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clayman
02-20-2002, 11:00 AM
Hey Guys,
I am getting ready to make a new engine hatch for my 18' classic. Has anyone ever done this, any advise. I figured I would make a 1/4" marine plywood piece to fit in the hole nicely, then layup glass on both sides and create the flange around the edges. then fair it out with fairing compunds and paint it. help...
James

jwright
02-20-2002, 11:40 AM
I bet you will get a lot of intrest in this topic! sounds fun....

My thoughts are that it may be easier to build a quickie mold and lay up a balsa cored part. The part will be much lighter. The techinique you are considering will build a very heavy part. I beleive most classic hatches are balsa cored.
A company called ATC builds foam strips with bead and cove edges so that with some frames you can assemble the shape of your hatch with the strips and then overlay each side. They have a website that may help (not sur of the address) but I know they are in Oakville Canada. Their foam is also very strong. Baltek balsa also makes a form of their balsa in strips, but I am not sure how easy it is to buy in small quntities. The Baltek website will have info on this building technique too.

jwright
02-20-2002, 11:42 AM
I may haev been confusing in my previous post....

The mold would be one way to build it. The strip techniques do not require a mold.

Jamesbon
02-20-2002, 12:06 PM
If I had an 18 hatch, I'd let you use it in a heartbeat.

Anyone out there with one??????? (close to St. Pete., right?)

mattyboy
02-20-2002, 12:13 PM
have not done any glass work, but thought this might interest you, my hatch and deck have 3/4 pvc pipe matted and glassed to the underside for strength

Matt

Steven Cohn
02-20-2002, 12:52 PM
Clayman,
I've done some FRP work on my flybridge sole. It was extremely difficult to get a flat smooth finish. My advise is to use a mold [waxed (releasing agent)plex works well]and a good gel coat to get a riple free finish. The previous replies referring to weight was right on the money. The other reply concerning reinforcement is also correct. However, you could glass in cardboard dowls (paper towel centers) to increase strength and reduce wieght. Laying up FRP correctly is more difficult than one would suspect.

oldLenny
02-20-2002, 03:22 PM
I have the mould for the X-18 hatch...I haven't a clue tho if it is the same as the Classic 18's hatch as there are NONE here to compare it with.

There are people here who know this answer and I am sure it will follow. :D

If it was the same, I'd be happy to lay one up for you, but the shipping charges from 400,000,000 miles away might be a bit too steep!

They would probably exceed the item itself.$$$

SS18
02-20-2002, 07:25 PM
Somewhere I read that you could buy new replacement hatch.Why not try donzi for a new one?
Maybe if they can't they know who could! :rolleyes:
Jim in NJ

RH
02-20-2002, 07:44 PM
Len, You may be right about the shipping charges, but I would definitely call Donzi direct. I would bet that they may be able to lead you in the right direction. I would be concerned about the weight issue as well. I have a friend who builds jet boats and he uses a material called divincel (sp)? I remember it being a lightweight material like a balsa coring, but impervious to water impregnation and extremely strong, Any others heard of this material, or am I mistaken?

clayman
02-20-2002, 08:15 PM
Hey Guys,
Thanks for all the insight, keep them coming. Devinacell (sp?) was also recommended to me by someone else, any one have a source for it?
James

jwright
02-20-2002, 09:24 PM
Divinycell is a cross linked PVC foam core made bt DIAB. It is equivalent to Airlite by Baltek. These are the two main PVC foams used by boat builders. The ATC product I mentioned earlier is called Core Cell.
Then of course their is balsa wood, which DIAB has it's Pro-Balsa. Baltek is the big player here.
Not sure where I am going with all this, jst thought I woudl pass some info along. I work with these companies in my job. So if any one wants to know about the products let me know!

tailwind
02-20-2002, 09:37 PM
Hi Clayman:

Having been in the FRP business for the past 30 + years, I will agree with the previous posts. In order to achieve your engine hatch, you must first form a plug, then a mold, then a finished part! Each of these steps will require a minimum of perhaps 50 hours for perhaps positive results. Not having this amount of time, I would suggest that you search the archives for your particular model and then seriously negotiate those that do have an engine hatch available in order to make a mold !

Best rgards,
Randy

tailwind
02-20-2002, 09:37 PM
Hi Clayman:

Having been in the FRP business for the past 30 + years, I will agree with the previous posts. In order to achieve your engine hatch, you must first form a plug, then a mold, then a finished part! Each of these steps will require a minimum of perhaps 50 hours for perhaps positive results. Not having this amount of time, I would suggest that you search the archives for your particular model and then seriously negotiate those that do have an engine hatch available in order to make a mold !

