Muscletang needs new floor pans - advice?

[tony-muscle]

And, Do not forget the SEM Products Copperweld Weld-Through Primer 40783.

Eliminate the corrosion that forms between welded substrates with SEM Products Copperweld weld-through primer! This copper-enriched formula has excellent adhesion. Copperweld weld-through primer provides superior conductive properties that minimize the heat zone, reducing distortion and welding spatter.

http://www.summitracing.com/parts/smm-40783?seid=srese1&gclid=CP6P1sTY2sMCFWRk7AodMyMA3g

mustang7173

I already purchased Eastwood's weld-through primer, which I hope works.

 

[cudak888]

I already purchased Eastwood's weld-through primer, which I hope works.

It will work fine. Scott will point out that epoxy primer is much better for seam longevity, but you can always clean up the paint afterwards and shoot epoxy primer after getting the pans in for an added bit of security.

-Kurt

 

[tony-muscle]

Now that we are talking about primers, etc. This is what I had in mind:

-Prep, grind, clean, etc.

-Use Eastwood's weld-through primer along the overlap that would be welded.

-Weld.

-Coat areas of original floor that had surface rust, but were cleaned, with POR-15 Rust Preventive paint (#45008)

-Coat the whole floor above and underneath with POR-15 Top Coat (#45904)

-Another coat of 3M Professional Grade Rubberized Undercoating (#03584) or Eastwood Rubberized Undercoating (#16007)

Please consider that I don't have a paint sprayer so I will be brushing the POR-15. The epoxy primer does not seem easy to apply without a sprayer. Any thoughts?

Is it overkill to use a rubberized coat on top of the POR-15? My thought is that it may help as sound deadener.


Also, I was planing on adding the Tinman subframe connectors some time down the line, but now that the floor is off I am tempted to installing them now. It should go easier, right?

 

[tony-muscle]

Any thoughts on the primer/painting plan listed in the above post?

Thanks.

 

[cudak888]

Tony, ideally, it would be:

-Prep, grind, clean, etc.

-Epoxy prime

-Weld.

-Grind

-Epoxy prime again

-Spray with Rust Bullet

-Undercoat

Now, since Rust Bullet is an isocyanate - if i recall right - your best bet is probably:

-Prep, grind, clean, etc.

-Epoxy prime (or weld-through, even though it won't be as ideal)

-Weld.

-Grind

-Epoxy prime again

-Spray with ? inside

-Undercoat outside

-Kurt

 

[tony-muscle]

Sunday did my first welding in the car. It was a small square section from the pan under the rear seat that was butt welded. I am posting the picture with the fear of becoming the laughing stock of the forum. I know the cuts and welds are ugly, but not being a structural component and after grinding they don't look that bad. Actually, the result is after four welding/grinding passes. After each grind I will find holes that I have to reweld until I finally got a close to solid piece. The underside looks ugly and still needs to be ground. Unfortunately, this area is above the muffler so I can't get the grinder up there. This is leading to my next step, which will be taking down the exhaust so I can grind/clean all the areas that need repair. No problem taking down the exhaust since I am installing headers and replacing mufflers. This step will have to wait until I am back from a 10-day vacation out of this miserably cold weather.

I am learning a lot throughout this process. Even though I practiced before I started welding in the car the learning curve is steep. There is a fine line between too much and too little voltage. Also, I know the gaps were horribly large and uneven, which probably did not make my job easy. You can see all the pieces of wire sticking through the bottom that made it through the gaps.

In regards to gaps for butt welding, I read a lot from different sources and still found divided opinions weather a gap should be used or not to weld sheet metal. Every where I read there are different opinions. Another inconsistency is some people seem to like the on/off method of tacking to build a continuous bead. Others suggest going for 1" and then jump 6" ahead. So that's a bit confusing. I guess it all boils down to practice and what works better for each situation.

Setup. Showing ugly large gaps and clever positioning using magnets:



After first welding pass:



After first grinding pass:



After third pass. I am proud of the small section on the right that doesn't look bad:



After four weld/grind steps:



... and the ugly underside that still needs to be ground after I have time to remove the exhaust/mufflers:

 

[cudak888]

Not bad. You might want to slow down your wire speed just slightly for better penetration. Most of those welds in the first pass look rather cold. The dime-type welds on the right edge of the patch in photo #2 are exactly as they should look.

Suggestion - put a piece of copper under your next piece to prevent a mess on the bottom. Hold it in with clamps or STRONG magnets.

-Kurt

 

[tony-muscle]

Thank you for all the help. Slowly moving forward. Here I am test fitting the Dynacorn floor panel. Is the black coat some type of primer? Do i need to remove the black coat before applying the epoxy primer or can the epoxy primer be applied over the black coat?

1971 M-code Mach 1

 

[turtle5353]

Nice job! Keep it up. The more you do it the better and easier it will get. This may have been covered but, what welder are you using? and what size wire? Gas? Ideally a 220 volt welder, but 110volt will work fine. Most welders have a cheat sheet for setup on the inside cover. The chart will tell you wire speed, and heat range for the size wire and thickness of metal your welding. They are usually very accurate. For doing sheet metal I usually use .024 solid wire with argon/co2 75/25 mix.

