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Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

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Old 01-12-2012, 04:13 PM
  #26  
retransit
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

I agree with saramos. I use West Systems epoxy products and have been using them for over 25 years. As a filler or repair on fiberglass, I mix micro balloons with the epoxy to get a paste. Similar in consistancy with polyester filler, but lighter. You also have control over the consistancy; more micro balloons, the thicker it is. And clean up can be accomplished with alcohol. I've had trouble in the past with polyester resin and paint. Some are not compatable. No problems with epoxy based resins. West sells pumps that measure the correct amount of resin and hardener.

I also use epoxy resin to make cowls.

Klasskote is another product I like because it has the ability to overcome high humidity because it has a long flash-off. Here in Florida, humidity can be a killer on paint, especially with lacquer based types. I've tried water base, but had trouble with grip to the primer. No problem for Klasskote.

By the way, using two different shades of primer to show the low spots during block sanding, is called using a guide coat.

Bob
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Old 01-12-2012, 04:20 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: speedracerntrixie


ORIGINAL: wingspar

Rapture, sound more like you used laminating resin instead of finishing resin. Thus sticky and not hard.

Dave N
Could also have been a lack of temp as both products should cure above 65 degrees. Epoxy is mix sensitive as well. 5% off on the ratio one way or another can result in an incomplete cure.
I'm not too accurate with my mixing. I have the graduated pumps for mixing but I usually just eyeball what I put in a mixing cup, unless I'm using a large amount. I've never had a mix that didn't cure, and I'm sure that I'm over that 5% threshold. Polyester resin is another story. I've also been told to not be concerned with the hardener turning brown. It has no effect on the product. I believe this info is on the West website or one of their distributor's.

Bob
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Old 01-12-2012, 06:31 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

Been using bondo resin and putty for 5 years, always had good results. Cheap, easy to get (Wal Mart) and does the same job as most other polyester resins out on the market. It takes no time at alll to mix polyester resin with a scale, I just get so many ounces of resin, add the required hardner, mix, and your off and going.

I also fiberglass a whole entire boat (32 foot cruiser) with bondo resin, and I built that in 1989, and it still floats today, so I like bondo.

Jason
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Old 01-12-2012, 07:26 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: nwadc10

.denatured is on the shopping list.

Fleet Farm has the best price on denatured alcohol, if it makes a difference.


Savvy tip on alternating primer coats, I like it.

You can also just mist some black on top to use as a guide coat. The mist should show through 90% of the primer. As you sand, the guide coat goes away leaving the black in the low spots. It's quite dramatic when you see it.
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Old 01-12-2012, 07:28 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

West epoxy resin is mixed by volume. I can't say how polyester resin is mixed, since I don't know the specific gravity of each component.

I've used Bondo or like products for years in auto body work and it holds up well. Glazing putty (Nitrostan) works well when filling pinholes. It is lacquer based and dries fast. It's best to let it cure for a day, since it shrinks somewhat. Sands easy.

Bob
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Old 01-12-2012, 09:05 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

ORIGINAL: raptureboy

There are many options. I have used polyester resin before and it is very smelly and you want to be careful where you buy it from. I bought some from a home center and it was old and the catalyst did not kick off the resin all the way and it stayed sticky, never getting quite hard. Ended up sanding off and redoing[:@] Same goes for epoxy, make sure it's fresh. Here is a link for another tecnique http://www.youtube.com/watch?v=1rcKyCMDBJE
This guy is quite the scale builder and he posts on here alot. He did a heck of a job on this Hellcat http://www.rcuniverse.com/forum/m_25..._1/key_/tm.htm
Noted. I suspect the epoxy optionsat the LHS doesn't see much movement so it could very well be old. Unfortunately that video says it was removed by the owner.
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Old 01-12-2012, 09:09 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: rgburrill
Also, you can use Solartex or Worldtex (I haven't tried Oratex) white covering. Using a primer such as Rust-Oleum and sanding it well gives a metal like finish. It is a little heavy so you should look at other ways to lighten the build first. But it also adds a lot of strength. I did this Royal Corsair this way.
I was tentatively planning on using Solartex for the rudder and elevator as an easy scale mod. That is another product I don't have experience with but it sounds like it is to be treated as iron on covering that is paintable. Pretty simple.
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Old 01-12-2012, 09:29 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

I'll check out that Krylon clear coat, thanks for the tip.
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Old 01-12-2012, 09:43 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

Another vote for West Systems. I don't want to commit to particular products just yet but so far I am leaning towards West Systems epoxy resin and microballons for filler because I think the process used for this method I understand the best. Bondo is still a possibility as well as some products others are pointing out as their most favorable.

Fortunately Iam in Minnesota, little humidity problem here.

Guide coat, got it
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Old 01-12-2012, 09:45 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

Fleet Farm seems to have the best price for a lot of things. LOL
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Old 01-13-2012, 06:20 AM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: nwadc10


ORIGINAL: rgburrill
Also, you can use Solartex or Worldtex (I haven't tried Oratex) white covering. Using a primer such as Rust-Oleum and sanding it well gives a metal like finish. It is a little heavy so you should look at other ways to lighten the build first. But it also adds a lot of strength. I did this Royal Corsair this way.
I was tentatively planning on using Solartex for the rudder and elevator as an easy scale mod. That is another product I don't have experience with but it sounds like it is to be treated as iron on covering that is paintable. Pretty simple.
Not only paintable but handles compound curves like the Corsair very well. Look for Worldtex though - it's the same thing and easier to find.
BTW, as I recall the Corsair had fabric tail surfaces. It would seem that a light coat of primer for the tail surfaceswould keep the fabric texture and still be able to be painted. I did not try that with mine but may with the Stampe I am building right now.
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Old 01-13-2012, 09:31 AM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

Justin,

have you thought of Sig Koverall and dope?

You first put down the adhesive, and then cover with their fabric, Koverall. It shrinks like film, but it is an open weave. You can then fill the weave with a finishing dope, and then final spray with dope colors.

http://www.sigmfg.com/cgi-bin/dpsmar...FV5.html?E+Sig

Colors:
http://www.sigmfg.com/cgi-bin/dpsmar...FV5.html?E+Sig

Clear filler dope:
http://www.sigmfg.com/cgi-bin/dpsmar...FV5.html?E+Sig

This method is kind of like glassing, but you will not get the shiny high gloss surface. And since this is a corsair, it will be more realistic. You will not have to worry so much about working times, nor mixing proper proportions.

You can cover easily over open structures this way and over curves with no seams. Just fill any seam areas with dope, sand smooth and that is it.

Since the Koverall shrinks like film, you do not have to worry about bubbles and adhesion as you do with glass. Glass has to be stuck down to the surface with epoxy, and a bubble under the glass can be difficult to fix.

With Koverall you basically put a light coating of the adhesive over your wing for example. Tack down the edges as you pull it tight. Then hit it with a heat gun to shrink tight. Next run your covering iron over it to stick it down to the balsa. Then just fill with dope, sand, fill sand, and paint with dope color of choice.

Either way, best of luck!


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Old 01-13-2012, 09:59 AM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

I have used Koverall on open bay structure and when it shrunk it pulled the ribs. That is when I went to Nelson Lite Fab, then when it became unavailable, Solartex.

As far as the gloss is concerned with finishing, Klasskote offers a satin hardener to take care of that and also a flattening agent to create a dead-flat finish.

Klasskote and Solartex allows you to skip the additional steps necessary to apply and finish Koverall and dope and give that subdued lustre you are looking for in fabric and still be able to see the weave.

Bob
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Old 01-13-2012, 11:08 AM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

Vailly aviation has a good info on painting with latex. i did a Bearcat with latex using a sample of Tamiya warbird color. Home Repo duplicated the color for $8.00. Cheap. Put on with a cheap spray gun. If you are thinking gas no need for a sealer. Give it time to harden (about 2 weeks) Good to go. Tom Pierce had on his site glassing 101 pro's and con's. Don't know if it's still on there. Been using Z-poxy for years.
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Old 01-13-2012, 12:41 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

Hi,

I would recommend Z-Poxy or Bob Smith Finishing Resin for small jobs and West Systems 105 and 205 for larger jobs. It is easier and more cost effective to mix up a small batch of a one to one mix to use on a touch up than it is to mix a "pump" of West Systems.

[link=http://www.bsi-inc.com/Pages/hobby/epoxies.html]Bob Smith Industries[/link]

[link=http://www.westsystem.com/ss/epoxy-resins-and-hardeners]West Systems[/link]

Take a look at our 1/4 scale Panther project, we used Red Devil type light filler under the glass and two part Bondo filler over the glass. If everything is done correctly, you should not need much Bondo two part filler, most of it will be sanded off and the weight will not be an issue.

[link=http://www.rcuniverse.com/forum/m_10009222/tm.htm]Panther Build[/link]

We have painted with spray cans of Krylon and Rustoleum on my Boomerang, nose repaired from the inlets forward.
I have sprayed flat house paint on my Ziroli Stuka.
I have used paint for leather jackets, waterbased and very flexible, on my Euro Fighter.
Rattle can laquer from the auto parts store on a Gremlin, and we have sprayed Omni Auto paint on a Ziroli Texan.
I have a quart of blue hi-gloss house paint for the Panther, I will probably use it when i am ready.

