From this thread:
https://sigforum.com/eve/forum...20022184&f=320601935

I'm building a Lotus 7 replica.

Below is the current state of the chassis. The majority of it is a bit more than tack welded together, enough that it wouldn't fall apart while mostly assembled.

Curious if anyone can ballpark the cost of having a local shop finish weld the chassis.
Not having a welder, I've been at the mercy of trying to find the time to get my dad & his MIG down, or haul the chassis up to his place for a weekend to work on it. But, he recently injured his shoulder & is on an activity restriction for a while.

Mostly curious if this is likely to be a couple hundred or a $1k+ endeavor?

I realize there's factors that can't really be figured via a photo & the internet, just looking for a ballpark number.

I know nothing of welding a car chassis. But based on what I pay for simple H-Bracing and other pipe fencing assembly, I'd budget at least $1k as a starting point, especially if you want them to come to your location. (Yes, this is an apples and oranges comparison of the scope of work.)

I've got access to a truck & it's narrow enough to fit in the bed, so getting it to a local shop wouldn't be too much of a hassle. It only weighs a couple hundred pounds at most.

I wouldn’t go cheap. Some great welders/fabricators around Houston.

I'm guessing you're talking MIG welding it, not TIG or nickel bronze brazing as the originals were.
First, I'd be careful choosing a welding shop for something like that. Appearance is important but also you need someone that understands the importance of the sequence of welds so the chassis doesn't warp or develop a lot of stresses that will later crack.
There are a lot of individual welds there so it will involve a lot of hours. I'd try to find someone locally or even regionally that has done other tube frames, even if it's a stock car chassis and look at some of their previous work.
You may want to do some trial fitting of the major components too, just to be sure nothing has been forgotten or is misaligned. Also be sure all the body mounting tabs are there.
After that's all done and it's been welded, run a reamer through any bolt holes, especially if they are tubular sleeves. Welding will distort the inside of those and doing that after partial assembly and painting may be very difficult and damage the finishes.

The extra power would be good, and if the $1 to $1.6 is your total cost, ie no rebuild, no parts to replace you might come out ahead in the long run with a running replacement engine vs rebuilding the old one.

I'd look for a shop that has a frame table to mount that on before welding, just to be sure it's all straight when welding it up. Sure there are plenty of shops in Houston that can handle that job, doubt the cost to do it would be much less than $1000, unless you can find someone who wants to do it after hours at your place.

Put an ad on craigslist and see who answers maybe find one of the guys at a shop wanting to make some christmas cash...

Thanks gents, all good points. Yes, it'll be MIG if we DIY. My dad has a MIG, flux core & stick at his place.

Partly it's my impatience to get this moving forward again.

May be in my best interest to see about hauling it up to my dad's place for a long weekend & take the time to do it right.

As it sits, all major drivetrain/accessory components were mounted prior to disassembly.

I say DIY. I learned how to Mig weld restoring a 66 Mustang convertible. Got pretty darn good after I finished. Carried over nicely to heavier stock. Initially I was a "lay it on thick, grind it off" kind of guy. Now I can produce reasonably good looking welds most of the time.

+1 on getting a table or jib setup to hold everything square. The frame can and sometimes will warp quite a bit if you don't have it properly supported. As stated , move around so one area doesn't get super hot. The cooler you keep it the less chance of warping something. My welding professional that builds cranes for my business once showed me a demo of how bad things can move around if done wrong. I was amazed. Things that were plumb initially were not even close after his demo

Sounds like an incredibly fun project! While I have raced cars on road courses and wrenched my whole life on cars, I have never had the nerve to start from scratch and build a frame.....for any car, Kudos for taking it on. I hope she turns out just like you wanted!

^ Thanks, luckily this one fell into my lap at about 60-70% complete.
Chassis is probably 90%, as the RR suspension needs to be finished, needs a couple pieces of steel & chassis will be done.

Yeah, I went back and read your build thread. Thanks for that. Still a lot of work. That rotary is tiny. I did all the mechanicals on the Mustang as well including complete driveline. Learned what I didn't know and had a blast doing it. I am sure you love working on it but are killing yourself you can't find enough time. At least that's the way I was on that project.

A shop should have some kind of “fixture table” that the entire chassis can be bolted to. It should be HEAVY, a ton or two wouldn’t be too much. If they are equipped that way they should know how to do the welding without distortion. Talking with the shop Forman you should hear about all the cars they have done. There should be pictures around, age on the equipment and signs of experience all around (piles of short pieces outside, other chassis around, projects in the works, projects in for repair). If there is no evidence of this kind of work you are in the wrong shop.

