Sand Blasting

I really want to get started on cleaning the bottom of the van. The plan was to lift it and scrape all the gunk and crap off the bottom but I am thinking I would like it to go a bit faster than that.

I have a very large air compressor, 22 CFM, so it can easily handle a sand blaster. Can anyone recommend one and what it will entail? Do I just buy sand from a gravel yard or is there a special kind I need to get? Certain options that I should look for and some to avoid?

I figure this will be ideal since I can then use it on small parts if I make myself a cabinet to use it in also. I have seen cheap cabinet blasters but not sure what to look for and what to stay away from in that area also.

Any advice would be greatly appreciated.

Matt,
I don't know a whole lot about using a blaster but I do know that regular sand from a gravel yard won't work. I think a lot of people are using walnut shells & soda mainly to blast with. I have read that both of these methods work really good. Some others are glass beads & natural silica sand. I think that the big reason that people are using the soda these days is to avoid the mess that the sand makes. I have read that it is hard to get all of the sand out of everywhere when everything is finished.

Matt, I posted a thread with a media blasting video on here. I'll look for it.

Dan beat me to it...

Let me help you out Lee.

Here's the link.

https://vintage-vans.forumotion.com/t24561-media-soda-blasting-and-liquid-chrome-paint-video-demo-by-eastwood

Matt the main thing is the sand has to be DRY! Any moisture will cause the sand to clog in the gun. My local cement yard sells dried sand by the ton. The biggest problem is that the sand get EVERYWHERE. If your planning on doing it in your shop I would suggest building a tent around the van to contain the sand and dust. That would be a big help for cleanup and possible recycle of the sand. You can also buy the sand in 100# bags but it's going to take a bunch to do the bottom of the van.

I've got one of the Harbor Freight pressure pots that works fine for home projects.

You can't even use sand for sandblasting in the UK. It has been banned due to the dangers of breathing in the silica. It can be very nasty, so should be avoided....!!

In regards to sand blasting underneath, wouldn't the sand get into lots of places you wouldn't want it, such as joints, rubber parts and places filled with grease? Always wondered about that...

I bought one of the harbour freight blasters several years ago & used sand in it and it didn't do nothing but stop up. It was bagged sand that I used but I don't really know of it was dry & I also used a 110 air compressor with it. I guess that's why I had no luck with it. I wish now that I hadn't gave it away knowing that I had the wrong sand & to small of an air compressor. There is a place close to me that all they do is sand blasting. They have been in business ever since I was a kid & they always have did there work outside. I always wondered why they didn't have a building to do it in but after reading about all of the mess that the sand makes I know why now. I now have a monster industrial 220 air compressor & might try another harbour freight blaster.

Sand will get everywhere!! also - good to remember - the friction caused by the sand will warp the metal sometimes if done too close & too agressively. Soda blast wont do the same that easily. Sand also will etch the metal deeper and give a rougher finish to metal- therefore will take more primar & such to cover it when done .Possible- with the eastwood / harbor freight blasters(sand) you could use soda also?? or change a nozzel if needed to accomodate?
yes they do take a lot of air also

Lazarusvan wrote:In regards to sand blasting underneath, wouldn't the sand get into lots of places you wouldn't want it, such as joints, rubber parts and places filled with grease? Always wondered about that...

The bottom is stripped of parts. Both front and rear ends off, all cables and lines, etc. It isnt real rusty, (a little surface) just nasty from the grease and oil and tar from the years. I want to get it back to new look and sealed so I dont have to worry about for the life of the van.

I seen the videos, very interesting. I had planned on sealing the bottom of the van for when I blast with a fan in front to blow air in and a large fan on the back to suck the dust out. I have very good respirator, not a dust mask, that I have used for painting and spraying chemicals.

The biggest job that I've done with mine was the outside of an 8'x 16' portable building. I used plain sand, dried ( in the July sun) and sifted it(through screen wire) myself. Was time consuming but it worked fine.

What Wideload said , the sand has to be dry! I have dried it using an old cement mixer and a biga$$ed propane torch but thats not the way to go. The silica threat for a almost one time exsposure is nil. We run an aggregate pit , I know dust. Yes the sand will get everywhere especially if you blast the interior. I bet I can still blow some out of mine if I try. The last time I bought sand/slag media I think it was around 10$ a bag. 80#s? How much it takes depends on how spotless you want it and how quick you get tired of sand in your shorts. I'm thinking I used 8 bags on mine but I wasnt shooting for a super clean result and also did some of the exterior edges where it wouldnt warp, roof rails and spots that werent flat.

