fiberglassing

willsonman

Builder Extraordinare
Mentor
No, oil-based will not work as well. It will take far longer to dry and because you will be working with a hydrophobic work surface, the spread of the oil-based will be uneven and dry uneven, whenever it does decide to dry.

Water-based is a bit of a misnomer. Just because it is water based does not in any way mean that water will dissolve it once it is applied. It is just a plastic that is suspended in an aqueous solution. Once you seal out all the pinholes through multiple applications of the poly, you should be well sealed from any moisture. Further still, once you apply paint over top of that, you have an additional seal of moisture.

Example: 72" span scratch built Sikorsky S-39 covered in mostly fiberglass but also tissue paper and water-based poly. I've had it out in very moist conditions as well as in a pool for some float testing. I've only had issues with the covering on HOT days, when the foam off gasses under the glass and creates bubbles in the glass.
 

The Hangar

Fly harder!
Mentor
No, oil-based will not work as well. It will take far longer to dry and because you will be working with a hydrophobic work surface, the spread of the oil-based will be uneven and dry uneven, whenever it does decide to dry.

Water-based is a bit of a misnomer. Just because it is water based does not in any way mean that water will dissolve it once it is applied. It is just a plastic that is suspended in an aqueous solution. Once you seal out all the pinholes through multiple applications of the poly, you should be well sealed from any moisture. Further still, once you apply paint over top of that, you have an additional seal of moisture.

Example: 72" span scratch built Sikorsky S-39 covered in mostly fiberglass but also tissue paper and water-based poly. I've had it out in very moist conditions as well as in a pool for some float testing. I've only had issues with the covering on HOT days, when the foam off gasses under the glass and creates bubbles in the glass.
Ok, really good to know! I'll stop and pick water-based kind later today.
 

GliderFlyer

Elite member
Nice to see there is already a thread for the question I needed to ask.
I was just given a phoenix 2m electric glider from a fellow member of the local flying field, and it needs some repairs. I was thinking about fiber glassing the wings.
Can fiberglass be put over foam that has been spray painted?
Also, is the stuff from hobbyking any good?
-Thanks
 

speedbirdted

Legendary member
I'm pretty sure the paint won't impact the adhesion of the cloth. Personally I would not cover it in fiberglass; doculam works perfectly on foam and will make it just as stiff for a fraction of the weight and cost. If you do want to use fiberglass though, be sure to use epoxy resin. Polyester resin will destroy most kinds of foam.

I've tried the Hobbyking cloth as well as the Sig cloth; I can't notice a difference between the two. Both have about equal strength, stretch about as well, and are equally as close to their advertised weight. I don't have a massive amount of experience with fiberglass in any application though so YMMV...
 

GliderFlyer

Elite member
I'm pretty sure the paint won't impact the adhesion of the cloth. Personally I would not cover it in fiberglass; doculam works perfectly on foam and will make it just as stiff for a fraction of the weight and cost. If you do want to use fiberglass though, be sure to use epoxy resin. Polyester resin will destroy most kinds of foam.

I've tried the Hobbyking cloth as well as the Sig cloth; I can't notice a difference between the two. Both have about equal strength, stretch about as well, and are equally as close to their advertised weight. I don't have a massive amount of experience with fiberglass in any application though so YMMV...
Ok I think Ill go with the Doculam.
Thanks
 

skymaster

Elite member
this is all nice but the one thing i keep thinking and pops in my head is. what if i hit some one with it's hard enough with just the foam board
 

Timmy

Legendary member
this is all nice but the one thing i keep thinking and pops in my head is. what if i hit some one with it's hard enough with just the foam board
Well then don't, fly away from people I guess. Be more careful. But yeah, hitting someone is something to think about.
 

The Hangar

Fly harder!
Mentor
this is all nice but the one thing i keep thinking and pops in my head is. what if i hit some one with it's hard enough with just the foam board
The prop is what I’m worried about. A small prop can chew you up pretty bad, and a big prop like what I’ll be using on this monster build could easily chop off your fingers, if not your hand.
 

Pony1023

New member
So I'm curious, and was going to start a new post, but someone already said, this one seems to be on target. So I have two questions, tied to fiberglass, as I was wanting to experiment after seeing FT's YouTube video (
) where they fiber two FT Arrows.

1. Has anyone already watched this Nov 13th video, and if so, have you been able to find the video on the tech channel that Josh refers to at the end of the video? I've looked daily, and either I'm looking at the wrong spot, or I'm stupid. (I'm guessing the later, which is why I'm asking)
2. Am I the only one excited and wanting to do a similar experiment?

I found all the info here very informative, and has me thinking. But now other than what can be seen in the 1st video, I'm even more anxious to see their step by step video.
 

chris398mx

Master member
So I'm curious, and was going to start a new post, but someone already said, this one seems to be on target. So I have two questions, tied to fiberglass, as I was wanting to experiment after seeing FT's YouTube video (
) where they fiber two FT Arrows.

1. Has anyone already watched this Nov 13th video, and if so, have you been able to find the video on the tech channel that Josh refers to at the end of the video? I've looked daily, and either I'm looking at the wrong spot, or I'm stupid. (I'm guessing the later, which is why I'm asking)
2. Am I the only one excited and wanting to do a similar experiment?

I found all the info here very informative, and has me thinking. But now other than what can be seen in the 1st video, I'm even more anxious to see their step by step video.
It has been a few days since I have looked and I cant find it either. I am also interested in doing this to a plane or 2.
 

The Hangar

Fly harder!
Mentor
So I'm curious, and was going to start a new post, but someone already said, this one seems to be on target. So I have two questions, tied to fiberglass, as I was wanting to experiment after seeing FT's YouTube video (
) where they fiber two FT Arrows.

1. Has anyone already watched this Nov 13th video, and if so, have you been able to find the video on the tech channel that Josh refers to at the end of the video? I've looked daily, and either I'm looking at the wrong spot, or I'm stupid. (I'm guessing the later, which is why I'm asking)
2. Am I the only one excited and wanting to do a similar experiment?

I found all the info here very informative, and has me thinking. But now other than what can be seen in the 1st video, I'm even more anxious to see their step by step video.
I haven’t actually made any progress on my fiberglassing project yet. I’ve been pretty busy lately and I haven’t gotten around to ordering the fiberglass.
 

The Hangar

Fly harder!
Mentor
My fiberglass finally arrived! I also got the polycrylic.
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56938C98-9C60-4A76-817E-16E5ADCBEBFF.jpeg
 

slowjo

Master member
I'm planning on fiberglassing a pink foam build I'm working on and need to know if the stuff I'm looking at getting will work. Here's what I'm thinking:

Fiberglass cloth:
https://www.homedepot.com/p/3M-Bondo-8-sq-ft-Fiberglass-Cloth-20128/202077813

https://www.walmart.com/ip/Minwax-2...-Protective-Finishes-1-2-Pint-Gloss/840225387

Here's the video that states the difference between the zpoxy and polycrylic. I'm mainly going for a protective outer layer since I have enough strength already. I'm not overly worried about weight, but I hope to have to do only one coat.

Thanks!
Thanx for this tred, I just sat back and soked up the knowledge :cool: ( now I need a nap)