I am a home shop guy and my primary welding experience is with TIG, though I would not claim to be great at it. I am working on building a horizontal draft tube for a blacksmith forge from 3/16" 304 stainless plate. The tube goes through the wall of the shop and supports the chimney pipe. I have the plate cut and edges are beveled for welds. I’m planning to use 1/8” ER308L rod. I’ve recently gotten the 30x60 Fireball fixture table & table kit #3 and am thinking through just how I’m going to clamp and weld this, so to that end I’ve made some drawings as I think about it.
I mainly do much smaller welding in steel (making tools and sculpture) so this is a bit of a challenge & I’m looking for feedback or guidance from those with more experience. I’m concerned about controlling distortion & not sure just how much of an issue that will be (again my lack of experience). I’m thinking that I’d start by using the table’s edges and clamp 3 of the plates to tack. Next I can use the opposite edge to get the remaining 2 plates tacked. I think the welds will want to pull the corners out beyond 90º so my thought is that I should just tack until I get the whole structure together and then carefully use alternating or stitch welds. Or, should I stitch weld the joints while clamped to the table’s edges? The goal is to fully weld all joints.
I’m thinking I’ll get the best constraint by clamping directly to the table, or should I use spacers since the table will absorb a lot of heat? While I have some squares and clamps, once the whole tube is tacked I think clamping to constrain is going to become more challenging. On the other hand, maybe I’m thinking too much & it will be easy…
Looks like your on the right track. Stainless is going to warp, no getting around it. Your going to have to be ok with some distortion. If it was me, Id tack the entire weldment together first. Then I would wire feed the joints down hill to go as fast as possible to limit heat and warp. Keep us updated on the process and take pictures along the way. Jason
I’ll certainly accept some distortion, but obviously I’d like to minimize it. Trying to make sure I understand your suggestion “Then I would wire feed the joints down hill to go as fast as possible to limit heat and warp.” Neophyte here, so you’re saying switch from TIG to MIG because you can make a higher speed pass to minimize the heat & thus distortion, correct? I’m assuming that speed is also important to you from a business perspective, but I don’t worry about my time too much. Could I accomplish something similar with TIG and an alternating or stitching approach, or am I more likely to do better with MIG and faster lighter passes?
I was introduced to TIG in a night class at a local tech school years back and went with it as I liked it even though I’m slow at it. I’ve only done a little MIG in the past (same class) but have occasionally thought that it might be handy to have as well as TIG. I use a Dynasty 300 for TIG, would a Millermatic 211 be appropriate for this? Looks like 3/16" stainless is within its capabilities; I doubt its limited duty cycle would be an issue for my use. I think I could use the same argon tank.
I was thinking that the fixture table was going to be the big shop purchase this year, but maybe I need to think about another tool as well…
@LarryFahnoe Yes if it was me I would wire feed weld it. It’s faster and with the proper settings you can limit the heat input. Just run some practice beads on some scrap. I’d use the fixture table and squares to get everything square and tacked up. From there I’d weld down hill or flat. Skipping around is optional. I’ve had weldments still warp even when I skip. You can clamp a piece of heavy bar 1x1 or larger on the inside to help with the warp if it starts becoming a problem. Avoid up hill your just going to dump a ton of heat in it . With the 3/16 plate you should be fine. You can tig the weldment but I find new tig welders move really slow and heat up the part to much. The circle around the top or flange I’d probably be most worried about warping. I’m not sure what’s is for but it looks like your going to put a fillet weld around it. Fillets are the worst just be aware. I think you’ll be fine go for it. Nothing a grinder can’t fix.
Looks good Larry. At work we would tend to make the groove preps a little shallower angle so a bit less filler metal is needed. Not sure that really matters on a one off to save time, but another means of helping control heat into the joint. Just a thought.
@Fireball_Jason I appreciate the feedback & it has gotten me thinking about getting a small machine like a Millermatic 211 for this project as well as some others that are in queue. I know I am slow at at TIG so can certainly imagine that I’m at an elevated risk of more distortion. I’d appreciate a thumbs up or down on this idea & any other thoughts you might have. I’m thinking about visiting my local welding supply tomorrow for a chat.
The circular flange is actually part of the square mounting plate for the chimney pipe so I will not be welding around the flange itself, I just need to do a few small welds at the edges of the plate.
