Re: Paint! pros and cons!

Rich Atherton (gumby(at)connectexpress.com)
Fri, 12 Jun 1998 11:05:07 -0700

Blasting with Sand can and WILLl eat through metal if left in one spot too long. be careful. Walnut shels chips also clean very well, and will not eat through the metal, but will have a tendancy to leave the walnut shell oil on the surface which then requires a laquer thinner wash afterwards. Porably the best solution, is to use Plastic beads. No damages to the metal, cleans a bit slower then sand or walnut, but leaves no oil or residue other than dust, which they all do. Disadvantage to plastic, is you have to replace the beads more often, becasue they get punded and no longer clean well. So the supply costs may be a bit higher..End result is better, in my opinion.

Rich

-----Original Message----- From: Jarrid Gross (Yorba Linda, CA) <GROSS(at)UNIT.COM> To: alpines(at)autox.team.net <alpines(at)autox.team.net>; jerome(at)supernet.ab.ca <jerome(at)supernet.ab.ca> Date: Thursday, June 11, 1998 8:30 AM Subject: Re: Paint! pros and cons!

>Jerome wrote,
>
>>I weighed the goop-vs-grit argument too, and went with bead-blasting.
>>$600 too. I figured vacuuming and blowing out the beads would be far
>>preferable to smearing and scraping, and would clean the surface better.
>>Beading also removes any metal that isn't of a certain thickness, even
>>when hidden by Bondo. I also beaded every other metal part that needed
>>or could use painting (I have a bead cabinet available). I have also
>>seen mention that beading effectively shot-peens the surface of the
>>metal, reducing its surface porosity and making the "skin" harder.
>>
>>Along with a vacuum I would strongly recommend compressed air. There are
>>a lot of tight spots that a vacuum can't reach but 80psi air will.
>
>
>I had the doors, hood and trunk blasted with walnut shells.
>I heard good stuff about the walnut shells, and heard only that some oily
>residue may be pressent that will add some prep work to the
>priming process.
>
>I wish now I had never blasted those panels.
>
>One thing that the blasters dont and wont tell you is the rate at which
>they shoot the abrasive material is variable. If they have a lot of work,
>they will hop up the volume one the grit, and get the job done quick.
>On my panels, the went in somewhat straight, and came back very
>warped.
>
>I spent some good money on a clean straight trunk lid, only to have
>the blaster warp all over it. The warpage occurs at the points of least
>thermal conductivity. On the trunk it was on the top of the panel around
>the 4 areas where the lids innere panel exposes the sheet metal skin.
>
>On the doors it was just plain ripple.
>
>I dont even want ot talk about the hood.
>
>
>Needless to say, I got really intimate with a body hammer, filler and the
>long board.
>
>
>The remainder of the car was stripped to metal using a body grinder.
>This was a lot of work per square foot, but not as much work as fixing
>my newly net panels after the fact.
>
>
>If you want to go the easy way, and have the parts shot stripped, thats
>your biz, but let me give you a word of advice, show the stripper your
>parts are straight on the input, cause if they arent on the output, the
>strippers gonna say you brought bent parts.
>
>
>
>
>Jarrid Gross