Dip or Sand Blast?

[Rob Glasgow]

I’m in the early stages of planning a complete restoration of my BT7after I retire in a few months. I have owned the car since 1963 and currently drive it about 3,000 miles a year. It’s in decent shape, maybe a 10 footer or so. A few rust bubbles and chips in the 25-year-old paint but mechanically sound.

I’m looking to build a nice reliable driver that I can be proud of. Not interested in a trailer queen.

I need your advice. What method would you recommend for stripping the chassis…. Chemical dip or sand blast? I am leaning towards chemical stripping if I can find someone to do it. Seems like the dipping process would remove all the rust and grease and get in the nooks, etc. On the other hand, getting it sand blasted locally would be fairly easy.

I plan on stripping the body panels.

Know any companies in California that can dip the entire chassis?

This will be the first of many questions I’m sure.

Thanks,

 

[roscoe]

Rob,
Both methods have their pros and cons. I don't think that anything gets the metal as clean and residue free as media blasting (whether it is sand, baking soda, glass beads, etc.) I prefer sand blasting steel and then priming it right away, or using a treatment like Dupont Metal-Prep to make a phosphate coating that is paintable. Sand blasting also stress relieves welds and curves, if done by someone who knows what they are doing. It can also expand a metal sufrace and cause sheet metal to warp. I'm not really sure what solutions are used for "dipping". I assume they are using some sort of mild phosphoric acid bath, but I would love it if anyone who knows, could expound on what dipping solutions are used. I would be a little concerned about flushing the solution out of the frame rails and outer sills. I'm guessing that water is used to wash out the rust removing solution, but again I'm not sure. If so, I'd hate to put water on a freshly etched steel surface because rust starts immediately after etching. Let the people who do the dipping tell you why it might be better.

Jon Robbins

 

[Randy Forbes]

There is an alkaline-immersion process facility here in Toledo; basically a hold-out, as most all of the former Redi-Strip shops have closed.

I had planned on doing the dip process when I restored BN6L-942 all those years ago. As it turned out, I sandblasted the chassis myself. If I had planned the sandblasting all along, I would've painted the insides of the sills and rockers as I was replacing them (a waste of time for dipping).

Downside of sandblasting, is that I'm still getting sand out of the car (twenty years later).

I finally did get to "test" the dip process when I restored this 1961 McCulloch R1 go-kart. It leaves the metal spotlessly clean and bright! A thorough rinsing with clean water, the usual metal prep for bare metal (PPG phosphate conversion products) and then epoxy-prime and paint. It still looks perfect three plus (3+) years later.

 

[Richard Dickinson]

I had my frame and all off the steel pannels dipped and E-coated. The stripper wouldn't strip aluminum. I was satisfied with the results. I had planned to blast the frame my self, but after blasting some smaller componets and seeing the effort and mess, I decided against it. The down side was the cost,about $3700 and a 400 mile round trip to the stripper, which I guess in the big picture of a frame off restoration, is not that bad.

 

[Rob Glasgow]

Richard, Did the E-coating take the place of the primer in the short term? In other words, were you able to fix/weld/work on the chassis before priming?
Since the dipping chemicals strip everything, how did you treat the in-sides of the rails, outridgers etc? Did you spray Waxol or something? I am thinking bare metal inside the rails would not be ideal. On the other hand, I assume since the orginal chassis was painted after it was assembled, the interior surfaces were never painted so leaving them bare would not be a big step backwards.
Unless I can find a dipper on the West Coast, it won't make any difference. Maybe I'm too late and dipping is another one of those technologies from the past.

 

[Randy Forbes]

Richard, Did the E-coating take the place of the primer in the short term? In other words, were you able to fix/weld/work on the chassis before priming?
Since the dipping chemicals strip everything, how did you treat the in-sides of the rails, outridgers etc? Did you spray Waxol or something? I am thinking bare metal inside the rails would not be ideal. On the other hand, I assume since the orginal chassis was painted after it was assembled, the interior surfaces were never painted so leaving them bare would not be a big step backwards.
Unless I can find a dipper on the West Coast, it won't make any difference. Maybe I'm too late and dipping is another one of those technologies from the past.

I don't think so. It's really more of an industrial benefit than it is a service for "hobbyists". Broaden your search for the steel industy, not just automotive.

