Walnut Shell Media

[Rick Iverson]

Gents;

I shall commence to chemically strip my chassis of the previous powder coating. I will do so upon the advice of an Apexer, who then recommended a light (psi) sand blasting (at 18” or so) to eliminate or reduce the heat.

As there will be an abundance of residual powder coat remnants in tight corners, curves, angles, welds …………..

I have a local vendor that uses walnut shell as the softest medium available. Safe????

[johndl]

The navy (contractor) has used walnut shells for years. They are pretty safe all the way around.
john

[Bob L.]

Pretty commonly used on turbine blading. Plastic media, soda, or dry ice are other low energy options.

[HB280ZT]

Rick,

The big issue with any type of media blasting is getting it out of spaces on the car once you are finished. If you can I would recommend any place that has holes in it that is a dead space cover the holes with tape of some kind to limit the amount of material that becomes stuck there forever. On formula cars that becomes extra weight that you did not plan for. Also in the areas that you can get to use compressed air, wire brushes and anything that you can get into the space with to remove as much material as possible. Because I have seen many car at shows that we blasted and the material is still coming out of blind areas.

Not sure what you plan to put on the bare metal once you are done. I would recommend POR15 as it can be sprayed and it comes in many different colors. Just follow the instructions and try not to get it on yourself as it is pretty hard to get it off. Plus the stuff is very durable and it can usually only be taken off with a sander or blasting again. it also handles fluids pretty well. So far the grey POR15 that I put on my car a season or 2 ago have handled many of the fluids that we use on our cars with no issues. Just my .02!

R/--
Harry FV#77 CFR

[sabre1fv]

Rick,

The walnut shells are fairly soft compared to other serious blasting media and may not be tough enough to get the last of the powder coating, though the paint stripper should have softened up the powder coating - check with the shop you want to do the work for their opinion, they should know. I don't think the walnut shells will roughen up the surface like a sand blasted finish, so that may play a role in the media you choose.

Harry has a great point about blasting media getting inside spaces and you will not be able to remove all of it. Plating/painting shops have tapered rubber plugs that can be inserted into holes to prevent plating or paint from getting inside holes/parts that might be of use to you. Alternately you could drill/cut 'drain' holes in strategic locations to remove most of the blasting media as well as drilled out pop rivet ends... Also, the POR15 in my experience is pretty tough stuff and will likely serve you well; only downside to this or any epoxy/powder coating is touch-ups. You might want to consider doing a 'rattle can' or similar paint job on the chassis for any future touch-ups or modifications....

Good luck.

-Jim

[Rick Iverson]

Gents;

I shall commence to chemically strip my chassis of the previous powder coating.

Three hours later, I was able to strip, say, fifteen inches of tubing. The chemical strippers of today are not remotely equivalent to the old Klean-Strip aircraft stuff back when. I am so done with this.

If I cannot find a dry ice blaster fairly near, or a recommendation of someone who knows how to CAREFULLY do a formula chassis, I will roll the dice and and do the walnut stuff locally.

[phantomjock]

Rick -

Haven't used these guys but have seen them around. Might check them out - Absolute Dustless Blasting, LLC I've had the card for a few years, so can't say, but it is a "lead." 850-496-1675 absolutedustless@gmail.com Card says free quote.

NOT AFFILIATED - just sharing info...

Cheers - Jim

[Ed Womer]

Not criticizing anyone's choice for painting, but if you are building/assembling a show car powder coating is fine and provides a beautiful finish. If it is a race car that will be used I would recommend Krylon spray cans. Cheap and dries fast. As a hobby fabricator/car builder, I sometimes get chassis that need repair and powder coating is a serious pain in the butt to have to weld near. you need to remove ALL of it or it will contaminate a TIG weld.

Real race cars that get used will need repairs some where in the future so plan on it, just a thought.

Ed

[Rick Iverson]

Rick -

Haven't used these guys but have seen them around. Might check them out - Absolute Dustless Blasting, LLC I've had the card for a few years, so can't say, but it is a "lead." 850-496-1675 absolutedustless@gmail.com Card says free quote.

NOT AFFILIATED - just sharing info...

Cheers - Jim

Jim;

There are about a million holes in my chassis: coach mounting, belly pan mounting, ancillary mounting etc.

Although this is certainly the most attractive approach, I have been cautioned about water getting inside the tubing and the likelihood of rust potential. I am supremely confident they use rust inhibitors, but I presume there is a finite time it is effective. Thoughts?

[Rick Iverson]

………I would recommend POR15 as it can be sprayed and it comes in many different colors. Just follow the instructions and try not to get it on yourself as it is pretty hard to get it off. Plus the stuff is very durable and it can usually only be taken off with a sander or blasting again. it also handles fluids pretty well. So far the grey POR15 that I put on my car a season or 2 ago have handled many of the fluids that we use on our cars with no issues. Just my .02!

I believe this is the ticket. Once powder coat is damaged, it cannot be repaired. But paint can be fogged in to repair cosmetic flaws. Comparison between DP90 and POR15?