underneath side of floorpans

Hey guys, I am in the process of replacing the floorpans in my 54 chevy 210. I but welded them in by spoting all the way around jumping from place to place. I have them dressed on the inside, but my question is what do you guys do to the underside to dress the penetrated welds? Should I hit it with the grinder or seam seal and undercoat? Sorry if this is a stupid question but underside looks like a pigeon flew upside down under the car. Thanks

 

I guess I'd use seam seal and then either paint or undercoat. If you have a large bead running then use a grinder first to clean it up, then the seam seal will do its thing to make it uniform..

 

thats actually a good question because i am about to do a half pan on my 65. good info.

 

use a 40 grit flapper wheel on a 4" grinder it will finish it off smoother then seam seal it then under coat

 

A good weld doesnt look like pigeon shit so the answer to your question is -- learn to weld.
Grinding it down and hiding it under seam sealer is something that would piss you off if you bought the car and found it

 

I knock the high-spots down with a sanding disk, use seam sealer on the seams, prime and then paint with Imron. You have to take every precaution with Imron as it is deadly but it is the most durable paint I have ever seen.

 

I have a quick dumb question: isn't it ALWAYS better to paint before applying undercoating, or are there undercoatings that seal consistently enough that you don't need to worry about it?

 

If you catch someone lying on their back looking under your car, step on their nuts. they are sure to bump their head and will forget about what the weld looks like.
Really, once you take the underside picture for your album, and put it on the road, what does the underside welds appearance matter.

 

Lower it enough that nobody can fit under it.

 

We don't all become expert at all things when we are born. It takes time to learn. I am sure we all appreciate your perfection but you come off sounding rather arrogant in my opinion, and did not really help him much either.

 

You beat me to it 56don.

 

Grind, seam seal, prime, then undercoat. If you want even more protection then paint it before the undercoat.

 

and howinthehell can you tell what the bottom side looks like. When youre welding on top ???

 

Fitting pieces accurately and proper welding heat and good welding control of technique and the bottom side takes care of itself.

It's almost like magic

 

Thats wasn't an arrogant answer, it was the RIGHT one! In this bullshit PC society folks have all become winners, well thats wrong their is the right way and the wrong way. The correct answer is below.

 

Cuz, if you can weld the top and leave the off side of the base metal looking pristine, then you have NO PENETRATION.
Maybe your girl friend could make a sugestion on that for you.

 

if you welded from the top, why does the bottom look like crap?

when I did some floor pans a few years back I butt welded them in solid all the way around. no seam sealer since there is no seam. the owner and I chose to finish the bottoms like you would a fender patch, this car was supposed to be painted pretty underneath.

I have no idea what you have done since you didn't really say, so it is hard to give advice. no need to grind down the undersides unless you are going for a really clean undercarraige.

 

Fitting pieces accurately and proper welding heat and good welding control of technique and the bottom side takes care of itself.

Thank you TMAN and BLUE ONE I hope no one here accepts the incompetence suggested by charlieb66, amodel 25 and some of the others on this thread.
Cutting out a crappy weld and redoing it is the fastest way to learn how to get it right so you dont have to cut it out and weld it a third time

 

i used bedliner in my 1946 chevy pickup on the floors

 

The same question applies to the inside of the trunk area lets say when fitting patches and quarters? So all of you guys that weld in quarters or patch panels do not have to prep inside the trunk at all, just prime it and spray it?

Not taking sides here but I have always been curious about that as well.

 

Well said.
Click on the link below. It takes you to a detailed documentation of an intense build with high quality workmanship.

http://www.metalmeet.com/forum/showthread.php?t=7309

 

Minor prep is one thing. Grinding globs and 1" long Mig wire refugees is another. And yes, there are some areas where you simply can not get to the back side, this is where proper fit is important to the final weld.

 

Thanks