2x6 arch build

[Bricklayer]

I'm getting all my materials ready to build a new 2x6 arch during the summer/winter. I have all 2x2 3/16 angle for the frame. I am not a welder but can do it if I take my time. is there a certain rod I need to use for the high Temps this thing will see? I have a mig welder but can borrow an arc welder if need be. Is mig ok? Only pan I have right now is a 2 x4 flat bottom pan but want to eventually get a drop flue pan and a syrup front pan. That's why I'm going 6' with it. What is the bearing of the pan? 1" all around ok? I'm going to make the unit 1.5" larger on both sides to account for the arch board and fire brick. So I might have to go with bigger stock for the top to bear pans.

[Super Sapper]

http://mapletrader.com/community/showthread.php?8805-2x6-homemade-arch/page7&highlight=divided+pans
This tread will give you and idea dimensions. A mig welder will work fine and 3/4 to 1 inch under the side of the pans will hold it up fine.

[lpakiz]

Keep the outside width of the side rails to about 26 1/2 MAX! Factory made flue pans need no more than this so that the connector ferrules can clear the side rails.

[VTmaplehobby]

Your MIG welder will work just fine, If you did want to stick it 7018 rod is what I would use, has to be very clean though.

3/16 mild steel will be plenty for load, can't really see any reason to go bigger. Just my 2 pennies.

[Bricklayer]

I asked before if mig welding my arch together would be OK. I call my welder a mig but it's a Flux core wire welder. It can be a mig welder if I had gas but have never had it set up that way. Seems to work ok without it. For my 3/16 welds should this be good? I'm going to weld both sides of all welds. Talked to a guy at work today and he said my little welder won't have enough heat to weld 3/16 properly.

[Super Sapper]

It will do just fine, I use flux core and it will do 3/16 without a problem. The gas gets less splatter and allows you to weld thinner metal but doesn't like wind very much.

[BreezyHill]

BL, I have had two migs and on the farm and in the feed mill I never use gas. I have been using migs for over 25 years and never an issue. From small jobs like welding a reclaimer out of 15# propane tanks to 1/4" plate on a feed trailer boom.
Currently I have a miller 150 portable...portable if you don't mind lifting 145# machine with one handle.

Turn it up to 6 on the power and adjust the wire fed to 90% and you can do 5/8" butt welds on plates.

For fixing items on Breezy Hill cored wire is the only way to go. Friend was the MG store manager and when he sold me it he thru in the bottle of gas and loaded it with flux core and said here is the small spool of wire for the gas...try it you'll hate it. Boy was he right! The gas does make your tips last longer. Silicone blue goo helps to cool the tip. dip in and leave between passes and dip a new tip heat it up and dip again for 5 seconds or they will plug with spatter.

I have a 2x6 air tight grimm and want to do AOF add on. I have a large Chicago fan that will feed AOF & AUF, 18 x 7" fan Old sawdust collector fan from a cabinet shop. It would suck 5 machines all running together. I need to get more boiling rate out of the machine for next season or it will be new evap time.

Let me know how you make out.

Ben

[jmayerl]

I taught myself to weld by making my 2x7 arch with a $90 flux core welder from harbor freight. Just saying!

[Bricklayer]

Since I will probley only be using my 2x4 pan on it for the first season should I place it to the front right above the firebox or to the back. I plan on just tacking a thick Guage steel plate to cover this opening for the time being. Almost act as a stove top. Can probley use it as a preheater somehow.

[Bricklayer]

Made up my mind. I'm going to get a 2x4 smoky lake hybrid. Maybe even a 2x5. Fell in love with it after seeing my friend using one. Amazing pan. His is a 2x6 so I will need to get some dimensions but what a great piece of equipment.

[Bricklayer]

Anybody have a smoky lake hybrid on a homemade arch. Just wondering what width I should make the arch to accommodate 1" arch board and 1" firebrick. Is the pan exactly 24"? I want to leave about 3/4" on front and 2 sides. Back will not have bearing because of the flues being flush with back.

