Is there a market for a 1kg DIY drum roaster?

[HV_MAN]

Re: Is there a market for a 1kg DIY drum roaster?

Sorry, back on topic... Which air flow 1 or 2?

Neither.
I dont know of a roaster that sucks the air through a fan, they all blow it and you will have to get the chaff out of the drum (else you will toast/smoke/burn it).

Nice clear drawings though!

Hi Andy, mmmmm.... blow or suck = same air movement through roaster/drum = chaff out of drum.....

From the small selection of roasters Ive seen they utilise low pressure burners bar type which heat the drum and surrounding air I dont recall seeing fans between or in front of the burner chamber forcing the air into the drum what I have seen are the 2 options Ive described both drawing air thought as apposed to blowing. I could select an air blast burner but I would then need to put a heat diffuser in to even out the heat distrubution on the Drum and these typically work at alot higher temperature than were after for coffee there mainly used in kilns etc

The pic below is typical of a 3kg roaster 1st motor drives the drum 2nd the fan/blower (which suck in this case) and the 3rd for the bean cooler and 4th for the bean cooler fan

Links to the pdf of some small roaster joper 3kg and joper 15kg which show some basic layouts, this arangement is like my ver 2 and also like poundy

[HV_MAN]

Re: Is there a market for a 1kg DIY drum roaster?

another view

[HV_MAN]

Re: Is there a market for a 1kg DIY drum roaster?

My only comment is that they are there for a purpose. Would be worthwhile for you to take a look at some other make designs if possible.

Hi Dennis, What is the diameter and length of your drum?

Looking at the position of the screw which sits in the middle of the drum it would only contact the beans during very large bean loads near capacity of the machine, a 1kg load I dont think it would service purpose.


People are most welcome to post pics of the inside of their drum

[HV_MAN]

Re: Is there a market for a 1kg DIY drum roaster?

Ive toyed with the idea of building a small "commercial like" roaster in the past.... but because of the engineering difficulties.... gave up on the idea.

As Dennis points out above, many of the features in these quality roasters are there for a purpose.... and to duplicate them is both difficult and expensive. Whilst I believe is possible to make something like a HT at home (Im not sure if even that can be done cost effectively) we are talking about a relatively simple roaster and a small volume of beans...... and a principle which cant just be scaled up to make a 1.5KG roaster.

The serious roasters are seriously heavy, using expensive materials and close tolerances in their engineering.

Im a firm believer that anyone can do anything that another person can if they put their mind to it.... so Im sure such a unit can be built..... Im just not sure how cost effective it will be - especially if only being made in relatively small numbers. Just look at the engineering of those drums.... that is some serious work.... and expensive to have manufactured..... and the design of the drums will have a lot of effect on the quality of the roast.

There is certainly a demand for a cheaper roaster...... Im just not sure how practical it is to make one for a reasonable price.

The engineering side of this is allot easier than one thinks, this is how I plan to make the drum for the prototype
(for the end production runs Ill probably get a fabrication firm I use to smack them out in batches)

The main part of the drum will be made of steel tube off the shelf (currently looking at available sizes & grades to suit our application )
All the internal bits, eg agitators, support spokes etc etc will be laser cut from steel plate from my supplier. I basically email him a autocad drawing he loads it into his cutting system and BAM I had all the bits precision cut to size... (some suppliers offer this as a free service but I suppose it depends who you know)

Most important part is aligning the spokes to ensure the drum runs true and then weld in all the agitators in place etc
I can weld very well a skill I picked up from my trade background and have fabricated many things over the years.
I have access to large MIG welders at work which I can use when their are not in use.
Special care & preheating has to be taken when welding all the bits to prevent distort of the tube

If needed the screw can be added later however I dont think it need for this size roaster and is additional cost

Basically nearly all the components will be laser cut from steel plate / sheet with the layouts optimized for as little waste as possible. even screw/bolt holes are cut by the laser, all I have to do is run a tap through them to add the the required thread etc

[Wine_of_the_Bean]

Re: Is there a market for a 1kg DIY drum roaster?

Youll certainly be doing no more than tacking to reduce the distortion.

Looks like fun manufacturing the things. Was heavily into metal fab/welding in high school. All I do now is make coffee :P

[HV_MAN]

Re: Is there a market for a 1kg DIY drum roaster?

Just a quick update...
I havent had much free time this week. however I did catch up with a some tube suppliers I soon I decide on the grade and thickness of the tube for the Drum and should have either a small off cut or 6M length of it by the end of next week

Craig A

[Ray_C]

Re: Is there a market for a 1kg DIY drum roaster?

Intently watching this thread with great interest...... Ray.

