compromise on temperature it would be better to use solid cement blocks.

But more firebricks would serve the best.
4 years ago

Just wanted to post a few pics of our 6" portable rocket heater that is now available for shipping. If you are interested and want to see more pictures, you can go here. It is a quick and easy way to setup a rocket heater.

4 years ago
How many bricks depends on if you have 3" or 2.5" thick. We had 3" and it takes in the 160-175 range.

All the gaskets, and exhaust collars are provided in the kit along with dimensions for all the cuts.

The lower temperature are very cool less than 170F. Slab or cement block will work.

The barrel caps are 3000F heavy cast refractory, that are reinforced.
4 years ago