Hello everyone,
im getting a fair amount of inquiries on how I made my hatches so I figured I would try to break it down step by step. Although there is a bit of an outline in my rebuild post, I have lived and learned and want to share how I would do them if I were to make them again. I want to make it clear this is my first attempt at mold making and I am in no way a professional or someone that should be giving advice. I tried it and it worked out for me and thats all im sharing. Im sure there are better ways to do this and if you know of any then please share your thoughts. I advise you watch a few YOUTUBE videos from a guy named "gasserglass" as his mold making videos were really good and taught me alot.
I will demonstrate the size that I made, overall 18 1/2 x 26 3/8. You can make them any size you want providing two things; you leave at least a 2 inch flange around the perimeter as enough materal to mount to a floor with, and the drain "triangle" is big enough to accomodate your drain.
1) The first and most important piece is the inner wooded piece which I will refer to as the "insert". Home depot had really nice 1.5 inch x 1.5 inch x 8 ft clear pine that was pin straight and blemish/knot free. One piece was enough for 1 mold. I set the table saw at 1/2 inch, then 1 inch and ran the piece through to create the cutout. I then set the blade at 5 degrees and ran the piece through again to add a taper. This adds to an easier mold release. You probably could run them straight without tapers as they should pop out as well. After the table saw, I took the full length and cleaned it up with sandpaper to really smooth them out and work out any saw blade marks. Once that piece is done set it aside for now.
2) Next cut a piece of material for the base. I like the white pressboard because it is relatively cheap, straight, no knots or grain, and the white finish is almost non stick without wax (but wax it anyway!!) for the base, material thickness doesnt matter but use something stiff enough to hold everything square and thats strong enough to hold up to the torque of finished product removal. Cut the piece to 18 1/2 x 26 3/8 (or 2" larger than the "inner box frame" which I will talk about later). (Displayed Below is plywood, but as mentioned these instructions are for what I would have done if doing them again. I advise using a stiff, non stick surface. On top of this plywood was the whiteboard, but plan modifications eliminate the ply now.)
3) next you want to make the inner box frame. The outside perimeter of this box represents the actual opening size. Take 3/4 white board and run it through a table saw creating a 2 inch wide plank. Cut this plank as you would a picture frame using 45 degree cuts, and then 22.5 degree cuts for the "drain triangle".
This is the piece you are looking to make. Pay no mind at this time to whatever else is on the image at this time as i will address everything.
Here are the dimensions for those pieces: (NOTE: Original/old design shown. Disregard the plywood middle on the base board. The updated design will have that middle as whiteboard and not plywood. If you build one it should be from one solid slab of whiteboard as your base board)
use a nail gun to tack it together in the shape in the picture, then tack it to the base plate, centered evenly. If you dont have a finishing nail gun you can get a cheap one for less than $30 almost anywhere. They are critical for this work as you can hold the two pieces and tack them together almost instantly without disturbing their placement. You cannot do this with a common nail or screw.
4) cut the insert to fit around the inner box frame. leave the "drain triangle" for last. you basically want to end up with something that looks like this:
Remember they are 45 degree saw settings for the corners and 22.5 degree setting for the drain triange.
5) Drain triangle - Cut, fit and nail a 1/2 x 1/2 piece of wood against the inner box frame to continue the smaller piece of the insert. Next use a piece of plain white paper and fit it into the remaining space to create a template for the drain triangle. Tranfer this to a 1.5 inch high piece of material (two pieces of plywood or white board tacked together) and send through a table saw being mindful of which sides get a 5 degree cut to match the inserts. Also be mindful that the drain triangle has to be large enough to fit your drain (in the photo its not!!!). IF you need to make the triangle bigger (or smaller) you can shorten (or lengthen) the inserts and the inner box frame to accommodate. (note, I would probably draw the whole thing out first. If you wait until this step to check your drain fitment you are basically going to tear the whole mold apart to make sizing corrections. These dmensions worked for my standard drain and are the dimensions from the other mold which worked out perfectly and not the one in the photo with the smaller drain triangle).
live and learn tip: make sure the drain triangle is cut square. Mine tapered in a bit on one of the molds which would have caused havoc on the hinge alignment as well as would have forced me to modify the door to fit. seal the open grain of the wood with whatever filler you are using (bondo, wood filler, caulk, etc) as the imprint will transfer to the gel coat
6) Do a final sanding and rounding of all applicable edges. Make it all smooth and slick. Fill any endgrain whiteboard with wood filler to prevent any gel coat imprint
7) Seal EVERY SEAM!!!!!!!!!!!!!!!!!!!!! Wood filler, clay, caulk, drywall spackle... whatever works. Seal every seam against gel coat that could creep inbetween the pieces of the mold and ruin your day. Even though it is easiest to use in tight places, you have to be really good at caulk as it cannot be sanded to shape.
