Although my 1st printer was too small to complete my long term project for my 1953 Chrysler sill plates I have used it for a number of other projects including several parts for Bob’s 1936 Nash.
Initially Bob came to me with a very simple project: replacement bushings for his shock absorbers. The lever action shocks rely on rubber bushings to capture the pivot points and eliminate noise as the shocks do their work. The originals on the car were hard and shrunken to where they no longer did their job. These were a very simple model to create, but I had a number of issues printing them. We did have to go through a couple of iterations to get them to where they would fit properly too. This was the 1st project I completed using a flexible plastic. They were printed in TPU with 100% infill to make them more robust. Although this was the 1st project with flexible material that I completed, they were not my 1st flexible prints. I had done some small prototypes of sections of the door sills for my 1953 Chrysler and was using the same roll of filament for Bobs bushings. Turns out, I had done my prototypes in my garage in mid summer and the plastic had absorbed so much water that it would not print reliably. I had multiple prints that failed with one common problem being that the parts were too soft due to the moisture boiling off in the print head resulting in air bubbles where plasitc should have been. Once I determined that moisture was the problem, I learned that to drive the moisture out of the plastic before printing I needed to put it in an oven at about 230 F for 3 to 4 hours. After doing this I got quality prints.
Bob now has a full year of use with no complaints.
The next project for the 36 Nash were hood corner pads. Bob had a single original pad for the front of the hood which I used for the initial design. He also provided a rubbing of the corner which I was able to use to design a pad that fit properly and included a post printed in the same material that fit into the hole near the corner allowing the pad to remain in place without any additional fastener or adhesive. Not knowing whether this would work, I also printed a version that could be attached with carriage bolts with a cover that would hide them. These were also printed in TPU with the bolt cover in ABS.
After completing the corner pads, we were onto something more challenging. The Bumper Grommets. As with the hood corner pads, Bob had original bumper grommets that were in good enough shape to use to take measurements from to draw up the new part. A 3d scanner would have made this step painless, but that’s a tool I don’t have access to. After multiple passes at a design, I produced a front bumper grommet that fit perfectly. I also did prints with the CR-30 to see how the parts would differ between the two. Because of how the CR-30 prints, it gives a very nice body but has a coarser finish on one side but a better finish on others.
I’ve yet to start on the rear bumper grommets, but Bob has promised to get me the original for use as a pattern in January.
For a rough idea on cost – Material cost for any of these parts is trivial. The bumper grommets use the most material and use less than $5 of TPU for each part.