Re: Engine hatches, how to build
 

Thanks Jon,

For something like I want to build I didn't think figuring the reverse would be too hard. It's just a rectangular box. I figure I can make it slighty larger and deeper.

Dave M.

Re: Engine hatches, how to build
 

Ya if you are going square box then you probably are ok. The MDF will work for you. As was mentioned earlier you can not do hard corners in a mold either so make sure you have the corners rounded off or the glasss will lift and create bubbles. You can always fix these things later and or glass hard edges in after you pup the thing out of the mold. Also make sure you will be able to pup the part out of the mold. In other words make sure that like the top is not wider then the bottom of the hatch (as it would sit on the boat) thus making it neccasary to break the mold to get the part out.

Jon

Re: Engine hatches, how to build
 

You can make your mold from wood. To keep the resin/gel from sticking coat the wood with PVA or release wax. Use clay to seal the seams and make your radiuses. If you are using reverse angles make sure you have planned a way to remove the mold from the part because the part will not release from the mold. Either way don't expect the part to just fall out.

There will be finish work post mold because the wood grain will transfer to the part.

Also, be sure your mold is stiff or shrinkage and heat of the curing resin can cause the mold to warp.

Re: Engine hatches, how to build
 

build a wood sand box the shape of the hatch you want. Tape the inside of the the wood with box tape. Yes box tape. if every thingis true you can lay in 60 mils of gel before you glass it up. Pop the part and wet sand it. of you have the tools and knowledge this should be an easy project. go buy a pair shoes and use the box as a small scale experiminet. Make sure you use a structure on the outside of the box from keeping it fro moving. You could make one hatch in 8 hours.

bottomsupboatrepair.com :evilb:

Re: Engine hatches, how to build
 

Thanks guys, great ideas here. I was planning on taking Bill's advice and doing a test run with a small box.


What type of glass should I use? I looked in some catalogs at the sizes available. Should I try to work with large pieces (I know it's harder) to avoid seems? The hatch is going to be approx 66" x 36".

My current hatch has the back seat built in. I like that, easy engine access. I hope to include that in my new hatch. See picture.

Re: Engine hatches, how to build
 

What's wrong with your current hatch? Is it fiberglass on both sides?

Re: Engine hatches, how to build
 

It is glass on both sides, the outside is gelcoated. If you notice in the pic, I attached the 2x2 angle iron to raise it a few inches. It BARELY clears the motor now. If I move the angle iron up any more the hatch will be higher than the gunnels and look crappy. Also, I had to doctor the way my hinges attach in the back. I don't think I can go any higher. I want to add CMI headers and need some more clearance. The raised part of the hatch in the back used to be flush with the back of the boat. I thought about modifying the existing hatch. I don't want to mess with it because I know I always have that to fall back to if my new project doesn't work right.

You know how it is. Winters coming, and I need/want something to do.

Re: Engine hatches, how to build
 

Got ya!

Re: Engine hatches, how to build
 

Thanks for the recomendation. I am also planning on eliminating the sunpad/engine hatch cover combo for an all glass unit. Can you provide the telephone # for Fiberglass Plus? Richard

Re: Engine hatches, how to build
 

Fiberglass Plus
Point Pleasant Beach, NJ 08742
(732) 899-8523