wet blasting

Started by 94touring, April 15, 2016, 01:37:45 PM

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94touring

42 bags of 80lb fine sand.

94touring

Well it takes 800lbs to do a roof and complete underside.  I'm interested in a comparison if I did the same area dry if it would take less.  The up side I've found is hosing the car out makes it easy to remove sand.  The down side is the flash rusting and all the scrubbing clean after spraying the acid on.  Interestingly enough the new cill didn't flash rust but the stock metal rust instantly.

94touring

4 wheels I can't imagine taking me more than 30 minutes, back and front.  I probably spent a couple hours doing the roof and underside today.  The underside went very quick compared to the roof, which had several layers to cut through. 

My thoughts were the old metal must be crap!  It was interesting to see the new cill stay shiney and everything else turning rusty.

94touring

So...phosphoric acid is like crazy glue when you get it on your finger nails.  I have smurf looking nails today.  And fwiw I took the pressure washer to the primed areas to verify adhesion and nothing flys off.  This is with the blast nozzle with 4000psi behind it.  I could remove most of Vikram's paint with just the water alone, so this is comforting to know.  Last thing you want as a painter is paint peeling off down the highway!

TDA

Hello,
I am new on this forum.  I have been a "lurker" in the past but now am registered and I am interested in you opinion of your wet blasting setup.  Are you satisfied with the results?  Did you ever come up with a better solution to the flash rusting?

I have done a little internet research and was wondering if you know anything about a product called Holdtight. Per their web site description, "HoldTight® is a wet blasting additive that decreases the water's surface tension, allowing it to get into the pores of the surface and remove ALL contamination, including salts, acids, abrasives, light oils, and greases. HoldTight® leaves behind zero unwanted residue, and evaporates with the water, providing a surface that is thoroughly clean and ready for a tightly adhered coating bond for up to 72 hours." and  "HoldTight® is safe and effective on a wide variety of surfaces, delivering superior surface preparation, with proven results on land, at sea, on storage tanks, on bridges, on oil rigs and even for specialty projects like restoring vintage cars."

Let me know if you know anything, positive or negative about this type of product.  If it is effective it seems like it would be easier that the Phosphoric acid scrubbing/wipe down.

Thanks!   

94touring

I did look up a couple products like you describe but haven't tested them.  Spraying with the phosphoric solution and wiping down hasn't been too bad honestly.  All in all I'm very pleased with the setup.  Be ready to go through tons of sand though.

Nicholasupton

As someone with a big setup (look up MMLJ dustless blasting) I can vouch for the Holdtight working very well, and is PPG approved undercoat for epoxy primers. I use it during the process, and then once more during the rinse out phase. After blowing the body dry inside and out I can leave it indoors for a few weeks with only flash rust occurring where someone's bare hand touches it.

MiniDave

Welcome to the forum, TDA - since I'm in KC to I wonder if we've crossed paths?

I'm MiniDave on the KC forum too........
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

TDA

Yes Dave, we met at the 2015 KC All British car show.  My brother Jim had his yellow race mini and red street car at the event.

MiniDave

OK, now I know who you are!  ;D
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

94touring

Just bought a 5 gallon bucket of hold tight.  I hope this stuff is rust magic.

TDA

Please be sure to let us know how well it works.

Thanks!

94touring

Ok the verdict is in!  The best combo seems to be wet blasting with plain water, then giving it a quick spray with phosphoric acid, then rinse off with the lock tight.  I bought a garden sprayer to easily monitor the amount of lock tight being sprayed.  This method uses the least amount of the stuff which is good since it's so damn expensive. Here are 2 doors.  One of them is not treated on one half to note the difference.

MiniDave

Cool, so that will save a lot of sanding and re-prepping?
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

94touring

Yeah it cuts down an extra step or two of lots of tedius cleaning.  Well worth it.

94touring

I'll have to grab a picture when I get home but I fabbed up a shorter wand to make blasting easier.  The current 30" wand is really too long and makes it tricky in some spots plus tires your arms out.  I put together a little 6 incher to plug the blast nozzle into. 

94touring

Here's a pic of the extension.

MiniDave

Cool, what's the little wingnut for?
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

94touring

The wingnut makes pulling out the piece that has the 0 degree nozzle easy, if it gets sand in it.

94touring

Updates.  The short wand didnt work, guessing a loss of pressure due to changes in inner diameter of the pipe.  But good news is it only takes a quart of the hold tight to rinse the car off after giving it a phosphate bath.

Lone Star Mini

Dan,   Without knowing how long you've had the kit nor how many jobs you have done with it, you recommend and I'm curious how well it worked with the various mini parts (doors, boot, bonnet, etc...).  Having never blasted anything, I've been reading any/all that I can find.  Loads of people warn against warping, not using sand, etc..etc.  Then too, directly after blasting, is it necessary to treat with rust inhibitor like you did on your doors?  For me, it's a nice tool expense on compressor and kit...  you are dealt with the exact project that I'm doing so I must rather trust your advice over the thousands of other experts out there..
Lone Star Mini
1982 Morris Mini 1000HL (heck of a lot of work ahead of me)
1992(?) Mini Cooper
1964 Austin Cooper
1980 Mini 95 (Pickup)

94touring

I've done a few shells now and several subframes with it.  If you point it directly at a flat piece of thin sheet metal an inch away, it will damage it. Angled 45 degrees a foot or more away is the ticket. You can saw trees in half with this thing.  You will want to use a rust inhibitor like I show, because it will flash rust within minutes.

Lone Star Mini

Ok,  I'm putting this on the 'wish list'.. did you ever get the shorter gun designed to work well?  I can see how having the long arm gun will not be able to get into tight places like the boot area...
Lone Star Mini
1982 Morris Mini 1000HL (heck of a lot of work ahead of me)
1992(?) Mini Cooper
1964 Austin Cooper
1980 Mini 95 (Pickup)

94touring

Never got the stubby one to work but bought an 18 inch wand that did the trick.

Lone Star Mini

Dan,  based on the description, do you think this 12" wand will work well enough (attached link) with the kit?

https://www.amazon.com/dp/B0053GIK8A/_encoding=UTF8?coliid=I2Y8ORI6QK6L3I&colid=10MDAV8W26KBZ
Lone Star Mini
1982 Morris Mini 1000HL (heck of a lot of work ahead of me)
1992(?) Mini Cooper
1964 Austin Cooper
1980 Mini 95 (Pickup)