Getting Ready To Install Two Full Length Floor Pans...any Tips?

JH96GT

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Dec 19, 2014

#1

• Dec 19, 2014

• #1

So the pans in my 65 Coupe are rotted in several spots. In looking at it, I decided to cut out each side and install full length pans. So, here is the plan:

1. Install floor jacks on sub frame, front & rear, on each side.
2. Remove seat riser pans
3. Lay new pans in and trace outline on existing floor.
4. Drop back 1/2" and scribe cut line.
5. Cut out old pan (one side only) with one of the small auto body sawzalls. Careful to watch brake and fuel lines, and definitley frame.
6. Remove old pan sections (one side only) and clean up frame.
7. Grind clean surface on floor of car and patch panel, then spray with weld through primer.
8. Fit pan and tack into place.
9. 1" stitch/lap weld pan in. Being careful to let cool.
10. Apply seam sealant.
11. Spray with paint or cover with POR-15 (not sure which yet).

12. Repeat on other side.

I'll be welding with a Lincoln Handy MIG. 0.025 wire with Argon.

Thoughts? It's not going to be a show car, just want it solid.

-Jh

 

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JH96GT

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Dec 19, 2014

#2

• Dec 19, 2014

• #2

Pics of current floor pan.







QC dog

 

horse sence

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Dec 19, 2014

#3

• Dec 19, 2014

• #3

If you are going to the trouble of doing two full length floor pans it would be well worth it to do a full floor pan instead . For one thing you would not have to do welds full length on each side ,there would be no visible lap joint under side ,it would be just the outer edges and the floor supports and new seat boxes that would have to be welded ,seat boxes come with the floor if you buy the floor kit .
Either way remove the gas tank first just to be safe .

 

Last edited: Dec 19, 2014

JH96GT

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Dec 19, 2014

#4

• Dec 19, 2014

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Why full length welds on each side versus stitch welding? Sturdiness being its a unibody car?

Thanks HS.

 

horse sence

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Dec 19, 2014

#5

• Dec 19, 2014

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I never really like to stitch weld any thing ,i prefer a full weld . 1 inch stitch weld would be kind of wide ,i would go at least 1/4 inch if you do stitch weld . Not only is it a unibody but the floor is what you sit on so the stronger the better .

 

JH96GT

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Dec 19, 2014

#6

• Dec 19, 2014

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Ok, thank you.

 

candphall

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Dec 20, 2014

#7

• Dec 20, 2014

• #7

I did mine in my 69 as you described. If I did it over again I would do as horse recommend. Much less welding. But in my case I am a one man show and a full pan is a beast for one person to handle. Are you doing toe boards as well.

 

JH96GT

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Dec 20, 2014

#8

• Dec 20, 2014

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Not if I can help it. I have a couple of small spots to patch but overall they seem ok.

One man show here too, so I get it.

 

candphall

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Dec 20, 2014

#9

• Dec 20, 2014

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There is another option as well. If your seat risers are in good shape you can just use the partial pans, front and rear, a lot less welding and those seat risers are a real struggle to remove. That's also my dogs favorite position.

 

horse sence

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#10

• Dec 20, 2014

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You will see a couple of clips coming through the side of the drive shaft tunnel ,pinch them with a set of pliers and you can push them through the floor .They are the clips that hold up the gas line and brake lines ,that will allow them to sag enough to keep them out of the way of your body saw .That is if you have to cut that high.

Here is my guard dog on duty ....watchit ,dont get to close ! she is vicious

 

JH96GT

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Dec 21, 2014

#11

• Dec 21, 2014

• #11

Haha that's great. Thanks guys.

 

Hack

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Dec 21, 2014

#12

• Dec 21, 2014

• #12

I'm by no means an expert but any sheet metal welding I've ever seen or done myself was one tack at a time and then gradually going back and filling in the gaps. I don't think longer stitch welds or welding a full seam at once is advisable. Short stitch welds like 1/4" or something would probably be fine. I understand you're going to leave a flange and weld to that rather than butt welding, so that will help some. However, I still think you're safer with lots of very small welds and skipping around/letting it cool between welds. Sorry if that's what you meant and I misunderstood.

Also, the disadvantage of lap welding is corrosion can get in between the panels. However you are doing seam sealer so that will help. I've seen weld-through primer recommended to help limit corrosion in that situation.

 

JH96GT

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Dec 21, 2014

#13

• Dec 21, 2014

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No Hack, you're fine. So if I do 1/4" stitch welds, how far apart should they be?

 

horse sence

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• Dec 21, 2014

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1/4 inch apart .

 

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JH96GT

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Dec 22, 2014

#15

• Dec 22, 2014

• #15

I got the passenger seat riser out today. What a pain. Drilled the spot welds, etc. Mocked the full passenger pan up and I don't like the fit/cut. Going to evaluate tomorrow some more and probably chop the pans into patches.

That way I'm not fighting with huge welds and I can hide seams easily. There is already an old patch under the passenger area about where your right foot would be. It looks solid still, but going to go ahead and remove it and use a full section.

 

candphall

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Dec 23, 2014

#16

• Dec 23, 2014

• #16

My pans were not a great fit at first either. But with the help of a large hammer I got a great fit. Also remember that the new pans will fit better once the old pan is removed, and they can be pushed into place.

 

horse sence

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Dec 23, 2014

#17

• Dec 23, 2014

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Yeah ,those floor patch panels don't have quite the same shape in some places as the original floor does .You may have to knock them around a little .If possible trim the patch panel to go just beyond the rusted area instead of using the full patch panel . You may have to screw the overlap together to keep the under lap from curling away and leaving a big gap under the car between the floor and the patch panel. I have redone floors where they left a gap wide enough to put your finger in.

 

JH96GT

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Dec 23, 2014

#18

• Dec 23, 2014

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The screws worked like a charm. Thanks.

I know one thing, my MIG doesn't like weld through primer (zinc). Was a pain.

 

horse sence

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#19

• Dec 23, 2014

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Mine doesn't either ,noting welds better than clean metal .The fumes off the weld through are not great either ,kind of like melted plastic

 

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7991LXnSHO

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Dec 30, 2014

#20

• Dec 30, 2014

• #20

Vaporized zinc is bad for your health so use plenty of ventilation.

 

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