So we made a hatch

[Madcow]

The hatch on my 18 was delaminated and pretty busted up, so I had Glassdave make me a new one. Really came out great. Here are a couple pics.

[Madcow]

I borrowed a good hatch from Tim at Brenner 75 marine here in Toledo THANKS TIM!

[Madcow]

I attached a sheey of 1/4' particle board to the bottom of the borrowed hatch to act as a parting board, applyed 4 coats of mold release wax to the hatch. Then Dave sprayed a coat of gel coat to the hatch then covered it with glass. Next thing you know we have a mold.

[Madcow]

Next Dave sprayed a heavy coat of white gel to the inside of the mold AFTER coating it with more wax.

[Madcow]

Then came fiberglass, 3/8 in balsa core then more glass. The releif holes are for the top of the EMI exhaust risers.

[gcarter]

Aren't you glad Dave was available?
Well done!

[Madcow]

And next thing you know, you have a hatch. Little blocking, little paint and we will be good to go. And the nice thing is we also have a nice mold so more of them can be made if need be. Anybody who is interested contact Glassdane @ davesikorski@sbcglobal.net (davesikorski@sbcglobal.net)

THANKS DAVE! Great job.

[glassdave]

Thanks Jim, ya know all ya had to do was ask :nilly: :D

Did ya drop it on the boat yet?

[gcarter]

I really like this thread!:yes:

How did you attach the particle board to the borrowed hatch?

[glassdave]

actually Jim just put kind of a spreader in the hole that was under the scoop and drew it up with a couple of screws. Particle board is used because it can be easily broken apart if need be. This was what i call a "quick and dirty" mold. It was meant for a limited number of parts and for the safety of the original part it was not meant to be a very heavy mold. I was more concerned that the mold release with no damage the the borrowed part. We waxed the heck out of it and sprayed a bunch of PVA on for a barrier of protection between the tooling gel and the painted surface. Worked like a charm but its still a bit touchy doing projects like these, if it goes wrong you run the risk of not only loosing what you have in time and materials but you would have to replace/repair the borrowed part as well. It could go hugely upside down quick. Also in the above pic the inside surface is in raw gel and has not been finished yet, Jims going to do the fitting and that will be gelled in white to cover the glass work.

[gcarter]

Thanks for the info Dave.
How long do you let the tooling gel kick before you start adding glass?????

[glassdave]

i usually let it go overnight. Tooling gel thickness is also very important, 25 mils or so.


Love you sig line by the way. One of my favorites is "Its easy to be credible and its easy to be creative. Its difficult to be both" - Albert Einstein

[Boatnuts]

glassdave - how many layers and what weights of cloth did you use on the mold? I have to make a similar but larger curved hatch for my Bertram soon.

[glassdave]

glassdave - how many layers and what weights of cloth did you use on the mold? I have to make a similar but larger curved hatch for my Bertram soon.


This one was pretty light by standard practice.

25 mils tooling gel
3 layers of .75 oz mat
1 layer of 1808 bi-ax
3 layers of 2208 bi-ax (had a bunch of that laying around and its to stiff for much else)

Alot of times for molds that will see moderate use (few dozen parts over their life) and not much bigger then this hatch I'll go

25-30 mills tooling gel
two layers 1808
4 mill core mat
two more layers 1808.

Rule of thumb for production molds is three times thicker then what your finished part will be, but that by old school standards.

[OFFSHORE GINGER]

This one was pretty light by standard practice.

25 mils tooling gel
3 layers of .75 oz mat
1 layer of 1808 bi-ax
3 layers of 2208 bi-ax (had a bunch of that laying around and its to stiff for much else)

Alot of times for molds that will see moderate use (few dozen parts over their life) and not much bigger then this hatch I'll go

25-30 mills tooling gel
two layers 1808
4 mill core mat
two more layers 1808.

Rule of thumb for production molds is three times thicker then what your finished part will be, but that by old school standards. Dave , yes that is pretty light by standard practice and is fine for a few small parts but not for hulls and decks and guys you do not have to actually make a Mold to make another part .

[glassdave]

Dave , yes that is pretty light by standard practice and is fine for a few small parts but not for hulls and decks and guys you do not have to actually make a Mold to make another part .

we werent talking about hull molds, my referance was just a general observation/suggestion to help enlighten Boatnuts on a small part mold he is thinking about building. In this business ask ten techs and you will get ten different answers. This was made light for a specific reason. The original part that we were working with, for whatever reason, had a lack draft around the perimeter (it may have been removed in the fitting process to that particular boat) at any rate the mold i made from it needed to flex enough to get past this problem. One other thing we did to accomodate the exhaust was to attach two tabs on the outside of the mold and rig up a bridge and turnbuckle system to induce an extra half inch or so of arc (warp) on the mold to allow just a little more clearance for the exhaust manifolds Jim has on the boat. fun stuff . . . . .

[OFFSHORE GINGER]

Dave , i know that your referance or general observation /suggestion is to enlighten Boatnuts but ...... you mentioned old school standards and to set the record straight not everything has changed by todays standards because a few things still remain traditionally and with that in mind i do not want everybody to think they have to go out and build a mold when they only need one part and to mention tec's .......... come on broooooo that is a word i do not even want to put into my vocabulary because it sounds so cheap , kinda like Kmart and the blue lite special . :shocking: Dave all in all i will call you a tomorrow ............Dawg .

[Boatnuts]

glassdave & others - thankyou for your input and comments, they will be helpfull. The the hatch I have to make will be aprox 30" x 76" with a crown of about 1-5/8" on the 76" dimension. This is a custom modification for this boat so I am working from scratch. I plan to make a pattern with reinforced 1/2" MDF board that has the proper contour, shape and fit. From it I will cast a one time mold that will be structurally reinforced with wood.

[OFFSHORE GINGER]

Boatnuts.......Cool!

[Madcow]

Sorry it took so long to post these, but the hatch is on now.

[Tony]

Very nice.
This is the best-looking scoop I've seen, not to mention the full-function design of it.

Well done!


:yes: