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Sep 23, 2005, 01:49 PM
Registered User
Great to hear that it worked out for you Jehitch! The Dumas Tuna Clipper is a neat looking boat! You should start a thread on it! I'm sure a lot of folks would be interested in it.
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Sep 23, 2005, 03:42 PM
Dragon Slayer
ropanach's Avatar
Yes we would be interested in watching a thread on the tuna clipper. you can start any time you like, no pressure, to day is good, I'll be back in about 10 min.to see how your doing. We would love to see your build threads. LOL
Sep 29, 2005, 11:16 AM

New thread started


I started a new thread on the Dumas Tuna Clipper. I also have a yahoo group dedicated to Dumas boats, where there are more pics, if anyone can't wait for the next post ( ) You can find it at http://groups.yahoo.com/group/dumasmodelboats/
Dec 09, 2005, 02:58 PM
Registered User
Mo.Hawk's Avatar

Fiberglassing mahogany boats


Pat, in all your glassing, have you ever been able to see the weave of the fiberglass cloth? Do you have any idea as to why I see it sometimes on mine?
I'm using Sig polyester resin.
Dec 09, 2005, 10:14 PM
Registered User
P. Tritle's Avatar
Thread OP
Classic, Generally speaking, if I get a little weave showing, it's usually on the painted bottom where it's not that big of a deal. On the mahogany sides and deck, you definately DON'T want it showing.
There is only one reason why the weave would still show, and that's simply because there needs to be more resin to fill and level it up. Now, within that vein, the reason it seamingly won't fill is possibly due to too heavy a cloth requiring a lot of fill.
Either way, simply add a coat and sand. If there's still weave showing, add another coat and repeat the process until you get a good smooth surface. Be carefull though, as you fill and sand, be very careful not to sand through the cloth.

PAT
Dec 09, 2005, 11:43 PM
Registered User
Pat, please help me understand. Why not just always try to use the lightest weight fiberglass cloth available, in an attempt to avoid the above problem with the coarser weave showing through. Or, do the lighter weight fiberglass cloths lack sufficient strength in applications like on fairly large hulls? Could you (or someone) please briefly discuss the proper use of lighter weight fiberglass cloth versus the use of heavier, coarser weave cloth?
Or, if you could refer me to a thread where this has been discussed, I'd appreciate it. I don't recall one recently. Thanks -
Bill
Last edited by jeepers1940; Dec 10, 2005 at 12:00 AM. Reason: Clarity
Dec 10, 2005, 09:20 AM
Registered User
P. Tritle's Avatar
Thread OP
Bill, I've tried several different weights and grades of cloth over the years and have pretty well identified both extremes. I've used the .6 oz cloth and found it to fill very nicely, but it's just too easy to sand through. On the other end of the spectrum, 4 oz. cloth is strong and offers lots of head room for sanding, but is at the edge of the spectrum when it comes to going transparent when wetted -- and requires A LOT of resin to fill which will add considerable weight.
Now, with that being said, my personal favorite is the 1.45 oz. cloth available from Aircraft Spruce and Specialty. I's a lightweight industrial cloth (known as Deck Cloth) with a nice tight weave that conforms nicely to compound curves, and fills very nicely with 3 - 4 brushed coats of resin.
If you want to look for it, it's #1080 (P/N 1080-50) at www.aircraftspruce.com It's listed at 50" width for $5.20 a yard, but my catalog is 2002-2003 so it's probably gone up a bit.
What I don't recomend using is the standard "Hobby Shop grade" cloth that comes folded in 1 yard packs. I've found that it's been treated with stiffeners which make it very difficult to get layed down and conformed to curved surfaces without wrinkles and bubbles.
PAT
Dec 13, 2005, 11:55 AM
Registered User
P_J_Glor's Avatar
Pat -- I found the 1.45 oz fiberglass cloth at this link:

http://www.aircraftspruce.com/menus/cm/fiberglass.html

They list a price of $3.50 but no dimension. D you know if that a "per yard" figure? If so, the price has gone down, which would be great!

Pete G.
Dec 13, 2005, 11:21 PM
Registered User
P. Tritle's Avatar
Thread OP
Pete, Sounds like a good deal, but would guess the cloth is 36" wide rather than 50" at that price. Either way, once you get used to working with good quality cloth you'll never go back to the other stuff.
PAT
Dec 14, 2005, 01:29 AM
Registered User
Pat, thank you for the excellent information on fiberglass cloth, and steering me away from the typical hobby shop type cloth. Not knowing any better, I might have settled for that because of its' ready availability.
Bill
Dec 14, 2005, 09:25 AM
Registered User
P. Tritle's Avatar
Thread OP
Bill, Glad to help out. I used the stiff stuff from the LHS for years for the same reason, and after the first go around with the good stuff, never went back. Resins were the same way. It wasn't until I worked with a friend on a UAV project using "full scale" quality materials that I realized what a huge difference there was in the level of performance between actual "fiberglass resin" and "glue."
PAT
Dec 21, 2005, 07:18 PM
It is very interesting, to read this thread. And I know, that my way is the right one: after planking the hull you have to put on glass on the wood.
I am a german modelbuilder and doing esspecially Riva and american boatmodels from the late 20/30ties.
When I have my fibreglass-hull, I put on very thin mahaghony with ca-glue. After sanding away the "ice" from the surface, I put on 25gram glasssilk.
When dried, the surface will be sanded wet with very fine paper (1200-2000 grind) and then brushed with polyurethan or 2component acrylic carpaint.
Dec 21, 2005, 07:51 PM
Registered User
Avanti, Really fine finishes on your very nice boats. Thank you for letting us see your work.
Pat, I take it that there is no practical way to remove the stiffeners found in the hobby shop grade fiberglass cloth to make it conform more readily; I guess they're 'in there' and can't be removed, huh? Neither heat applied nor any chemicals would help?
Merry Christmas to both of you.
Bill
Dec 22, 2005, 12:45 AM
Useful Idiot
Acetone would take out the "stiffener" but I think the stiffness is more due to over-generous use of the bonding agent, without which the glass would be almost impossible to apply cleanly.
Aug 26, 2008, 04:24 PM
Registered User
dash8man's Avatar
Just wondering if SIG 1.5 oz. cloth is recommended for fiberglassing hulls or is it too difficult a cloth to lay down smoothly? Cheers.

Bill.


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