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Sand Blasting a Model T

Posted: Mon Mar 25, 2019 1:47 am
by Mike Robinson
I am getting ready to prepare my 26 Roadster Pickup for new paint. Does anyone have a recommendation on what media would be best? Sand, glass beads ect. I have been told sand can damage the metal and warp panels. The local powder coating shop said they do car bodies using sand without any problems .I don’t want to get this wrong and destroy a nice straight T body.

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 5:39 am
by Ruxstel24
Sandblasting is risky, depends on who's doing it.
Thickness of metal and how much paint is a factor. Warping is possible.
They have to be careful not to get the metal hot, blasting generates heat. Paint should be removed in layers, about like it was coated.
Glass beads are about the same.
Walnut shell or soda are other options.
Myself, I prefer a chemical stripper, and blast only the rust where necessary.

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 8:20 am
by Humblej
If you are sand blasting it yourself, the cheapest media is best as you will use a lot and you may or may not be able to reuse it depending on your setup. Warping is low risk with do it yourself home equipment. Air pressures over 90 psi could cause a problem with warping, but I do not know since I have never blasted over 90 psi. My personal experience with a pressure pot blaster is you will not heat it up enough to warp at 90 psi. Forget about a syphon feed blaster for anything very large. If you have thick paint it is faster to chemically paint strip before blasting. Media is expensive due to the large amount of it you will use. A 50 lb bag will last about 10-12 minutes in my pressure pot, that's 5-6 bags an hour at 5-12 dollars a bag, gets pricy. Play sand is cheap at about $3.5 per bag but it has rocks in it and will need to be sifted clean first. If you take it to a professional, they have equipment that they can sand blast a cement truck, they WILL warp it.

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 8:56 am
by DanTreace
Sand blast for vintage heavy steel like our T’s is ok. Results completely depend on the skills and experience. So ask for previous customers on their results.

Took all the removable parts, fenders, aprons, hood shelves, hood panels, rad. shell to sandblaster/painter locally , he had just finished blasting entire body of vintage Mustang. Results were fine, he blasted off old layers and cleaned then primed with epoxy primer. All I needed to do was putty little spots, spray coat of filler primer, block wet/sand, then finish with sealer. Finish was so good decided to haul parts to local painter with spray booth who used my supplied enamel for the top coats!

Oh, I did chemical strip the body and doors as there was no rust, and my experience with sandblast on wood framed or metal framed bodies is that sand residue remains in crevices that you find rolling out of those spots after touring for a while :(

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 9:19 am
by Dean Kiefer
Dave's advice is the best.

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 9:23 am
by MikeSommers
I was at a Model T event and talked to a guy who used a service that had a sand blaster that used high pressure water with the sand suspended in the liquid. No heating problems., and no silica floating around. He said the guy franchised the unit, which was on a trailer. I don't remember the name.
Mike

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 9:27 am
by DanTreace
Sand blasting is now what I like others to do :D , have done several bodies and fenders with simple gravity and pressure feed tanks, but in FL the humidity is awful.

Good sand blasting goes slow, as the pressure is low to prevent metal issues. Even with moisture traps, and heavy PVC lines, running up with drop lines and drain from the compressor, moisture (FL!)just causes issues in sand clogging, and the smallest grits can get clogged. Used bags of play sand, with fine mesh filter above the holding tank when loading. Hate it when the work is progressing well, and oops, the line clogs and you have to remove the head hood, respirator mask, uncover, unhook, take apart, and clean :x

DCP_1078.JPG
For the effort, time and agony, have gotten rid of this equipment, and now use a professional!

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 10:56 am
by George Andreasen
I have one of the original TIP pressure sand blasters, purchased back in the eighties. Since the only media I could get was coarse sand, that's what I used. The results were good, BUT the coarse material leaves a bit of a rough finish (big surprise, huh?) so I finally bought 60 mesh sand. It made a world of difference, as the surface was only slightly frosted and took primer and paint like nobody's business.

Pressure will NOT be an issue if you attack the surface at an angle instead of shooting straight at it. It really isn't heat that does damage, it's the "shot peening" of the sand which can work harden the surface. So, shoot at angle and take your time. Got a spot where the sand won't remove the old paint or rust? Stop! Use a sanding disk instead on that area.

My sand blaster came with a straining screen, designed to placed over the blaster opening when refilling. USE IT. Even bags of "graded" sand will contain lumps that won't pass through the screen. Once I started using that screen, all my clogging problems disappeared.

Store the blaster in a dry location, empty of possible. Cover the opening with a cloth, not plastic material, to prevent condensation and keep critters out. I found a very dead, desiccated mouse in mine before I started doing that!