Besides blasting, other options for cleaning the bottom. I know the "Gunk" removal would be time consuming but not impossible by hand, its the whats under that. Paint? Undercoating? on the steel that worries me, and the surface rust but if I am going to shoot the whole bottom with POR15, how much of this do I need to get off and how smooth?

I used a heat gun for the undercoat and a puddy knife. the chemical are hard to use under the van.

After blasting plan on using a air gun the clean it out a least 2-3 times that crap get everywhere

I wonder how the dry ice method is done?

Well maybe I should give G-man's idea a try first. Instead of rushing out and spending $250+ on a blaster a $20 heat gun and puddy knife with some labor might be the better way to go.

I grabbed a couple of pictures under the van.

1. So paint was used only in the wheel wells and not the whole underbody?
2. Should I strip that also so I can respray this area with POR15 also?

Drivers side Wheel well...



From the passenger side by the side doors looking towards the drivers side...



I have a high pressure washer but since the van is inside my garage with no way of getting it out till the under body is done, I dont want to go that route. I know I could get the van OUT if I put some of those car dolly wheels under it, its getting it back in that would be near impossible since I dont have a paved area to move it out to, washing it would turn the ground to mud and it would never roll back in.

Want to add I did blast the 64 after scraping it. A lot of work , but worth the time

I know the warnings about silicosis, but I use the fine playground sand from Home Depot. I just suit up and wear a respirator. It is very messy, but cheap and does a really good job. Not an overly aggressive cut. In my case any feed problems are usually caused by having the material valve on the bottom of the blaster open too far. It can be a little tricky to set the material flow and air flow just right. Waiting for better weather to do the underside of my van.

I spent the last 2 hours scraping just the passenger wheel well... Holy hell... I have got to find a better way than this...

When I was much younger,workin in weld fab shop,low man on the totem pole(me),went to blast room. Respirator,eye&skin protection,is a Must.Like all above have said,DRY sand.Moister catcher(s)on air supply,drain often.Maybe drier on air supply.Remember...your in the humid south.A clogged system can turn a good day bad.Coarse sand &constant pressure on 18/20ga.panels can warp easy.If just a 1 time deal,look into a rental on big job.A cabinet can be used for about anything you can fit in there,home or auto.IMHO

Matt that how the scraping goes it a long boring job, heat gun does help. Just keep plugging at it.

There might be a soda Blaster guy around in buisness close to you also. Usually some of the custom car guys know where there is one & might ask around??

heres your alabama area soda blasters = http://www.sodablastingalabama.com/Soda%20Blasting/index.html

I just got done blasting the underside of my van last weekend (halfway done at least...) and I had pretty good success with a product called "black beauty" sold by harsco minerals. It is made from coal slag so there's supposedly no silicosis risk. At first I started with the medium grade but that was too coarse and jammed up the machine. the fine grade is probably roughly equivalent to 60 grit sandpaper and worked great with the material valve open about 2/3 and air pressure at 120. The particles are hard, sharp and angular and I was able to collect, sift and reuse the material too. My local supply store sells it for $15/100# bag. I went through about 1.5 bags to do about half the underside of the van (not to bare metal, just blowing off the junk and leaving a tooth for the paint to stick to)

I have a pressure tank blaster from Tractor Supply Co. (probably the same as the Harbor Freight unit) and a small gas powered comressor that can't really keep up. Your compressor should be fine.

With a respirator and full face sheild I was still miserable underneath the van because the sand will hit any available surface and reflect back onto you. A hood is the best way to go and I will be investing in one before round 2. I taped a tarp up on 3 sides of the van to catch the material and it worked pretty well.

Good luck!

angle grinder with wire wheel might help. it isnt perfect either but good in open areas. the tar/undercoating will fling off and some will stick somewhere else but it gets some off quickly. spraying cleaner under preasure will get some of the hard to reach areas. i have used gas on more than one occasion but seriously doubt that it is an osha approved method. after doing all that, you will still need a sandblaster but at least the sand will be cutting threw paint and rust instead of bouncing off the tar or sticking to the grease. i never had any luck keeping my sand dry and welcome any advice. evan the black beauty seams to clog from moisture.