[martybean]

Re: Is there a market for a 1kg DIY drum roaster?

HV_MAN, You might want to use S/S grade 310 or 321 to fabricate any parts that get very hot, because if you use steel you will get mill scale coming off the steel, in the heating and cooling process and possibly ending up in your beans.
The Lincoln Arc welding book will be a good advantage if your not sure what types of steel are available or use Atlas steels website.
Distortion will be a problem it always is when heat is involved, so when fabricating your parts the use of a tig and a mig welders would be handy.
Goodluck HV_MAN.

Marty

[HV_MAN]

Re: Is there a market for a 1kg DIY drum roaster?

HV_MAN, You might want to use S/S grade 310 or 321 to fabricate any parts that get very hot, because if you use steel you will get mill scale coming off the steel, in the heating and cooling process and possibly ending up in your beans.
The Lincoln Arc welding book will be a good advantage if your not sure what types of steel are available or use Atlas steels website.
Distortion will be a problem it always is when heat is involved, so when fabricating your parts the use of a tig and a mig welders would be handy.
Goodluck HV_MAN.

Marty

Thanks Marty
You have just hit the nail on the head, scaling is one if my main concerns with steel and the info Im waiting on before making my decision pends on this.
Problem with SS is it poor heat performance but I support you just crank up the burner to compensate 8-)

Ive basically requested what material/grade ( preferably a food grade) is stable=(no warping, scaling, loss of strength) with continuous heat cycling from ambient to 300 degC. see what they come back with.

MIG will be the first choice, TIG is there as an option but Ive only used it on AL a few times...

Craig A

[martybean]

Re: Is there a market for a 1kg DIY drum roaster?

In my experience H_VMAN, the use of food grade at 300 deg tempretures may lead to cracking, but these grades are great with corrosion and weldabilty.At work we use grades 310 and 321 on our heating elements to heat up 1000s of litres of bitumen.Also the availabilty of these steels is always a problem

[Sparky]

Re: Is there a market for a 1kg DIY drum roaster?


Is there a chance that deposited coffee oils will help to prevent scaling in the drum?

[martybean]

Re: Is there a market for a 1kg DIY drum roaster?

Sparky, mill scale is a form of corrosion and refers to the scale you get when the steel is new and comes from the mill, as you heat or cut the new steel, say with oxy acetlylene cutting a thin layer of steel flies off.
This also occurs with constant heating and cooling of steel,{much like the cast iron burners on a BBQ} whether coffee oil would prevent this I couldnt say, but using the correct grade of stainless steel certainly would.

[seedlings]

Re: Is there a market for a 1kg DIY drum roaster?

I want your project to be a flying success, Craig!

I am VERY interested in the theory in your designs, but to me this seems eerily similar to a reinvention of the wheel. The only exception is the goal of a sub-$1000 price point. That being said, your competition will be the BBQ grill setup. The price conscious home roaster will likely shy away from a $995 machine, while the flexible spender can pull the trigger on the already available $3k model wihout much hesitation. You may be targeting a narrow niche of customers, which tosses profit out the window. However, if youre not-for-profit, than this may be a noble cause.

Id like to see a new new $1000 1.5 Kilo roaster design. One looking nothing like the traditional drum. Why not a "Corretto Professionale"? One could easily design a corretto-style roaster, PID, cooler for considerably less than $1000, right?

In theory, theory and practice are the same. In practice, theyre different.

CHAD

[Sparky]

Re: Is there a market for a 1kg DIY drum roaster?


The cheapest commercial roaster on the market here is a fluid-bed roaster that roasts 600 gm of green and costs around $6k. The cheapest drum roasters in the 1kg range are around $8k. IMO any decent roaster that can handle 1kg and cost under $2k will have plenty of buyers.

It looks like Craig is doing this properly, so were all waiting with baited breath to see how he goes.

At least thats my take on it.

Cheers,

Mark.

[HV_MAN]

Re: Is there a market for a 1kg DIY drum roaster?

Hi All, Ive been extremely time poor for the last couple of weeks. SS is looking to be the drum material for the prototype.

Just to clear up my motivation for this project.
Im not doing it for the money
Im doing it basically for us coffee snobs and fellow coffee addicts
Some of us like the agressive DIY projects other want a more polished setup.

My plan as shown in my first post it to produce a roaster that is upgradeable over time.
An initial cost of around 1k for the core roaster is probably the limit for most of us, the other bits eg bean cooler and advance control stuff etc can then be purchase later on as needed or $ permits.

I just want to make it solid and as cheap as possiable but with the feel and performance of an 8k drum roaster.

Cheers
Craig A