The Krylon and flat house paint can be softened by glow fuel, but each of the paints have their place. I like the waterbased paint cleanup and leveling. The house paint really seems to flow nicely and drips from over coverage disappear.

There is more than one correct answer.

Good Luck, have fun and learn new techniques,

John


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Old 01-13-2012, 01:36 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: jroth

..... West Systems 105 and 205 for larger jobs. It is easier and more cost effective to mix up a small batch of a one to one mix to use on a touch up than it is to mix a "pump" of West Systems.
You can mix any epoxy laminating resin by using a gram scale. I personally dislike the pumps because I rarely ever need a full pump. In fact I don't trust the pumps. With a scale that goes to .01 grams you can mix small batches accurately. Even on large jobs it is typically easier to work with smaller batches rather than one big batch. The mix ratio of resin is different by weight than by volume. You usually can't use the volume mix ratio to mix by weight. Manufacturers will typically give both.

There are some good laminating epoxies that perfrom better than West Systems, have better handling, and are the same price or cheaper.

Resin Research Composite Pro
Adtech 820
US Composites 635




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Old 01-13-2012, 02:52 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: wingspar

Rapture, sound more like you used laminating resin instead of finishing resin. Thus sticky and not hard.

Dave N
I do layups of airplane parts. I use laminating resin. Pro Build brand name. Any part you get from any manufacturer that makes epoxy glass parts uses laminating resin. The parts dont come sticky So it makes no difference. Some resins leave a wax on them as they cure. That is probably what you are feeling. Other than that, high humidity will leave epoxy in a softened state. We call it tuperware finish. Also, most slow cure epoxy's require at least 5 days of cure before you can effectivly sand it without it gumming up sandpaper. You can cheat on this a little by wet sanding after a day or two.

As long as epoxy is in a SEALED container, it has a very long shelf life. Hardners are the same way. The hardner tends to turn a brown color after a while, but its still good. I have used some resin that was 6 years old before and didnt have an issue with it.

Epoxy also penetrates deeper into the wood for a better bite. It will add to the stucture of the airframe if used with at least 3/4 oz cloth.

I always squeegy a second coat of resin on after the first is cured to fill in any pinholes and fabric weave. Sand it down and start shooting primer. From this stage on its the same as painting a car. Spray on a gallon of primer, sand it all off LMAO.

I use only PPG or Shopline paint. I also like Klass Koat paint. The Klass Koat paint has a funky smell but its epoxy based. The other is urthane base. Use proper ventalation for both and wear a resperator, not a dust mask. Your lungs will thank you for it years down the road

Hope this helps.

WBG
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Old 01-13-2012, 02:56 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: SIMCO

Vailly aviation has a good info on painting with latex. i did a Bearcat with latex using a sample of Tamiya warbird color. Home Repo duplicated the color for $8.00. Cheap. Put on with a cheap spray gun. If you are thinking gas no need for a sealer. Give it time to harden (about 2 weeks) Good to go. Tom Pierce had on his site glassing 101 pro's and con's. Don't know if it's still on there. Been using Z-poxy for years.

OMG!!!! I have seen everything now. A Bearcat on floats.....how did it fly ? That is something I think I would have tried LOL

WBG
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Old 01-13-2012, 03:01 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: nwadc10


ORIGINAL: rgburrill
Also, you can use Solartex or Worldtex (I haven't tried Oratex) white covering. Using a primer such as Rust-Oleum and sanding it well gives a metal like finish. It is a little heavy so you should look at other ways to lighten the build first. But it also adds a lot of strength. I did this Royal Corsair this way.
I was tentatively planning on using Solartex for the rudder and elevator as an easy scale mod. That is another product I don't have experience with but it sounds like it is to be treated as iron on covering that is paintable. Pretty simple.
I use solartex on the tail feathers of my C47. Been using it for years. easy to apply, excellent ability to go around curves and corners, sticks well, and seams are almost non existant. Here is a picture of the rudder and elevators of the C47. Will get painted eventually.

WBG
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Old 01-13-2012, 03:02 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

It's funny how "the landscaper has the worst kept" yard on the block.

I am a Chemist and manufacture cleaning and specialty products for a living. I have a dozen gram scales in my laboratory and not one gram scale at home, my girlfriend has one in the kitchen, but if I got resin on it she might kill me in my sleep.

