New member, new build

[aquamike]

Hi guys,

I've been reading here the last couple days and love all the great information available! I've got a couple questions.

I have a 100lbs propane tank that I'm getting ready to cut. I have limited tools but did get myself a decent 4.5", 11A angle grinder that I'll be doing my cutting with. I've already purged the tank with water then soap and water several times. The tank has a small hole in one end, maybe 1mm, but that's where I'll be cutting off to attach a firebox so no concerns there.

First question is about making the top cut for my lid. I can mark a pretty close line and I understand the trigonometry in how to calculate the exact locations of the endpoints of the cut but actually marking those in practice is a different story. Are most of you guys just eye-balling/free-handing a cut like that?

Next is the welding. Part of wanting to build a smoker is to have a project to teach myself to weld. I'm really running into sticker shock with welders though. There are some decent looking machines out there for fairly cheap but they cap out at 90amps. I'm concerned this won't be enough to get proper penetration on a tank of this thickness. Really have a hard time finding/picking something.

The smoker doesn't need to support a truck driving over it but I don't want to have to redo anything, either.

My wife suggested renting a welder but it looks like they're mostly ~$100/day or $300+/week. For $300 I can buy a decent machine; I was just hoping to get away a bit cheaper than that.

I'd love to hear some thoughts or recommendations. Thanks!

Mike

 

[brnhornt]

First....welcome!

I did my build with an angle grinder and cutoff wheels. It's long and painful...but works. I did all of my cuts free hand, but definitely followed lines I drew using straight edges/etc. No way I'd trust or try eyeballing.

As for the welder...have a harbor freight near you? Got an electric dryer within a reasonable distance from where you want to weld? If so...don't overlook a 220V stick welder....I had no problems getting good penetration on my 3/16 inch steel...

Good luck and be sure to post pictures as she comes along!

 

[aquamike]

Thanks for the recommendations and info. The 225 sicks they have calls for a 50A circuit, my dryer is on a 30A. :-/ I've read it will still work at lower output but at $200, I'd rather spend the $50 more and get a Lincoln refurb. I talked to Lincoln today and they suggested trying their 225 on a 30A would probably pop the breaker.

I found someone today who is willing to do the welding for me. I'm not stoked about doing it this way because I'd rather do it myself but with no other welding projects or ideas, I think that's the course I'll take for this one.

I actually made some cute today with an angle grinder. I did the same as you: free-hand but with a straight-edge drawn line. It worked alright. I got the top and sides of the door cut and started cutting the ring off the bottom. Not sure if I'll be able to get any work done after I hey my kid down tonight or if that would upset the neighbors too much.

Here's some pics of the tank and preliminary drawings. The legs are too short--target is comingc grate to be ~36". And I think the firebox will actually be 12x12x16

 

[brnhornt]

Gotcha...know that all the welders want 50A...but all I can say is that I welded all day on dual 30A and never popped once...

Looks like a good start...!

 

[gmc2003]

Aqua, is there a tech ctr. at a local high school that teaches welding, and offers adult education? You may be able to enroll and use it as class project. Just a thought.

Chris

 

[aquamike]

Didn't realize that about all welders! Would have been nice to know. I actually found someone to help me for a reasonable price. I'm eager to get the project done because out second child is expected in 2 weeks!

As far as classes, I'm currently a career changing student so, other than this semester with no classes to focus on family life, am taking a full load of classes already in mathematics so additional classes are not feasible.

 

[brnhornt]

Sorry...I shouldn't have said "ALL" welders. I meant in reference to the stick machines that I was looking at. Not literally all.

 

[aquamike]

Yea, I know what you meant. Thanks for clearing it up.

I said above I found someone to help me but I had to cancel with them; I just don't like the idea of paying someone to do things like this for me especially when it's a skill I want to learn. I ordered a Lincoln stick welder today. If my dryer outlet can't handle it then maybe our plan of upgrading our 70+ year old electric service will be moved forward a bit. ;)

I also ordered all my steel for the firebox today. I went by the scrapyard first but didn't see anything I liked so I ordered what I need to make a 16" (internal) cube. Due to price, I ordered 1/4". I know that's on the thin side but should still be better than a cheap store bought smoker, I hope!

 

[brnhornt]

You'll likely have to do some creative wiring as the welder might have a different plug than what your dryer outlet is.

 

[aquamike]

Yea, looks like it's a Nema 6-50p. Will double check, but I know my dryer cord is not that; pretty sure I don't have a multi-style receptacle, either. So instead of being creative, I think I'll just get an adapter. Thanks for the heads up on that.

 

[brnhornt]

No problem. Good luck and enjoy welding! I found this site very helpful as I was learning:

http://www.weldingtipsandtricks.com/

 

[aquamike]

Thanks! I'll check it out. I picked up three books from the library today, too.

I've got a design question/issue to think over regarding the chimney. My original plan was to just cut a 4" hole in the end of the tank to accommodate the stack but I'm wondering if this will have adverse impact on airflow/convection throughout the cooking chamber. It looks like Franklin (had his book a couple years; love it!) cuts basically a rectangle off the end then creates a box that tapers away from the cooking chamber in a triangular shape before reaching the chimney. I'm wondering if this is just because it makes supporting the pipe easier or if it has better airflow characteristics.

I don't want to short-circuit my chamber and obviously the aim is for the most even temperature gradient throughout the cooker possible without using tuning plates or reverse flow. I'll have a deflection plate welded on immediately above the firebox opening but otherwise, it's open chamber. Any thoughts on the stack connection?

 

[aquamike]

Around my terrible sleep schedule from caring for our 1 month old boy, I've made a bit of progress! There was some learning curve to figuring out how to use a stick welder because I've never welded before and then getting the right rod has made a huge difference. The hinges were welded on with 5/32" 6011 which was nasty and way too big but I could lay anything down with 3/32" 7018. Luckily, I'm finding I can do alright with 1/8" 7018 so that's what the heat deflector and back of the firebox are attached with. I'll likely ultimately go back and clean up the hinges once I get better with the welder.

The last 3 pics, the tank is upside down so I could access things well to weld.











https://imgur.com/N6RWkhy

https://imgur.com/YBkzbcw

 

[Lonzinomaker]

It looks like you found a 30 amp welder. I have one just like it that is about 20 years old. You should be able to weld anything you need for your bbq with that.

 

[aquamike]

Nah, it's 50amp running on a 40a circuit. Fortunately, I'm not running anything near capacity; 66% load is as high as I've taken it and the rest of the smoker will likely be closer to 50% since I've been able to use smaller rod.

 

[Gmwelder86]

Good progress on the build. Understand the struggles of a new born have a 9 month old and I am fortunate she’s a pretty heavy sleeper. Anyway I am a pipe welder by trade and instructor for welding at my union hall. Try 3/32 7014 it runs similar to 7018 but doesn’t have the issues with moisture that 7018 can. Although not critical for a smoker build 7018 should be kept dry. If you have an ac/dc machine make sure your running on dc the arc is much more stable. Only time ac has an advantage is on aluminum or magnetized metals. Might also not hurt to pick up some scrap to practice on before you start laying beads on a finished product.

 

[aquamike]

Thanks for the recommendations. I figured 7018 is fine because this isn't a lot bearing structure and so it's not critical that low humidity be maintained on the rods.

My buzz box is an AC only unit (way cheaper!). I di buy some scrap but after playing with that for a while, I got bored and eager to get to work on my project. The welds are ugly but this is almost as about teaching myself to weld as it is building a smoker.

I've got some more work done on it but haven't been able to hey any photos; mid this coming week probably.