 

[Richard Dickinson]

I had it E-coated as a short term corrosion prventative. I still had a lot of welding and repair to do. In hind sight I should have done more of the repair before stripping. Because I have had this car since it was new I didn't realize that there was so much work that needed to be done. Over the years I had the rusted-out dog legs repaired and several areas of minor collision damage fixed. Some of that work was a lot less than stellar. As I understand it, E-coating is the way after market body parts are finished. After I get through with with all repairs, I plan to use an epoxy primer.

 

[HEALEYJAG]

Rob:

Back in 1984 when I was restoring my BJ8, I had the same dilemma. Dip vs blast. The blast people said that the paint would never stick to the metal once it was dipped. The dippers said you will never get all the material(sand etc) out of the chasis.

I chose a company here in Columbus, Ohio that dipped my frame , fenders, doors, trunk lid and boot lid for a VERY reasonable price.

They came out beautifully. They automatically spray a compound on it immediately to prevent surface rust. This needs to be washed away copiously before preping the panel.

After the ground up I owned the car for 12 more years and never had a proble with paint adhesion etc. We did fill the inside of the frame rails with a sealer and had six of us flip and rotate the frame to "slosh" the sealer inside the rails.

I am sad to report the car is now in Germany....we all make mistakes sometimes.....Best of Luck

Pete

 

[MadRiver]

Downside of sandblasting, is that I'm still getting sand out of the car (twenty years later).

I've had the same experience (thirteen years later in the case of my BJ8). We sand-blasted the chasis using black sand-blasting sand, and I still find traces of it to this day. And we had the chasis on a rotisserie since we had to do a lot of cutting and welding of the usual trouble spots. A bunch of sand freed itself during the process, but there are lots of cozy little hiding places in a Big Healey chasis!

To be honest, the discovery of sand doesn't bother me. In fact, it makes me smile and laugh!

 

[Rob Glasgow]

I don't have a problem with a little sand falling out years later. I get that everytime I wash the car and flush the insides of the fenders. Amazing what gets kicked up just driving down the road!
I'm more concerned about derusting all the hidden areas of the chassis. Lord knows there are enough nook and crannies in these frame that probably can't be reached by blasting. Maybe that's not an issue. If the rust if left alone, maybe it will just lay there for another 50 years!! The pictures I've seen of dipped frames are impressive. The rust is gone, replaced with either clean metal or holes. Either one is OK.
I've still have not been able to locate a California dipper, so maybe this decision will make itself.
Thanks for your comments.

 

[Silverghost]

I was watching a show on cable called "Wrecks to Riches" where they take an old car, do it up, and then send it out for auction. One particular episode dealt with soda blasting. In the show, they said how the soda would dissolve easily and wash away with water better than sand. They also said that the soda generated far less heat and therefore was not as likely to warp panels, etc.

I have been exploring this same subject as I am preparing to do my Mini. I have found a shop here that has the bodies they have stripped painted with a green primer/sealer immediately after being stripped/blasted and before any repair work is done. Even they were not firm one way or the other on stipping vs blasting. Based on what I saw on that show, I am leaning towards soda blasting at this point......

 

[Leebo]

Curious, but why is galvanizing never mentioned? We spend so much to ensure our cars are preserved forever.

-Lee

 

[roscoe]

Lee,
Do not forget that welding galvanized materials is something for which you need an outside air source under your welding mask. Toxic fumes. Bad stuff.

 

[Cutlass]

Galvanizing involves dipping a metal part into molten zinc. Can you imagine the cost and the extra weight of a galvanized Healey chassis? Zinc electroplating, on the other hand, deposits much less zinc, but will not cover interior spaces or "shadowed" spaces, so is probably not very viable for these cars. Jon's comment about fumes generated by welding is correct as well. It would be nice to be able to get these complicated chassis run through the modern chassis coating processes used in new car manufacturing, though.

 

[Leebo]

Hear ya on the welding. Want to make sure that is all done first. Making paint stick can be a problem.

I'm not sure what the add'l weight is, but the cost for HDG should be less than $500.

It's done all the time for Series and Defender Rovers. They do the bulkheads too, but they need to be air cooled rather than quenched in a water dunk tank to prevent warping.

 

[DougF]

My feeling with blasting is, if you can reach it with media, you can reach it with paint. As long as the media doesn't fall into my wet paint, I'm fine.