Patio Reverse Flow Build

All about smokers hot and cold
rustoration
Posts: 18
Joined: Thu Jun 12, 2014 9:49 pm
Location: Adelaide

Patio Reverse Flow Build

Post by rustoration » Tue Jul 21, 2015 10:12 pm

Howdy all

I've been lurking around the boards for a while but as I am about to embark on a patio reverse flow build thought i would share the process and perhaps tap into some knowledge along the way.

As a bit of background, I've been smoking for a few years on a UDS (generally fairly successfully), but felt like the time was right to join the stick burners, increase my smoking capacity and tech myself to weld at the same time.

And so the build starts here...

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Found this 250l compressor tank at a local machinery dealer, $120 delivered to the shed door. I've already made a bit of a start trimming off the excess compressor mount and a few of the pipe fittings to get a better idea of what i am dealing with.

Tank itself is approx 47cm diameter, 150cm long and approx 5.5mm thick. By my reckoning, I should end up with something like 1.2sqm of rack area, more than double that of two racks in the UDS.
Low n' slow... The art of bbq and classic VW's


rustoration
Posts: 18
Joined: Thu Jun 12, 2014 9:49 pm
Location: Adelaide

Re: Patio Reverse Flow Build

Post by rustoration » Tue Jul 21, 2015 10:35 pm

Next step (for me a least) was to come up with a decent design and play around with it in a CAD programme as I don't do so well with the whole engineering on the fly approach.

The design itself started with the best science I could find on the interweb which was Feldon's BBQ Pit / Smoker Calculator - http://www.feldoncentral.com/bbqcalculator.html - which seems to be regularly referenced by many USA builders and gets plenty of good reviews and feedback.

Once I applied my tank dimensions and pulled out the necessary supporting parameters (like firebox, air intake and chimney sizes) I used a free CAD programme to come up with a firm design with the intention of getting the necessary metal work laser cut in 6mm steel.

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The above is an extract from the final CAD file but this only evolved from spending plenty of timing sourcing / stealing ideas for my build from all manner of commercial and DIY builds I found on the web. Found loads of good ideas, ignored others and only used the ones that made sense to me.

Next step, getting a file off for laser cutting the parts.
Low n' slow... The art of bbq and classic VW's

beachbums
Posts: 1278
Joined: Sun Dec 05, 2010 5:51 pm
Location: Smokefireandfood.com

Re: Patio Reverse Flow Build

Post by beachbums » Wed Jul 22, 2015 3:18 am

Welcome to the board Rustoration. Love the look of your project. Will be following it with mucho interest. Good luck with the build and plenty of pics please. :D


Cheers, Wayne and Jan

urbangriller
Posts: 9453
Joined: Sun Sep 14, 2008 8:46 pm
Location: Perth WA

Re: Patio Reverse Flow Build

Post by urbangriller » Wed Jul 22, 2015 1:19 pm

Yep, keep em coming Rusty!

I've got one of them in the backyard at BBQ School!

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Cheers
Chris
Common Sense is so rare these days it should be a Super Power!

Dez
Posts: 66
Joined: Sun Jan 18, 2015 1:52 pm
Location: Adelaide Hills

Re: Patio Reverse Flow Build

Post by Dez » Wed Jul 22, 2015 3:02 pm

Excellent!
I love build threads. This one looks to be taking shape nicely. Best of luck with the build mate. I will be following this closely, so plenty of pretty pictures please.
I tell ya though, id rather engineer on the fly than teach myself to weld on the fly. Make sure ya got plenty of scrap lying around to dial in your settings on. So only your best welds are on the smoker and your crap ones are in the steel bin.
Cheers.
Dez

rustoration
Posts: 18
Joined: Thu Jun 12, 2014 9:49 pm
Location: Adelaide

Re: Patio Reverse Flow Build

Post by rustoration » Sun Aug 02, 2015 6:47 pm

So I can't really take much credit for the next step other than a few emails and picking up some smoker parts from the laser cutters.

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One thing worth pointing out, if you are going to get some stuff laser cut yourself, get two or three quotes. For the what I had done, cheapest quote (which I went with) was approx. 40% less than the most expensive.

Everything that I have had cut is in 6mm steel and for the smaller parts I've labelled them in the photo. Unless you want to claim hand made for everything, laser cutting is great.
Low n' slow... The art of bbq and classic VW's

rustoration
Posts: 18
Joined: Thu Jun 12, 2014 9:49 pm
Location: Adelaide

Re: Patio Reverse Flow Build

Post by rustoration » Sun Aug 02, 2015 7:07 pm

And if I haven't said enough about laser cutting already, the value is in getting parts cut that pretty much just fit. In the photo below, I've had to fettle the openings a bit but those small repair blanks are all in place and ready to go with not a whole lot of effort.

