Should I undercoat?

I have recently removed my stock fenders and am awaiting fiberglass replacements from Rennspeed. My question is, while I have the fenders off, should I sandblast the unibody and then undercoat it? If so, should I prime the area prior to undercoating or should I just spray bare metal with undercoat?

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William Armentrout
1973 911T
2.7 carerra rs specs
www.geocities.com/william_armentrout

Hmm..some guys are positive that the ungalvinized metal of the pre 73? era was worse off with the factory undercoating than without. I think they said it would sweat or something. However, I have a 71e-Turbo look-and when I did metal flares on the front, and had everything off--I undercoated-nose metal and wheel wells-under the gas tank..you name it, even the fenders underside.
If you do this..clean the metal--yes blast if you can, and use an etching agent--incase your coating chips off somehow. AND whatever you do, Don't use the Cheap crap in a spray can. You need TRUCK BED LINER. It set up with a very rough ttexture. Since driving my car, I've powerwashed under there to remove dirt, and it's some really really touch stuff.

good luck...............S

You know...
I've thought about buying some of that truck bedliner material or undercoating and covering the inside of my engine compartment.
I've got it really clean since it is devoid of an engine but as I cleaned, almost as much paint came off as grime. So I was thinking about sprucing it up a bit.
Any ideas? any problems?

That stuff looks really heavy.?!

I used the brand -hercules- and it came in a can. I basically painted it on, but it did not lay heavy like you see in a truck bed (good thing). It actually had these little bubbles/chunks-I really don't know, but it dried with a rough bump texture. DOn't even worry about brush strokes....they disappear right behind the brush! Great stuff, and cand be painted over too...........

Luck.............S

When I first got my 911 I cleaned the bottom and coated it with an undercoat from Wurth called SKS Stoneguard (Part# 0890030-U). You can order it directly from Wurth at www.wurthusa.com. I've used the cheap spraycan undercoat but no more as I think the Wurth is far superior. Costs more, about $18 a quart, and you'll need about 3 quarts for the entire car.

Great stuff

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Allan Broadribb
'70-911E, 2.2l with Webers
http://www.cheaterswayside.com/uploads/Mvc-002s355.jpg

One thing i was told and have read in autobody books is that on any new fiber glass pieces you shoild undercoat them(that is the under side). This help with any damage that can occur with rocks spinning off your tires and slamming into the fiberglass. If a rock hits fiberglass hard enough it will cause it to spider web. Just a little extra insurance.

Thanks for the tip Isolon. I'll undercoat the new fiberglass fenders too.

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William Armentrout
1973 911T
2.7 carerra rs specs
www.geocities.com/william_armentrout