stunthanger.com
Building Tips and technical articles. => Paint and finishing => Topic started by: Paul Smith on March 04, 2024, 11:05:03 AM
-
Today I found that both Sig and The Prop Shop are out of lightweight fiberglass cloth.
I forgot what the lightest weight is. Is it 3/4 ounce? Or maybe lighter?
Can somebody suggest a current source?
-
Horizonhobby.com has fiberglass cloth in several weights. The brand is "Deluxe Materials". Mecoa.com sells K&B fiberglass cloth. Both of these are traditional hobby vendors.
-
Paul,
You can get small quantity of 3/4 oz fiberglass from K&B at http://www.superpoxy.com/.
Best, DennisT
-
That's actually the same as Mecoa. ;)
-
Thank you for the advice. I ordered 3/4 ounce cloth from MECOA at $8.99 per yard.
This is a small fraction of what Sig charged for the product when they last offered it. Hobbyzone did not have what I need.
I use a lot of this cloth in conjunction with 30-minute epoxy for center sections, rudder fins, and repair work.
I do not like messing with polyester resin but prefer epoxy thinned with acetone.
-
3/4 oz/yard is the standard for light fiberglass cloth in the USA, but in Europe, there is .6 oz/sq. meter (?) available. I would try "FAI Supply" for that. The FAI FF guys go to the extra effort and expense. I used it on the C-tube LE on my F1A gliders...but that was more than four decades ago!
"I do not like messing with polyester resin but prefer epoxy thinned with acetone."
Yes, polyester has a much shorter shelf life and is difficult to get the right amount of hardner because it's such a small proportion of the whole.
I'm not so sure about using acetone to thin the epoxy, though. I believe alcohol is the correct thing to use, but I'm also not 100% sure what sort of alcohol is the one to use...but NOT isopropyl alcohol from the drugstore, because it typically has 5%+ water. I get "shellac thinner" from the paint/hardware store, but would have to read the fine print to see what sort of alcohol it is. And, I just checked...and I'm out of it. Good excuse to get out of the house and go to the hardware store. y1 Steve
-
3/4 oz/yard is the standard for light fiberglass cloth in the USA, but in Europe, there is .6 oz/sq. meter (?) available. I would try "FAI Supply" for that. The FAI FF guys go to the extra effort and expense. I used it on the C-tube LE on my F1A gliders...but that was more than four decades ago!
"I do not like messing with polyester resin but prefer epoxy thinned with acetone."
Yes, polyester has a much shorter shelf life and is difficult to get the right amount of hardner because it's such a small proportion of the whole.
I'm not so sure about using acetone to thin the epoxy, though. I believe alcohol is the correct thing to use, but I'm also not 100% sure what sort of alcohol is the one to use...but NOT isopropyl alcohol from the drugstore, because it typically has 5%+ water. I get "shellac thinner" from the paint/hardware store, but would have to read the fine print to see what sort of alcohol it is. And, I just checked...and I'm out of it. Good excuse to get out of the house and go to the hardware store. y1 Steve
I HAVE USED ACETONE TO THIN EPOXY..IT ALSO SLOWS DOWN THE HARDENING TIME A LITTLE BIT ALSO...HAVNT HAD ANY PROBLEMS WITH IT...
-
The epoxy doesn't know or care after the solvent has evaporated.
The can of "lacquer thinner" that I bought says "acetone" on the back side.
-
I use pure methanol to thin epoxy.
(in very small amount once, typically 10 ml Resin + 4 ml hardener plus some 3-4 ml methanol. (Or double: 20 ml resin + ... )
In a small medical tube I make a "shake" , very often with some Talc added, for better sandability. )
This mixture is usable on blue or pink foams, not harmful at all.
Acetone is better to wash the brush finally, strictly in another room... :)
Istvan
-
The epoxy doesn't know or care after the solvent has evaporated.
The can of "lacquer thinner" that I bought says "acetone" on the back side.
Some don't, some do. Sometimes there are ingredients that that leave with the diluent as it evaporates. Also, if the laminate/coat is too thick, some solvent can get trapped inside as the resin polymerises.
So, it's always a good idea to make some tests first, or even better to look for lower viscosity resins if you really want to play safe.
Our stuff is not so important, at least the CL stuff, that a rule of thumb is if the hardened resin powders nicely when sanded, it's good enough. L
-
I received the 3/4 ounce cloth from MECOA.
Good price, good shipping, overall good transaction.
But,,,,,,, It seems like 3/4 ounce is quite a bit heavier than the old pack of Sig that I depleted. I'm still on the hunt for some 1/2 ounce or lighter.
1/4 ounce per yard is nothing in the square footage that I use, but the resin weight is the issue.
So I'm still looking for some 1/2 ounce FG or lighter.
-
3/4oz will take less resin to fill than .5oz.
Sig use to sell .5oz.
I use to use .5oz but you have to fill the grain under it a little or you'll get pin holes and print through. 3-5 coats of nitrate dope then sand it back a bit then let it gass off for a week. I apply cloth with Zpoxy finishing resin. Clear epoxy paint works well too. I've even used polycrylic to apply glass cloth, works great, comes out stiff and different paints will stick to it well.
MM 8)
-
Agree with MM using 3/4 oz fiberglass comes out lighter than 1/2 oz because of the extra resin needed to fill the wave in 1/2 oz. If you apply several coats of clear dope to the wood then use the card scrap method (apply resin then use a playing card or business card to scrap off as much of the resin as you can, after cure do second coat same way) it will be stronger and lighter with the 3/4 oz glass. Lots of guys do this to stiffen flaps.
Best, DennisT
-
https://stunthanger.com/smf/building-techniques/fiberglass-sale/msg669238/#msg669238