[Ghs57]

Since I will probley only be using my 2x4 pan on it for the first season should I place it to the front right above the firebox or to the back. I plan on just tacking a thick Guage steel plate to cover this opening for the time being. Almost act as a stove top. Can probley use it as a preheater somehow.

I'm running a 2x4 pan on a 2x6 arch. i covered the back 2' with a quarter inch steel plate. Looked great, worked terrible. The plate bowed down in the heat and pulled out the lags holding it in place. it took every pipe clamp I owned to hold the plate down. it also did not work well as a preheater. If I were starting over, I would make a 2x4 arch or get a 2x6 pan. Probably the latter, which should have given me more gph. I have not yet decided what I will do for next year.

Just saying...and your mileage may vary.

[Bricklayer]

I'm gonna build it for the 2x4 pan. If I ever need to extend it I will.

[Stu007]

Hi Bricklayer,

You will love your 2x4 hybrid pans. The pans are exactly 24" wide. If you are using your 2x2 angle then your max outside width should be 25-1/2". It won't matter much with the hybrid pan but if you upgrade to separate flue-syrup pans you will need the outside clearance for the sanitary fitting clamps. There is no need to have the front or back sitting on the top rail. I suggest you look at the front of some larger commercial rigs and take notice of the angle that is usually turned up to seal the front and back pan then copy. It will keep the heat in, the cold out, and hold your pan in place.

Good luck!

[Bricklayer]

Should I put a seal like a rope style gasket like a woodstove door has around the perimeter where the pan sits and where the angles on front and back snug up to the pan? I was thinking of slotting the angles and using a bolt so I could have some adjustment in the angle on back to tighten it up to pan and when it needs to come off I could loosen the bolt

[Newbie18]

I am thinking about putting a piece of angle iron on the inside of my home made evaporator so that I can recess my pans a bit into the evaporator. Any thoughts?

[chad]

I use a rope gasket on mine where the fire seeps out and flat gasket under to level the pan if the frost has moved the footings.

Should I put a seal like a rope style gasket like a woodstove door has around the perimeter where the pan sits and where the angles on front and back snug up to the pan? I was thinking of slotting the angles and using a bolt so I could have some adjustment in the angle on back to tighten it up to pan and when it needs to come off I could loosen the bolt

[Bricklayer]

I'm going to attach the skin (16 ga) to the angles with spot welds every 3 inches or so. Is there a need to use a high temperature silicone around the perimeter? The highest temp one I can find is 600f. And I have used that stuff before and it stinks like hell when you heat it up.

[bkeith]

No chance that the silicone would survive. I'm considering kiln cement or muffler cement for some small gaps on mine.

http://www.tuckerspottery.com/tkps/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=1584&category_id=171&option=com_virtuemart&Itemid=1

[Pibster]

I riveted my skin every 2 or 3". It worked great until I decided to add AUF. I had lots of smoke leaks when the fan was turned on. I tried using high silicone between the skin and the angle iron, it helped some but did not completely stop the leaks.

[Bricklayer]

I would assume it would be pretty air tight if you used refractory cement on the arch board joints and also on the fire brick.

[Bricklayer]

Is there a certain size the stack at the rear of arch should be? I'm going with 8" flue size. I was planning on going 24" wide x 12" deep and 36" high tapering off to the 8" flue pipe?

[Bricklayer]

Do those measurements seem right?

[Bricklayer]

Finally getting around to building this arch
For a 2x4 pan setup what is a good size of fire box? I was thinking of making it 24x24 just in case I ever wanted to add on to it. I'm going to use a Vogel Zang barrell stove door for the door. I've had it for years sitting in my garage doing nothing. So it should work out good. Hopefully can hold up to the heat.

[Ghs57]

24 deep would be good. I made mine a little shallower, and now wish it was deeper. I used a barrel stove door also, but be sure to insulate it well. I used 1 inch ceramic insulation board. Before that was done, you could not stand in front of the evaporator. The door was almost glowing.

