Sandblasting

[VaGuS510]

I have a 510 project, I'm hoping that by the end of the summer i can have it painted and running. It is basically a shell right now. Anyway the previous owner spayed the engine bay with rattle-can primer and didn't prep it before. The primer comes off easily in many areas. I figure i should paint the engine bay while i have the chance but I need to remove this primer. I was thinking of bringing it to a sandblasting place but then thought that the cost would probably be similar to that of a cheap sandblaster and material. How well do these cheap (sub $100) work? Is it worth the money? Thanks.

[my_mad_z]

I purchased a sandbalster to also sand blast my engine bay..... Let me start by saying it's the messiest process I have ever experienced!!!!

You will need a full body suit and proper breathing aparatus.... I used the blaster without this protection and I was completely black after a few seconds (I could taste sand for days!) Not only was I covered in sand, my garage was filthy!!! I'm still finding traces of sand and it been 2 years since I used it!

Don't get me wrong, it strips the paint well, however it is a messy and slow process! I payed $25AU for the sand blaster and $10AU for 5kg (~10lbs) of sand. I used 10-15kg of sand.

Apparantly, it's better to bead blast, not as harsh as sand blasting and it also leaves a protective layer over the bare metal.

I ended up using the sand blaster on small sections to remove rust.... I used paint stripper to get rid of the paint..... I was considering getting the whole car sand blasted but was told not to as it was too rough on the metal and also that it can warp panels.

My 2c.

Marc.

[webdawg1]

You might want to check into "Soda Blasting". It's not quite as bad...in terms of how it interacts with the metal during the blasting process. The soda itself breaks up into smaller pieces.....

webdawg1

[Bonzi Lon]

I agree with my mad z using paint stripper with high pressure water for the paint and agree with webdog1 on the soda for the rust areas. Sand blasting at the wrong grit, wrong pressure, wrong distance and inexperienced operator will result in diaster on that thin of metal. Ask my parents about the lawn furniture I did for them years ago, my first blast job, and 100% mess.

[kenz240z]

I cleaned & prepped the engine bay in my Z the hard way, lots of scraping to get the heavy stuff off. Then a lot of scrubbing with a toothbrush & solvent, followed by a good general scrubbing over everything. With all of the oil, dirt & grime removed, I then sanded everything with 220 grit paper, then 600 grit wet/dry paper. A lot of work, but all the prep work payed off, the engine bay now looks great!

Another mess I had to address was cleaning a bunch of undercoating off the bottom of the toeboards & transmission tunnel. I used a propane torch to heat it up and then scraped it off. Messy, and a lot of work. After the heavy stuff was off I used paint thinner to clean it up real good before sanding.

[kmack]

If you have been convinced to avoid sand blasting, then disregard this post.

I sand blasted my entire car in my garage with a portable baster unit from Northern Tools. (Not sure of the cost as I borrowed it from my Dad) The trick with blasting is to get a good media for use on the area you want to treat. Since you are talking about the engine bay and primer that is already coming loose, I would use regular play sand. The fine grain stuff you can get at Home Depot or such. I say this because 1) the sheet metal in the engine bay pretty structurally sound and a little thicker (it has to tie the lower frame rails into the upper frame members along w/ the radiator support), 2) the primer is already coming loose, & 3) play sand is pretty cheap compared to glass bead, walnut shells, etc., that way you don't have to worry about not picking all of it up.

The rest of the process involves making an area that you can blast in w/o making a BIG mess, and protecting yourself from the media. I went to Home Depot (sorry for the plug, my bro-n-law works there) and bought a roll of black foundation plastic. This is a 6 mil thickness plastic. Pretty heavy-duty. It comes in a 20' w x 150' roll. (You can sometimes strike a deal w/ concrete guys building a house to get some of this also)

Cut it into 10' wide strips about 30-40' long. Starting on one side of one of your roll-up garage doors, staple the plastic to the ceiling moving toward the back of the garage, across the back, and then toward the front on the opposite side of the same door. Then duct tape the bottom of the plastic to the floor. You have now sealed off the rest of your garage from the blasting area. You'll need a dust mask (at a minimum) and some good goggles that will seal to your face (or a hood face shield). Put the car in and get busy.

