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> WET SANDBLASTING A 914
Curbandgutter
post Aug 10 2016, 04:45 PM
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Well I'm getting ready to wet sand blast (WSB) my project car and I wanted some input form those who have done it and or have some direct or indirect experience with it. I purchased a wet sand blasting kit from a company back east. I tried a sample piece and was thoroughly impressed. I was able to remove the paint down to bare metal on the underside floor in under 5 minutes. It was incredibly fast. The primer that I am using is an epoxy primer by SPI. I spoke with the manufacturer and they said to steer away from using a rust convertor as they can be very tricky to remove from seams. They also said to just blast it and spray it the next day. The flash rust will not be a problem. What has been your experience
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Tom_T
post Aug 10 2016, 04:54 PM
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TMI....
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I know that the guy at my shop wont sandblast at all because the media is too aggressive, & can warp the panels.

As for waiting to the next day to spray the primer - especially with wet sand/media - since I've had flash rust over night when I wire wheeled small areas & thoust it would be okay overnight (I'm also in relatively dry SoCal).

You might consider using soda or walnut shells or other less aggressive media for blasting.

Hopefully Rick/Alien or some of the other body shop members will chime in here on your question.

Good Luck! (IMG:style_emoticons/default/beerchug.gif)
Tom
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Curbandgutter
post Aug 10 2016, 05:01 PM
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I'm WET blasting therefore there shouldn't be any warping? Right?
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SirAndy
post Aug 10 2016, 06:29 PM
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Don't do it! You'll have sand coming out of the cracks for years.

Don't ask me how i know, still makes me angry talking about it ...
(IMG:style_emoticons/default/headbang.gif)


5 years (FIVE!) after the sandblasting: (IMG:style_emoticons/default/icon8.gif)

(IMG:http://www.914world.com/bbs2/uploads/post-179-1151215349.jpg)
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Jeff Hail
post Aug 10 2016, 06:39 PM
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I'm old school BUT for a full strip "dustless blasting" is the new kid on the block

Its wicked fast, uses about 80% less media versus straight media blasting. The wet plasma helps everything along and flushes the debris away. Correct is does not generate heat, in fact it gets cooler a couple degrees below ambient which eliminates any fear of warping. I've seen glass beads used as media.

Water will get everywhere so making sure the H20 has a place to exit is a must.
Warm weather would be an advantage. The bare metal finish is interesting since the water buffers the media impact and you don't get a gigagazillion micro craters.

I saw this demo'd on truck body parts both on aluminum and steel. On aluminum I would use it in a heart beat. I would do it on steel but I would still machine sand AND use a lite chemical metal prep.

You can also learn from Andy the resident German that in some places duct tape may help sealing off areas you do not want media to get into. In the end you are going to have media in places including your ears that you thought it wouldn't get into.
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Vapor_locked
post Aug 10 2016, 07:11 PM
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I'd second & listen to what Jeff has said, and what Sir Andy has pointed out! Good luck with the project!
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charliew
post Aug 10 2016, 08:19 PM
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I would use a rust converter especially if the color of the metal is still dark, but with a sponge to keep it out of the seams. Avoid any runs or sags and watch for little parts of the sponge hanging on the rough metal when you start painting. I spent about 4 months on a 42 ford jeep and it had so much converter on it we reblasted it and then I rewiped it with a thin coat of converter and primered it before I started wiping filler on it. The driver side and floor was pretty far gone. Epoxy non sanding primer then seam sealer then when it is ready another coat of epoxy non sanding primer thinned with the same brand single stage reducer ie: dt reducer to keep the orange peel down. Then I apply the sanding primer. I try to spread filler on the non sanding primer pretty quick like it was a coat of paint otherwise the primer will need to be roughed up and then you gotta watch for scratching through the primer. I use a lot of epoxy non sanding primer to avoid all the extra sanding. You can put the mixed paint in the refrigerator and even the cup off the gun If you gotta stop for awhile. You will need to watch the gun head and blow wash thinner through it if it has to set very long. I would also try not to blow the blasting material into cavities. Hope it turns out like you want it to.

Once a contractor asked me how did I like the job he did on my driveway and I said nothing turns out like I imagined it but it was ok.
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jcd914
post Aug 10 2016, 09:48 PM
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Mark Whitesel (Mikey914/914Rubber) did this to one of his cars.
You can read his thread and watch the video he linked in.

Mark's Stripper Thread

Jim
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jmitro
post Aug 10 2016, 10:29 PM
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my car was media blasted (non WSB) for $1100 in my driveway. No panel warping that I'm aware of. It came out very clean, but there IS a lot of hidden media in the car like Andy described (not a big deal to me since it falls out as I rotate the rotisserie frequently).

As far as flash rust.....In my experience, I've left the bare chassis in my climate-controlled garage for two months with minimal rust since then.....except where my sweat gets on the bare metal. Ideally it would be nice to immediately primer the entire car, but I had too much grinding/welding left to do. I probably should have primered the areas that were finished (like the front trunk or hood)


(IMG:http://www.914world.com/bbs2/uploads_offsite/i75.photobucket.com-18986-1470889782.1.jpg)
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scotty b
post Aug 11 2016, 06:46 AM
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rust free you say ?
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I own the wet system. ( Dustless blasting ) I have used it on a couple different cars. The main problems are :

The sand PACKS into the corners and crevices. You will have to dig it out with a screwdrivers or something similar. In the time it takes to get the blasting done, rinse it off with the HOLDTITE and then clean out the crevices and rinse them, the flash rusting has already started.

