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by fa1321. 05/08/21 07:26 AM
Downhaul under spinnaker
by CapriSun. 04/22/21 09:01 AM
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Re: best way to bed your beams ? [Re: downsouth] #243377
02/01/12 03:33 PM
02/01/12 03:33 PM
Joined: Jun 2002
Posts: 1,658
Florida Suncoast, Dunedin Caus...
catman Offline
Pooh-Bah
catman  Offline
Pooh-Bah

Joined: Jun 2002
Posts: 1,658
Florida Suncoast, Dunedin Caus...
Beam me up Scotty... There is no intelligent life on this planet.


Have Fun
-- Have You Seen This? --
Re: best way to bed your beams ? [Re: rehmbo] #243385
02/01/12 06:38 PM
02/01/12 06:38 PM
Joined: Feb 2005
Posts: 4,118
Northfield Mn
Karl_Brogger Offline
Carpal Tunnel
Karl_Brogger  Offline
Carpal Tunnel

Joined: Feb 2005
Posts: 4,118
Northfield Mn
Originally Posted by rehmbo
A bottle of red wine always worked well for me!

-sorry - couldn't resist-


Mix up a Roofycollada.

[Linked Image]


I'm boatless.
Re: best way to bed your beams ? [Re: downsouth] #243394
02/02/12 12:43 AM
02/02/12 12:43 AM
Joined: Apr 2004
Posts: 713
WA, ID, MT
davefarmer Offline
old hand
davefarmer  Offline
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Joined: Apr 2004
Posts: 713
WA, ID, MT
What is PVA, and where can it be obtained? Thanks!

Dave

Re: best way to bed your beams ? [Re: davefarmer] #243397
02/02/12 07:56 AM
02/02/12 07:56 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Poly vinyl alcohol. It's a spray on mold release (spray with paint sprayer). You build up several layers to form a film that is almost like saran wrap and can be peeled off when cured or washed away - it's very water soluble and easy to remove. It makes a pretty bullet-proof mold release or an air barrier for gelcoat that you need to cure in the open air.

When spraying on a waxed surface, you have to mist on the first coat or two and let each coat dry for about 15 minutes. Then you can lay down two or three nice glossy coats. It dries pretty smooth and glossy but it's about impossible to get a completely glassy smooth finish on it so it's probably not the best thing out there to use as a release for a very high end mold. It is waterbased so it works very well with ester based resins. You have to be sure to get a thick enough barrier when using epoxy...but it doesn't seem to affect the finish of the epoxy at all.

I buy mine at www.uscomposites.com but I'm sure www.fiberglasssupply.com or www.aircraftspruce.com has it as well.


Jake Kohl
Re: best way to bed your beams ? [Re: downsouth] #274554
08/09/14 04:23 PM
08/09/14 04:23 PM
Joined: Mar 2013
Posts: 22
RParentsail Offline
stranger
RParentsail  Offline
stranger

Joined: Mar 2013
Posts: 22
What's the best epoxy (with what characteristics) to use for this? I've decided to use epoxy and a pigment to color it in order to avoid that yellowing. Also, can you use cabosil with all epoxies to thicken it?


"Nothing that is worth knowing can be taught." ~Oscar Wilde
RPSailing.blogspot.com
Re: best way to bed your beams ? [Re: downsouth] #274560
08/09/14 10:13 PM
08/09/14 10:13 PM
Joined: Apr 2012
Posts: 190
B
Bille Offline
member
Bille  Offline
member
B

Joined: Apr 2012
Posts: 190
ANY decent epoxy , mixed with :
West-Systems 404 High-density adhesive filler ; will do
the job.

Do NOT use just any filler,(like micro-balloons) because
they are hollow spears that will break down with time.Some
fillers were designed as a sanding/fairing compound, and won't
work for a structural application !!

The splice i made for my Hobie-21se, i actually installed grease-nipples, and pumped in the filler with a grease-gun
from Harbor freight; then removed the nipples after the epoxy
gelled-off, but before it cured.
It worked Great !!

Bille

Re: best way to bed your beams ? [Re: downsouth] #274571
08/10/14 08:27 PM
08/10/14 08:27 PM
Joined: Jun 2003
Posts: 712
mikekrantz Offline
old hand
mikekrantz  Offline
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Posts: 712
I've had good success using teflon tape on the beams and West Six-10 as the bedding compound.


-Mike

Re: best way to bed your beams ? [Re: downsouth] #274572
08/10/14 09:18 PM
08/10/14 09:18 PM

S
Scarecrow
Unregistered
Scarecrow
Unregistered
S



Packing tape.

Re: best way to bed your beams ? [Re: RParentsail] #274583
08/11/14 06:57 AM
08/11/14 06:57 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
No matter what pigment you add (unless it's black and use also use aluminum powder), epoxy will yellow.

The boat I have now had the beams previously bedded (by POs) with gelcoat. It's holding up just fine and where it oozed out it matches the boat perfectly.

I also just wax the beams with four or five coats of a good carnuba wax. I've never had a problem with them releasing (you have to go to some advanced etching to get epoxy or polyester resins to adhere to aluminum).


Jake Kohl
Re: best way to bed your beams ? [Re: Jake] #274682
08/13/14 02:49 PM
08/13/14 02:49 PM
Joined: Mar 2009
Posts: 932
Solomon's Island, MD
S
samc99us Offline
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samc99us  Offline
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S

Joined: Mar 2009
Posts: 932
Solomon's Island, MD
Originally Posted by Jake
Originally Posted by Mike Hill
I don't understand why you don't just spray PVA on the beams. It would take about 10 seconds to spray with PVA. Some people just like to work harder I guess.


Because PVA adds thickness which results in a not-as-tight fit as possible after it dissolves away. The wax works just fine. A semi-firm tap with a rubber mallet and the beams will release perfectly with a coat or two of wax.

Mike (the other Mike), I'm not sure I see the point of leveling the beams or even loosening the dolphin striker. I will take an "X" measurement on the boat to check squareness and try to do a little to square it up if it's out much...but you're not moving it much at all since the beam bolts are threaded into the hull. You have only the minimal amount of slop available in the beam through holes for the long bolt anyway..so most correction you put on it is just going to spring back after you release it anyway. Canted hulls introduce another level of difficulty (not the case with this F18 in question).


PVA is 2-4 mils thick in a heavy application (0.002"- 0.004"). It can be applied thinner to aluminum (0.001-0.002"): http://www.rexco-usa.com/documents/TDS_Partall%20Film%2010.pdf
If 0.002" is a concern to you, go ahead and not use the PVA. PVA guarantees a release every time.

I use 2-3 coats of wax (Rexco Partall Paste #2), followed by a light brush coat of PVA, tape off beam sockets with drop cloth and add thickened (with cabosil) gelcoat to the sockets. Plug the holes in the beams with the Partall Paste wax and avoid putting gelcoat near the bolt holes.

Last edited by samc99us; 08/13/14 02:50 PM.

Scorpion F18
Re: best way to bed your beams ? [Re: samc99us] #274684
08/13/14 02:58 PM
08/13/14 02:58 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by samc99us


PVA is 2-4 mils thick in a heavy application (0.002"- 0.004"). It can be applied thinner to aluminum (0.001-0.002"): http://www.rexco-usa.com/documents/TDS_Partall%20Film%2010.pdf
If 0.002" is a concern to you, go ahead and not use the PVA. PVA guarantees a release every time.


So does waxing the bare aluminum beam and not going through the extra step with PVA. I've seated more than my share of beams and they all released with a slight tap with a rubber mallet.


Jake Kohl
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