very confused on glassing

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Well-Known Member
Apr 7, 2004
Reaction score
Hey all. I have been reading about fiber glassing for about 2 weeks now, and I'm still confused... Please don't tell me to search for 'glass', I've done that several times, but in vain. Okay so let me know if I'm right or not. In order to fiber glass, you mix fiber glass with epoxy glue, then cover your rocket in it? and let dry?

And when using Kevlar, you wrap Kevlar cloth around the tube, while painting on epoxy inbetween each layer?

Please let me know if I'm right or wrong, I plan on practicing this summer!

You need the fiberglass that's looks like a cloth. It generally can be had for rockets in 4oz or 2oz cloth. Use the west systems epoxy and wet the airframe then lay the cloth on the airframe and work your way around the airframe with a brush getting the cloth layed evenly but make sure you don't over saturate. If it's shiny then you have too much epoxy in it. Just keep brushing till it gets a dull look to it and let cure.
Can you replace the fiberglass cloth with any other cloth, such as Kevlar or Carbon Fiber?

When you say wet the airframe, do you mean with epoxy, or water?

What do you mean by 'work around with a brush'?

How many layers of cloth do you use?

And I'm assuming once the cloth is on, you put it in a vacuum bag?

And what do you mean by 'keep brushing until you get a dull look'?

Sorry for all the questions.


To answer a few questions, yes you can substitute different types of cloth such as Fiberglass, Kevlar, or Carbon Fiber.

The airframe is wetted out with epoxy resin before the cloth is applied.

You need to use Epoxy Finishing Resin found at hobby shops. It is much thinner than regular epoxy glue and wets out the fiberglass cloth better. Other quality resins such as West Systems are also very thin and work well for glassing. Epoxy glue is way too thick and should not be used.

Layers of cloth depends on what you are glassing and why you are glassing. Larger tubes should have more cloth. Smaller tubes 4" diameter or under can do with one layer of 2-6oz cloth, depending on what you want to do.

Vaccumn bagging is not required and is rarely used. Most rocketeers spend thier money on rocket stuff rather than bagging systems.

Here is a link of mine showing step by step how to glass, all in should clear things up quite a bit:

To see a larger pic, click on one of the smaller can step through from there.

Good luck and keep the questions going, that's how you learn! :)

Other quality resins such as West Systems are also very thin and work well for glassing.

Like Rocketsonly, I'm new to glassing as well (actually haven't done it yet, but it will be part of an upcoming L1 project.) I've got a pretty good picture of the process, but still a bit vague on exactly what epoxy product to use. I've used some of the Home Depot/Lowe's epoxies (the kind the come in syringes and have 5, 30 or 90 minute cure times) for fins and centering rings on my MPR fleet, but that's it.

Carl mentioned Epoxy Finishing Resin, and West Systems. My hobby store does not sell a finishing epoxy, but I stopped by a nearby boating supply store and noticed West Systems Resin (numbered 105) and two different "hardeners" a slow (206) and a fast (205). Both were mixed w/ the Resin at a 5-to-1 ratio.

For glassing, would I use the West Resin and the slow hardener? Or be looking for something else?

Thanks for any suggestions.

NAR 83277
Pittsburgh Space Command
Tripoli Pittsburgh

Good questions! Your Hobby store should carry or be able to order Epoxy Finishing Resin. Brands such as Hobby Poxy Finishing Resin and Pacer brand Z-Poxy Finishing Resin are two that they can aquire.

However, it sounds like you found the West Systems brand at a typical store that handles it. West Systems is one of the highest quality epoxies you can use for building and has been used to build many a high power model...and some lower power too! West Ssytems is a thinner based resin making it ideal for glassing.

It is mixed in two parts and although it is not mixed in equal halves as other Epoxy Resin based adhesives, it is still Epoxy based resin, NOT polyester. For future reference, stay away from the polyester resins like those sold at Lowes, Walmart or other stores.

The base for West Systems is the 105 Resin. This is the only number available for resin and different Hardeners are mixed with it for different applications. I use the 205 Hardener pretty much for everything, even glassing large body tubes. I also keep some 206 and 207 Hardener on hand and have used them at times, although the 205 pretty much can do it all. Note that West Systems also makes a great adhesive for assembling a rocket as it's thinner consistency allows it to penetrate and soak in wood bulkheads and centering rings better than standard Epoxy glue. I use it to assemble the entire airframe, then use it again for glassing the same airframe.

You will need to purchase a pump system for West Systems to make sure you mix it correctly. The pump set used for 205 and 206 hardener is a "5 to 1" pump system, while the one for 207 and 209 hardener is a "3 to 1" pump system; make sure you get the correct pumps. Also, one pump from the resin and hardener will mix about 20cc of glue, or about 2/3 full of a mixing cup. for smaller ammounts, you need to fill to the gradient on the side of your cup in smaller quantites. I have done 10cc's for resin and twocc's for hardener (5 to 1) and it works fine. About the only downside to West Systems is that you do waste more, but cost-wise it is much cheaper in volume compared to hobby epoxies.

I hope this cleared it up a bit and wish you luck with your glassing. Ask again if you have any other questions...there are many of us here that can help.