[Bricklayer]

My arch board and fire brick leave about 1/2 inch of rail exposed inside the arch. Will they warp if not protected? I was thinking of tucking 1" or 1/2" fire blanket in behind the arch board and bending it over the rails and it doubles as a pan gasket? Will that work? Or is that 1/2" exposed not a problem?

[maple flats]

I had about 1/2-3/4" exposed when I did mine, then I just troweled refractory from the face of the brick out to the edge of the angle iron. That has worked fine for the last 7 seasons. It tapers out to the edge of the angle iron at about a 30 degree angle.

[Bricklayer]

That's what I was thinking of doing. I'm a little ways away from bricking it but just trying to plan ahead.

[Bricklayer]

Started welding my arch together today. Just a quick question about the arch rails. Is there a certain type of joint I should do on the 4 corners connecting to the legs. My idea was to 45 the angle iron and then butt to 36" legs to the rails. I've looked on ever arch build post here and can't seem to be able to zoom in far enough on any pictures to see how others did it.

[Super Sapper]

That's how I did mine.

[Bricklayer]

Just tacked it but I'm just going to butt the legs to it. Went 2x3x 3/16 for the top rails. Got it for free so why not

[maple flats]

On many older commercially made arches, they just overlap and weld. The pan gasket takes up the difference in elevations. My 3x8 arch and my previous 2x6 arch had overlap joints. The front and back was over the side angle at that weld.

[Bricklayer]

I thought about doing it that way but decided just to take the time and make the rails flush. im basically trying to copy all the ones ive seen pictures of on this site.

just noticed my picture of the rail corner is upside down, must be because I posted it with my phone, weird

[Bricklayer]

Ive got the firebox all done. 24"x24" will be the inside measurements after the insulation and firebrick is in place. I've seen a couple arch on this site where the transition from the firebox to the ramp is not angled. I've made the back of the firebox 90 degrees and the ramp straight not angled. I've spent hours in with the door open watching my friends evaporator run and it seems like the flames follow the ramp and never touch the pan. We put firebrick to square off the back of the firebox and the flames hit the pan better and 90 right over it. So this is what I'm going to try. Should work right? I will post some pictures when I figure out why my pictures get posted upside down. Will try to get that fixed today.

[maple flats]

I think you want some ramp, but maybe not as much as the older arches had. I reworked mine when I added AOF, I raised the back wall to just 5" under the bottom of my raised flues, after placing the back wall air nozzles at 6" down. The arch still looks like it has the original ramp, but behind the wall, I filled it with vermiculite and capped it with flat half bricks, maintaining the original angle, so now my ramp is higher and maybe 1' shorter, front to back. I get a great boil.
What you describe is usually how a half pint is bricked, but that has no distance behind the wall, it simply drops to the bottom of the arch and then exits via the stack. You want to drive the heat up, not choke it off.

[Bricklayer]

When I have the drop flues in the entire distance will be about 2 " down from the flues from front to back with my setup. Right from the firebox. I'm making the transition stack 24" wide by 10" deep using a 8" pipe. So it should get a good draft.

[maple flats]

Too much space. You want the heat to get pushed up. About 1/2" space is max under the flues, behind the short ramp. On mine I have 1/4" under the flues.

[Bricklayer]

I was leaving room for 1 1/2 " fire brick incase I wanted to brick it eventually. I can always put 2 sheets of the Roxul IS board I'm using. It's 1.5 " also.

[lpakiz]

I agree with Dave, you want the insulation/brick to be just about touching the undersides of the flues. 1/2 inch is perfect.
You want almost all the flames up into the flues, but you want to expose the narrow bottom of the flue to the heat and fire too.
You can start out several inches below the flues at the start of the flue pan, but at some point in the length of the flue pan, you should force the flames almost all the way into the flues before you get to the stack.