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I was given some advice to V the joints to help with weld penetration given the steel thickness and my welder is in the DIY category. Anyway, before I welded it looked like this...

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After the weld it looked like this...

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And after some more prep, welding and grinding it looked like this...

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I really don't know if those welds are OK or not (thoughts Dez) but hey, in the end it's only critical that the meat gets smoky and tender.
Low n' slow... The art of bbq and classic VW's

urbangriller
Posts: 9453
Joined: Sun Sep 14, 2008 8:46 pm
Location: Perth WA

Re: Patio Reverse Flow Build

Post by urbangriller » Sun Aug 02, 2015 8:08 pm

I'd be happy if my welding was like that! :oops:

Chris
Common Sense is so rare these days it should be a Super Power!

chrisg
Posts: 782
Joined: Mon Oct 28, 2013 7:21 pm
Location: Perth WA

Re: Patio Reverse Flow Build

Post by chrisg » Sun Aug 02, 2015 8:30 pm

:)

Yeah....

I stay away from welding because my kid bro puts me to shame every time, so I just get him to do it but yours looks pretty damned good - better than I'd ever do :)

Cheers

Dez
Posts: 66
Joined: Sun Jan 18, 2015 1:52 pm
Location: Adelaide Hills

Re: Patio Reverse Flow Build

Post by Dez » Thu Aug 06, 2015 5:33 pm

I'm jealous.
Those laser cut pieces look amazing. How much was it to get em cut? If you don't mind me asking that is.
Welds look good. Wont have any dramas there. MIG is the way to go. Are you planning on grinding all the main welds off?
This thing is gonna be a beast, love it.
Keep up the good work.
Cheers,
Dez

rustoration
Posts: 18
Joined: Thu Jun 12, 2014 9:49 pm
Location: Adelaide

Re: Patio Reverse Flow Build

Post by rustoration » Tue Aug 11, 2015 10:48 pm

Dez wrote:I'm jealous.
Those laser cut pieces look amazing. How much was it to get em cut? If you don't mind me asking that is.
Welds look good. Wont have any dramas there. MIG is the way to go. Are you planning on grinding all the main welds off?
This thing is gonna be a beast, love it.
Keep up the good work.
Cheers,
Dez
Hey Dez,

I'm not sure you've got anything to be jealous about after checking out your build. Laser cutting inc materials was just shy of $250 which i was pretty happy with. Not sure how pretty all of the welds will end up, definitely clean up the ugly / most embarrassing ones for sure and see how we go.

Cheers, Jon
Low n' slow... The art of bbq and classic VW's

rustoration
Posts: 18
Joined: Thu Jun 12, 2014 9:49 pm
Location: Adelaide

Re: Patio Reverse Flow Build

Post by rustoration » Tue Aug 11, 2015 11:01 pm

Back on the build, not much real progress to report other than setting up for and making the first cut for the smoker box lid. One piece of advice that i took on board for this step was to just cut the top edge of the smoker door before welding on the hinges and then cutting the rest of the door.

After measuring, thinking and measuring some more I strapped a 4x2 to the tank on the top centre line to use as a guide for cutting the top edge with the angle grinder.

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The guide worked out fairly well, not a perfect cut but pretty happy overall. Next step is the prep to weld on the three hinges ...

Image
Low n' slow... The art of bbq and classic VW's

urbangriller
Posts: 9453
Joined: Sun Sep 14, 2008 8:46 pm
Location: Perth WA

Re: Patio Reverse Flow Build

Post by urbangriller » Wed Aug 12, 2015 10:03 am

Wow....those hinges look great! I need to get some Lazy Cut for mine! Do you have the file they used?

Cheers
Chris
Common Sense is so rare these days it should be a Super Power!

rustoration
Posts: 18
Joined: Thu Jun 12, 2014 9:49 pm
Location: Adelaide

Re: Patio Reverse Flow Build

Post by rustoration » Wed Aug 12, 2015 9:12 pm

Hey Chris, like the lazy cutting reference, sums it up in one.

Anyway, i designed a couple of hinges for the smoker, one for smoker lid which suits 47cm diameter cylinder and another for the fire box door which is a bit more upright.

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For both of the hinges, I've used 12mm stainless bolts and penny washes to put them together as follows.

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Happy to share the cut files, just can't find a format that will attach to the board or photobucket. If anyone wants it, send me a message with an email address and i will send it on.

Cheers, Jon
Low n' slow... The art of bbq and classic VW's

urbangriller
Posts: 9453
Joined: Sun Sep 14, 2008 8:46 pm
Location: Perth WA

Re: Patio Reverse Flow Build

Post by urbangriller » Thu Aug 13, 2015 11:11 am

The fittings look fantastic Jon, and I know they are going to fit my tank as it is identical (even the colour) to yours.

PM Sent!

Cheers
Chris
Common Sense is so rare these days it should be a Super Power!


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