How many layers of bondo should I do on each armor piece?

[AverageAce]

Should I do more than just one on the outside and inside? I was under the assumption that you only had to put one coat of bondo/rondo on and then it was done after sanding, but I have a feeling that's not the case haha. About how many coats should I put on it? Also, say theres 4 layers on a piece (this is totally hypothetical) would the process be something like this?:

1. 1st layer of bondo
2. Sand with low grit SP
3. 2nd layer of bondo
4. Sand with medium grit SP
5. 3rd Layer of Bondo
6. Sand with high grit SP
7. 4th layer of bondo
8. Sand with very high grit SP

or would it be
1. 1st layer of bondo
2. Sand with low grit, medium grit, high grit, AND very high grit SP
3. 2nd layer of bondo
4. Sand with low grit, medium grit, high grit, AND very high grit SP
5. 3rd Layer of Bondo
6. Sand with low grit, medium grit, high grit, AND very high grit SP
7. 4th layer of bondo
8. Sand with low grit, medium grit, high grit, AND very high grit SP

P.S. I'm very prepared to spend as long as it takes on this project and I'm very patient, I just like to make things, even if they're not of the highest quality. I mean I dont expect to have a production-type prop at the end of this but I'd sure like to try for it

Thanks guys!

 

[Boba Fett]

it's however much you need. If it doesn't need any bondo, don't use it. But 1 coat is enough, then with spot applications for imperfections. Rondo is for hardening and getting a smoother bondo coat, meaning less sanding.

 

[Hickeydog]

For the inside of the helmet, I like to do 2 layers of Rondo to harden it.

For the outside, I apply 1 layer of Rondo, sand it with 60 grit (or courser grit), apply another layer, sand, and then see if I need a third layer. Just keep applying and sanding until you get the shape you want.

 

[Brandon McClain]

That my friend is an excellent question, and a wonderful example of how to frame it. It shows you have put some actual thought into the process. The number of layers you will do depends on the actual part itself and the quality of the pep. For example: the FlyingSquirrel MKVI helmet. If properly and carefully pepped, you will need very few layers of bondo. I have yet to find any part that needs only one layer, but this comes very close. The key to bondo is THIN layers. NOT one thick layer you sand. Work in smaller areas. I generally only sand with something like 80 grit until I am satisfied with the curves and detail, occasionally jumping to 100 if I want to really smooth a spot. Sand after each layer,just to get it mostly smooth. This will help keep subsequent layers smoother and prevent bubbles that will have to be filled. If you have anymore bondo related question, feel free to hit me up. Don't be scared of doing a lot of thin layers, my LT helm has probably 20 or so paper thin layers. You can see it in the various shades of the helmet before painting.