Soda Blasting Test

[Chopper]

Hi all,

Well, as it happens a soda blaster is coming over on the weekend to blast the A-frame tongue for me.

After the tongue, I will ask him to test out a bit on the body too...especially the rust spots on the steel endcaps.

If that goes well, there's the rest of the body to do.

I'm having him blast the plywood floor inside as well. Thanks for the advice Bob, I'll go and find Git-Rot.

And I don't know about this, but I'll try some of the blasting on the interior walls as well...down below the cabinet level where the grime is pretty thick.

What I will watch for...warping due to the burnishing effect of the soda on the outer surface of the exterior. I'll test out different air pressures and I'll keep an eye on the temperatures generated on the surface.

What else I will watch for...effectiveness of the removal method and ease of residue wipeaway. Effectiveness primarily because I've got one morning of the blaster's time

And one last thing...I'm wondering how the interior will come out after the test blast.

Cheers! (of course I'll post the results)

[LI Pets]

You can order the Git rot here

[Chopper]

Ok, here's the scoop from the actual soda blasting test on the Argy this past Saturday:
1. soda blasting for 5 hours cost CAN$1400,
2. everything that was heavy gauge or thick cleaned really nicely - including the endcaps, tongue, water fill lid, bumper, screen door frame, interior plywood floor, window frames,
3. the main body and roof held up ok, but there is definite gentle warping that is hard to photograph, but looking down the length of the Argy, every panel is wow'd in very slightly, and I don't think that was there initially, it's not too bad at all,
4. however, the thin aluminum at the corners, the skirt, and the lid on the back bumper all warped noticeably. The skirt was the worst because much of the rivetwork had fallen off and there was nothing to hold the skirt back. Ditto for the lid on the back bumper (which warped into a curve about 2" out of alignment, and it was flat when we started).

The most disappointing was the effect on the curved aluminum below the front windows and around the back end. True the soda blaster used the least air pressure that would still chip away the paint, but the surface is warbled to the touch. Again this is hard to photograph because the pictures only show an even sanded surface, but running my hand along the curve, there are waves in the curve.

However, the job is done, and the painting will reveal how significant the damage is.

Would I recommend the process? Only for the endcaps, window frames, bumper, tongue, aluminum doorframe, waterfill lid, and plywood inside.

Any caulking or rubber will just deflect the soda. There was a blob of rubber caulking on the body and the soda just cleaned everything around it and the rubber was unaffected.

For any future projects, though it may take longer, I would start earlier in the summer and strip using some other method, chemical or even sanding by hand before I soda blast, especially if the original body is good.

In the end, it is Monday after the job is done and though I'm not estatic about the effects, the Argy is sanded and it's not jaw droppingly bad. I may go for a less glossy finish to compensate for the waving.

Cheers! And I hope you can use this lesson!

[LI Pets]

I guess you can skim coat areas you're not happy with Bondo auto body filler.

That's a hell of a lota work to sand out??????

Certain paints will hide some of this also

[SafeHarbor]

Hi, Chopper,

Thanks for this post. I have some de-rusting of front and rear domes, hitch A-frame, and back bumper to do on my Argosy.

I actually have a hopper-type sand/bead blaster and have some background experience with using plastic beads to dry-strip small aircraft back in the 80's. If I recall correctly, it required 60 psi at a very high flow rate and a very, very gentle touch to avoid etching the aluminum. The stripping shop was next to the maintenance hangar, and when they cranked up the big Ingersoll-Rand scroll compressor, we put on our hearing protectors INSIDE. The idea was to keep vacuuming up the beads, running them through a separator to get the paint chips out, and reusing them until they were worn out.

I don't know if these things later fell out of favor or not, but I do remember that it took an awful lot more thickness of coatings to get a good paint job on an airplane that had been dry stripped than it did for one stripped with conventional chemicals. And I well remember exactly how dreadful chemical stripping anything bigger than a puddle-jumper was, too.