@Stuarts_Shed I don’t have the engineering background so have done the design work more or less by the seat of my pants and gathering together lots of tidbits from here and there. I had all the plate laser cut at Coremark & then milled the bevels (a fun project for the little Deckel) though I think I’ll have to revisit one of the plates as I’ve noted a design error. I see from your other videos that you’ve also got a passion for model engineering, neat! I’ve often thought that I’d like to make a model locomotive like they run at the St Croix model railway but that’s an endeavor well beyond my current skills. (Minnesota references as I note you’re nearby)
Hey Larry, I think you’re doing a great job. My comment was more so that I could add something to the discussion. It’s a minor point honestly.
Thanks for checking out my other videos! Model engines is how I got into all this. It started as making small engines, and then I needed to fab something to make a fixture, and then it transpired that if I could weld then the fixtures could do more or I could make better fixtures… and so it goes on.
A Deckel is a great tool to have - very versatile for sure.
As mentioned initially, the draft tube is for a blacksmith’s forge, but I might have provided a little more context. I’m patterning this after https://www.iforgeiron.com/topic/23197-bp1048-side-draft-chimney/ though mine will be a bit more complex because the wall that it goes through is of ICF construction & I want to avoid problems from too much heat on the Foam portion.
My high school had a well equipped metal shop (machine shop, foundry and welding) which I spent a lot of time in but never got to welding, a missed opportunity I’d always regretted. Although my career was focused on computers, some years back I noticed a class titled “Welding For Artists” at the local tech school. A survey course more or less focused on O/A and stick, but one of the teachers was fond of TIG and that piqued my interest. Once I completed that class I was allowed to enroll in “independent study” which provided an opportunity to focus on TIG projects.
My wife’s take on all this is along the lines of: “More old tools… so now you’re going to want more tools to fix the old tools & then those may get you interested in even more tools…” to which I (who sees no problem with this) can only sheepishly grin. Guilty as charged. Keeps me off the streets and out of the bars though!
When I picked the parts up they had a bit of a warp to them so I supported them at their ends and stacked a bunch of weight on them trying to get the warp out. No such luck & I didn’t want to press my luck by adding too much weight and wind up with an even bigger bend. Today’s project was to test fit the parts & thank goodness for the Fireball table system! After a couple of false starts I found a pretty reasonable strategy for clamping and dealing with the warped material. Really happy that I got the #3 fixture kit rather than trying to guess which components I would need…the kit seems very well thought out.
Fireball to the rescue! Well not an emergency situation, but the thought has occurred to me several times during this project that the system of tools that Jason has designed works really well.
My projects often end up taking a ridiculous amount of time to complete due to a variety of circumstances. In this case there’s been some time considering getting a MIG machine but in the end I decided to continue using TIG. I spent some more time prepping coupons and then practicing with the focus on trying to get my travel speed up and heat down. The weld guidelines I was following were suggesting 150-200 amps, 1/8" filler rod and 10 IPM for the 3/16" stainless material. To reduce heat I eventually settled on pulsed settings (175A, 200 PPS, 60% peak, 25% background) that were delivering roughly 123 effective amps . I divided each joint into a series of 4" segments and did each segment in a single pass. I alternated segments to better distribute the heat over the length of the joint. @Stuarts_Shed suggested that I might also reduce heat by using smaller rod and more passes which I may try down the road.
Due to lack of experience I was concerned about distortion, so I opted to focus on constraining each joint as well as I could and then fully weld it before going on to the next joint (rather than tacking everything together initially). The wide sides of the Fireball table worked really well for this as did the clamping system. The project will be over 300lbs once it is complete, and I don’t have lifting capability where I weld so the table’s casters make it possible to roll the table underneath the crane to reposition. At this point I’m pretty confident in saying that I do not think I could have achieved the results I’m getting without the Fireball table and tooling; I know I could not have done this project on my prior table. To see the sides wind up being at crisp 90º angles and no distortion was very gratifying.
I need to get some more rectangular tube before going further, but here are some pics from along the way.
That’s looking grand Larry - coming on really well. Also, thanks for letting me stop by in person and see your project and shop in person. Really appreciate the chance to see the table - a very nice piece of kit and I’ll be trying to add one of those as soon as I can.