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 11:44 am
by Rich Eagle
I have a TIP like the one George mentioned above. With a compressor that really isn't big enough and sand from the local sand hill I cleaned up several Model Ts and my Yellowstone Bus. It took many hours but worked fine with no damage to sheet metal. I believe the sand get sharper each time it goes through the blaster.
Rich

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 12:07 pm
by R.V.Anderson
I have no experience blasting sheet metal, so I won't chime in on that. But large (too large to fit in your blast cabinet) chassis parts can easily be done outdoors using play sand, which is also the cheapest, as has been pointed out. However, play sand has way too much moisture to work in a sandblaster, so the thing to do is to spread it out in the sun on an asphalt surface such as a driveway for an hour or so. Sweep it up and run it through a sieve before putting it into your blast hopper. Do the blasting on your back 40, or 20, or your back lawn. The sand will quickly work down to soil level, and next year you can raise a bumper crop of melons there.

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 2:51 pm
by Rich Bingham
Ah ! Sand-blasting ! I wouldn't trade for the world the countless hours of joy it has brought me . . . ;)

Re/ "warpage" - it's not entirely a function of heat. The coarseness of the sand can be a factor, but mostly the pressure and the way it's handled. Think of a gazillion tiny hammers beating on your panels . . . could "form" them into something you won't like. I agree with Rich, the sand particles often fracture on the way through the first time, "sharpening" smaller grains. It's counter-intuitive, but the finer the sand, often, the faster and better it "cuts" through rust. Moisture in the form of condensation can be a problem owing to the volume of air needed to blast. When the air passing through the sand pot is damp, sand stops flowing. When I did sand-blasting, I found I needed three extractors in series to keep the air dry enough. Lastly, the big drawback to sandblasting is that no matter how carefully you design to protect areas you don't want to collect sand, there will be sand !! I would never recommend sand-blasting anything mechanical unless it is stripped down so far that there's no question all traces of abrasive can be removed. Have fun !! :lol:

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 2:58 pm
by Ruxstel24
I always used white sand, much cleaner and less clumps.
Most sand will work 3-4 times before getting dull, if you can catch it and keep it clean.

And yes, it gets everywhere !!
It loves to magically appear after blowing and sweeping...right when you get the first coat of paint on !! :twisted:

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 3:58 pm
by Mike Robinson
Thanks for all the input from your experiences. I will try it myself first with sand and see how it works.i will also try paint remover. If I end up taking it to the local shop I will have them do a test piece like the tailgate and see how it looks. The paint on the T is very hard and fairly thick. It chips easily but won’t scrape off. There must be a lot of hardener it it. Thanks again. Mike Robinson

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 4:11 pm
by Joe Voller
Has any one tried the sandblaster that works with a pressure washer? I don't think there would be a problem wit heat warping.

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 4:22 pm
by JimDix
I don't think warping is caused by the heat, rather by the peening action of the grains of blasting media. I have bead blasted too many chassis parts to count but I will not media blast sheet metal! Paint stripper, but that has its own problems healthwise.

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 4:31 pm
by Barth_Tool_Co
Anybody try the new "dustless blasting" on a Model T? Something about C02 pellets that evaporate or something?

Re: Sand Blasting a Model T

Posted: Mon Mar 25, 2019 6:38 pm
by John kuehn
If your going to use a sand blaster REMEMBER to always a hood, mask or something to keep it out of your lungs.
Yeah I know you can just use a painters mask or something similar but remember when you start coughing later that night and can’t seem to get anything up and after blowing your nose and it’s dark or black you may have wished you would have worn a blasters air tight hood.

Hate to sound harsh but silicosis ain’t fun. Something to remember.

Re: Sand Blasting a Model T

Posted: Tue Mar 26, 2019 12:22 am
by Bob McDaniel
A pressure feed blaster with sand WILL warp the flat sheet metal. I have done it and it only takes a second to destroy a good panel. The Model T may have heavy enough metal to get away with it if you don't hit it with much air pressure and stay back from your work and do it at an angle. Do not stay in one area or it will raise the metal up in that spot. I have never used anything but sand so the other stuff like walnut shells might be better, I don't know. Parts like a fender with the raised bead should be a little safer but it depends on how good you are. I would not recommend sand blasting sheet metal to anyone that has never done it before and then finished the panel to see what they have done to it. It might look good till you put a gloss finish on it and see all the bumps you created. Just a little free advise from someone that knows and has done it.

Re: Sand Blasting a Model T

Posted: Tue Mar 26, 2019 12:56 am
by Greg Griffin
Mike, look up "dustless blasting". As others mentioned, it is sandblasting with water. Cannot overheat anything. I had my roadster body stripped (of fiberglass!) this way and no damage whatsoever to any panels, even where they were "thin" from rust. (That fiberglass concealed alot of sins. I used up my upholstery and top budget on body work.) I believe there's an outfit in Temecula that does this kind of blasting. Good luck.