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Ok so my future son-in-law wants to help me restore my HMV. We have been going back and forth on the merits of having the body dipped in a costic solution or having it media/sand blasted.
So my question is this....Which is better and why?
Is dipping the body better for rust killing or is media blasting better. Both camps will tell you there method is the best...duh they want my money, but I thought the knowledged persons here might be able to shed some light on this.
I had a hood on my 72 ford dipped, it came back looking just like new, the company put ospho on it, I wish I would have had them prime it , there was some rust spots on the hood but after it was dipped, only the holes were left, The only draw back was it took like two months for me to get the hood back . but that might just be cause the place was so busy, If your thinking about dipping, I think its better than sandblasting because it gets in all the cracks and crevices, THe bad , you have to get paint back in the crack and crevices, Sandblasting only gets what you can get to with the blaster, just what you can see. Asked how long is going to take to dip it , and also how much more to prime it. the company should have the primer guns with the extened wands to get the tigh spots, I sandblast all my stuff but only because Iam set up for it, but if I had a place close by i would opt for the dip
Blast, but NOT with sand.
When you dip, you never get all the solution out of the cracks and joints. It will later cause your paint to peel off when it slowly seeps back out.
Blast with baking soda or dry ice, but never with silica (sand). The blasting media also gets into every corner and is impossible to wash out. However, sand retains water, and starts rusting your vehicle from the inside out. Soda won't do that as much - it will mix with water and drain out easier. Dry ice is the best. It leaves no residue at all, but is a newer process and there may not be someone around you that does it.
Zach (the noobie)
I get my truck back today from the blaster. They used plastic. I already got all the removable items back and have primed them. I'll write up a report on the entire porcess as I sure learned alot.
Blasting also leaves the surface of the metal in beautiful shape for taking paint, from what I've seen...
I beadblasted my truck with plastic beads almost 10 years ago. No problems to report since then. Just about ready for paint again. My friend had his dipped 8 years ago and has not seen many issues either. I have seen the "seepage" of the solution creep out and eat paint on other projects though.
I dipped my windshield I got from someone here, it came out clean, I let it sit for a couple of weeks befor I had it painted about a year ago, so far no problem. I've used both, blasting works real well on wheels and such, but to get into all the cracks and corners I kinda like dipping. 02.
Dry Ice??? I've never heard of such "Tom Foolery"!!!Quote:
Originally Posted by vacca rabite
lol, Actualy could you just elaborate on the dry ice procedure and benefits for us noobs.
Also wont blasting with air, clear out any residual silica debre from cracks or crevices?
Blasting has its advantages, but using something like sand can warp the sheetmetal, as it does generate some heat from the friction. Silica or aluminum oxide is better in that respect. Soda blasting is a good method, but requires its own equipment, so it can get pricey.
Getting all the blasting media out can be a challenge, particularly like the inside of doors and cabs and such. Leftover media can hold moisture and cause rust as mentioned above.
Dipping in a caustic solution can also create problems if not all the solution is neutralized or removed, in that it can cause paint adhesion problems.
Whatever method you use, be sure that if it is stripped to bare metal, that you use a self-etching primer before doing any painting. Regular grey primer or rattle-can isn't good enough. You will need something that will etch the metal surface and truly get a firm grip, so you don't do all this work for nothing.
Another note on blasting with sand.... you actually loose some metal in the process. Be careful with thin stuff you'll bend the snot out of it if you're not careful.
Well...we don't have anyone in our AO that does the dip method any more. I think the EPA has gotten to alot of them. We decided that we wont start the process till maybe this fall so we're going to give it a face lift (i.e. fresh coat of paint and some puddy) for the summer.
I have a media blaster who I've worked with before that does a very good job. He uses plastic beeds, corn husks, coco shells and a few other media to achieve the right job. He also uses a primer (priming is included in the cost of the job) that is incredible. He did some parts for me a few years ago and I didn't get around to painting them for another year and they were still as good as when I got them from the blaster. So I'll have him blast and prime when we get to that stage.
I too am interested in the dry ice method....
One of our departments at work has a dry ice blaster. We use it for cleaning crystal and glass prior to bonding. It leaves an incredibly clean surface and does not etch the crystal. We use it specifically to remove residues that might interfere with our bonding processes. The machine however is not a standard sandblaster. It is specially made to use dry ice. You feed the machine pelletized dry ice (usually available at places that refill fire extiguishers). The pellets are somewhat smaller than the pelletized ice some fast food joints use for drinks. Before anyone asks, no I can't blast parts for anyone (including myself). If I remember correctly, our machine is manufactured by Coldjet. It is a fantastic machine (for our purposes), but I can't speak to its abilities/capabilities on removing paint, rust, etc. You can check these guys out at www.coldjet.com. I am sure there are dozens of other companies making these things. One of the nice things about it is that there is no blasting media. The only trash that would be left on the shop floor or in nooks and crannies is what is removed from your material. In other words, no sand, baking soda, glass beads, plastic beads, etc on the shop floor, only rust and paint and dirt that comes off what you blast. It does however, generate a large amount of fog. It is also non-toxic unless you are removing toxins from what you are blasting (leaded paint, chemicals, CARC paint, etc.)
I've read through some of the dry ice blasting information found online. It appears to be a superior method for many uses. What I intended to locate was some disadvantages of its use versus other forms of blasting (sand, corn, etc.), but could not identify any detrimental aspects. Could it be that the equipment and material are expensive compared to other blasting techniques?
If not, this would prove to be a great tool for home restoration, as well as vehicle bodies. Being that some folks here are in the trade of painting contractors, I'm curious as to the industry acceptance of this form of blasting for paint removal and wood siding preparations in their business, or if they have any experience with this blasting method. In the past, I have anticipated using corn, as the debris would be considered biodegradable and therefore wouldn't require an extensive cleanup. Dry ice blasting appears to be a better option.
Another great biodegradable media is Walnut Shells.
The big issue though in the environmental aspect is what you remove. That seems to be the biggest issue.
Many new degreasers claim to be biodegradable as well, but the grease they remove is not.
I simply need to remove 100 year old, and multiple layers of, lead paint...and potentially clean a little asbestos siding. So, I'm pretty confident in the subtle environmental impact, and mostly just concerned with the media debris.Quote:
Originally Posted by randyscycle
Google the Dry Ice blasting. If you can find it in your area it is the way to go. It is a newer tech, and only a few places do it.Quote:
Originally Posted by rip68
As to blasting with air... Nope. You can air blast, vacuum and wash all you want, and you will never get all the blasting media out of your vehicle. Too many hidden corners, too much static cling, too much rust and cobwebs and stuff you can't see to get lodged in.
Zach
I agree. I have only ever blasted one complete vehicle, and I wished I hadn't. It was a total mess that kept coming back time after time until I finally got everything primed and sealed twice. I still found that stuff sifting out of body seams a year later.Quote:
Originally Posted by vacca rabite
Media is still pouring out of cracks in my truck. The truck floor is again all white from it. Air gun and vacuum over and over and still it comes out. It is a job to keep it off the new primer and/or paint. Also, it is wedged in all the seams so a packing knife blade in the seams, to clean out the beads, is also needed.