The patch you made looks good, but could be tighter. I personally like as small of gap as possible. The tighter the better. Also a lot of the issues your having with the weld messing up could be from contamination from underneath. You need to have both sides of the area your welding nice and clean. That patch should of been able to be done with 1 round of the welder and 1 round of grinding. But that will come with more practice. Some of your welds look a little too small. The ones that look good in 2nd pic, look like you held the bead for a second or so longer giving it a chance to form a nice weld puddle. Like cuda said, it does help to have a copper backing plate if you have some holes or gaps and don't want to blow threw.

Another helpful hint when your doing your butt welds is to try to always start your weld on the new piece of metal. The new metal can usually take more heat than the old stuff your trying to weld to. So you want to start the weld on the new piece and make "U" type movement whipping the puddle onto the old metal getting them to bond together. Then you should move and tie next "U" into the first moving in the direction of the open end of the "U". By using this method you have less chance of burning through and less likely that the backside of your patch will look like a porcupine. Just kidding!! Your doing fine. Takes a lot of practice to get your groove. If you have any more question just ask and keep the pics coming.

Also, for the new floor pan being black. The coating is EPD. A very tuff coating that is applied with an electrical charge of sorts. You will have to grind that off anywhere you are going to weld. When you are done and want to epoxy prime the pans, you can wipe it all down with wax and grease remover then scuff it with a red scotch brite pad, blow it off, wipe again with wax and grease remover, then shoot the epoxy primer.

EDIT: Just a heads up. The u shape technique is good for when you have a gap to fill. Otherwise, if the patch is nice and tight you can just start your spotweld on the new metal and just touch into the old. No need to really move your weld puddle around too much. Also when doing your rosette welds, try not to start in the middle of the rosette. A lot of people start right in the middle and just let the puddle fill up the hole. This will work, but it tends to hump up more in the center and causes a lot more grinding to be done. I usually start on the outside perimeter of the hole and weld in a circular motion. The weld tends to lay down much nicer this way with a lot less grinding.

 

[tony-muscle]

Nice job! Keep it up. The more you do it the better and easier it will get. This may have been covered but, what welder are you using? and what size wire? Gas? Ideally a 220 volt welder, but 110volt will work fine. Most welders have a cheat sheet for setup on the inside cover. The chart will tell you wire speed, and heat range for the size wire and thickness of metal your welding. They are usually very accurate. For doing sheet metal I usually use .024 solid wire with argon/co2 75/25 mix.

Thanks for the tips. I am using an Eastwood 175 220volt. I started with the cheat sheet and then fine tuned a little. I am still getting the handle of it. I used .030 wire with the Ar/CO2 75/25 mix for gas. I am using .030 because it came with, but I should try .024.

Is there a trick to blend the old coats on the car with the new ones. Meaning, I can't buff the whole underside or top side. At some point the new primer/top coat has to meet the old coatings, so I want to avoid having future issues at the interface.

 

[turtle5353]

Nice job! Keep it up. The more you do it the better and easier it will get. This may have been covered but, what welder are you using? and what size wire? Gas? Ideally a 220 volt welder, but 110volt will work fine. Most welders have a cheat sheet for setup on the inside cover. The chart will tell you wire speed, and heat range for the size wire and thickness of metal your welding. They are usually very accurate. For doing sheet metal I usually use .024 solid wire with argon/co2 75/25 mix.

Thanks for the tips. I am using an Eastwood 175 220volt. I started with the cheat sheet and then fine tuned a little. I am still getting the handle of it. I used .030 wire with the Ar/CO2 75/25 mix for gas. I am using .030 because it came with, but I should try .024.

Is there a trick to blend the old coats on the car with the new ones. Meaning, I can't buff the whole underside or top side. At some point the new primer/top coat has to meet the old coatings, so I want to avoid having future issues at the interface.

That's the welder I have and it works very well. But there is a misprint on the cheat sheet under the cover. One of the heat settings is way off. I will have to look when I get home. But 1 of them is way out of whack. This may have been fixed since you got yours. Definitely get the .024 wire for body panels. Uses way less heat to do the job.

Not sure on what coatings are on your underside of your car. But if its just undercoating, you can wire wheel it back some from around your patch. Prime the patch, then spray with undercoating and just try to feather the edges in so they don't look so noticeable.

 

[tony-muscle]

Thanks for the tips. I am using an Eastwood 175 220volt. I started with the cheat sheet and then fine tuned a little. I am still getting the handle of it. I used .030 wire with the Ar/CO2 75/25 mix for gas. I am using .030 because it came with, but I should try .024.

That's the welder I have and it works very well. But there is a misprint on the cheat sheet under the cover. One of the heat settings is way off. I will have to look when I get home. But 1 of them is way out of whack. This may have been fixed since you got yours. Definitely get the .024 wire for body panels. Uses way less heat to do the job.