Best rgards,
Randy

oldLenny
02-21-2002, 12:05 AM
Hey Clayman!, you know what?...if my mould, (X-18) would fit your (...???Clasic 18???...) I could lay one up for you, "sanding Gel-Coat", no colour or 7" stripe to match here... :rolleyes: , and then I could ship it to Owen in Oregon, he could take it to AOTH in Kentucky, then give it to HP-500 (Ted), or 'Poodle, they could then drive it back with them to Florida, (somewhere) and then about another half dozen people could "relay" it and eventually hand it off to you!

That would work and be cheaper...

RPD
02-22-2002, 08:37 PM
Cool.. but florida is >1000 miles long.... first try to find one that fits, much easier than making one... then if that doesn't work there are two ways to fabricate from frp.. (1) make a plug, then a mold, then a hatch.. or (2) make a hatch from plywood, balsa, or foam and glass it..... method #2 requires lots of hand finish work but on a one-off basis may still be easier... I would recommend foam (there are several, one is klegecell used in my fishing boat's transom; depending on the resin you use, you may even be able to use everyday styrofoam) as it is light, doesn't rot, can conform to gentle curves, and is available in sheets which may make the initial form easy....

Jamesbon
02-22-2002, 11:36 PM
Clayman,
Aren't you near St. Pete, FL? If so, Fiberglass coatings has divinicell and everything else.

Fiberglass Coatings Inc
3201 28th Street North, Saint Petersburg, FL 33713
(727) 327-8117

Robert Geoghegan
02-23-2002, 08:09 AM
Clayman,
I'm doing a similar project, hatches for a 28' Magnum. You can obtain professional results inexpensively by making a female mold out of formica. Use the shiny side for the mold. One sheet of formica should do it,usually the ugly colors are the cheapest. Approximately $15.00 a sheet for formica,(one sheet of 4X8 should be more than enough) use a couple of inexpensive firing strips to brace your mold, less than $5. One of the most important steps is to wax the mold with "Mold Release Wax", Do Not use regular wax! A couple hours of labor and $20.00 in materials for the mold-you can't go wrong.
After waxing the mold, brush or spray in Gel-Coat, make sure the Gel-Coat has "wax" in it, this will give you the "shine" when it is pulled from the mold.
When the gel-coat becomes tacky, apply fiberglass. At this point,you can add any core materials, Balsa etc.
Good Luck, let us know how you make out!
BOB G.

oldLenny
02-23-2002, 10:56 AM
I don't agree with this "wax" idea. Wax (actually air-dryers) are to seal off the product (lay-up) so that when dry it actually feels dry to touch.

Any future lay-ups to this surface MUST be ground first for adhesion and even then the polymers do not cross-link properly but the effect is good.

"Wax" (dryers) is added to vinylester resins and such on the LAST lay-up in the hull, or added to a coloured (Gel-Coat pigmentations mixed with Vinylester) resin mix if you are finishing off an engine compartment or interior hull sides that are viewable or could pass light through them. I have never heard of adding wax to Gel-Coat in a mould lay-up situation.

The NEXT thing you will be doing is laying up matt to the coating and you want it to cross-link, go off, and bind.

Waxes (dryers) have nothing to do with the shine of the part being created. The only wax we have in play is the Mould Release Wax that you use in the mould for release purposes.

The part is only as good as the surface that represents it. If the female part is flawless and shiny, and you see an undistorted image of yourself true to form and glossy, then the Gel-coated piece will be as well,...SO LONG as you control humidity and monitor/supply a constant temperature while curing.

Gel-Coat does NOT like to have "things" (chemicals) added to it other than a catalyst. It is a chemically complex product and should be used as supplied, and never overmixed. Thinning of it is NOT recommended either. (eg: Styrene)

If you are worried about release qualities of the mould, then use "release agent". It is a watersoluable film applied by spray gun, that dries quickly and is a barrier between your "new" part and the mould. After a lay-up or two of light matt the part can be assisted in release by running water between the mould and the part and it "dissolves", thus releasing.

In any new mould there are a few "skins" taken out of it prior to actually using it to start production runs as this process "conditions" to mould.

Moulds ("plugs") are NOT made from regular Gel-Coat. There is what is called "Tooling Gel-Coat and Tooling Resin" which are used for the plug and are inherently different from the Gel-Coat used to create a finished usable part.

Tooling Gel-Coat" has different properties and "likes" the thermal aspects of a part "going off" against it. :) ...man!,...that sounds erotic!!! eek!

clayman
02-25-2002, 08:11 AM
Thanks for all you input everybody,
I'll take some pictures along the way and post the progress.
james