[Ghs57]

Also agreed with Dave and ipakiz. Too much space = weak boil. I'm no expert, but found some problems with my home built arch this year. Too much space and the back of my pan will not boil. I have an angle on the ramp, but too much space between the brick the pan. I will be working on this over the winter.

[Bricklayer]

So as long as I have as little room as possible under the flues my straight ramp under the flues will be OK? I can get it to about 3/8 under the front flue. And that will stay the same right to the back where it transitions to the stack.

[n8hutch]

I have a vertical wall at the end of my fire box maybe 12" back from the front of my flue pan, then it is flat from there to 8" of the back of the flue pan where it can drop back down & go out the stack, my flat area is about 4 feet, like others have said, you want to be very close to your flues with the insulation or brick, I went flush with my arch rails with my insulation. I figure my pans gasket 1/2" gives me about a quarter inch of space once compressed.

[lpakiz]

Mine is 10 feet long, so the two designs here won't agree, but my flues hang out into the 42 inch long firebox, so the flues see flames right from the firebox. The back wall is 90*, but it starts out with about a 5 inch gap right above the back wall, then slowly transitions to 1/2 inch by the time it gets to the back end of the flues.
For the stack, I made a "stack base plate" from 3/16 flat metal. It is the width of the arch and about 12 inches, front to back. I cut it 14 inches by 26? and had the metal shop form a 90* bend on the front and rear, turning up 1 inch to form a real shallow U, for stiffness and anti-wrapping. Then I cut the hole at 6X20? and welded a 1 inch lip all around the hole, to keep the transition stack in position. The stack just rests on this plate then, held in position by gravity and the lip. The near lip is used to anchor the stack end of the flue pan when I tighten the jack screws over the door, which compresses both pans and creates a tight joint between the pans, and also the stack base plate flange.

[lpakiz]

Nate, are you describing a raised flue setup?
And I see in another thread where you have a question about air into your new airtight door.
If I were to build another INTENSOFIRE with both AOF and AUF, I would consider two separate blowers. Right now, AOF never gets adjusted, whereas the AUF (grate air) is adjusted several times per loading, to keep stack temps consistent. Currently, this is accomplished with dampers, but each time I adjust the grate air, it influences the air pressure of the AOF. Separate blowers would eliminate this.

[n8hutch]

Sorry I missed that it was a drop flue don't know how. Thanks for the tip on two separate blowers. I have an oil burner I was going to use for under fire air. & I still need to source my High pressure blower,

Either way be sure to account for the pan gasket material,

[lpakiz]

Nate, I think you're on the right track. Just about any blower will supply the air under and make it rumble and roar. It takes a special design to achieve pressure AND volume. Figure out a way to regulate each blower, although if there was a sure-fire calculator for the high pressure and you got it sized right, you wouldn't have to ever change it.

[maple flats]

An oil burner blower is a high pressure blower, use it for your AOF. Then you can get a simple squirrel cage blower for AUF. That will cost far less than having to buy a HP blower.

[Bricklayer]

So is there really any need to have from the firebox to the stack sloped? As long as I can get it within 1/2" of clearance under the flues it should be good?

[lpakiz]

The idea I operated under was to gradually "squeeze" the heat up and in to the flues. I would be concerned that if you forced the heat into the flues all at once, it might boil very hard at that particular point, and less farther down the line. This is just a guess, nothing to substantiate this. Hopefully someone with real experience will help out here.
I would add that the way mine is built, it boils very evenly from front to back, and I would definitely build another one the same way, using the same theories.

[Bricklayer]

So what's a good "slope". I ve got a little over 3' of run to work with before I have the stack. Would 4" below flues sloped to basically nothing work?

[lpakiz]

Yes. I would take advantage of that. Actually, it seems about perfect to me.
Whatever you end up doing, I hope you come back to this thread after the season and let us know how it worked.

