VHF Radio - Sundowner 225

Project date: 2001

Maybe I just like to tinker, or maybe i'm just bored, but I always like to have some kind of project going. This project is the installation of a VHF Marine Radio in my 1999 Four Winns Sundowner 225. Now, I could just use the bracket to install the radio like everyone else - but what fun would that be? Nope - I have to have a custom installation.

When deciding on the location for the radio, I looked at pictures of a Four Winns Sundowner 285 radio installation. My goal was to have a psuedo factory look. This photo is from the 2001 Four Winns brochure. The radio is at the lower right of the helm, and angled up for easy viewing. This photo became the inspiration for my project.
One thought on the location is that just about all radio manufacturers recommend a minimum of a 3ft distance between the radio and antenna location. Any closer and feedback could occur. I am not yet sure where I will place the antenna, but the locations I am considering will be at least 3ft away from the radio.


The selected location for the installation of the radio box is in the utility tray located at the helm. This location will allow me to construct a radio box made from fiberglass, and mount it in the forward section of the tray. In my mind's eye (right picture), I can visualize the approximate location and design of the box. The white box on the lower part of the picture is a pop out drink holder. I need to make sure that I can still reach my favorite beverage with the radio box in place.



The first step is to cut out templates from cardboard and test fit them in the proposed location. From these templates, I was able to create a working drawing.

Next, I constructed a "one-off" mold using 1/4" plywood. Normally, fiberglass fabrication consists of creating a plug, then casting a mold from the plug. However, this is usually done when multiple pieces are desired. Since this was a one-shot project, I did not take the time to make a finished plug. After all, why take time to create a polished plug, when I could spend this time finishing the final piece.
One mistake I made was the inclusion of three cleats as shown by the small triangular objects in the picture. My idea was for the cleats to create indentations where I could screw the box to the boat. As you will see later, this idea did not work out.

The rear view of the mold shows that I simply fit in the proper pieces of wood as needed. It may not have looked pretty, but it was effective.
After sanding and filling the seams in the mold, I applied 5 coats of Deft Polyurethane Varnish. After the varnish dried for two days, I applied 3 coats of Kit Wax containing Carbuna. Finally, I applied two coats of White Rain Heavy Duty Hair Spray. Turns out that the Hair Spray has the same PVA chemical as used in mold release agent.
Note: If you use Polyester resin rather than Epoxy resin, you must use a mold release wax. You won't be able to use an automotive wax like I did, because the high heat generated during Polyester curing will melt it. Using Epoxy doesn't seem to generate enough heat to melt the automotive wax. Also, be sure the wax you use contains Carbuna - otherwise, the piece will stick to the mold.

I used the WEST Epoxy System (105 Resin and 205 Fast Hardener), and two layers of 12 oz Fiberglass woven cloth to begin the process. I put an initial "skim" coat of resin in the mold. When it began to gel, I started applying fiberglass. The casting became tacky after about 3 hours, and completely hardened in about 8 hours.
When I attempted to remove the project from the mold, it would not come out - uh oh!
I ended up having to break the mold apart to get the casting out. I discovered that some of the varnish stuck to the casting - especially where I used wood filler to smooth the corner radiuses. I am not sure what went wrong - maybe I did not let the varnish dry long enough. Oh well, all I needed was a one-shot casting anyway. I guess this became a "lost-plywood" casting.

The resulting cast piece after it was removed from the mold. The casting ended up being too thin - only about 1/32" to 1/16" thick. However, that made it much easier to remove - since it was a bit "rubbery". Also, I removed it before it was 100% cure, so that probably made it easier as well - since I basically had to bend the casting to get it out.
You might notice the afore-mentioned cleats. They basically snapped off the mold and became stuck in the cast piece.
The corners of the casting are white - which is the filler that pulled out of the mold. Also, the casting is not a real nice green - which is the result of varnish being stuck to the mold.
You can now begin to get an idea of the design of the radio box. The radio face will mount in the lower angle section. This will allow viewing of the radio from either sitting or standing at the helm. I am thinking I might mount a fire extinguisher on the flat spot forward of the radio location. I will cast in a piece of plywood in the next layer of fiberglass to facilitate the possible fire extinguisher mounting.

This photo shows the cleats stuck in the casting. I used a Dremel Moto-Tool with an abrasive cut-off disk to remove the fiberglass around the wood cleats, then popped them out.
Another thing I found out is that the rough edges of the casting are very sharp. I cut my hands several times while handling it. Next time, I will "de-burr" the casting with the Dremel tool before removing it from the mold.
The cast piece is still too flexible, and not quite straight. Therefore, I re-used the large piece of the mold, and affixed the casting to it with double-sided carpet tape to keep it straight when I applied the next layer of fiberglass. I also put plastic baggies under the square holes created when I removed the cleats. These baggies prevented the next layer of fiberglass from sticking to the mold again.
Finally, before adding the next layer, I had to prep the rear surface of the casting by sanding it until all of the "glossy" surface was removed. This was pretty time consuming, since the initial casting process left the rear surface uneven. However, if it isn't sanded well, you won't get a good bond between the already cured fiberglass and the next layer.

