I've got my car tore down for some extreme engine detailing. I've got my block painted and masked and now I'm moving to the firewall and cowl.

I had two large holes drilled in the firewall where a previous owner had installed aftermarket AC at some point.

I filled them with kitty hair backed by a screen mesh earlier in the season and
it seemed to hold up pretty well, However there was some hairline cracking in other areas and an unsmooth look to it. Someone mentioned using a block sander for finishing prior to paint.

Now I'm block sanding to remove lines and cracks and one of the smaller 3/8" holes I filed has popped ot. (this had no screen backing)

I still have many divits and dips in the firewall and would like a smooth surace.

An suggestions for smoothing and hole filling? I don't want to redo this again. http://www.chevelles.com/forum/frown.gif

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Check out my 69 SS 396 (http://community.webtv.net/johnlord/1969ChevelleSS396)

Happy motoring!

The 'standard' correct method for filling holes is to weld a patch panel in from behind and smooth it over with a little plastic filler. However, if you don't have access to a welder, you can purchase some body adhesive from an auto body supply shop and 'glue' a piece of metal instead of welding. Just don't try and use seam sealer or caulking or even JB weld. The kitty hair stuff will crack and fall off sooner or later.

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Triple Black 69 SS 396

on my 65 What I did was weld patch panels from behind on any unwanted holes the filled with a little putty. also I removed all the seam sealer and filled with bondo then sanded with a Da sander this cleaned it up preety good. I didnt spend a whole lot of time on it but it sure looks 100% better then it did before. had I had more time I would have spent more time in the sanding and prep area.

69396SS,

The method I like to use is as follows:

Cut out a template that will fit inside the hole you are trying to patch. You can do this by having someone holed a piece of cardboard against the firewall on the inside of the car and tracing the shape from the engine compartment side.

Use the template to cut a patch piece from metal that is the same gauge as the firewall.

Butt weld the patch panel in place and metal finish the weld seam (you will need good penetration on the weld otherwise you will have pin holes when you metal finish the seam). Do this on both sides of the firewall if you can.


CAUTION: Make sure any electronics you have on the vehicle are isolated prior to welding. I have seen a lot of ECU's, TCU's, etc. get the smoke let out of them during welding because people forgot to isolate them.

If you are extremely meticulous, use a very thin coat of filler over the patch panel and sand it to perfect the hightlights.

You can take it as far as you want. Some of the cars I have worked on have had the entire firewall and fender inners covered with Sikkens Poly Surface and the block sanded to perfect the reflect lines prior to painting.

Hope that helps.

Bill

Good advce guys! I would agree welding is probably the best method. I'm not sure the location will allow welding without alot of additional teardown as the backside is not easily accessible. (not to mention lack of skill) I think I'll try the body adhesive on metal cutouts and then a finishing with the sikkens poly.

I also have alot of smal dings and dipps in the metal surface of the firewall and cowl (small dents) Would this Sikens Poly work good for filling and smoothing these ares as apposed to kitty hair?

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Check out my 69 SS 396 (http://community.webtv.net/johnlord/1969ChevelleSS396)

Happy motoring!

[This message has been edited by 69396ss (edited 10-30-2000).]

SS,

That's the stuff I like to use. It works well at filling in dings provided they are not deeper than a 1/8 of an inch. Any deeper than that and you should try to knock the dings out some first.

Good Luck,

Bill

Excellant advice by all! Now I have a direction to take. We'll see how it turns out. Thanks again for all your help guys!

By the way, this is alot of fun with the motor still in the car working in a one car garage! http://www.chevelles.com/forum/smile.gif

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Check out my 69 SS 396 (http://community.webtv.net/johnlord/1969ChevelleSS396)

Happy motoring!