Can I go with the store brand for seam sealer, or do I need to go with one of the other brands? It is for floor pans.
Also, anyone have a photo of how much needs to be put on the seam? The stuff is obviously not cheap and I am assuming needs to put on top and bottom of the lap, correct?
This is a daily driver 69 vert (Well, that is "daily" when it wants to run at least!!!)
How much: Enough to prevent any water from getting inside any holes or gaps, and enough to satisfy your cosmetic desires of how the finished seam looks.
Where: Everywhere there is a potential hole or gap (along the entire welded seam), or everywhere you want to cosmetically camouflage/hide a weld.
Brand: Meaningless in my mind, buy any brand you want that is compatible with whatever refinish process you plan to use. Some are runnier and more difficult to use. Some cure faster and some slower. I usually prefer to look for a heavier bodied seamsealer for ease of use, especially if working overhead.
I personally usually like to run a bead along the seam, and immediately spread it lightly to work it into the seam with a disposable acid brush or similar, to give it a uniform brushed look. Others who want cosmetic perfection in seamsealer will often mask either sides of the desired seamsealer bead (maybe approx 1/2" to 1" wide gap?), then apply/brush it on or smooth it to their satisfaction, and immediately pull the tape off before it cures to get beautiful/clean/crisp lines along the seam, for cosmetic perfection of a symmetrical and straight seam. You can also choose to wipe with a little thinner before curing if you want to smooth it perfectly instead of brushing and leaving it with a brushed look like I usually do, especially on a floor or hidden area like you're talking about.
Basically I feel there aren't many rules here, unless you're trying to do concourse reproduction of what the factory did, in which case I am of no value because I'm much more of a hot-rodder than a restorer...
Want other ideas, Google "how to apply seam sealer" and read 100 other opinions, and even see some Youtube videos and photos.
whatever brand you use choose a urethane seam sealer instead of latex. seal over primer 1-2 hours before paint or undercoating. do not use seam sealer over bare metal. urethane truck bed liner works very well as an undercoating/sound deadener.Cheers
once your welding and grinding are complete sand the surrounding area and apply your prefered primer (etch and high build or epoxy). allow them to cure and apply seamsealer. the primer is to create a good bond to the bare steel so you don't have peeling/flaking later.
This varies by product, but is indeed the conventional wisdom, particularly with urethanes, which is what you'll end up using if you insist on keeping costs low and using a one part product.
But there are also many seam sealers on the market that are specifically formulated to be used on bare metal and will not adhere properly to primer. And indeed many urethane seam sealers are supposed to NEVER touch bare metal and which will actually cause rust to form.
If you'd like to skip the priming step and save time, just purchase a "bare metal seamsealer" of which there are multiple brands available today. They're usually 2 part epoxy, but now Lord offers an acrylic (also a 2 part) that's designed to be used on bare metal. I lately have been using 3M's epoxy bare metal seam sealer and really like it. It does cost more $$. I'll let you know in 30 years if my seams rust.
It is critical to read instructions for the products you choose (all the way from bare metal to the last clear coat) to confirm proper prep, proper order of application, and compatibility.
