VCCA Home Forums TECHNICAL - GENERAL Body - Sheet Metal, Paint & Wood interior sheet metal

looking for ideas on how to treat the interior sheet metal that was not originally painted . Mostly in the door and window areas . There is some surface rust so was considering a rust converter.

On my 38 I wire brushed the interior floor then sprayed a coat of rattle can undercoat just to act as a sealer. I didn't have a lot of rust present so the wire brushing took care of mine. Spraying with a converter would be a good idea I think if there's still rust.

Well three of the floor panels are new and the floor is now painted. The areas that I am concerned with are the inner quarter panel beneath the window and behind the wheel wells.

I found the hard way primer/undercoat is porous and rust will occurr through primer, for a complete surface seal you need to put a coat of outer paint to fully seal moisture out.
Tony

You can certainly slow rust by removing as much as possible and/or using a conversion product or wire-wheeling/painting/undercoating if the remaining rust is very light. If you live in a low humidity climate and the car is garaged and only occasionally used, it will outlast most of us so no need to overthink it.

Having restored cars in the salt belt, there is really only one surefire way of stopping the rust beyond replacing the metal with new and that is blasting to physically remove it, prime and paint it quickly after blasting. You can contain the mess from media with plastic sheeting. All you need is $20 of crushed glass, a respirator, a decent compressor and a $150 cheap pot blaster. I have found it way nicer to do than other rust removal methods and there is zero chemical contamination. You are left with rust free, perfectly cleaned metal. You can do very small areas and contain the mess. Harbor Freight should even sell a small handheld blaster that will work for small areas with a small compressor.

I'm media blasting every single part of my 1938 Coupe. Most is done except for some suspension and steering parts. It cleans it, make defects easier to detect, removes the rust, welding slag, contaminates and previous cheap paint and gives the metal good tooth for new prime/paint. It is very satisfying to end up with such clean, rust free parts.

FWIW the owner of the shop that did the body work on my 38 told me etch primer is basically waterproof. He said the manufacturer claims you could store your parts at the bottom of a swimming pool after they are properly primed without any rust. I don't think I'll try that though.

I do have a small blasting cabinet that I use for smaller items and the glass works great. Tomorrow i hope to get the body to a blasting shop that also uses glass but he will not do inner panels as he is afraid of warpage even with low pressure. He did my hood, fenders, and trunk lid a few months ago and they are zinc phosphate coated so no problems with rusting but storage is in my garage overhead space and not in the pool (which I don't have anyway). I took a photo of the areas in question . That area is double walled and the space between the panels is about 3 inches .

Attached is a 1938 door picture just after blasting and another after epoxy priming. Also a picture of my trunk lid that had less than a half inch between inner and outer panels. I had to airbrush and use an actual paint brush to get the epoxy deep into the interior corners. Blast media bounces into the remote corners, but paint does not! Thus a couple sags in the primer inside.
I vacuumed the loose debris after blasting with small attachments.

Tiny
If parts are constantly under water they dont rust near as quick as if they are dampened occassionly.
Tony

Tim that looks good. Any before photos and any idea what the backside of the panel looks like?

I used a product called Honey Coat Rustproofing inside my doors, behind the quarter windows and inside the trunk. It is made by Crest Industries in Trenton Michigan. Here is what the website says, "Honey Coat (Rustproofing) – Paraffin wax base with rust inhibitor. Seeps into seams and crevices. Long-lasting protection. Remains pliable. Will not crack or chip. Color: Amber." Also, on a hardtop, there is NO weatherstripping for the glass in the doors. All the water will enter the door cavity and drain through the weep holes at the bottom. I had my body guy drill two more hole through the bottom of the doors so I would have better drainage. I also applied the Honey Coat with a spray wand inside the rocker panels. A messy job but well worth it.

Thanks for the info Hawkeye. I will check out the Honey Coat. My doors on the inside appear to have had what I call the waffle mat insulation . I am guessing someone removed it as there is some tar still remaining. It's the same mat that is used in the trunk lid and the underside of the hood for noise suppression . Possibly it was sprayed with a "tar" product to waterproof it but that is only a guess. I'll ask to my upholstery installer for his recommendation .

That material reminds me of a heavy roofing tar paper.

Something like this? I think it was an early form of sound deadening. Mine was removed, cleaned and painted by my body guy. I then coated the inside with the Honey Coat. I don't have a photo of that, sorry.

Yes that is the same stuff I found in the roof and and the seat back panel. None was left in the door and nothing installed to replace it.

I tried to find before pictures of my doors and trunk lid Steve, but my photos are a mess right now. There are thousands and the order has gotten messed up. They looked very similar to the condition of your pictures. The blasting DID get the backside of the panels. I put the epoxy primer on the backside with a foam paint brush.

I had the tar based sound deadener on my panels. It had the waffle pattern cellulose outer layer that you describe. Pressure washing removed the cellulose and then varsol wiped away the base deadener. I replaced this with a modern 1/8" thick stick on deadener and then repop waffle deadener.

The cavity oil/wax like the Honeycoat is a very good idea. I am doing inside my frame, inside body panel corners, door bottoms etc once everything has it's final paint. Blasting is great for removing rust but can leave trace bare areas or seams and the cavity wax works great in these areas. I don't want rust again in my lifetime!!

Tim I appreciate the info and a photo is not necessary knowing what you posted. I may skip the undercoating on the interior as I think the epoxy primer will long outlast me as I am 77 and it won't see any Winter driving. I am curious as to what you found for the "repop waffle deadener" as the blasting company eliminated mine in the trunk area.

The repop waffle insulation is available from the usual vendors like The Filling Station and Chevs of 40s. Not cheap so could just use for visible spots like the trunk lid openings that you can see when the trunk is open. Current aftermarket sound deadener is more effective than the original tar. I found plain black deadener on amazon. See link. Canadian price shown so cheaper on your side of the border...

https://www.amazon.ca/Noico-Deadening-Automotive-Restoration-Insulation/dp/B01BKKZ1AM/ref=sr_1_7?crid=26GXGCCLTEVWM&keywords=sound+deadener&qid=1646270492&sprefix=deadener%2Caps%2C160&sr=8-7

Thanks Tim. Looks like it comes in a 36 sq ft piece which is plenty for the trunk area and then some. Price was around $70.00 US and I have yet to find anything for this car that is not expensive. I priced vent window seals today and it varied from $257.00 to $71.00. The cheaper ones may not be the best but have to be way better than the rock hard broken ones I have now.

https://www.chevsofthe40s.com/detai...ener_Insulation_Felt_Waffle_Pattern.html

FYI, It is "tarpaper" embossed and then two sheets glued together by a two sided sticky plastic film. After a while it tends to separate. I went ahead and pulled it apart then cut and fitted then glued it in place on the trunk lid.
Steve, how much do you need. I might have enough left over to help.

I can send you a small piece in a standard envelope so you can see what it's like if you PM me a address.

Ruscar that is certainly appreciated. Not sure if I will try to keep the trunk area original as getting it installed may be difficult but I will send you my address in a PM for the sample.