Rust Proofing Door Bottoms

[Meissen540]

Hey Bruce,
Do you have a technique that you like for treating the inside door bottoms from water standing in the seam and rust starting? You have been in the biz a long time. I assume you have developed a technique that works, and have seen many that don't.
The doors on the Speedster are original, and there is zero rust in the bottoms. I want to keep them that way. After getting caught in 2 thunderstorms on the way to Birmingham I decided that I need to get this done.
What I did on the Coupe was to paint the inside bottom with POR15, then after that was dry I used body caulk to fill in joint. I left the caulk standing proud of the door bottom so that any water that did get in there would run away from the seam.
I was wondering if you had a better method of doing this.
thx
Tom
Atlanta

[bbspdstr]

Tom, I had a bad experience with an air-cure urethane poured in the (repaired)door bottom seams. That was done just prior to a paintjob which was baked, and the urethane swelled where not fully cured (as a catalyzed product would have probably been) with the heat...so I don't do that anymore!

Long ago, Tim Kuser told me his Speedster doors were staying just fine by receiving some trans oil as he occasionally drained it. "Nuthin' like 90 weight!" Ah, the Brit method usually termed "controlled seepage"! I just worried about the smell, so I used Texaco 'compound L.'

Now, we use a 1K primer, reduced to seep into all the nooks and crannies...and out. Tape the drain holes and crimped-over seam well, pour in the juice and let it marinate for a while with jacking the 356 up in the front and then in the rear and opening and closing the door (with sills protected by a plastic bag and newspaper if the car is finished...or remove the doors). Then, drain the excess by pulling the tape off a bottom hole and let it dry for a day or so before replacing the door panels. So far, about 20 years with that method has had no come-backs.

I know guys who swear by WD40 and other lubes, but the theory is to keep water from getting to bare metal and sitting there. Speedsters have just started to show door rust due to their no windows and an overhang that protected them, so all are vulnerable after 50 or more years. Something, anything, is better than nothing!

[JTR70]

Hey Tom,

I realize you were asking Bruce but here is what I did on my old coupe doors:

The insides were cleaned of all old rust (muriatic acid bath) thoroughly rinsed and neutralized, epoxy primered and painted like I would the exterior. Crevis was packed deep with axle grease as an added inhibitor. Excess cleaned and sealed over smooth with clear silcone.( I am rethinking the silicone BTW; if there is a breach and water gets between its a perfect incubator. Its better to leave open so the air can evaporate it. So I will be removing it most likely) Just before the door panel goes on for good the entire floor will be skim coated in grease. As I said in my build thread I would much rather have a nasty, gooey mess down there than to find rust bubbles forming under my paint again. My last bit of prevention will be keeping as much water from getting in there as possible in the future. Example when it gets washed a piece of plastic will be draped over the door frames to shield the gap at the base of the door glass. As Bruce stated just like a speedster door is shielded and capped from direct water entering.
Justin

[Meissen540]

Justin,
The inside of your doors are show quality!!
I have considered oil, but your method sparked another idea that I use in another application.
I have a fishing boat in Florida, and the outboard motor is constantly subjected to a salt environment. One issue that you contend with is corrosion under the hood of the outboard engine. Bolt heads can rust, spark plugs, etc, making a simple service or repair turn into a nightmare with a broken bolt. An old mechanic told me to purchase some OMC Corrosion Proof spray (a similar product is called Fluid Film, but I find the OMC product superior) and coat the entire engine under the hood. It makes for a damn messy job when you do anything under the hood, but when you wipe away the oil/grease (it is almost like a cosmolene coating) the engine and fasteners look brand new. After 12 years of doing this, the underhood has zero corrosion.

So, I think I will utilize the OMC Corrosion spray product. It will be easy to apply, and its reversible.
Thanks for throwing in your 2 cents, that sparked the idea.
Hopefully this helps out someone else.

Tom
Atlanta

[JTR70]

Thanks Tom! It took alot of work to get them to look like that. I am liking the sound of that OMC; where do you buy it? Justin

[speedykiwi]

We have always used a "cavity wax" product. This is a non hardening waxy rustproofing. I think Shell "Ensis" is one. Dynotrol is another German one which is one of the best - I believe the VW factory option. Still waxy after 14years. Sounds like OMC is similar. I'd be surprised if Wurth don't make one.

Some systems use two stages - a thinned down version as the first application which will soak all the way into the seam (like the thinned paint mentioned) and then a second stage thicker which will provide thicker film. We do this and have never had any problems.

(Its mandatory in New Zealand for certified crash repairs to be rust proofed)

Some fish oil products may still be out there but they tend to stink and eventually dry out from my experience.

[Qtip]

This works well at the bog &at the beach.

[JTR70]

Thanks Steven, I look this product up on line.

Hey Ivan, So glad to see that you finally made it here! WELCOME to our little forum! As I said earlier, I was just going to use grease but I will most definitely look into the product you mentioned as well. Welcome once again and thanks!
Justin