The second layer of fiberglass was cast using 3 layers of chopped fiberglass.
The resulting casting is now about 1/8" thick - and is very stiff and strong. At this point, I have almost used up an entire quart of resin. I have to be careful not to use much more, otherwise I won't have enough for fairing.
Next, I sanded the outside of the casting smooth. This process exposed quite a few imperfections and air bubbles. That will be taken care of with the fairing procedure.

After sanding, I used the template that came with the radio's flush mount kit and made the radio cut-out. I again used the Dremel Moto-tool to make the cuts.
Next, I mixed up a batch of epoxy with West 410 Fairing Filler (to the consistency of Peanut Butter), and filled in all of the imperfections. The white looking stuff in the picture is the unsanded filler.
After the filler hardened enough, I test fit the casting in the boat to get the first glimpse of my idea. Pretty neat, huh!

A slight amount of trimming is necessary, especially at the end of the casting. Also, I need to make clearance for the steering rod. I marked these locations with a magic marker. When I attempted to remove the casting, I found that it fit so well that it was difficult to remove. Therefore, I marked a bit more area to cut away.
Unfortunately, the flush mount kit requires mounting the radio from the back. Therefore, I need to make the casting removable - in case I need to service the radio.
You might be able to see the block of plywood I cast into the back of the unit for possibly mounting a fire extinguisher. You can also see the unsanded fairing compound in this view.

I just had to try the radio in the casting. Yep, thats exactly what I wanted.
Next, I need to sand the fairing compound and apply a second coat, if needed. I am now researching which paint I will be using. I am thinking of painting the casting gray to match the carpet. Well, I guess I will now start calling the casting the Radio Box.
I did notice one problem with the radio location. The Mic cord's coiled length is such that you need to stretch it a bit to talk on the radio - even while sitting down. I believe that through normal use, the stretching process will eventually take care of this problem.

As I indicated, after the initial sanding, you will open up air bubbles. This is just a result of the one-off prototyping process. The bubbles must be faired out. Otherwise, your project will look like craters on the moon.
To patch the blisters, use compressed air to blow out any fiberglass dust deposited in the blisters from the sanding process.
Next, if possible, use a scribe or other pointed tool to roughen up the blister's innards. The roughing up process provides a good surface for a mechanical bond with the fairing compound. You can also use a Dremel Moto-tool with a grinding tip - however, you will have to patch a bit more surface area. I use a dental pick with the tip ground down to a micro chisel. This works pretty well, and keeps from making small holes bigger.
Next, mix up some epoxy and wet out the blister. While the epoxy is still wet, mix up some fairing compound and patch the hole. After the fairing has dried, I used #400 grit sandpaper used wet to smooth out the patch. If done properly, the blister patch will look like this.

I decided to use plain old Enamel paint. According to the WEST documentation, Enamel is OK. I did take one extra step, and decided to use a gray primer, as shown in this photo. This will allow me to do a final check for blemishes and blisters.
Although this picture doesn't show it, I still have several very small blisters on the surface. Sometimes, applying primer the project is the only way to find them. Back to the fairing step.
If you compare this photo to the one earlier, you can see the notches and clearance areas I had to cut out of the Radio Box.

For the mounting mechanism, I used some common hardware and made 3 right-angle brackets. I epoxied the T-Nuts to the brackets. I used epoxy to completely fill the void between the T-Nut and bracket. All hardware is either Stainless Steel or Brass.
When I drilled holes in the Radio Box for the mounting brackets, I had to make elongated holes - since the alignment is really hard to get right.

With the Radio installed in the Radio Box, I finally mounted the box in place. I think the project really came out great. I am also impressed with the closeness of the color match - especially since this was a standard color.
One observation. The chrome strip on the upholstered kick pad is fastened at the rear with round head screws. These screws will scratch the paint off the lower lip of the Radio Box as it is fitted in place. However, this will not show when the box is fully installed.
For the final color, I applied 3 coats of Krylon #1605 Stone Grey Gloss, wet sanding with 600 grit sandpaper between coats. Finally, I applied one coat of Krylon #1313 Clear Satin finish.

From the overhead shot, the Radio Box looks like a factory installation - which is exactly the look I was after.
A final check with the cup holder, and I have adequate clearance for my favorite beverage - Diet Coke, of course!