[nymapleguy607]

Nate, are you describing a raised flue setup?
And I see in another thread where you have a question about air into your new airtight door.
If I were to build another INTENSOFIRE with both AOF and AUF, I would consider two separate blowers. Right now, AOF never gets adjusted, whereas the AUF (grate air) is adjusted several times per loading, to keep stack temps consistent. Currently, this is accomplished with dampers, but each time I adjust the grate air, it influences the air pressure of the AOF. Separate blowers would eliminate this.

I run into the same problem on my arch, I am switching out the dampers for blast gates, this will allow the air to be fully shut down. The dampers will always have blow by.

[Bricklayer]

I plan on working on it this weekend and getting all th welding done. I'm hunting this week so I'm away. Plan on doing a test boil on th rig before it get really cold so if there are miss t make I have time to fix.

[RileySugarbush]

So what's a good "slope". I ve got a little over 3' of run to work with before I have the stack. Would 4" below flues sloped to basically nothing work?

That should be fine with AUF. I think the more open slopes were more ikmportantfor natural draft rigs, so that abrupt changes didn't cause draft restrictions.

For what its worth, my home designed 2x6 ( AUF/AOF ) has only right angles, with nearly no space under the flue bottoms for the entire length. I get 40 to 55 gph depending on how I run it and it boils evenly for the length of the flue pan. I do run pretty high stack temps though, so not so fuel efficient, but I have lots of wood.

[Bricklayer]

What is a normal stack temperature for an arch just running AUF?

[RileySugarbush]

What is a normal stack temperature for an arch just running AUF?

I don't think you can define normal! If you really pour on the air, you can get very high temps, up to 1800°F with prob thermometer. Not very efficient, but real fast boil. That is one of the advantages of adding AOF. You can cut down the air under quite a bit, and add some air over to efficiently burn the combustibles before it is heading up the stack. All with less total air flow so longer residence time under the pans and less lost energy. A more efficient rig from a fuel use standpoint would have a lower stack temp, say 900 to 1000°F and would have a much slower boil at the back end of the flue pan and less evaporation rate.

[nymapleguy607]

Before the steamaway I could boil average 48GPH running a 1200-1300 stack temp. Did a few modifications to the area under the flue pan and now get a pretty hard boil through the entire flue pan. Running with the steamaway gives me 75-80GPH for the same 1200-1300 temp.

[Bricklayer]

Finally able to get some pictures posted. Still have to weld some angle under the firebox for the ash clean out and some at the bac for the stack. The firebox seems a little big but I think I will be happy with it bei bigger. This arch is for a 2x5 hybrid pan so it's 6' long. How wide should I make the stack transition where it comes off th arch. It will bee 24" wide by 8" deep th way I have I now. Is that enough? I'm going to turn a angle iron backwards to sit against the pan to hold it in place and create a 2" space between the pan and the stack. Skin is my next big project before I worry about doors and insulation grates etc. Is it OK to use galvanized sheet metal? I have access to 24 and 26 Guage galvanized sheets. Should I tac weld it or rivet it. Thanks in advance.

[Zucker Lager]

Hey Bricklayer:
I'm right behind you with my slightly smaller hobby build. I got 3/16 hot rolled A-36 for my sheeting and I'm going to just tack it in. I got sick from fumes from welding galvanized once so I'm kind of scared to use it anywhere it will get super hot. I'll post pics here too once I finally get welding. Your's looks great so far Jay

[Bricklayer]

Galvanized worries me too. Will probley pass on it and go with something I can just paint. Can someone comment on the stack size. I'm going to be welding it up sometime tomorrow.

[Ghs57]

Looks great. Nice work. I think the fire box size is right. That's just my option based on mine being too small. I had my house chimney guy look at my set up (2x6), and he said 6" would be fine. He had done chimneys on a number of local evaporators. I went with 8" and reduced the flue size of the stack base I bought (10") down to 8". I have plenty of draft at that size, and 6" probably would have worked just fine.

[Bricklayer]

They way I have it now my grates will be about 20-22" away from the pan. Should I decrease this or is it OK? I

[RileySugarbush]

They way I have it now my grates will be about 20-22" away from the pan. Should I decrease this or is it OK? I

That is exactly what mine is and it works fine.

