Molded Interior: Fiberglass/Wood interface

I

iggy

New member
I know very little about this topic, so I'll just throw out a few questions for the group . . .

Many of us have previous experience working with wood, perhaps beginning with wood shop in junior high (middle school for the younger set). I have various saws (hand, circular, jig, miter, and radial arm). I'm planning to update my collection with Festools in the near future. In comparison, I know almost nothing about working with fiberglass.

This appears to be widespread throughout the boating community -- look how often we read about windows, cleats, etc. being installed improperly, allowing water intrusion into the core. This is probably due to a combination of expedience, economics, incompetence, and ignorance, but really, there is no excuse for such shoddy work.

Several members (Chris Bulovsky, Bob Austin) have extensive experience with FG fabrication and modification. Also, the last two issues of Passagemaker Magazine have in-depth articles on various FG structural options, coring, etc. Perhaps a lot of the anxiety over the molded interior is due to a relative lack of knowledge regarding cutting into the fiberglass to enlarge the doors, add pull-out drawers, and so on.

As I said, I know virtually nothing about any of this, but perhaps more show-and-tell discussions from the experts would be in order. In the long run, I would feel much more confident if I could acquire the ability work with both materials, and just as importantly, with the interface between the two. This would (i) open up a great many new options for interior modifications; (ii) make me much more knowledgeable regarding hull and deck modifications and integrity; and (iii) give me the knowledge to know what not to mess with, or when to call in the professionals. (Hull extensions simply amaze me, but there are several successful examples. And, of course, Chris' restoration of Scout is beyond belief - I guess others have actually seen Scout in person? Otherwise I'd think this was all Photoshop tricks . . . )

Bottom Line: Is the new molded interior really 'not customizable'? Or is it just more scary, because it is less familiar? Bob? Chris? Anybody?

Ed Gallaher
 
While not supplanting the expertise you mentioned, the West System Epoxy manuals are very good at explaining construction and repair. You don't really have to know enough to build a boat just to repair one, but it is important to know the key areas of concern.

John
 
Iggy-

I think you've hit upon a very important area of concern that has been largely hidden in our discussions. No doubt most folks feel much more comfortable working with wood and plywood than they do with fiberglass and other plastics and laminates.

I'll be looking forward to the developments in this discussion!

Joe.
 
I've worked with epoxy/glass quite a bit in sea kayaks, and am in the process of constructing a plywood boat which has some glass in it (polyester resin is to be avoided if you are trying to adhere wood to something).

As others have said, epoxy/glass is not difficult to work with, especially when wood is part of the modification. Anybody who is comfortable with basic joinery would find adding epoxy and glass to their repertoire easy and fun.
 
One thing about working with fiberglass is that when you cut fiberglass with a saw, it splinters and throws shards or strands of glass everywhere. These strands are sharp and when they get into your skin you get the dreaded 'itch'.

Prior to cutting into a f/g cabinet, all fabric and cushions should be removed from the boat. After the cut there is a large cleanup to do and it is very difficult to remove all of the glass shards. A cut fiberglass edge is rough and needs trim to prevent cuts and scrapes to the hands and arms.

If you are bonding something to a f/g panel, the bond area has to be sanded which creates more of the shards. The sanding dust is also a health hazard and a respirator must be worn.

If the project is installing a shelf inside the galley cabinet, you could drill and bolt the parts to the f/g instead of bonding them. Now the accurate location and spacing of the holes is very important as you will be looking at those screw heads. And one misdrilled hole can ruin the appearance of the interior.

Adding a shelf to a decragard (plywood) cabinet is easy as the screws are on the inside of the cabinet and don't show on the outside.

The f/g interior must be worked on 'in place' as it is bonded to the hull. The wood interior parts can be removed from the boat for modification by pulling a few screws.

I would not want a boat with bonded-in f/g interiors. I found that to be a major drawback to the CC boats and now to C-Dorys.
 