High humidity makes the whole system uselss as fas as the rust prevention goes. Here in Va where we get jungle like humidity, I have the panels starting to flash rust almost immediately, despite putting 2-3x the recommended amount of HOLDTITE in the mix, and the rinse

Despite what Tom T says about sandblasting in general, this setup WILL NOT warp panels. I have tried. When I first unboxed it I held the nozzle 1" off the center of a 914 trunk lid for well over a minute and it did NOTHING to damage the metal

It's a great system for the outsides, but IMHO it plain sucks in enough ways that I almost regret buying it
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VaccaRabite
post Aug 11 2016, 11:32 AM
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QUOTE(scotty b @ Aug 11 2016, 08:46 AM) *


High humidity makes the whole system uselss as fas as the rust prevention goes. Here in Va where we get jungle like humidity, I have the panels starting to flash rust almost immediately, despite putting 2-3x the recommended amount of HOLDTITE in the mix, and the rinse


This would be the case for any blasting though, right?
Blasting stuff clean in PA on a humid day you could see flash rust forming before I was even done clearing the pedal cluster (using aluminum oxide from a bucket blaster).

I know when I was painting my 914, I tired to do all the body work pre-paint during the winter to control flash rusting (and this was with mechanical and chemical stripping).

Humidity sucks ass.

Zach
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mbseto
post Aug 11 2016, 12:19 PM
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Need a nitrogen atmosphere paint booth.
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Jeff Hail
post Aug 11 2016, 12:57 PM
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QUOTE(mbseto @ Aug 11 2016, 11:19 AM) *

Need a nitrogen atmosphere paint booth.



Not really. Nitrogen does not carry moisture. You need atmosphere to bind water or solvent molecules to carry them away.
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mepstein
post Aug 11 2016, 01:24 PM
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QUOTE(scotty b @ Aug 11 2016, 08:46 AM) *

I own the wet system. ( Dustless blasting ) I have used it on a couple different cars. The main problems are :

The sand PACKS into the corners and crevices. You will have to dig it out with a screwdrivers or something similar. In the time it takes to get the blasting done, rinse it off with the HOLDTITE and then clean out the crevices and rinse them, the flash rusting has already started.

High humidity makes the whole system uselss as fas as the rust prevention goes. Here in Va where we get jungle like humidity, I have the panels starting to flash rust almost immediately, despite putting 2-3x the recommended amount of HOLDTITE in the mix, and the rinse

Despite what Tom T says about sandblasting in general, this setup WILL NOT warp panels. I have tried. When I first unboxed it I held the nozzle 1" off the center of a 914 trunk lid for well over a minute and it did NOTHING to damage the metal

It's a great system for the outsides, but IMHO it plain sucks in enough ways that I almost regret buying it

The shop where I work bought one before I came on. Same experience as scotty b. I think it's sitting in a box, in a corner.
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Vysoc
post Aug 11 2016, 01:38 PM
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I agree humidity is a monster, come to Florida its so humid it rains every afternoon between 1:00 and 5:00!

Now the fun two months August & September putrid heat (IMG:style_emoticons/default/barf.gif) !

Vysoc (IMG:style_emoticons/default/flag.gif)
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worn
post Aug 11 2016, 02:44 PM
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QUOTE(Jeff Hail @ Aug 11 2016, 10:57 AM) *

QUOTE(mbseto @ Aug 11 2016, 11:19 AM) *

Need a nitrogen atmosphere paint booth.



Not really. Nitrogen does not carry moisture. You need atmosphere to bind water or solvent molecules to carry them away.

But nitrogen does not easily create rust, which would be nice. The time when the sand from wherever becomes most apparent is when the spray gun mixes it out of the crevices and straight into the paint. Not fun at all.
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Curbandgutter
post Aug 11 2016, 06:47 PM
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Thanks guys. After talking to paint manufacturer, I'm going for it. Will strip with water and sand, have rotisserie so will spin often to get sand out of hidden areas, will mask off tubes, etc. We will see how it turns out. I'll post video as well. By the way this will also be in my build thread "V8 914 speedster build"
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914forme
post Aug 11 2016, 07:30 PM
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Times a wastin', get wrenchin'!
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(IMG:style_emoticons/default/popcorn[1].gif) good luck
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mbseto
post Aug 12 2016, 08:14 AM
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QUOTE(worn @ Aug 11 2016, 04:44 PM) *

QUOTE(Jeff Hail @ Aug 11 2016, 10:57 AM) *

QUOTE(mbseto @ Aug 11 2016, 11:19 AM) *

Need a nitrogen atmosphere paint booth.



Not really. Nitrogen does not carry moisture. You need atmosphere to bind water or solvent molecules to carry them away.

But nitrogen does not easily create rust, which would be nice. The time when the sand from wherever becomes most apparent is when the spray gun mixes it out of the crevices and straight into the paint. Not fun at all.


Exactly- no oxygen, no rust.

My comment was a a little tongue in cheek, but it would be interesting to try it...
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Mark Henry
post Aug 12 2016, 09:15 AM
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Actually this looks interesting and you can get cheap ones now. Not pro models, but it may be all you need for a few jobs. You could use it to augment regular blasting and stripping, get all the heavy rust off, then sand and dry blast off any flash.
The big thing would be prep, blocking all holes to keep the sand out.
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