dacolson wrote: ↑August 5th, 2020, 12:21 amHow big is the gap at the seam? A lot of door related issues could be solved right here for you. Since it’s not welded, there is not stress on the metal so your door wont spring out of shape when you cut it. If your gap is tight right now, I don’t see why you wouldn’t use the seam as part of your door cut, other than looks. Personally, I’d probably put that seam at the back.
Help me understand why the firebox needs to be downsized? If I size my vent, opening, and stack according the calculator, I shouldn't have a flow issue, right? 24x16 would give me a firebox that is 100%. My thought is that at that size I am going to be challenged to get a burn basket in it that will really function. I would like to have room to put in a burn basket that I can have some room to move back and forth to really "tune" how I heat the chamber. I am only going off my previous experience with pits that I have bought. My trailer pit had an undersized firebox and it drove me nuts.Dirtytires wrote: ↑August 5th, 2020, 12:49 pmFirst off, welcome.
Secondly, a firebox that is at 150% is a BIG red flag. The numbers on the calculator are pretty stringent and ignoring them will lead to problems. Cut it down to 100-105%.
Most rolled steel has a certain amount of spring to it as well as “flats” at the beginning and end of the roll as the machine usually does not roll perfectly to the edge. Is your roll sitting with the edges perfectly aligned and touching at the edges? If not, you are going to introduce some energy when you pull the edges together to weld them. Secondly, how big are the flats? They might be better hidden on the bottom of the cook chamber.
Either way, put your ends on and weld (at least part of) your seam before you cut the door.
Thank you, Big T. I am a sales engineer in the commercial HVAC business so heat exchange and air flow is what I do for a living. I also don't believe in needing to recreate the wheel. If there is empirical evidence to support why something is done a certain way, that is good enough for me. Now I might just for fun break out the calculator and do some figuring to see if I can by my own means get to the same answers that the pit calculator does.Big T wrote: ↑August 5th, 2020, 8:15 pmThe ratio of the components are all based on volume. The cook chamber requires X amount of heated air to achieve the desired temperature range. Normally the FB is 1/3 the size of the CC and then you have the ratio's of the throat, baffle plate gap and exhaust stack. If you check out the pit calculator you'll notice that any time you change any single dimension, it changes all of the rest of the dimensions. If you're heating too much or too little air in the FB then it can lead to temp issues in the CC. Most pits that are designed with a calculator all run very similar, usually once you have a good bed of coals you add 2 small splits of wood every 45-60 minutes to maintain temperatures. With that being said, I have seen many pits with huge FB to CC ratio's and the pit master seems to manage just fine once they get a few cooks on it. I'm not an engineer or a scientist so I can't explain it in great detail but I hope this helps you to understand the thought process behind designing/building a pit. I've read that the first pit calculators were designed by a group of guys that were scientist and engineers, however I wasn't there so who knows. lol
That's correct, usually about 1'' between the shadow plate and baffle plate.
That is an excellent point. I will come up with a support to tie into the cart.Dirtytires wrote: ↑August 12th, 2020, 10:18 amYour firebox is gonna be heavy. Don’t think I would just hang it off the end...probably want a support under it tying it into the cart.
On the welding, you need to start your weld on the thicker material and only hit the thinner tubing briefly. I use a motion like a string of small circles or cursive letter e’s. Go slowly over the thick stuff the speed up over the tin. Good luck!USMC1995 wrote: ↑October 5th, 2020, 8:23 pmThank y'all for the feedback. I am thinking that I will take the door off and try to address it that way. I will also do the flat bar on it while it is off.
One of the biggest issues I am having is when I am welding something thinner to the tank. The tubing that I used for the hinges is at most 14ga. If I had enough heat to weld the 3/16 tank, it would just blow through the tubing. Any suggestions? Ultimately I would like to have some thicker walled tubing. What do y'all use?
Hogaboomer, is it the tires or the whole caster assembly? And I do have to admit that I did have two fixed casters, but in true moron style I welded the plate to the frame the wrong way. So I said screw it and put four swivel casters on it. Probably need to address that.