[Zucker Lager]

Hey Bricklayer:
Quick correction on my last post I did 3/16 under my ash pan but the rest of my side walls and back etc are only 1/8" had a small mind block there. I did go heavy with the gauge hoping after bricking I'll have no warping. Jay

[Bricklayer]

I'm insulating it and bricking it. Got a good quote on some 20 Guage cold rolled today. 20 Guage ok?

[Zucker Lager]

Hey Bricklayer:
This is my first build too. I'm kind of a belt and suspenders kind of guy anyhow and usually go overboard with anything I'm making so I went with that 1/8 inch or just over 11 gauge. 20 gauge is about 1/3 that thickness BUT like I said I usually go way over board............is that like OCD? ha ha I will defer to the other guys on the site who have way more experience than I will ever have hopefully someone has a good input on the sheet size. I plan on insulating with both blanket and brick also. Wonder if you'll be using cement on your bricking or just dry stacking??? that is something I haven't decided on yet or if one is better than the other? Jay

[Bricklayer]

I will be using refractory cement (fire clay) on my firebrick. It's my trade. So that's actually the easy part.

[Bricklayer]

Couple things I'm trying to figure out
1. The angle that is turned around at the stack and sits up against the pan. Does it have to be protected with insulation? And the metal at the base of the stack ?
2. At arch front where door opening is. When I cut hole and put angle around it. Does that have to be protected also? It's a vogelzang door I'm using so it sits flush with the outside of arch.

[Bricklayer]

Stack started. It's all one piece. Can I just bolt it to the arch rails? Gasket needed? I've noticed in other members builds that some put an angle iron lip on the arch rails for the stack to fit over. I kind of got excited and forgot that step. Is my bolting down idea dooable? Sorry about the crapple pics. My phone is a piece of junk

[Bricklayer]

Anybody have any input on thread #68 & #69?

[psparr]

Just my 2 cents. Bolting will be fine. I would protect the angle. If your firing correctly then it will warp. As far as the angle around the door, insulate up to it.

[Bricklayer]

What's a good way to protect the angles at the stack base?

[psparr]

Screw blanket to it somehow.

[Bricklayer]

Google some pictures of factory arches, saw a smoky lake silverplate, and a Patrick Phaneuf evaporator that have a plate at the back of the evaporator that bolts to the arch and the base stack attaches to that. It looks pretty thick. I've got some 3/8 or 1/2" plate that I could weld my stack to then bolt it down. 3/8 wouldn't warp without being insulated would it?

[nymapleguy607]

Google some pictures of factory arches, saw a smoky lake silverplate, and a Patrick Phaneuf evaporator that have a plate at the back of the evaporator that bolts to the arch and the base stack attaches to that. It looks pretty thick. I've got some 3/8 or 1/2" plate that I could weld my stack to then bolt it down. 3/8 wouldn't warp without being insulated would it?

For comparison when I built my arch I used 1/4" plate, I welded bolts to the bottom and insulated with 1" blanket. I have ran 1500 degree stack temps and not had any warping issues.

[Bricklayer]

I ended up using a 1/2" piece of plate steel for the base of the stack. I'm going to weld an angle to the front to rest against the pan. Maybe cover the under side of it with 1" blanket also and curl the blanket into the first 12" of stack to protect it.
The door I salvaged from an old wood furnace is 13" x 13". It's double walled and has insulation in it already. I'm going to attach 1" blanket to it and install rope gasket around the flange to seal it up. The way I have it now the firebox is 27" high. I've just got the sheet of steel sitting in there now. I screwed up my measurements. I was hoping for 19-20" from grates to pan. Can I leave the bottom the way it is and insulate it and build it up with firebrick to my desired height and set my grates on that? I will end up having about a 6" ash door. I'm using a squirrel cage blower for AUF. No AOF for this year.