8 ) mount the drain and latch -
I wanted the drain a touch recessed so I placed a washer under it and used modeling clay to fill and sculpt the area. I dont think it is necessary but thats up to you. You have to screw down the drain. I sent a screw right through the middle hole into the drain triangle. Duct tape the threads to protect/seal them.
The latch - heres where it got tricky. The latch I wanted to use needed recesses in the mold for them to have clearance to work. I opted to put the catch in the frame and the latch in the door. If I were to build these again, space wise it would be easier to put the latch in the frame and the catch in the door, although this would make it a bit awkward to open the door. As you see I had to make adjustments to the frame to accomodate the latch
Here is the latch I chose to use. What I liked about it is that it is a beefy 100% stainless construction and it does not go all the way through the door. At this point in the game i am not interested in hardware that isnt stainless or brass/bronze. Many turn style latches require a catch that would go through the door defeating the thought of making it waterproof. Its from Sea Dog... thanks Sea Dog!!!!
here is the catch as it was placed in the mold. That rectangular glob of clay is the pocket for the latch to sit in. You may also notice that the catch has clay under it, lifting it from the white board. This is to overcome a manufaturing error where the catch and the latch do not line up straight. If I were to install it flush to the bottom, it would have allowed the door to creep upwards a bit before the catch caught the latch. That would have drove me bonkers! Details details. Lesson here is get all your hardware in advance and see how it fits/works/sits... etc. The clay on the vertical side again the wood is to counter the 5 degree cut of the wood. The screw holes are also filled in with clay. SEAL EVERYTHING! If its not sealed, it will fill with gelcoat or resin and ruin your day.
Heres the problem: the catch mechanism has thickness and needs clearance to operate. I reduced the well height by 3/8th's of an inch leaving 5/8th's plus a gasket to shed water. The latch is located facing the bow, so this low point will always be at the highest spot opposite of the drain. If i were worried about fishing the Flemmish Cap during the perfect storm, I would have placed the latch in the floor and the small catch in the door. That would eliminate the need for the relief in the sealing channel but would have made pulling the door up awkward requiring some other harware to grab the door with.
Here is the relief as it sat in the mold (note: the inner box frame is removed). You can see that it has minimal effect on the depth of the channel leaving 5/8th depth to shed water with.
heres another angle of how it was set up. You can also see the latch pocket the block of clay created behind the catch
9) Wax the mold with a mold release wax as directed on the product lable. 4-6 coats should do fine. I did 2 coats and it came out fine (where it wasnt stuck by creep). You can use PVA if your used to using it. I opted not do due to fear of runs and puddling with such an intricate piece. Wax was easier for me to wipe off.
10 ) Gel Coat - I gave it about 3 coats of gel coat out of a dump gun. It didnt work out too well as it was impossible to shoot evenly into such a tight crevice (at least for me). However, after the last coat I fixed it up with a plastic spreader and squeegee'd gel coat where ever it was needed to smooth it out. This is one of the good things about a mold is that the finished side is protected. You can correct many a mistake and it will never be seen or make a difference. If you are building a race boat then maybe it may matter. At the end of the day you pop the mold out and all looks good!
Please be certain you are using UNWAXED gel coat. Waxed gelcoat will require sanding before each new coat and would be near impossible with the complexity of this mold. the ONLY layer that gets waxed at all is the final layer of fiberglass... basically the last thing to hit the mold. More on glass later...
whatever you do and how ever you apply it, make sure your gelcoat looks more like the "after" pics than the "before".
