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Machspeed

Metal Prep After Media Blasting

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Spoke with a local media blaster yesterday. Said he'd blast my car with plastic media and promised me he would not warp the body panels. Think I'm gonna hand it over to him. I need advise now on what to do the blasted metal before epoxy priming....i.e.  DA, clean, etc? After blasting may be a week before it makes it to the painter. My plan is to get it blasted, bring back to my shop for prep for epoxy priming, then haul to painter and let him prime. Car will then come back to me for seem sealing and some minor body work, then back to painter for paint.    

Thanks!

 

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1 hour ago, Machspeed said:

Spoke with a local media blaster yesterday. Said he'd blast my car with plastic media and promised me he would not warp the body panels. Think I'm gonna hand it over to him. I need advise now on what to do the blasted metal before epoxy priming....i.e.  DA, clean, etc? After blasting may be a week before it makes it to the painter. My plan is to get it blasted, bring back to my shop for prep for epoxy priming, then haul to painter and let him prime. Car will then come back to me for seem sealing and some minor body work, then back to painter for paint.    

Thanks!

 

I recently had my 70 mach dustless media blasted right in my driveway. Dustless uses a mixture of water with a rust inhibitor. It does not create any heat, so no possibility of warping. I had it done two months ago and I am pleased with the result. Although I have to say it still created a mess of the area and I am still blowing media out of the car's nooks and crannies. I have not primed it yet and still no flash rust.

Getting ready to sand and prime it. I plan on using a gallon of Evercoat super build 4:1 with a quart of 4:1 catalyst and then work up to a 2k primer for blocking. 

 

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We have a guy around here that does that too. I have heard good things, but it does make a mess. That process remove all the undercoating too? I've been in the shop tonight with an air scrapper removing some the heavy factory undercoating. Some of that stuff is tough to get off. Curious, what did that cost you? 

Yeah Ridge, had planned to hit it with a DA and some 80 grit. Was wondering if the body needed to be cleaned before and after the DA work. 

 

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It does need to be cleaned after sanding, you will be surprised at how much dirt will come off it, some people just blow it down and prime it but I would not be happy painting over all that crap.

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11 hours ago, Machspeed said:

We have a guy around here that does that too. I have heard good things, but it does make a mess. That process remove all the undercoating too? I've been in the shop tonight with an air scrapper removing some the heavy factory undercoating. Some of that stuff is tough to get off. Curious, what did that cost you? 

Yeah Ridge, had planned to hit it with a DA and some 80 grit. Was wondering if the body needed to be cleaned before and after the DA work. 

 

The guy spent a full 8 hours doing the car inside, out and underneath, and a bunch of other parts, and then debris clean up afterward. Cost $1,200. He removed much of the undercoating and sound deadening in the wheel wells and firewall. The guy said that it is hard to get it all off. I did tell him to skip the floor pans since they were going to be replaced.

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4 hours ago, Rich Ackermann said:

The guy spent a full 8 hours doing the car inside, out and underneath, and a bunch of other parts, and then debris clean up afterward. Cost $1,200. He removed much of the undercoating and sound deadening in the wheel wells and firewall. The guy said that it is hard to get it all off. I did tell him to skip the floor pans since they were going to be replaced.

 

 

Wow, 8 hours.....longer than I thought. As to the sound deadening, bought a pneumatic scraper yesterday and began scrapping. Interesting how at times it seems to come off easy and other times it is incredibly tough to remove. I was thinking last night that there is no way a blaster would remove some of this without warping a panel. Ridge made comment to that, actually.   

Question to all, the window sealant is a nasty gooey mess. What is the best was to remove it? 

 

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Scrape ,then gas on a wrag .

8 hours is about right for blasting ,depending on how much build up it has under it . The wheel tub under coat usually blows out fairly easy ,but the tar just about has to be scraped out . Lots of tar up around the cowl sides and inside the trunk ,and around the wheel tubs and floor joints . Oily under side can be a pain in the butt also ,and if they have ever been under coated it somtimes has to be scraped before blasting or tbe sand just bounces off or smears soft under coat

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1 hour ago, mustangstofear said:

1200 is more than reasonable.  I don't  really  trust any 2K primer over Epoxy.  Maybe on a small  area , but  not a full  body.

Hmm. Curious why? Appreciate if you would elaborate why you don't "trust" it. I not all that experienced with it.

Thanks

 

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Epoxy primer is the best primer for metal, as it fully bonds to the metal and seals it as well.  No need to layer on another primer layer unless the epoxy had set for a long time with a top coat of some sort.  Even then, a simple scuff of the epoxy is more than adequate for the next layer of paint material. 

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After I had mine soda blasted ~20 years ago, I wiped it down with some forgotten liquid to counter act the soda. I then immediately sprayed it with epoxy primer. No adhesion issues since then. 

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Standard  operating procedure for  us is strip  to bare metal  then epoxy.   Then the next  day we can start with the  body work  providing  we haven't  broken  through the epoxy  we will prime with PPG  VP 2100. After all  body  work is  done we will do a final prime with 3 coats of  PPG NCP 271 primer.

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4 hours ago, mustangstofear said:

Standard  operating procedure for  us is strip  to bare metal  then epoxy.   Then the next  day we can start with the  body work  providing  we haven't  broken  through the epoxy  we will prime with PPG  VP 2100. After all  body  work is  done we will do a final prime with 3 coats of  PPG NCP 271 primer. 

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So Rich, I'm assuming PPG  VP 2100 is an epoxy primer and  PPG NCP 271 is a urethane primer, which differs from a 2k primer? I'm curious, have you had problems with a 2k primer over epoxy? I'm a fan of SPI products and unless things have changed, they recommend their 2k primer over their epoxy. They provide very detailed instructions on application of their products in an outline by SPI, titled "The Perfect Paint Job". I've spent a lot of time researching this and reading comments from people on the Autobody forums that are very pleased with this combination. I'm no painter, so I have no input into this. Those like you whom work in the field know much better, however, we do tend to also go with what works for us. I'm just curious if you have had issues.  And, I don't want this turning into a pissing war, as I've seen threads like it. I just desire the input. Thanks! 

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