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I haven't really seen this anywhere, but was wondering at what point have most of you quit tacking up your build and actually stripped the car back down to do the final welding before rebuilding back up for the final finish.
Any Comments?
Al

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Super Seven 3.4

I did my finish structural welding before I welded on my steel floor. Once the floor goes on you will have a hard time getting to certain areas.

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He is a wise man who does not grieve for the things which he has not, but rejoices for those which he has.

I tryed to get all the tubing and brackets welded on first. I do wish I had welded on the emergancy brake brackets and fuel pump and filter in the rear but I got everything else. I guess. then I painted the chassis. If you want to weld a steel floor ,like chetcpo says, that would be good after all the rest and before the paint. I welded some joints then fit and welded in a lot of the bracing along with the final welding process.
Wayne

How do you guys handle corrosion in the welded-on joints since paint doesn't really get in there?

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Midlana book: Build this mid-engine Locost!, http://midlana.com/stuff/book/
Kimini book: Designing mid-engine cars using FWD drivetrains
Both available from https://www.lulu.com/

I finish-welded my frame once all the main members (including the tunnel) were in place. I was mainly concerned with preventing warping in the main structure. Once it was fully welded, there was no warping and the frame was almost perfectly straight (full-length diagonals were within 1 mm or so). From that point on, extra bits (like hoops for the scuttle, tabs for Dzus fasteners, radiator supports, etc.) can be welded on without fear of warping anything on the main structure.

As previously discussed, great care should be taken in doing the final welding. We clamped the whole frame down HARD to the table while doing the welding so nothing could warp. Do a weld on one side of the car, another on the other side, back & forth, varying ends of the frame, to keep everything as cool as possible. Also, if you do a weld on one side of a tube, there will be twisting, but if you weld the opposite side (once the first weld has cooled), it will pretty much come back to its starting point.

For anyone who doubts how much 1" square tube will warp, we tried a simple test...we clamped a piece about a foot long to the table (clamped only in the middle of the piece), and did one good tack on one end. We were amazed to watch the other end warp about 3/8" out of line in just a few seconds! Then we did another tack, directly opposite the first one (at the same end), and watched it straighten back up again....

Welding and warping is always a concern, in my case it was not much of an issue and it all went well, maybe partly because of the better heat control of my Miller welder compared to my old one that I bought nearly 20 years ago.
Basically I have the engine/transmission/driveshaft, tunnel, steering rack, front suspension, rear suspension shifter, handbrake (no cables) in place.
But until I remove everything and permanently weld my motor mounts and trailing arms etc I still feel like I am working my way up hill, once I remove it and then reinstall it then I start to feel like I am getting somewhere as the items then become a permanant part of the car/rolling chassis.
Judging from the comments most people seemed to do the floor and paint around this part of the build, which I guess I am going to do as well.
KB58 has a good point, even welds themselves can be difficult to clean well enough to have paint take hold. I am not overly concerned as the car is just a summer street car and will sit in a heated garage, maybe a bit of a pampered life.
On some of my previous build projects I used the lost water method and dipped my tubes and other parts, even part of the suspension on my AMX was done that way and has stood up very well, but no way I would be dipping this frame, though I have thought about it, one would have to be absolutely sure never to need any future welding, highly unlikely.
In the end a heat gun and a paint brush for the frame, it is not a show car, just a fun road car.
Al

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Super Seven 3.4

I actually gave serious thought to the idea of hot-dip galvanizing my frame! Unfortunately (or, maybe, fortunately) there was no-one who could do something that large. I keep thinking back to how long the old galvanized steel garbage cans used to last, even full of rotting, acidic garbage, getting hit by cars, being full of water, etc. Imagine how long a pampered car frame would last if it was galvanized?

Yeah, but sure as shootin' the day you got it back, you'd find something you needed to weld to it....

-dave

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...nowadays people are so intellectually lazy and lethargic that they can't build ANYTHING with their hands. They'll spend hours watching whiny people marooned on an island, but won't spend a second adding anything to the world. -weconway
Visit my [Locost 7 build log]

Yup! That's why I didn't do it...and why I probably won't powder-coat the frame, either...

I don't. My my car is stored in a climate controlled garage where bare steel laying on the floor doesn't rust. I drilled drain holes in the floor so no water will stand in it and I let gravity and AC do the rest.
I suppose if I were worried about it I would run a bead of silicone along the edges.

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He is a wise man who does not grieve for the things which he has not, but rejoices for those which he has.

I second that

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Super Seven 3.4

I plan on completely "finishing" the car and then IF I have the money I want to powdercoat it satin black

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After my basic frame was complete and well tacked together I just kept adding parts right up to the rolling chassis stage. Even fitted several body panels, drive train, the whole works. This summers goal was to strip it down to bare frame, add any missing brackets etc. so that no further welding would be necessary after the frame was painted. If I had to do it again I would've finished the basic frame welding before adding all the other stuff that gets added on to the basic frame because some of those brackets are in the way of welding the basic frame. It took me way longer to finish the welding than I thought it would but I TIG'd it and my TIG welding is much slower than MIG.

I went over the frame looking for missed welds so many times. Dispite that I still found a couple when I started to paint. Best part: used a cheap little HVLP gun, little overspray or waste and the frame painting went much quicker and easier than expected.

Started making my seats today, nice change from weld, weld and more welding.

Hey, another West Coaster! What kind of paint did you use for your frame? I, too, bought a HVLP gun (Princess Auto, of course...) to paint my frame, but haven't worked up the courage to spray anything with it yet. I was thinking POR 15...

If I remember corectly from my fab shop days You can't galvanize any tube unless it can completly fill without an explosion. I will use a steel floor and sides then Linex the tub area inside and out then Por15 the frame sections beyond the tub.