It's not hard and it can go pretty quick. Plus, you won't run the risk of chemical burns on your hands/skin or splatter that will burn scars on your eyes as with paint stripper.

(Ever seen what happens when your spray water on an irregular surface with acid coating the metal? It sometimes sprays right back at you!)

[cremmenga]

i bought a very small sandblaster that holds like 2lbs of sand, it cost me 55 bucks at car quest and it works like a charm!! i love it!! i'm doing my engine bay with it!! and 50lbs of sand is only $11 at car quest as well!!!

[ZCCOR#109]

I think kmack has some good advice.

Random thoughts.

If blasting think everything/results out. One issue is the removal of sand from hidden areas, cracks and crevices. It will be everywhere, including your A%^.

You can make a "booth" for blasting by using metal tubing from electrical conduit. Not too expensive. Hange from ceiling and other places making a box around the car, then hang the plastic mentioned by kmack. Cover the top of this w/plastic as well. This allows you to retain storage, etc. around the perimeter of the space.

You have a lot of control over the effect of the media by how close you hold the "gun" from the work.

The "finish" of the metal will be anthing but smooth, and require a good fill paint to cover that.

Any method of removing paint is "messy" stripper, media, sanding, lots of work.

The media blasting insures a clean down to bare metal where as stripping leaves rust if it is there, as does sanding.

If you are just trying to get a clean smooth surface to begin painting on, and the original paint is sound, then it would seem that sanding off the top layer of "junk" paint would be your best solution. The original primer and a layer of finish paint is good for a base as long as you use a good sealer that adheres to start the finished job.

Good luck

[VaGuS510]

Thanks for all of the great advise. I am still considering sandblasting. I figured it would be dirty. I was planning to basically put a tarp around the whole engine bay. It does seem like it would be easy to remove the primer by other methods since it is coming off. But the engine bay has some really hard to get to places, I figure that sandblasting would surely get all of those areas. Anyways, thanks again and keep the advise coming.

[ncz]

Tyler, I used a combination of methods from above. The points about a mess are well taken, and the stuff will get everywhere. I am lucky that I can roll my car outside the garage,so that cuts down on the mess but I have to have good weather to work. I would go with Kennys suggestion about sanding what you can. Still creates mess but not as widespread. Then use the sandblaster for seams or hard to get at places. The air duct inlets on the radiator support, the battery tray area, the hollow areas in the lower cross member, corners, etc. Couple of notes. Get a good water separator. Your compressor will send a ton of water through the lines and gum up your blaster. Use a good media. I used glass bead, it is more money but it leaves a good finish and worked in my blaster better than others(less jams). If you sand and blast you won't need tons of the stuff. DON'T use metal shot, total mess. I have heard aluminum oxide works great also. I tried a silica (sand ) material and it gets real wet and had to clean the blaster out a bunch. Also a fine wire wheel on your grinder will get a lot of stuff off and won't tear up the metal. Good Luck

[shamus11]

Hi VaGuS510,

I'm at a similar stage to you and there's some great advice on this thread.

I've been using paint stripper on all of my flat panels lately and it works well but is messy stuff. My 2c is to consider that where the paintstipper drips and then sits, the paint is compromised. I'm taking most things back to bare steel but if you only want to create a good foundation to paint over, how do you tell how deep the paint stripper has reacted? If I wasn't going back to bare steel I'd sand it by hand.

Another tip, paint stripper and a wire brush works extremely well in seams, gutters and other tight spots. Straight back to bare steel.

This thread has swayed me back to getting hold of a do-it-yourself sandblaster and some glass bead to experiment with.