Re: [bolger] Gluing plywood sheets
snip
take a while to get just right so I don't have to hurry.
I'd be careful using a shop vac and not leave it
unattended. I
which will pull pretty hard and still last a long time. Probably a
few hundred $. I'm sure there's some cheap gadget that will do.
For instance there are valves you can put on your compressed air
supply that will pull some vacuum. Very cheap, not very efficient.
You can still use a shop vac or similar for the initial pull down.
snip
use
the existing hull as one side of the bag and make it work just fine,
assuming it's airtight.
>fast
> I usually only leave the vacuum on for 4 or 5 hours with System 3,
> hardener.I like to use really slow epoxy when I'm doing something that will
take a while to get just right so I don't have to hurry.
I'd be careful using a shop vac and not leave it
unattended. I
> had one catch fire once from the wiring overheating. Also, have aback up
> as they do burn up some times. Kurt Hughes, who has done a lot ofvacuum
> bagging for Cylinder Mold construction where the whole side of ahull up to
> 40 or more feet long is bagged together of 2 or 3 layers all atonce, says a
> shop vac will last 20 sessions.If you're going to do such a big hull, you can afford a real pump,
which will pull pretty hard and still last a long time. Probably a
few hundred $. I'm sure there's some cheap gadget that will do.
For instance there are valves you can put on your compressed air
supply that will pull some vacuum. Very cheap, not very efficient.
You can still use a shop vac or similar for the initial pull down.
snip
> No, bagging wouldn't work well for adding layers to a framed hull.I'll bet if you have a layer of epoxy on the existing wood you can
>
> Gary
use
the existing hull as one side of the bag and make it work just fine,
assuming it's airtight.
----- Original Message -----
From: Lincoln Ross <lincolnr@...>
To: <bolger@egroups.com>
Sent: Wednesday, April 12, 2000 9:26 AM
Subject: Re: [bolger] Gluing plywood sheets
> I vote for vacuum bagging where possible also. I don't know what
> visqueen is, but you can make a serviceable bag with heavy
> polyethylene and automotive strip caulk. Paper towels will work for
> bleeder material, tho you might need something more. Try web surfing,
> I think a lot of the model airplane guys have articles on this. Not
> sure about leaving a shop vac on 24 hrs tho (necessary with slow
> epoxy).
Visqueen is just another name for polyethelene, probably a brand name I
picked up.
I usually only leave the vacuum on for 4 or 5 hours with System 3, fast
hardener. I'd be careful using a shop vac and not leave it unattended. I
had one catch fire once from the wiring overheating. Also, have a back up
as they do burn up some times. Kurt Hughes, who has done a lot of vacuum
bagging for Cylinder Mold construction where the whole side of a hull up to
40 or more feet long is bagged together of 2 or 3 layers all at once, says a
shop vac will last 20 sessions. I've used a refrigerator compressor too but
they don't suck much volume so won't do well on a big project or if the bag
leaks. Some day I'll invest in a real vac. pump!
No, bagging wouldn't work well for adding layers to a framed hull.
Gary
In a message dated 4/12/00 9:35:57 AM Pacific Daylight Time,
lincolnr@...writes:
<< I vote for vacuum bagging where possible also. I don't know what
visqueen is, but you can make a serviceable bag with heavy
polyethylene and automotive strip caulk. Paper towels will work for
bleeder material, tho you might need something more. Try web surfing,
I think a lot of the model airplane guys have articles on this. Not
sure about leaving a shop vac on 24 hrs tho (necessary with slow
epoxy). >>
Hi Everyone,
I'm not an expert, but I did watch an expert (Derek Kelsall) vacuum bag
composite hull where he only keep the vacuum on for approx. 20 minutes in 70
degree temp. Now he was using the old resin (don't remeber the tech name),
vs. epoxy, but why would the vacuum need to be on overnite with epoxy? Seems
like overkill.
Also, we drilled several holes in the vacuum tube to keep the vacuum from
overheating.
Chuck C., almost done with taxes, and then a final push to finish the F.S.
and the sailrite sails.
lincolnr@...writes:
<< I vote for vacuum bagging where possible also. I don't know what
visqueen is, but you can make a serviceable bag with heavy
polyethylene and automotive strip caulk. Paper towels will work for
bleeder material, tho you might need something more. Try web surfing,
I think a lot of the model airplane guys have articles on this. Not
sure about leaving a shop vac on 24 hrs tho (necessary with slow
epoxy). >>
Hi Everyone,
I'm not an expert, but I did watch an expert (Derek Kelsall) vacuum bag
composite hull where he only keep the vacuum on for approx. 20 minutes in 70
degree temp. Now he was using the old resin (don't remeber the tech name),
vs. epoxy, but why would the vacuum need to be on overnite with epoxy? Seems
like overkill.
Also, we drilled several holes in the vacuum tube to keep the vacuum from
overheating.
Chuck C., almost done with taxes, and then a final push to finish the F.S.
and the sailrite sails.