I usually prime the West Systems pumps and then mix a full pump at a time for larger jobs, but I still mix a lot of one to one finishing resin for small jobs.

I have never mixed resin by weight.

By the time I finish the Panther, I should be out of my West Systems set, it is pretty old and has turned blood red, i will look at the other resin systems on the market, thanks for the options.

John
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Old 01-13-2012, 03:25 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: jroth

It's funny how ''the landscaper has the worst kept'' yard on the block.

I am a Chemist and manufacture cleaning and specialty products for a living. I have a dozen gram scales in my laboratory and not one gram scale at home, my girlfriend has one in the kitchen, but if I got resin on it she might kill me in my sleep.

I usually prime the West Systems pumps and then mix a full pump at a time for larger jobs, but I still mix a lot of one to one finishing resin for small jobs.

I have never mixed resin by weight.

By the time I finish the Panther, I should be out of my West Systems set, it is pretty old and has turned blood red, i will look at the other resin systems on the market, thanks for the options.

John

I used the west system to begin with. Dont have anything bad to say bout it. The main reason I use Pro Build is 1. Locally obtainable, 2. has a UV blocker in it. I also use the pump system with it. Its 4 to 1 ratio. I keep a new set of pumps on hand all the time. When you start getting air bubbles its time to change pumps. Been doing that for years and no issues with resin setting up. Also, the Pro Build almost comes out crystal clear. Here is a picture of the fuse parts of my C47 and the tint you see is actually the fiberglass cloth.

But, for glassing wings, any name brand finishing resin is good. Instead of thinning, try working in a warmer room The resin will thin naturally when warm.

WBG
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Old 01-13-2012, 04:05 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: jroth

I am a Chemist and manufacture cleaning and specialty products for a living. I have a dozen gram scales in my laboratory and not one gram scale at home, my girlfriend has one in the kitchen, but if I got resin on it she might kill me in my sleep.
I've been using this one for small batches and really like it. Some of them stick or shut off while your adding more resin.....makes me mad. I've thrown quite few in the trash. I like the one that linked because it has a stainless platten, which is easy to clean, and I can put a baggy over the buttons. This allows me to operate the scaled with sticky gloves and not get the scale all sticky. Putting a baggy over the whole scale can mess up the readings. Sometimes just the static electricity can throw them off.

Mixing by weight is typically much more accurate than mixing by volume or pump. Most quality resin require you to be within 6% for maximum performance. On a 10 gram batch that requires you to be with .12 grams with some resins which is 2 drops out of spout top. Many will cure hard with deviations as large at 30% but the performance drops off considerably.

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Old 01-13-2012, 04:43 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more

That is really a nice scale for small quantities, I will look in to it next week.

I do not remember, does West, Z-poxy and others include mixing by weight instead of volume as an option?

Thanks,
John
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Old 01-13-2012, 05:46 PM
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Default RE: Fiberglassing questions: Why Bondo Specifically and Regarding Seams and now, more


ORIGINAL: jroth

That is really a nice scale for small quantities, I will look in to it next week.

I do not remember, does West, Z-poxy and others include mixing by weight instead of volume as an option?

Thanks,
John
Here is the data for West Systems.

Pacer doesn't put anything into writing in respect to the mix ratio by weight. They don't publish the specific gravity of the resin or hardener either so it can't be calculated. Maybe a phone call would help.

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Old 01-13-2012, 06:17 PM
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ORIGINAL: nwadc10


ORIGINAL: kenh3497

MY opinion on thinning epoxy....

If you are only using the thinned epoxy to apply light weight cloth (3/4 oz or lighter) the thinning agent will evaporate fast enough so the strength is not affected enough to matter. You are only ''gluing'' the cloth to the surface not using it as a structural component. If you are doing a layup of a fuselage or cowl, never thin the resin as the strength will be affected. The thinner has no chance to evaporate from the thick layup.


Have you looked at using the water based polyurethane varnishes to glass with? Never done it myself so I can't really comment. I'm told it is a bit lighter than epoxy, not quite as durable and less messy as it is water cleanup. I guess you need to watch the product soaking into the wood as it is water based? Some are using some sort of sealers as a first coat.


Ken
I plan on using 3/4 oz glass so this is applicable. What is ''layup of fuselage''? I am glassing purely as a finishing process rather than iron on covering so in my application it is not intended to add strength.

I have read some posts about the water based polyurethane and while it does sound easier cleanup it also sounds more complicated. Until I get more experience I need to keep this simple.

Justin

Layup in general is generally in a mold to produce a composite part.

like this 109F

Steve
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