During the planning stages of every properly done restoration project, what to do with the underbody or frame, demands consideration.
The 1970 El Camino resto mod is no exception. You guys and gals didn’t think we were going to bolt on a lot of cool stuff and not properly detail the frame did you?
Over the years, we at Easton Muscle and Custom have explored, and even tried some approaches, to what are we going to do with the rusty frame. Some things work. Some things work really well, and some things don’t work at all.
The real honest approach to the “rusty frame” problem is very simple: You only want to do it once – and you want it to last.
The car frame, or underbelly, takes the most wear but needs to look great on an outstanding car. It is the foundation for your project.
I am not going to discuss all the possibilities we have considered, like soda blasting, rust converters, or Por15. If you want to discuss these options with me, send me an email: email@example.com
What works for us:
The rust and scale must be removed down to bare metal. The best, less time consuming and least expensive way to do this, is by blasting the frame with sand or glass. Easton Muscle and Custom started with very inexpensive equipment which has evolved over the years.
1. A common inexpensive approach is with a gravity feed blasting unit. The media hopper is filled while gravity allows it to flow into a mixing valve where air pressure forces out of the hose and nozzle onto the work piece. This approach gives good results, but is more labor intensive than the upcoming equipment choices. Pluses for this method are; low equipment costs for the blasting and air compressor units.
2. Small Pressurized blasting units and a higher CMF Compressor. Similar to the above, but the hopper is pressurized which forces the sand or glass down to the mixing valve in greater volume. This type of equipment provides a greater flow and higher nozzle pressure, which cuts to bare metal faster.
3. Commercial grade Pressurized Equipment with a large CMF compressor.
Strictly a volume upgrade to the unit in #2. High volume at high pressure reduces completion time.
The choice of sand or broken glass for frame blasting. Which ever one you choose will work well. Why? Unlike other media choices, blasting sand or reconstituted glass is sharp edged and durable to cut through the rust to bare metal. Both can be used more than once, if properly screened to remove all debris. Sand is a little more dirty and causes an elevation of heat friction. It is also hazardous to the operator and environment. Broken glass product has all of the pluses of sand, but is less hazardous and causes less heat. Note: blasting heat is not a concern on the thick frame material. Thin sheet metal is a different story. We use “Fastblast 40-70” reconstituted Glass. Check with several material suppliers to see what they recommend for the equipment you are using. I say “several” suppliers, because they may recommend what they have in stock, not what is best for your equipment. You can always bounce it off us at Easton Muscle and Custom.
Please make sure you use the proper safety and protection gear when blasting. This stuff can hurt you or a bystander.
Finally, get the bare metal covered with epoxy primer or powder coating as quickly as possible, especially in high humidity areas. Bare metal will start the rust phase in a matter of hours. There are very few options that prevent rust on bare metal. For cost and the ability to do it yourself, nothing in my opinion, is better that Epoxy Primer. Other things can be better or cheaper, but not both.
Epoxy Primer, not to be confused with regular primer, look alike but are not the same. Epoxy Primer seals the bare metal from the elements. Regular primer does not.
Next best is powder coating. Not only does it prevent rust, you can also choose colors for a real custom look. Powder coaters often prefer and will do the blasting part as well. If you are leaning towards this approach, check pricing with your Powder Coater.
Best option, in our pinion, is E Coat, a specialized approach to preventing rust on your frame for a long time.
Got a question? Give us a shout or send an email firstname.lastname@example.org
In the next issue we will discuss paint removal on the sheet metal body and preparing for metalwork.