[Public-List] removing the coamings

[crufone at comcast.net]

Hello Dave, 



As I mentioned before the sealant will fail if kept under tension over a period of time.  One way to do that is with wedges.  It is best to sharpen the edge of a drywall mud blade and carefully insert this between the coaming and the fibreglass.  Use a rocking motion and keep it close to the fibreglass surface by placing a curve in the blade as you would play a crosscut saw with a bow.  The teak will be damaged well before the glass surface.  Drywall blades are much thinner than putty knives.  The wedges are then placed between the mud blade and the glass surface, again this helps to protect the teak surface from abrasion.  The wedge can just be another drywall blade or purchase wedges at the hardware store for setting door and window frames, or you can make them from plexiglass (R).  Yes the wedges are acute but are MUCH less than 90 degrees.  Use something like no more than 5 degrees. Less is better.  To increase the tension over time simply drive another THIN wedge between the existing wedges.  Remember the secret is tension over time.  Driving too quickly a steeper wedge in will for certain damage the teak or glass surface.  I also will mention that many of these sealants are softened with the application of heat.   Once you have created a space between the glass and the teak you can carefully apply heat with a heat gun set at the low setting or a hair dryer.  For this application you need to be present to observe the results of heat, driving the wedges in further as the sealant softens. Infrared lights might work as well. 



Anyway the key is working slowly and cautiously.  You can drive the wedges and then go away for a day and then drive them in some more and go away again, repeat.  Work the entire top edge at one time.  Start at the end that has the most degraded sealant and work your way down to the other end.  It would also be best to work the lower edge at the same time, if this is possible.  Once one end is pried away from the glass surface, you can use the natural spring of the teak, perhaps 5 degrees or less to your advantage.  Hold away the loose end and place blocks of wood between the glass surface and the teak, slowly working your way toward the other end. 



I think that the black stuff is called Dolomite.  I don't know how it will react to heat.  You just want to soften it NOT turn it into a liquid mess! 



It is best to sever the bond between the glass and the sealant.  Once the coamings are free you can scrape them to remove the sealant from the teak while on a workbench. 



Michael 


















----- Original Message ----- 
From: "Dave Terrell" <DTERRELL at message.nmc.edu> 
To: public-list at alberg30.org 
Sent: Sunday, November 2, 2008 4:42:13 PM GMT -05:00 US/Canada Eastern 
Subject: [Public-List] removing the coamings 

I am removing the coamings to refinish them. 
  
I started by reading the e-mail traffic on this topic.  I found the e-mails very helpful and  have printed a number of them out. At this point, all the bolts are out. The current problem is: separating the coamings from the fiberglass. I learned from reading the e-mail record that putty knives and acute angle wood wedges can be used to separate the coamings from the fiberglass. I have been using a putty knife and I think I am making progress piercing through the sealer. I will look around for some wedges tomorrow. 
  
What I would like to know is if there is a solvent that will attach the black sealant but that would not bother the fiberglass or the teak? While I am willing to use force if  necessary, I would really like to finesse this problem. 
  
For example, could "unbond", the product used to remove 5200, work? I know it does not attack fiberglass, but do not know about its reaction with teak or the black sealant between the coamings and the fiberglass. 
  
David, 432 
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