Smooth Cast VS. Fibreglass


Active Member
Hey Guys!

I have a full body armor project coming up, which is going to need either a whole chunk of smooth cast, or fibreglass.

But to determine which way to go I'm asking anyone who has worked with smooth cast about its properties. (It's easier to ask here than to get it shipped from overseas to test it out).

Normally I would use fibreglass, but Im wondering :

1. Practical strength of smooth cast? - Does it warp and bend easily once set / Can it be reinforced with a builders bog layer over the top (I normally cover FG. with builders bog as its safer to sand and easier to patch surfaces.

2. How far would a 1 gallon bottle go? Aiming for a solid cover that does not warp.

Thanks heaps for your advice guys!!!! :D


I've never used smoothcast or any of Smooth-On's products, but I'm pretty sure I'll always stick to fiberglass. Mainly cause of the difference in price. I'm like to do a bit more finishing to save a few bucks.


Sr Member
Not even close to the rigidity of fiberglass, you would need to build it at min 2x as thick. It is heavier and will warp. I would never use it for main large armor sections that are open at all, as in a 2 piece. If the piece is solid like say a bicep or gauntlet NP. I hate working with fiberglass mat but it works well in it's application and a little cheaper than urethane resin.


Well-Known Member
Well, I experimented with Smoothcast before WITH fiberglass cloth before on a pep. It worked fine, but the cost is 3x more than using polyyester resin. If you wanted to stick with a Smooth-On product then I recommend using Epox-A-mite instead.


Active Member
Thanks for the Feedback guys! You've saved me the time and cash of getting some smooth on sent over to Aus. hehe.

@theP13RC3 - Yes, A bit more elbow grease is better than paying 3x the cost :D

@Finhead - Yeah working with FG can be a pain in the butt. I had heard that smooth on is safer to use so I was investigating it. But hearing that smooth on requires 2 x the amount and is still prone to warping you've sold me on sticking to fibreglass (pun...Intended? xD)

@Tigerblood - I thought it might be more expensive seeing as it seems like a specialised product. Working with mat will probably see the same problems as using resin anyways (although the brand of resin I use 'Diggers' has an added wax that prevents the harmful fumes from getting out. I called them about it and they guaranteed that you dont need a mask as long as you work outside. Depending if I feel like ill wear a mask to be safe, if not meh - I could sue them if something happens xD)

Once again thanks everyone! :D


Sr Member
I want fibreglass. However, where do you guys even buy it? In the Netherlands I can't seem to find it at all... but that might be just us. :lol


New Member
Hey guys,

I was wondering if it was possible to layer epoxamite 101 on an abraded plastic surface, eventually making it as thick as a filler, and then sand it just like how you would bondo. any information would be appreciated, thanks!


New Member
I started with fiberglass + resin then moved to fiberglass + smooth-on. Smooth on is easier to mix, much less toxic, and works better with silicone brushes (easier clean up).

It's not as strong as the resin, but with fiberglass it's strong enough to do the job just fine. It also has much lower viscosity than resin, so it doesn't pull on the paper as much when you're doing that first coat.

It's really expensive though.


Sr Member
You don't want to try sanding down epoxamite .. this stuff is hard as hell!!!

Why would you want to do this? Just get some good putty and bit the bullet :)
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