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Re: Hull and deck lifting off forms
By:Rob Macks
Date: 11/1/2001, 11:01 am
In Response To: Hull and deck lifting off forms (Brad)

: I am close to glassing the hull and deck however they are both springing off
: the forms quite badly around the shear line. Is this common? How do I fix
: it? Is it OK to use hot melt glue? Once the outside layer of glass is on
: and the epoxy is cured, will that be the end of the problem or do I need
: to be careful until the inside is glassed as well?

I would use hot glue to hold the strips in place. Any distortion in the strip surface will be frozen once you glass one surface. However you can have larger distortions after one surface is glassed if you have a change in humidity in you shop or if you wait a long time before glassing the second surface. Winter usually means shops are closed up and the air becomes very dry. Once you glass one surface of your boat the wood on that side is frozen in epoxy and will not expand or contract. BUT the other uncoated surface will continue to dry out. If you left your boat for a couple weeks it will curl inward once the stations are removed. You can counter this by wetting the wood so it will expand back in balance with the other surface. I do mean wet the wood. I've had to wet the inside of a few hulls with a soaking wet sponge to get the wood to expand back to the shape it should have been. I WAS surprised at how much water it took to do the job. All you have to do is let the wood dry for a few hours until the surface is dry and the hull remains at the correct dimensions.

If you use hot glue make certain you buy hot glue that is formulated for woodworking purposes. Any other hot glue will not hold as well. This glue is usually a opaque yellow/gold color. I use hot glue extensively and love the stuff. It will hold very well if you give it a chance to set fully undisturbed. This may mean you’ll need to use a spring clamp in places that need clamping.

The biggest problems people have with using hot glue are #1, they’re not using a hot glue designed for wood; #2 they don’t hold the pieces in place and still for the 90 seconds it usually takes for the hot glue to totally set: and #3 they try to glue over tape. To achieve the highest holding power you must hot glue bare wood to bare wood.

I urge people working on my designs to not cover or coat the edges of their stations. I do recommend using duct tape on the stem edges for easy removal.

All my boat designs have fine stems for tracking. This means they have recurve or concave areas below the waterline near each stem. The strips MUST contact and remain in contact with the stations to create the correct hull shape. If you cover the stations with duct tape or any other non-stick coating AND do not use staples the strips WILL come away from the forms making work difficult and correct hull shape impossible. EVEN IF you used duct tape and staples once the staples are removed the hull will lift off the stations and can cause the hull to deform. I WANT my strips to stick to the stations until I’ve glassed the outside surfaces to LOCK the correct shape in place. This becomes even more important if you take more than a week to strip your deck or hull because you can have fluctuations in humidity that will distort your strips.

The small amounts of glue squeezing through from the strip joint and the hot glue on the bare wood stations are not a problem.

I built many boats with this method and have never had serious tearout or station removal problems.

If each strip is not stuck to the station in some fashion how can you expect the next strip to align properly?

All the best,

Rob Macks
Laughing Loon CC&K
www.LaughingLoon.com

Messages In This Thread

Hull and deck lifting off forms
Brad -- 10/31/2001, 2:17 pm
Re: Hull and deck lifting off forms
Rob Macks -- 11/1/2001, 11:01 am
Re: Hull and deck lifting off forms
Chip Sandresky -- 10/31/2001, 7:02 pm
Re: Hull and deck lifting off forms
Nick Schade - Guillemot Kayaks -- 10/31/2001, 3:07 pm
Re: Hull and deck lifting off forms
Rob Macks -- 11/1/2001, 11:29 am