In normal operation, I intend to simply lay the Mic in the tray, rather than hooking it on the Mic Clip each time. By recessing the Mic Clip out of the way, it serves as a stowed position. This prevents the possibility of snagging the Mic cord (at least - as much as possible).
You can see that the curved surface of the radio box matches the curvature of the hull just about perfectly. This was a result of careful creation of the cardboard template.

From this view, you can see how the Mic clip stows the Mic out of harm's way. In addition, you can see two of the mounting screws at the left side of the radio box. The third mounting screw is not visible, but is located at the base of the end surface containing the Mic clip.
Before drilling this hole, I verified I was not going to drill through the hull. In this boat, you can remove two drink holders located aft of the helm seat. Once the drink holders are removed, you can use a flashlight and inspection mirror to look down the interior of the utility tray channel and determine where the hole will be drilled.
Hmmm .... I seem to have this blank space on the Radio Box forward of the radio itself. Originally, I thought I might put a fire extinguisher here. I may still do that, but I am also thinking about locating a Battery Drain indicator here as well.
Note that the upholstered kick pad has a slight angle, as shown in this photo (looking at the bottom of the radio box). However, the radio is mounted parallel to the bulkhead - which makes the bottom of the radio box look a bit crooked - in respect to the kick pad. However, when viewed from above, you don't see the angle of the kick pad, so it is correct.

Antenna Mounting I decided - at least temporarily, to mount the antenna on the transom grab rail. This mounting keeps me from having to drill holes through the fiberglass. I can always drill holes later, but it is hard to un-drill them!

I found a Tram fiberglass antenna from eBay of all places. The antenna was new, never out of the tube. I paid aout $38 for it. The antenna is 5ft long, and just overhangs the side of the boat by a couple of inches - not enough to be a hazard. Antennas less than 8ft usually are limited to 3dB gain, so the real idea is to get the antenna as high as possible. Unfortunately, this mounting location is not the highest point in the boat. However, I did a test with this antenna and another one temporarily mounted higher on the boat - and there seemed to be no difference in performance.

To test the antenna, tune into a marginal signal - one you can barely hear, then do an A/B test. That is, switch each antenna in and out, and listen if the weak signal improves or decreases. It does no good to do this test with a strong signal, as the signal strength will be too good to distinguish which position is best.

This closeup of the antenna mount shows the antenna in the stowed position. The antenna mount is a Shakesphere model 4188, which I purchased at beoutdoors.com for $19.98 (a good price for chrome plated brass). You can see that there is just enough room between the sun pad and deck for the coax to slip between. It took some work to get the mount just right so it would clear the sunpad when it opened, and clear the swim ladder hatch.

With the antenna in the up position, it looks pretty sharp. From the side view, the antenna has a slight rearward angle.


Bill of Materials
Radio Uniden MC 1020
Radio Accessories Uniden Flush Mount Kit
Epoxy and Fairing Compound WEST 105, 205, 410
Fiberglass Cloth 1yd 12oz Woven and 2yd Chopped
Mold materials Plywood, Auto Wax, Hair Spray
Finishing Materials Paint, Varnish, and Sandpaper
Hardware Stainless Steel Items
Antenna Antenna, Mount, Coax, Connectors

Intangeables: First of all, I have a great looking radio installation. In addition, I learned quite a bit about fiberglassing. Lastly, the sanity factor (aka: sawdust therapy) was priceless. All told, it took 3 weeks to complete the project. However, much of the delay was waiting a sufficient amount of time for the paint to dry. The wife didn't much care for the smell of curing fiberglass, paint, or the fiberglass dust I tracked into the house though.

Lessons learned. The Epoxy method of fiberglassing is much more expensive than Polyester - about 10 times as much. However, it gives you much more working time than Polyester. Also, the smell from the curing process is not as bad with Epoxy. For small projects, the cost differential isn't all that bad. For larger projects, I would need to consider the cost.

If I did this project again, I would have waited longer for the varnish to dry on the mold. Also, I would keep the mold as uncomplicated as possible. These two problems accounted for a significant amount of time to correct.

Repairing the blisters (caused by air bubbles near the surface of the casting) also took a lot of time. Next time, I would consider using a roller rather than a brush to apply the initial coat of epoxy - and then let it set up a couple of hours before applying the first layer of fiberglass.

I still am not all that happy with the mounting method I used. I would have liked to mold in the mounting "ears". Just needed to come up with the right design I guess. However, this is typical with the evolution of a design.

Epoxy sticks to just about everything. It would be a good idea to tape a plastic garbage bag to your workbench. Otherwise, you may have tools, sandpaper, epoxy cans, and whatever else you use on the project permanently stuck to your tool bench. Also, use rubber gloves. I know it is hard to use them sometimes, but Epoxy sticks to your skin pretty good.

Other than these issues, I don't think I would have changed much else.




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