Sand blasting valve covers-is it safe?
#1
Drifting
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Sand blasting valve covers-is it safe?
Title says it all. Wondering if I can sand blast my valve covers or if that's a bad idea. Never sand blasted anything before. I used paint stripper on them and they're a lot better but still need a little work and I'd rather not sand by hand if I can avoid it. Eventually going to repaint them high temp silver. They're the original magnesium covers.
Being stripped
After strip. Hard to see but still paint in the cracks and on the ends a bit.
Being stripped
After strip. Hard to see but still paint in the cracks and on the ends a bit.
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Bfenty (05-21-2017)
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Bfenty (05-21-2017)
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Bfenty (05-21-2017)
#6
Melting Slicks
probably better to 'media' blast them, just wash and blow them out really well afterwards.
I media blasted mine with fine crushed glass then power coated them and they came out really nice.
I media blasted mine with fine crushed glass then power coated them and they came out really nice.
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Bfenty (05-21-2017)
#7
Melting Slicks
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PS: The casting quality on the early ones (at least) is TERRIBLE.
Expect to spend a little time with a file and sanding to get them to look decent. The thick factory paint hides a bunch!
Expect to spend a little time with a file and sanding to get them to look decent. The thick factory paint hides a bunch!
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Bfenty (05-21-2017)
#8
Melting Slicks
I have a simple sand blast gun. It only uses play ground sand. This type of blasting should be fine. Your next decision after blasting will be to clear or paint your valve covers. This type of spray gun is cheap but you need an air compressor.
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Bfenty (05-21-2017)
#9
Drifting
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Thanks for all the replies! I decided to sand them down the old-fashioned way, by hand. They turned out pretty well but there were a few imperfections that showed up when I painted that didn't before. Annoying because of all the work I put in, but not so bad I want to strip them down again.
Now the question is, do I need to use high-temp clear coat on them? I've seen conflicting opinions elsewhere, so I'm curious if anyone has used normal dupli-color clear on their valve covers, and if they have any issues. I'd just go buy the high temp, but I've got like 4 cans of regular clear I'm trying to use up.
Now the question is, do I need to use high-temp clear coat on them? I've seen conflicting opinions elsewhere, so I'm curious if anyone has used normal dupli-color clear on their valve covers, and if they have any issues. I'd just go buy the high temp, but I've got like 4 cans of regular clear I'm trying to use up.
#10
Pro
Your work looks great. I wouldn't use clear, it might turn yellow over time. Just my opinion.
#12
Racer
Did anyone else get "bubbles" between the fins on top .Why does this happen
. also could I use Bondo or something similar to cover casting defects? Yours did come out NICE! Sorry to high jack but I did mine a while ago and now the bubbles are getting worse..
. also could I use Bondo or something similar to cover casting defects? Yours did come out NICE! Sorry to high jack but I did mine a while ago and now the bubbles are getting worse..
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Bfenty (05-22-2017)
#13
Melting Slicks
If the bubbles are in fact bumps in the actual metal from casting defects then you can grind/sand them smooth before painting or maybe use filler but I'm not sure how well body filler does in a high-heat application like and engine.
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Bfenty (05-22-2017)
#14
Flatulent Dwarf
Thanks for all the replies! I decided to sand them down the old-fashioned way, by hand. They turned out pretty well but there were a few imperfections that showed up when I painted that didn't before. Annoying because of all the work I put in, but not so bad I want to strip them down again.
Now the question is, do I need to use high-temp clear coat on them? I've seen conflicting opinions elsewhere, so I'm curious if anyone has used normal dupli-color clear on their valve covers, and if they have any issues. I'd just go buy the high temp, but I've got like 4 cans of regular clear I'm trying to use up.
Now the question is, do I need to use high-temp clear coat on them? I've seen conflicting opinions elsewhere, so I'm curious if anyone has used normal dupli-color clear on their valve covers, and if they have any issues. I'd just go buy the high temp, but I've got like 4 cans of regular clear I'm trying to use up.
After each step I wash them in soapy water with some simple green ( use the simple green sparingly )
Just before I shoot them I always wipe down the surface with a good quality lacquer thinner, of course I shoot a primer coat. Easier to remove crap from the primer than expensive epoxy.
Quality paint work ALWAYS requires meticulous surface preparation.
Here's a couple of pictures of what time in preparation will give you.
Before ( with millscale removed ) and after.
Last edited by 1800Wing; 05-21-2017 at 11:48 PM.
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Bfenty (05-22-2017)
#15
Drifting
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Wow those are good results! Yea I wish I had bead blasted mine. I just hand sanded, thought I had a pretty good surface, but the metal was a bit pitted I think. I did wash them pretty well with simple green then wiped down with isopropyl alcohol.
#16
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One thing I did that I don't think I mentioned in the original post is I baked them in my BBQ on low for about 30 minutes and then cleaned them again. Vikingtrader recommended this step to me because the metal is porous and can get oil in it that bubbles out at heat. Mine did "bleed" a little oil this way, perhaps that's what is happening to you?
#17
Safety Car
here we go again with baking VC's. baking VC's in a BBQ is absolute - you bake cookies not valve covers! de-grease before bead blasting. magnesium VC's should be cleaned with a solution of TSP (tri-sodium phosphate), and solvent clean before any paint work. an initial coat of etching primer prior to any topcoat is a must.
Step 4.
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Bfenty (05-22-2017)
#19
Melting Slicks
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With used parts, it REALLY DOES help before powder coating. I have an electric oven here dedicated to powder coat, and the pre-coating heat up evaporates a lot of oil and nastiness that hides in the crevices.
The smoke on the pre-heat compared to subsequent bake makes it completely obvious you're removing hidden oil and grease.
The smoke on the pre-heat compared to subsequent bake makes it completely obvious you're removing hidden oil and grease.
#20
well, since I assumed the subject was PAINTING valve covers, and not powder coating, and while an outgassing step might apply to powder coat, baking parts in a dirty, old, greasy, outdoor BBQ grill, prior to painting is utter BS. personally, I could care less what anyone does, but FWIW, I've been refinishing (paint) various types of castings for well over 40 years, and have yet to throw anything on the Weber outdoor. as a mater of fact, I've probably refinished a dozen sets of corvette magnesium covers over the last 20 years without a "cookout." I guess while you're at it, you guys could save some time, and throw on a couple burgers.