As you have seen from the replies, there exists a variety of these
power-driven, self-drilling screws. the most common are called "drywall
screws" in the USA because they are intended to fasten gypsum board
("drywall") to studs in construction. They are threaded all the way to the
head, so they will tighten in very thin material, but you risk stripping
them out. There's a "touch" to develop with your drill or electric
screwdriver, then you can just zip them in on 12 inch or so centers, then
back 'em out after the glue dries. I think the shortest ones are 5/8 inch
or 3/4 inch (14-18 mm?)
Don Hodges
dhodges@...
http://www.ecoastlife.com
Your Cyber-Vacation - Loafing on the Emerald Coast
Small Boats, Building, Fishing, Paddling, Rowing, Sailing
power-driven, self-drilling screws. the most common are called "drywall
screws" in the USA because they are intended to fasten gypsum board
("drywall") to studs in construction. They are threaded all the way to the
head, so they will tighten in very thin material, but you risk stripping
them out. There's a "touch" to develop with your drill or electric
screwdriver, then you can just zip them in on 12 inch or so centers, then
back 'em out after the glue dries. I think the shortest ones are 5/8 inch
or 3/4 inch (14-18 mm?)
Don Hodges
dhodges@...
http://www.ecoastlife.com
Your Cyber-Vacation - Loafing on the Emerald Coast
Small Boats, Building, Fishing, Paddling, Rowing, Sailing
----- Original Message -----
From: Roger Dewhurst <dewhurst@...>
To: <bolger@egroups.com>
Sent: Wednesday, April 12, 2000 1:05 PM
Subject: Re: [bolger] Gluing plywood sheets
> At 21:04 11/04/00 -0500, you wrote:
> >Drywall screws are much better - just be careful not to strip them out as
> >you tighten them. Back 'em out and patch the holes after your glue is
set.
>
>
> Thanks. What is a 'drywall' screw? We must have these but known under a
> different name.
> If the first two sheets of ply are each only 7mm thick there is not much
> meat for any screw to hold in.
>
>
>
>
> ------------------------------------------------------------------------
> eLerts
> It's Easy. It's Fun. Best of All, it's Free!
>http://click.egroups.com/1/3080/6/_/3457/_/955574024/
> ------------------------------------------------------------------------
>
>
Hi
When I said earlier that flooring screws were better than drywall, I didn't
realize you were laminating sheets together. I have laminated two layers of
1/4 inch (6mm) using 3/4 inch round head screws on 8 inch centres. I
drilled the top sheet but not the bottom, letting the screws make their own
holes in that. When I put the screws in I worked from the middle to the
ends to allow air pockets and excess glue to get squished out as I went.
Works like a charm but leaves lots of little holes to fill after you take
out the screws.
Sam Devlin's book describes this method -- he recommends 6 to 8 inch centres
for the screws, if I remember rightly.
Jamie Orr
-----Original Message-----
From: Roger Dewhurst [mailto:dewhurst@...]
Sent: Wednesday, April 12, 2000 11:05 AM
To:bolger@egroups.com
Subject: Re: [bolger] Gluing plywood sheets
Bag that?
------------------------------------------------------------------------
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When I said earlier that flooring screws were better than drywall, I didn't
realize you were laminating sheets together. I have laminated two layers of
1/4 inch (6mm) using 3/4 inch round head screws on 8 inch centres. I
drilled the top sheet but not the bottom, letting the screws make their own
holes in that. When I put the screws in I worked from the middle to the
ends to allow air pockets and excess glue to get squished out as I went.
Works like a charm but leaves lots of little holes to fill after you take
out the screws.
Sam Devlin's book describes this method -- he recommends 6 to 8 inch centres
for the screws, if I remember rightly.
Jamie Orr
-----Original Message-----
From: Roger Dewhurst [mailto:dewhurst@...]
Sent: Wednesday, April 12, 2000 11:05 AM
To:bolger@egroups.com
Subject: Re: [bolger] Gluing plywood sheets
>The best way to hold large sheets together is vacuum bagging, which issearch
>really a lot easier than it might seem. Just envelope the sheets in a
>visqueen bag and suck the air out with a shop vac. Works great. Gives a
>lot more pressure evenly distributed than mechanical fasteners. The
>Gougeons have a good pamphlet on it and you can find out more doing a
>on "vacuum bagging"I am talking about second and subsequent layers of plywood on a framed hull.
>
>It's fun too.
Bag that?
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At 08:27 12/04/00 -0700, you wrote:
12mm. The ones I have seen here all have a countersunk head.
>I've had drywall screws break off when driven -- I use flooring screwsI know the screws you mean. But I do not think that I can get them down to
>instead now, they are much stronger and come with a Robertson (square hole)
>head that lessens the chance of the screwdriver slipping. The thread is
>still fairly coarse and goes all the way to the head, and they can be driven
>easily with no drilling.
12mm. The ones I have seen here all have a countersunk head.