Prepping for paint

[Doc B.]

You guys know I have been working on a motorcycle build of and on for about 9 months. In the process I have had to strip a lot of funky old paint for repainting. When I look at the blogs of other builds I see a lot of "I used aircraft stripper" or "I used a flap wheel", "wire brush", or whatever.

I gotta counter all that advice - if you plan to do a reasonable amount of paint prep, just go out and get yourself a soda blaster. This thing is da' bomb. It cuts through most paint like butter and the soda is so mellow that it just barely leaves a bit of texture on aluminum. I've been just whipping through the frame, engine cases, wheels, you name it. Just blast the part, scrub it with lacquer thinner and a scotchbrite pad, wipe once more with lacquer thinner and shoot paint.

It makes a mess for sure. I shoot the soda outside of my shop. But the baking soda sweeps up easily and up here in the Pacific Northwet I can be pretty sure that any residue will dissolve in the next rain, leaving no trace.

[johnsonad]

Thank you for the info Dan. I can see myself needing something like this in the future.

[pdxgrampa]

Doc;
How much air compressor do you need to run this critter?

[Doc B.]

I'm using a 12 gal compressor that flows 2.4SCFM at 90 psi and 3.7SCFM at 40 psi. I run it up all the way to 120psi and set the regulator to about 95psi. It starts out really blazing and as the pressure drops it will maintain around 40 psi and keep removing paint even though the flow is reduced. I can easily go for several minutes. Occasionally I will stop the blaster and let the pressure tank fill back up. One trick is to put an extra water filter in the line to keep the soda from clumping in the pickup tube. That really made a difference up here in the Northwet.

Here's a before and after of an engine cover that I blasted, cleaned with lacquer thinner, shot with VHT engine enamel and baked for an hour at 200 degrees. The red stuff on the before was apparently overspray, complete with green primer under it. Took a little extra time but the soda blasted through all of it. Sorry that I didn't get a pic of the blasted surface. The red parts on the finished cover have Duplicolor and Krylon "fake anodizing" on them. Back in the day us old timers called it candy coat.

[ironbut]

Wow,..
Looks awesome!
I dig that crazy boomerang wallpaper. Looks like it came from the dining room of a 1955 space craft!

[JamieMcC]

Smashing colour it reminds me off the very fist hot rod magazine I drooled over as a youngster the centre page was a Chevey something or other the roof was chopped low with big V8 and a massive chrome supercharger sticking out and it was painted in this beautiful deep Candy apple/Brandy wine colour. I still have that image in my head 35 years on.

[electrovice]

Dan, what type of soda blaster are you using? I have some old Delta power tools that I want to restore. This could give me an excuse to finally get a compressor for the shop.

John

[mcandmar]

Love the polished Honda logo, looks great 

Every shop should have an air compressor IMO, its right up there with the most useful tools i have ever bought.  Surprisingly its the regular air blower attachment i find i use most..

[Doc B.]

The logo was simply sanded out with 100 grit wrapped around a narrow stick, with painter's tape covering anything I didn't want to touch with the sandpaper. I agree that a compressor is high on the list of must have tools, along with a drill press and a big bench vise. And a BFH, of course.

@John, the blaster is from Harbor Freight. It's a 30lb. model. They sell big bags of soda too. I will refine my comments about how well it strips. It's awesome for removing paint and cleaning up aluminum. However I notice that the soda doesn't really cut through rust all the way to bare metal. It will take off the more loose crust, but you may have to wire brush that last darker layer of it.

Today is a big day. Now that I have managed to wrestle new tires on the wheels (and with the resulting scratches sanded out) I will be masking the tires and and painting them. Red.

[mcandmar]

90% of what i blast are cast suspension parts and i found the Aluminium Oxide powder works the best to bring them back to bare metal. I wouldn't use it on body work or anything requiring a smooth finish. I'm also cheap so i run the powder through a strainer and reuse it over and over

[saildoctor]

FYI for any bare metal protection rust removal the Boeing company developed some awesome stuff.  http://www.boeshield.com/

One is called Rust Free and it's acid based.

The other is called Boeshield T-9 - it's a lubricant, displaces moisture, acts as a corrosion barrier, and it seems to do just as well as WD40 at dissolving rusty stuck parts.  It's awesome! 

[Paul Birkeland]

Dan, what type of soda blaster are you using? I have some old Delta power tools that I want to restore. This could give me an excuse to finally get a compressor for the shop.

John, you are welcome to come borrow mine if you like. 

[Doc B.]

A jug of phospate cleaner works great on steel too. Lifts light rust right off and leaves a grayish layer of zinc phoshate on the steel, aka Parkerizing. I used it on the inside of my gas tank after de-rusting it.

Total process was soak with lacquer to remove varnish, gross rust removal done with electrolytic rust removal with a washing soda solution and steel electrode (1st pic - yuck!), rinse with mild oxalic acid solution to remove a bit more rust, soak with warm zinc phosphate solution to do last rust clean and rustproof (2nd pic) and spray with a coat of fogging oil to keep it nice until the first gas fill (3rd pic)

Oh, and for stuck nuts and bolts PB Blaster is da' bomb.

[saildoctor]

holy smokes, that was some rust!

[Doc B.]

Yeah it was fairly crusty inside, but only one tiny dent. Yesterday's prep and paint was the wheels shot with Krylon "X-metal" (which I guess is the comic-book-superheros-on-film generation's version of what we called candy apple red back when X-Men and Iron Man stories were only a quarter and printed on paper), transparent red over silver base coat.