Yes... I took your advice. I remember you suggesting that welder. It was the me-to-me Xmas present. Little I knew that was just the beginning of expenses:huh: Then I have to find helmet, welding jacket, gloves, mat, clamps, pliers, HB welding table, gas tank and cart... I was able to convince some family members on getting me some of those from Xmas. Now I am a happy camper Thanks!

 

[turtle5353]

Ya, its definitely not cheap to buy tools! But you have them forever if you take care of them. Plus the pride you get and money you save from being able to do this work yourself. Hell, doing this floorpan job yourself will pay for the welder. I was able to get a pic of my cheat sheet on my welder. Notice the setting for 20G. with .025 wire. E-5 Its way out of whack. It should be B-5. But other than that one, the settings will get you in the ballpark. Then you can fine tune if needed.

If you haven't got a welding cart yet check out harbor freights cart. It is actually put together very well and holds everything you need. I like having the drawers on top for tips, nozzles, hand tools ect. The bottom door you can put you helmet in. The side hangers are good for C clamps and wrapping your leads up. I have mine Loaded to the max. Its heavy as hell but rolls around the shop with ease. Really nice cart that you can usually pic up on sale for $150. http://www.harborfreight.com/welding/welding-accessories/welding-cabinet-61705.html

keep the pics coming and keep us up to date on your progress!!

 

[tony-muscle]

Mine says B-5 so they must have fixed it. I bough my cart from Northern Tool. It is smaller than yours. It was $60. I got the welding table from Harbor Freight. I think it was a decent deal. It is small, cheap, but sturdy. So far I use it for practicing welding. http://www.harborfreight.com/adjustable-steel-welding-table-61369.html

Correction: I don't know what was I thinking, but this still is not fixed. Mine shows "E-5"

 

[tony-muscle]

So last night I was able to work a little under the car. I was on a much needed 10-day vacation away from winter.

I took down the exhaust pipes/mufflers so now I have a lot more space. I ground up the weld from underneath and I see crevices. I don't have a smooth surface throughout. This is probably due to my poor welding techniques. What's the advice here. I understand that the crevices would be areas where rust can initiate, but does it matter after it gets primed and undercoated? if it is critical, then, should I reweld those surfaces? I am afraid that if I keep grinding it will end up too thin.

 

[tony-muscle]

Finally had some time this week to continue working in the car. You know, work and family keeping me busy.

I need the advice of you knowledgeable guys. I am trying to fit the replacement floor panel as tight as I can to the sheet metal in the car. The picture show the forward side of the driver's side. The new floor panel is fitting about 1/4" lower than the old one. You can see in the picture that about half of the original spot weld is showing up. The screw you see in the picture is keeping the replacement pan flush with the bottom of the original firewall panel. The floor pan is also flush with the subframe. So I don't see a way the floor pan can go any higher. Also, the lip of the replacement panel is about the same height than the original. Actually, I measured the floor to the rail and it is about 1/4" lower than the passenger's side, which still has the original floor on.

I don't see any other way than welding it like that, but before I proceed are there any ideas or advice? Will my seat position be 1/4" lower as well?

Thanks.

 

[judge]

Sounds like you are thinking your way through it. If its laying on the center frame rail and hitting the firewall right, you are probably on the right track. If it's laying on the rear torque box, you have more indication you are right on. There won't be a difference in seat height if you are hitting the center frame rail and the rear torque box.

 

[turtle5353]

Sounds like you are thinking your way through it. If its laying on the center frame rail and hitting the firewall right, you are probably on the right track. If it's laying on the rear torque box, you have more indication you are right on. There won't be a difference in seat height if you are hitting the center frame rail and the rear torque box.

+1 If its sitting on the frame rail nice and tight that's what you want. The sides will pretty much land where they land. As long as you have good metal to weld to on the sides you should be good. You wont want to raise it up to match the line you have because you would then have a gap above the frame rail which is no good. Put a self tapping zip screw in the pan where it over laps the firewall and one on each side of the frame rail flange to hold it down tight and go from there. You can add as many screws as you need to pull it down tight as you weld. then just take out the screws and weld the holes shut. Looking good! keep it up man!

 

[tony-muscle]

I had a slight gap on the right side of the subframe. After moving and refitting the pan now all is tight and the floor came up a bit on the left side (door rail side), so I am about 1/8" lower than before. I feel a lot better. Now the next steps are clean, prime, prep, weld, grind, prime, seal, paint.

 

[tony-muscle]

I have not fallen off a tree. I am still working on the car, but slowly. The last couple weeks I worked on fixing the sheet metal of the rear-driver side torque box. This one was tough. It is a thick gauge sheetmetal, plus it has a double curvature. However, a home made bender with a vise and pipe worked well. I had to cut the piece where the two curvatures meet so I can have a two plane bending. I also cleaned and primed inside the torque box as far as I could access through the cut. The sheetmetal in the inside was in very good shape.


The last two pictures are pictures of the inside of the subframe. Since this area will be covered after the floor pan is in, should I do something to the inside of the subframe? I cleaned all the gunk and oil. All looks great in there, so I am thinking I could spray a coat of chassis primer on top of whatever is in there. But I don't feel like grinding the existing layer unless you guys feel it's really necessary.