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glassing fuse question

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Old 04-02-2013, 04:15 PM
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codydaniels
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Default glassing fuse question

I am close to glassing my new project and have a couple questions for you guys. I have fiber glassed in the past just not on r/c planes

I have read that minwax urethane is a good alternative to resins. What are you thoughts pro and con.

Has anyone tried minwax Helmsmen Spar urethane? It is available water based and is for outdoor use where the regular minwax urethane is for indoor use. Or does it really matter.

Has anyone used gelcote over minwax? It seems like it would build faster than primer plus it is stronger.

It seems most people are using 3/4 oz cloth. Is this best or would a 1/2 oz cloth give the same results. Or is one just easier to get?


Thanks in advance for the help guys.

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Old 04-02-2013, 04:38 PM
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Default RE: glassing fuse question

The 3/4 is easier to get, and I use Minwax oil based urethane, then just prime fill and top coat.

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Old 04-02-2013, 06:12 PM
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Default RE: glassing fuse question

I have always used epoxy resins and 3/4 oz cloth. i would think that the Minwax would be lighter and faster to do. Gelcoat is usually a polyester base and should not be used along with epoxy resins. Also it adds no real strength per say and cures best when used as a surface coat when making a part in a female mold. The stuff dosen't cure well when exposed to normal atmosphere. At least it didn't for me.
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Old 04-03-2013, 03:06 AM
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Default RE: glassing fuse question

Speed is right, gel coat is not the way to go on top of epoxy, and will leave a gummy residue after full cure. Now if you decide to use the gel coat anyway then you must spray it on and allow it to begin to gel, as it does immediately spray the entire surface with PVA, this will seal the gel coat from a free oxygen supply and allow the gel coat to harden completely throughout it's curing cycle, leaving a non gummy surface to sand on. It will be your heavier and more work intensive way to go and have poor adhesion properties to the epoxy substrate below but it can be done...

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Old 04-03-2013, 10:45 AM
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Default RE: glassing fuse question

Agree, that a good laminating epoxy resin and light cloth is a good way to go. One of the other threads talks about all the different kinds people use that flow out nicely.

Spar urethane is interesting stuff. I have tried it for a clear coat and it's not bad and I went with the Varathane UV water based version. It is non-catalyzed and takes some time to dry but is really friendly stuff. I like it and is a lot more clear than the oil based versions which have a yellow quality with even just 1 coat.
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Old 04-03-2013, 10:57 AM
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Default RE: glassing fuse question

Thanks for the input guys I appreciate the advice.

As far as gelcoat, it looks like I wont use it. Just primer.

Member speedracerntrixie mentioned curing issues, I have used a lot of gelcoat and it has to have wax added to it or it never sets up completely and will always be a little taky. The wax is a clear liquid that is added. You can get gelcoat with or without wax.
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Old 04-05-2013, 06:57 AM
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Default RE: glassing fuse question

I think more people use 3/4 oz cloth than 1/2 ounce.
The weight difference on a model is minimal. However,
the 3/4 oz cloth is definitely easier to work. 1/2 oz
will get runs in it easily (think of nylons that women
used to wear - or maybe we should not be thinking
about that!!!), it takes really sharp scissors to cut
and just generally more aggravating.
brad
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Old 04-05-2013, 01:09 PM
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Default RE: glassing fuse question

I just finished glassing a F 86 wings and tail of a modelbau/troybuilt version. I was wondering what is best weave filler after using finishing epoxy on 3/4 oz glass cloth. I primed the items with a sandable primer the sanded to 220 first coat of paint and the weave is still quite visible, any suggestions. Thanks
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Old 04-11-2013, 04:59 AM
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Default RE: glassing fuse question

I use lightweight drywall spackle.. Add a little water so it's the consistency of creamy peanut butter and work it in... I just put some on my fingers and work it into the glass.. Let it dry and then hit it with the 220, a couple coats of primer and then repeat if necessary.. Otherwise, I know guys that just keep putting down the high build primer and blocking it all off until the weave is filled.. Probable takes about the same amount of time either way..
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Old 04-11-2013, 05:12 AM
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Default RE: glassing fuse question

Is the Urethane Glow proof? I am still on the fence on what to use to complete my Chippy. Using a lightweight cloth and dope to set it, but the overcoats I am trying to find a different method to seal it all up. Since my P-51 doesnt have open bays at all, and runs gas, I have water based glassing liquid, which the name of escapes me at the moment, but the open bays on the Chipmunk are a different story.

EZE-Kote is the stuff I have for the P-51.
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Old 04-11-2013, 11:09 AM
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Default RE: glassing fuse question

Two post up diggs74 said to use drywall Spackle then prime. I would think that if you got a scratch, as all plans seem to get, the fuel will get into the Spackle and cause lifting problems.But on an electric plane this might work.
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Old 04-11-2013, 05:34 PM
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Default RE: glassing fuse question


Quote:
ORIGINAL: blakeketcham

I just finished glassing a F 86 wings and tail of a modelbau/troybuilt version. I was wondering what is best weave filler after using finishing epoxy on 3/4 oz glass cloth. I primed the items with a sandable primer the sanded to 220 first coat of paint and the weave is still quite visible, any suggestions. Thanks

What I do is sand the resin/cloth surface smooth being very careful not to sand through the cloth. Once smoothed out and overlaps feathered I mix up a batch of thinned epoxy and rub on the surface. This seals and fills the remaining weave well. If you fill the weave with primer or paint it will actually come out heavier due to the clay in the primer and the pigments in the paint.

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Old 04-12-2013, 05:03 AM
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Default RE: glassing fuse question


Quote:
ORIGINAL: codydaniels

Two post up diggs74 said to use drywall Spackle then prime. I would think that if you got a scratch, as all plans seem to get, the fuel will get into the Spackle and cause lifting problems.But on an electric plane this might work.
Actually, if all you're looking to do is fill the weave (and not large low areas), there is so little spackle left after sanding that the primer pretty much soaks in and seals the spackle.. I've wet sanded after this process with no issues.
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Old 05-30-2013, 01:10 PM
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Default RE: glassing fuse question

I use microballoons sprinkled onto the fuse and rubbed in witha paper towel. Have to work fast though. I do this as I finish wetting out the glass cloth on the wings or fuse.
After curing, beging sanding and looking very carefully. Your weave should be full; after sanding it becomes smooth and ready for wet sand and final sand. Finish comes out light.

Orlando
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Old 06-01-2013, 06:24 PM
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Default RE: glassing fuse question

Believe this or not, I used Polyester resin for 25 years on a couple of dozen models if not more.

I built a few CL models and was undecided as what to use. Many CL guys still use silk and dope.

They talked me into it! I gotta tell ya, silk and dope has it all over glass cloth and resin. I can't offer advice about using Miniwax, although many guys use it with great success.

The silk and dope thing? I'm saying this from actual experience, even though I'm difficult in trying new things.

Take it from a hard head like me, these CL guys do know what they are doing.

Here's my recent CL model with silk and dope on the fuselage. Primed with NAPA's 540 primer.

Yes, I was talked into using this primer also. Aerosol can and it's great stuff.

For the time being, this is my winning game.

Charles

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