what is clear coat exactly?
 

I hope to not feel stupid for asking. but since 2006, I have attacked my first attempt at restoring anything realistically auto related (beyond repairs, but restore) with an 87 subaru as the target.
I have tried every chemical known to a parts store, and recently dove into something new: base coat , clear coat.
I made some mistakes, as it is "panic month" for me in maine. Paint this weekend or forever hold the rust till next june... August nights dipping into high 40s.. I drew the line of body work after lessons learned at <56 degrees.
Anyway, today I let the old sube have it. Within 30 seconds..I am in awe. that year car has a dual tone paint job to boot. I noticed the rockers after 2 days are very very hard, tinny sounding, and photos before and after show that they shrunk. My question in disbelief...what is clear coat, and at what psu does it harden?
I learned from a non-pro, it is a tenth of mig weld..ie, 60k psi is a mig weld, proper urethane is 6k to stay with it. Is this true? Could I use my extreme coat, 2 part urethane to make bushings in a mold? what would I need to have a liquid urethane harden enough for bushings? How do I learn psi?

One way to get urethane parts is to machine them from skateboard wheels. I don't know what you are using for clear coat, but if it hardens rather than dries, casting is probably an option. You might need to unlearn "psi" in this context, and start fresh. Reading books by J.E. Gordon is the quick, easy way to absorb engineering.

Just a thought, but I've used 2-part plastic epoxies for making parts in molds, as well as products like JB-Weld and PC7 and PC11 Epoxies. All seem to work fine, unless you're going for a specific interest. I probably wouldn't use either of those for suspension bushings, but I'd make spacers and adapters with them.

The only other thing that comes to mind with urethane epoxies is to pay attention to the Durometer rating of the finished product, or the "stiffness" of the cured urethane.

thanks for replies. the skateboard wheel idea, I have heard of it, and forget.
The epoxy stuff, I use it for light duty, fast repairs, my pc duct for example.

The engineering books could be helpful. I am a habit of net only, making me a bit slow with the subject...no clue where to begin. thanks for book idea.

I did find on the net, there is indeed hardness ratings, temperature. I would love to make my own bushings for a sube, but it seems my welding revealed stuff similar to boron, and bushings so perfectly petrified I don't want to replace them.
I guess "psi" is just another way about urethane, 2 part chemistry.


found an excellent site, the author knew what I was asking

http://www.gallaghercorp.com/urethan...hardness.shtml

two urethanes, the same hardness on a durometer, tensile strgth 100% different than the other..exactly what I was seeking answers for. I also found two different sets of directions for the clear coat on the car, there is a 4:1 and a 2:1, I went with 2:1 mix, and it seems I could throw a rock at it after just 2-3 days. I am keeping an eye on the door jam seams to spot shrinkage, like the rockers did, but the old urethane was still on the job I was doing and it seems I just added to it. In car ecomod relation, a squishy body is non-economical one. I am glad to have chosen the hardest mixture, it is still taking its time with discipline as far as calming the area painted. good stuff.

I'm glad you found that site. Studying the properties of materials by starting with elastomers is like learning to swim from the diving board.