It's really pretty easy once you understand the principles... Say, to put a totally wood front on a fiberglass cabinet:

1 - cut the opening , cut and seal some interior opening outlining wood pieces

2 - wrap a layer or two of thin glass matt over that (with epoxy)

3 - screw and/or clamp the interior outlining pieces in place with epoxy

4 - use normal wood construction procedures to make new cabinet front or door and just drill and screw into the previously bonded interior outlining wood pieces. (best to use a swab or pipe cleaner to line all holes with epoxy in areas open to water intrusion, but prob not too big a deal on an interior cabinet. On outside screw/bolt openings, over drill, fill with epoxy with filler bubbles, then redrill thru the epoxy so no wood can be exposed to water)

John
 
Face Mask - you would need one if sanding and finishing an all wood boat.

Fibers, Cleanup - the boats are made of fiberglass anyway, and even wood fibers need cleanup.

Screws showing on shelf installation - You could bond metal or wooden, pre-drilled adjustment strips, or bond wood shelf supports , or bond wood strips inside into which normal screw installation could be used.

Hard to measure and line up holes - Use a jig or measuring stick to set shelf levels evenly down from countertop.

Basically using epoxy with wood carpentry is like adding welding ability to metal construction - it only enhances the opportunities and choices.

John
 
John,

I appreciate your answers.

Have you done much fiberglass work? I have, and don't want to do much more. F/G dust is much more annoying and dangerous to your health than wood. Even a shower doesn't relieve the itch!

The easiest solution might be to epoxy a plywood panel to the inside of the f/g cabinet and then use screws or glue to install shelves, etc. (Build a wood cabinet inside of the fiberglass one??) :teeth (What am I thinking??) :crook Might work !! :wink

Larry H
 
DrJohn --

Although we've barely scratched the surface, this is exactly the kind of debate/discussion I had hoped for. I look forward to more of the same.

As with any medium, experience and familiarity is always a plus, while lack of familiarity creates anxiety. Some years ago I added a brick patio to our previous house. We built the forms, dug out the base, laid down a weed barrier, and filled with sand. We then hosed down the sand (carefully), screeded to create a precise, level base, and then laid the carefully spaced brick. Finally, swept in sand and watered several times, resulting in a very stable, solid brick surface.

In contrast, I have never built and poured concrete, and I currently face several jobs. Our front walk has settled, and one section needs to be broken up (sledge? jackhammer?), removed (wheelbarrow and utility trailer). Then we'll need forms, concrete, surface tools, expansion joint . . . ?) I'd really like to do this, and add these techniques to my bag of tricks. OTOH, this walk should have been replaced 10 years ago -- I've been avoiding the job because I'm not quite sure how to do it.

Under the rear deck (9' feet high) we have mud. We need a better surface - could be brick, could be gravel, could be concrete. As you might expect, my first inclination is brick - just because I'm familiar with it! Concrete might be quicker, easier, and cheaper, and maybe I'll recognize this if and when I fix the front walk, but right now I'm not so sure.

I'm sure many can relate to these experiences. Having said all that, I tend to agree with some of the concerns about the new interior, but still wonder how much anxiety is due to lack of familiarity.

Lab exercise? Would it make sense to pick up an old fiberglass shower enclosure at a recycling center, take it home, and try working properly with the material? Gloves? Masks? Tools? Add a door? Add some trim? (I'd sure feel more comfortable working on salvage material before cutting into my boat . . . ) If the lab exercises are successful, imagine the possibilities!

ejg
 
Larry,

Yes, that's the answer - the proverbial 'ship inside a bottle'. We'll just build cherry wood, burled walnut, etc., EXOTIC cabinets INSIDE the fiberglass!

My wife would never let me buy a decent boat, so I had to buy wrecks from the salvage auction and rebuild them. I studied up to build a dory-like boat from those epoxy plan ppl. I spent two years completely rebuilding the decks and house and flybridge of a 30 foot houseboat, and use composite/glass materials in my everyday profession.

Yes, the fibers are a mess. If the project is big, best to buy disposable paper coveralls. Small projects, like bonding wood to screw to inside a cabinet opening is alot less mess than building a complete deck, deckhouse, transom, swim step, etc..

