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Wed Jun 10, 2009 6:13 pm

Hey guys,

When I am welding in a patch panel to an area that I cannot access after it is welded in, how do I protect the back from rusting out?

Currently, I am tack welding in the panel, filling it with 'metal to metal' aluminum (waterproof) body filler, and then coating it with paint comparable to master series. The question I have is, the back of the welds are still exposed on the inside area, won't this rust out??

Luckily I used galvanized steel as much of a b*tch it is to weld with, it protects it, but I am worried about the back of the welds.. what do you guys do?

Thanks in advance!

Andrew

Thu Jun 11, 2009 5:33 am

Weld-through primer, it's a metal-based coating that melts when the steel is welded and solidifies again when it cools off. Comes in a spray can, they were about $20.00 when I checked how much it costs.

Thu Jun 11, 2009 6:17 am

The only way I know is to drill an access hole on the backside and spray from the inside with a rust preventative. I have torn apart panels that I used weldthru primer on and they still rust, I'm talking only a year. Things like heater channel's can be accessed thru vent holes and rear opening with a long tube made for this purpose.

Thu Jun 11, 2009 8:41 am

That Wax/Oil stuff the English use sounds the best to me.

Thu Jun 11, 2009 1:49 pm

We use the stuff described below to protect inner panels. The areosol version comes with a straw type applicator so you can spray through very small openings. If needed, you can drill a small access hole and even cover it with a plug or grommet after spraying. I would describe this stuff as a non-hardening waxy coating that flows in to cracks and corners. Similar to the stuff Mercedes and Volvo use inside their inner panels.

3M™ Rust Fighter-I Amber (Internal Coating Compound)
• Non-hardening compound.
• Designed to coat inner body panels and other
metal parts.
• Replaces protection which is applied at factory
and destroyed in repair procedures.
• Low odor level permits use indoors.
• Easily applied with 3M™ Rust Fighter-1 Application
Wand (PN08998).
Part Number Size Containers/Case
051135-08891 1 Quart 6
Part Number Net Wt. Cans/Case
051135-08892 24 fl. oz. Aerosol 6

Thu Jun 11, 2009 3:20 pm

Mike Fisher wrote: That Wax/Oil stuff the English use sounds the best to me.

Actually, this is what Mike was referring to....its Waxoyl : http://www.roversnorth.com/waxoyl/
It's good stuff but messy.

Thu Jun 11, 2009 10:12 pm

Your local automotive paint store should be able to sell you a "wand" that connects to a pressurized cannister which holds the waxoil. Cut an access hole to feed the wand into the area you want to apply this stuff. I use it to spray inside frame rails after sectioning them in the center section. It seals the inside of the frame rail from any contamination. Remember to also use the weld-thru primer as previously stated by somebody, first! The products by "Wurth" are usually the best and there mostly German, too.

Tue Jun 16, 2009 10:38 am

The only stuff I can find (so far) is the canadian equivalent called 'rust check'. There are a couple different types, but this one is called 'coater / sealer'. It says it is a gel-like substance (rattlecan that comes with a red straw) that is :"

A multi-purpose lubricant and corrosion protectant. Protects metals from corrosion, keeps moving parts and mechanisms well lubricated, penetrates to loosen seized parts and inhibit corrosion in vulnerable crevice areas.

To me sounds like a gel-like version of wd40. Would this be an ok equivalent?

Fri Jun 19, 2009 6:50 pm

The main ingredient in WD40 is fish oil and I seem to remember reading someone,somewhere on here, using fish oil on their inner panels. I wonder if it would work?

Sat Jun 20, 2009 10:13 am

Try also calling an aviation supply store and ask for some Dinitrol AV25B
made by Dinitrol Aviation , Sweden. It's a corrosion prevention product that you spray on. We use it in the aviation industry to protect water from damaging metal sufaces that are covered up. I used to work in Calgary and this product was available there.

Sat Jun 20, 2009 5:35 pm

I have a 74 Beetle (Standard) which is really good heater channel wise. This was mostly due to the PO spraying fish oil in there every year. I'll continue the same treatment.

Sun Jun 21, 2009 7:49 pm

sirzo wrote: I have a 74 Beetle (Standard) which is really good heater channel wise. This was mostly due to the PO spraying fish oil in there every year. I'll continue the same treatment.

Fish Oil???? What the hell does it smell like? :shock:

Sun Jun 21, 2009 9:54 pm

getgeoff,

does this stuff spray in from a rattlecan through a straw? or how is it applied? Interestingly enough, I happen to know a person that is an aviaton supply sales person.. :D

Mon Jun 22, 2009 1:23 pm

Back in the 70s they used a stinky fish oil which would take months to settle down odour wise. Today the stuff is marketed as odourless fish oil which has very little odour to it that you (I) can notice - although I'll never get a job sniffing parcels for customs. Can buy it in rattle cans as well as in bottles/paint tins.

Like said a few posts up by finefettle the major ingredient in WD-40 is fish oil. I have heard of people using WD-40 on bare metal panels to keep rust at bay during storage and before final prep & paint. WD-40 is also used on roofing and wall metal sheets to help protect the paint and cut exposed metal edges.