Doing it yourself - It is possible. If you are in the learning phase of MIG welding, good for you! MIG is a great way to weld and with some practice it is possible to do some very nice work. I personally would not use flux wire for this project. I have yet, in some 30+ years of welding and machining, seen flux wire used to produce a quality job. I am sure it is out there, I have just never seen it.
So the recommendation would be to get a gas bottle (CO2/Argon mix) and get a pile of scrap metal from the scrapyard (100 - 200 pounds?). A good welder helps (mine is a Miller 251) and plug it into 220v. .035” wire is pretty good for a variety of metal thicknesses. If the frame is something like a special chrome-moly steel, check with your welding supplier as to which wire to use. Then practice.
Welding on the chassis - heat causes metal to move, cooling and it moves some more. Don’t allow for it and things end up misaligned. A sloppy job and it might be unsafe to drive. A “pretty good job” can be safe but might hurt resale at a later date. Your aim will be a very good job. Remember the last line in the paragraph above? Practice. Then maybe some more. If you can you need a space inside to work with a flat floor. Out of the weather the project stays in place and the flat floor is a reference while working on it.

So, all this advice from a stranger - one, it might be worth more than what you paid (might not be) - I am a retired shop teacher. Have taught from grade school through to college level. Worked in industry (machining, welding, hydraulics). College level was teaching future shop teachers all areas of metalwork (machining, casting and welding). Most of that was undergrad work (introduction and a little advanced work).
I think all that I have offered is accurate information. I welcome corrections for your benefit.
You have a neat project, take your time, do your best. You will love the finished product.

Thanks, thinking I'll stick with the DIY route.
My dad has an old, but good MIG, forgetting the brand, MAC i think, probably a rebranded of some other make.

I've done a bit of welding with him in the past, but it's been a while.

Should be able to pick up the steel I'm lacking between now & when his shoulder heals up. Then I'll haul it up there & spend a weekend working on it.

Adding a thought to this.

Thoughts on Flux Core?

My dad's MIG is an older MAC Tools branded Miller 140, but the gun is currently inop. I believe it needs a new trigger switch.
Priced a replacement gun & it's nearly 50% of the cost of the machine

He's also got a Flux Core machine, but I'm unsure on the brand.

I know it tends to need a bit more cleanup after, but for welding up the remainder of my chassis, thoughts on FC over gas MIG?

I gave the chassis some more look over last weekend & realized the bulk of the structure is actually done, it's the things like suspension pickups & engine compartment mounts that predominantly need finishing.

Honestly, if it were my ass going into turn three hard on the brakes, I'd want the chassis to have been welded by a pro who knows what the hell they are doing.

I do some basic welding, and know something of what to look for in terms of proper heat penetration to assure a good bond, but I'm no professional.

A broken weld on that chassis at the wrong moment can kill you. I would go with a pro shop with chassis experience.

^^^^ I'm with Artie on this one, but then I've only done stick welding on a trailer I built 20+ years ago, but it has held up to some pretty hefty loads of stone and gravel.

Good luck finding somebody to weld that with all the bracing and cross members that's going to be difficult to even get to some of that, I would scrap it.

Find a welder with current certs and pay him on the side.

We employed 100+ certified welders who could do that no problems at all for 500$ + materials and some beer on the weekend.

Don't do it in front of him but you can dye-pen test if you were concerned, though the weld quality would likely pass an eye test. Both sides tied in, etc.

Aint nothing in that hard to get to.

These guys should be welding full beveled shit daily so 90 degree tubing aint nothing new.

If you wanna be part of it, let him weld and you clean up all the joints in front of him. Depends on how friendly he is, may want to be left alone to work also.

Another thought, check around for locals that have done homebuilt airframe work. That's very similar to what you are doing here.
I don't think anyone that hasn't done this type of project realized how many small & short welds there are on this.
Mostly 1" square tubing and 4 sides. Many are tight inside angles that have their own challenges. Also the tubing is likely .063 or less and when you get to the last weld on each tube, when its a sealed up tube, burning through can be a challenge for someone not experienced.
This isn't stick or MIG welding a trailer with 1/4" or more steel plate.
Cleaning the area to shiny bare steel with a good fit is essential. Several stainless wire brushes and 1" x 50 sandpaper rolls and a can of acetone to clean at the end will be needed to do a nice job. Rust left in the joint after sandblasting and small particles of that sand will make a crappy weld. A MIG may weld over that but it will be the basis for stress cracks later.
I'll be watching to see how this goes once heat meets metal with your standard welding shop or hobby welder.
Here's a video that shows someone doing something similar and there are lots of online articles and videos too.

https://grassrootsmotorsports....s-welding-etiquette/