A word of caution- be aware that the gelcoat is barely hanging on to a slick waxed surface. If you try to spread hardening gelcoat you run the risk of pulling it off of its position and creating dimples that you will have to fix later. Let the gel coat harden as is and fix it later with another coat of gel coat. Do your best not to disturb the gel coat. Take a look at the photo just before line 9) above. You will see some dimples in the lower lrft corner of the picture. These were a result of disturbing the gel coat. As you can see in the other finished photos, gel coat can be easily fixed perfectly, so fear not and do your best.... you can fix gel coat now or in 20 years.
10 ) Fiberglass
Please note that I used vinylester resin. You can use polyester resin as well. I dont think you can use epoxy resin with chopped strand as it is the styrene in the other 2 resins that releases the fibers in the chopped strand. Please look into this further if you are into epoxy resins.
I used the following layup schedule: 3/4 oz chopped strand, then 1.5 oz chopped strand, then 1708 biaxial, or in my case, i used 2408 biaxial as I didnt realize the difference and I thought I had 1708. Basically it is 24 oz instead of 17 oz, so it was a bit stiffer and harder to work with but was a thicker and stronger layer.
Past the 1.5 oz, i dont think it matters much what you use to strenghten. If you dont have 1708 I think 5-7 more layers of 1.5 oz would have done it as well. Sure, 5x 1.5 is 7.5oz and not 17 oz, but 17 oz may be overkill. its up to you.
But why the 3/4 oz? This I believe is a critical 1st step. Im sure we all have corners or ridges on our Aquasports that have a chip in the gel coat revealing a crater of missing fiberglass behind it. This was because after the gel coat was sprayed, the chopped strand that was applied after wasnt pressed into every crevice leaving a space.
The 3/4 oz is so thin that it almost turns to mush making it very easy to conform to almost any shape. It is so important to get this first 3/4 oz layer pressed into every nook to basically back the gel coat. in fact, to further secure the gel coat, I mixed a "mayonaise" mix of West Systems 404 (like stronger cabosil) and applied it into the inner crevices before laying the 3/4 over it.
The 1.5 oz is a little thicker and obviously adds more stability to the mold, while any additional coats past that add to the overall strength of the piece. The thicker the glass the harder it is to get it to bend. fiberglass is rigid to some extent and doesnt take to well to sharp bends. Its like trying to bend a fishing rod into a corner... it wants to stay rounded to some extent and wants to spring straight as well.
Here is the layup schedule that worked best for me for this mold:
Notice the biaxial (blue line) is broken and not continuous. I tried that on the first mold and it wanted to spring straight off of the verticals. It will sit well in the valley to the right and the right angle to the left. Vaccuum bagging may be an option but that is beyond my experience at the moment. This layup worked well and was done in 3 sessions
Layer 1: paper thin, even veil of 3/4 oz chopped strand:
Heres a good shot of the 1.5 oz pieces for layer 2, and the 2408 biaxial for layer 3 in the foreground. I tried to use as few pieces as I could because I didnt want to overlap the corners too many times for fear of uneven buildup of the final piece.
Here is a shot after the final biaxial lay up:
11 ) Tools
You tubes' "Gasserglass" stresses that you can never have too many rollers. My go to roller for this mold was this small round one. It fit everywhere and made rolling in glass and rolling out bubbles a breeze.
12 ) Removal
I cut around the outer perimeter and the upper edge with a 4 1.2 inch angle grinder with a metal cut off wheel. YES it throws quite a cloud of fiberglass goodness so doing so outside or in a well ventilated area is highely recommended. There are other ways to cut, I like the grinder with a cut off wheel. Cleaning the edges reveals all the seams that you will attack with the plastic wedge:
I used plastic wedges to seperate the piece from the mold:
Thats all it should take to get this piece off of a well made mold. As mentioned, I didnt seal all my seams and the gelcoat that creeped make this step hell. I had to get quite evil with a chisel to get all the wood out without damaging the gel coat further. with a well made mold the piece should come out fairly easily just by wedging it all around the edge of the mold.
13 ) finishing the piece:
Fill any oops marks with gel coat. Once all is filled, I sanded with increasing grits until I got the finish I desired. I started with 100 to knock down the edges and rough spots, then 150, then 220, then 320 wet, then 600 wet. After installation i will compound with a buffer.
14 ) Doors.... to be continued as soon as I make them! ASAP!
