How to seal welded areas that not accessible
 

To avoid rust, what are the proper techniques to paint or seal the back or undersides of welded body areas that are not easy to reach?

Would it be best to spray a weldable primer on these areas before welding, then try to spray epoxy primer on them after welding?

In the past I used a weldable primer (maybe from Eastwood) that came with a 24" long plastic tube that could be snaked into difficult to reach areas, but since you can't see what you're spraying, it's a crap shoot. I ended up with paint dripping out of holes and running down the exterior metal in some places.

Maybe I have answered my own question, but I have to believe there may be better solutions, or maybe techniques that are specific to specific models of vehicles. I'm curious what a professional would do.

Re: How to seal welded areas that not accessible
 

I am no pro but the only method I know of is a schultz gun and cavity wax.

Oh, now I see some cavity waxes come with an applicator.

Still, if not done, the rust will come back quickly, DAMHIKT

Re: How to seal welded areas that not accessible
 

As the car is still apart and I wanted to use SPI epoxy to match/adhere well to what was already there, we went high tech with some modified paint rollers to address the rocker panels that were accessible from the back side. rotisserie was used to direct paint flow and epoxy filled between flanges well. Or as least I could tell it ran through...

Re: How to seal welded areas that not accessible
 

Getting any kind of epoxy in there is great.
Getting a cavity wax in there is paramount. The multi directional spray nozzles work great. Spray until it runs out drip holes. Let it drain... may take a few days even... but you're protected.

Re: How to seal welded areas that not accessible
 

Great information! So epoxy primer then cavity wax. I had never heard of cavity wax.

Re: How to seal welded areas that not accessible
 

http://search.eastwood.com/search?w=cavity%20wax

Not sure how this is but the ratings seem good on it. Any other recommended waxes ?

Re: How to seal welded areas that not accessible
 

That's the idea.

I am NOT a 3M fan but this one is nice because of the wand.
http://3mcollision.com/products/feat...avity-wax-plus

google cavity wsx for many options

Re: How to seal welded areas that not accessible
 

3M 08852 "Cavity Wax Plus" is about $18 a can, or $30 for a 2 pack. Not horrible for a 3M product and for the peace of mind of knowing it will hopefully prevent rust.

Thanks!