Sealing the Deal
Posted: May 1, 2014
I have a hatch that is sealed to the cockpit floor above the engine. The upper hatch edge fits over the lower deck opening edge — the edges are not accessible to mechanical scrapers. There is a joint on the inside under the deck into which solvent can be sprayed to get to the caulk.
It is important to be able to remove the hatch (infrequently) — mechanical fasteners secure the hatch down — and sealant adhesion is not needed to secure the hatch.
What is the best sealant to use in this case, where periodic removal is required, without access to scrape out the caulk?
Based on the information you have provided, I think you would be better off making a “gasket” to seal the area. Try this: Apply wax paper or plastic wrap over the area where you want to apply the sealant, then apply the sealant, then apply another piece of wax paper or plastic wrap on top of the sealant and lay the hatch into position. When it dries, you should be able to peel off the paper and have a perfectly fitting gasket that will not be adhered to the surface but will provide you with the sealing properties you desire when the hatch is fastened down tight. This way you won’t need to be concerned about getting any mechanical scrapers in the area in the future.