Plastic Media Blasting vs Glass Media Blasting

[rboltz]

I just retrieved my M-101A1 from the blasting guy I know. I had my entire '715 plastic media blasted a few years ago but when I picked up the trailer today I noticed a difference right away. He told me he now uses a 50-50 mix of plastic and glass in the blaster. The glass removes more material and will get into rust better he told me. However, like sand and other abrasive media, the glass "opens the pores" of the steel. It will quickly rust and you can see the rust film appearing in a few hours if the humidity is high. The M-101A1 was blasted yesterday and already the film is there. Priming must be accomplished immediately. I like the plastic better!!!

My blaster friend has an El-Camino in his shop for several years that he is rebuilding. It was plastic blasted 4 years ago and still no rust on the bare steel.

[SAC715]

Thats good to know, even soda blasting only lasts about 2 weeks around here with the humidity during the Summer.
I have been using a new (or different, might not be new) process lately. They call it a sand bed tank, it has sand in a liquid solution that heats up to 700+ degrees and removes paint and rust. I was nervous at first about warpage from the heat, but it heats everything up evenly with no problems. Alot of my students and friends have been using it. After the sand bed it goes into a tank of acid to eat ALL the rust off then into a neutralizer tank which leaves a coating on the metal that lasts for months (It needs to be washed off before priming).
This process removes EVERYTHING including paint, sealers and the dampening materials between the inner and outter layers of the hood and doors so they will need to be replaced.
It works great on gas tanks too, I have a motorcycle tank and frame getting done right now.

[randyscycle]

Here at the shop we use glass beads, sand and soda blasting. I've not used the plastic media, but it was developed mainly for stripping fiberglass like on Corvette bodies.

Anytime you strip off any coatings on metal, if it is ferrous, then it needs to be primed very shortly thereafter. If not it will flash rust quickly. Even more so if there was any moisture in the compressed air used to do the blasting, or if it is a place where there are big temperature swings which will cause condensation.

That El Camino must be in a very well-controlled environment to not have rusted at all with bare metal in four years. Even just chemically stripping a motorcycle fuel tank and leaving it on the bench in the shop for a few days will cause some flash rust, and that is in an air conditioned environment at a constant 72 degrees in the Summer.

[rboltz]

That El Camino must be in a very well-controlled environment to not have rusted at all with bare metal in four years. Even just chemically stripping a motorcycle fuel tank and leaving it on the bench in the shop for a few days will cause some flash rust, and that is in an air conditioned environment at a constant 72 degrees in the Summer.

It is in a controlled area but I personally believe the 1/8" layer of dust and crap is protecting it!!

[randyscycle]

It is in a controlled area but I personally believe the 1/8" layer of dust and crap is protecting it!!

That may sound funny, but actually, I don't advocate cleaning or doing anything with something until you are ready to actually restore it. That layer of grunge does provide some protection.

[77amc]

An older gent that I work for once a week had a 77 chevy pickup soda blasted and they state to wash it down with Vinegar before painting.. (I got the info AFTER I painted it, masking tape peeled paint off)
Another thing.. We were told and friends also stated that "you just blow it off, wipe it down and you paint.."

WELL, now we are scrounging yards trying to find most all wiring because the humidity in the Memphis area caused severe corrosion in almost EVERY wire connection.. Even the steering column was too corroded to use. (we towed it as a NO-glass shell except wiring )
I don't know what the heck they used to blast it with (hose and pressure) but I couldn't blow it out enough.. IT KEPT COMING OUT EVERYWHERE!! Even when I thought it was enough and mixed up a quart of paint, and started to shoot... Crap would come out!
And re-assembling it, caked soda was still falling in my face from under the dash and bed.

I had the bed of my 715 sand blasted (only the outside) just because there wasn't any 'hidden' areas but that cose me 200.00

If I ever go that route again, I think that I'll try the plastic or chemical and a steam pressure washer.

OH, and watch using silica sand.. It can cause problems in your lungs without a respirator!! I don't know about playsand/white sand though.

Just my .02
Errol

[randyscycle]

Errol's experience is why I rarely will ever blast anything as big as a car or truck.

I do motorcycle bodywork and small parts, but even frames I hate to blast because they fill the tubes with media you can never get out. I am not sure the plastic media will take off powder coating either.

[rboltz]

Errol's experience is why I rarely will ever blast anything as big as a car or truck.

I do motorcycle bodywork and small parts, but even frames I hate to blast because they fill the tubes with media you can never get out. I am not sure the plastic media will take off powder coating either.

Plastic is still falling out of my M715 and its been years now. The floor gets full of white beads after a trip.

[randyscycle]

At least one good thing with the plastic is that it likely won't hold moisture, and it isn't so fine that it will stay there forever.

[77amc]

Of course AFTER that experience, then was told by a friend that one should run a tape strip to seal ANY cracks, such as door jambs, hood/fender seams to block stripping media and go after the 1/4 - 1/2 of paint left (under the tape) to some 60-80grit and save the hassle.

I'm not changin the subject here BUT..
I stripped a roof of my ol 72 Monte Carlo and then coated with Por-15's Metal prep. NOW, that sat outside for over 4 months without even getting flash rust!!
So, if I ever soda blast again it will be wire free and get a bath/shower with the steam pressure washer and some metal prep after.
The directions state to wash that off with water also, let dry and proceed with the other Por-15's products. BUT, I've just gone right to primer and paint with good results (so far..)

E