Lamar

[boatdoc]

Hi Chopper; On 15th of September I have purchased 1973 Argy 26' with intent of ground up overhaul. The skins in and out are perfect except for couple of very minor dings which i will straighten out. Paint job is slightly weathered. Floor rotted out. Interior is in nice shape but everything will undergo redesign to our liking. There is only me and my lovely wife Kay so we do not need a lot of storage. Double bed will be a pull out in the center. Front will have custom wrap around couch from the door to fridge with a drop in table. Oven will go, three burner stove comes in. Black tank will be dropped down into a new 6" Stainless Steel frame which is about ready.
Will have pics soon. New 22.5 degree torsion drop axle's are ordered from Dexter. Inside skins will come off, will be cleaned and painted. 1" x 1/2" urethane strips will be glued in to the inside of outer skin to provide a airspace. Prodex insulation will be glued to the urethane strips. This will provide air space on both sides of Prodex and leave space for new wiring. Floor will be 5/8" signboard. Marine like ply with aluminum skin bonded on both sides. It is extremely rigid and will eliminate moisture problems. Inside the belly pan same as the exterior skins for insulation. All contact area's to frame will have a 3M sealing tape and SS fasteners. Univolt will be eliminated and sealed Marine Pro Charger will take it's place. 110Volt system will be replaced with all new componnents including GFI's. Marine Grade lighweight carpet glued with 3M Spray Adhesive on the floor. Wife will decide on color since she is a great decorator. So as you can see there is another guy as ambitous as you are. Sometimes I am not sure if I am not on the edge of crazy about it. Last week I pulled 36 hours straight taking only breaks for meals. Aside of that, I have a boat bussiness and cannot steel time from it. I guess some of us for the love of Airstream's will do anything. Good luck with your own project. "boatdoc"

[LI Pets]

Boatdoc, can you explain the "3M sealing tape" in a bit more detail?

The Prodex has to be the best product to insulate these units.

[Chopper]

Yup, it's my baby alright, 'cause I've got 9 months to get it cooked up and ready to roll for our trip next summer 2006!

My goal is to get the interior layout the way I want and make it new and livable. The floor was in really good condition after I blasted the surface stains and one soft spot at the hotwater tank location. But I know that my Argy is a leaky ship. So I'll live with that.

Speaking of which, the wheel wells (once the inside fiberglass covers were taken off) are not sealed to the body or floor and there was a lot of water leakage stains from the wheel wells, but it's not easy to trace unless you've taken it all apart. I can even see daylight through some of the gaps, which are big enough to poke my finger through. So just a caution if you are doing a rebuild without removing the floor!

I also have no illusions about having the time to get a pristine boat together on the exterior. The battle scars on the outside will be fine just like that. Tho' I did get that fogged up plexiglass out of the wrap window frame and am replacing it with LEXAN COVERED WITH MYGAR (CAN$200 for a 25" x 48" piece). It's bulletproof, scratchproof, and UV proof (so they say, we'll find out!). It's also much cheaper than the quoted CAN$1000 (that's US$720 for the window and plus shipping and handling) for the replacement which will take until December sometime to get.

About the exterior, I'll patch the holes and paint it up nice, but instead of a sleek mirror-finished pony, I'll have a well travelled workhorse. If next year's summer trip across Canada works out, I'm sure I'll keep this Argy with all its dents and wrinkles. If I ever tackle another one though, I hope I'm not in such a rush and I'll take the time to polish up the exterior!

Cheers!

[3Ms75Argosy]

Really, I can highly recommend the ICI Hydrostrip as a "safe" stripper to use (or otherwise known as Removal sold in Canada). Paint it on, and hose it off - it's peroxide based. I used three gallons of it, at about $50 a gallon.

Good luck - I'm sure paint will hide most of the flaws.
Marc

[Chopper]

Yes, I would have liked to have used the chemical strip option, but the Argy was/still is full of holes; the skirt cauling is all but gone, I've removed one wrap window, the two vents on the roof, and the AC, the hotwater tank, and the tire protection awning channels, and all the awning fixtures. In other words, if I hosed the Argy down, I'd probably fill the walls with water, so I proceeded with the blasting.Plus, there's no water at the staging yard, so it would have been doubly hard.

In retrospect, if I kept going with the deconstruction and took down the interior skin as well, then all that water wouldn't have been such a concern. Live and learn!

Cheers!