John
 
To make the cut (which generates the most dust) , put a big sheet of plastic in the cabin and cut out only the area upon which you are working. Then tape the plastic sheeting opening around this access area. Make the cut. Rinse, vacuum, whatever, then roll up the sheet and toss it. use disposable protective coating and use sticky putty to help remove any fiberglass that got onto your skin. We-re not talking about a lifetime of production fiberglass work here. It should not be too hard to prepare the cabinet inside for bonding - much less than a gel-coated surface. Use well=ventialated setup.

If you really don't like fiberglass cabinets, don't buy a boat with them, but remember that there are reasons why few new boats are all wood, or fiberglass free.

John
 
What would be the appropriate precautions to take when simply drilling a hole in fiberglass that will hold a bolt and silcone sealant?

I'm beginning to see why some people (e.g., Bob Austin) use epoxy rather than bolts!

Thanks,
Warren
 
In my job as an aircraft maintenance technician, I am trained in composite repair...kevlar, fiberglass, carbon fiber, etc. These materials are extremely strong, lightweight, weather and chemical resistant...and in my personal opinion a pain in the #*% to work with. I hate working with the stuff!

For boat projects, I'd much rather work with wood than toxic chemicals. Wood is just so easy to work with...quicker, cheaper, and easier for the average Joe to do. Yes, glass is "customizable" for sure. Look at what the custom car and motorcycle guys are doing. Wow. It's just more complicated and requires a bit more planning and set up time as well as time for the matrix (the "resin" mix) to cure. The matrix is temperature sensitive...cold temps require a much longer cure. That can be partially solved with a heat lamp...just be very careful!

One other thing is that to get the best bond, a vacuum should be used to suck down the layers of cloth and hold everything in perfect position while curing. This requires a vacuum source (usually compressed air and a venturi) and sheets of poly vinyl alcohol with the associated fittings for the air lines. A pain! For minor, non load bearing applications, one could skip this method, but if you are building up the strongest bond, vacuum is the way to go. Lots of stuff to go through when one could just screw in a wood shelf!

Doesn't totally answer the question of how to work with this material, I know, but it does explain why I am so opposed to the new interior. I know, a C-Dory is not a helicopter and yes, simply cutting an access hole is easy, like stated by the other posters here. It's when one wants to do something a bit more involved that the beauty of plywood shines through.

Rick
 
Ed!!!! :oops: :oops: :oops: Thanks for you vote of confidence but I would not lump my fiberglass knowledge into the "Expert" class.

416Rigby pretty much nailed it. Its not easy to work with. Even sawing the stuff is hard to do. Then lets talk about the mess!!!!.....sweet mother....... Can a guy do it him self? You bet you can but you better be committed.

I went with the west system (epoxy) because it would do it all for me and less fumes than the polyester based stuff. Building flat surfaces without a mold is a real bitch. Requires lots of time and multiple applications of fairing material to make it look halfway decent.

Hypothetically if purchased a New boat and had to......say install a Force 10 heater and needed to make modifications I would use wood if at possible. Now for structural repairs you gotta use Epoxy or a traditional glass to do it right.

A 22 cruiser is smartly laid out and most are pleased with its current configuration. I would think very little modification would be required. But on the inside wood is much easier for the guy at home to manipulate and alter.

Looking back I ask my self what Crack pipe was I smoking when I took on SCOUT as a project. In the end I took pleasure in most of the work and doing the "impossible" in spite of the nay sayers was a quiet pleasure. Easy? No...... but hardy any thing worth doing is.

Photoshop trick??? :lol:

Chris Bulovsky
Washburn Wi :wink:
 
I guess what I am trying to say is that most of the modifications C-Brats might be doing would involve minimal, or no "re-installation" of new fiberglass. We would mainly be cutting some fiberglass out, bonding in boards to screw into, and then applying wood structures.

That type of work will not require the vacuum, the shiny, flat, heavily worked surfaces, or critical structural work that is so difficult in fiberglass.

John
 
If cutting a hole in the existiing fiberglass in order to attach wood is so difficult, you could take the boat to a fiberglass shop and have them cut the hole, I guess. How do you guys attach accessories to your FIBERGLASS boats if you can't handle drilling or cutting a hole into it?

John
 
Warren - to answer your question about drilling a hole in fiberglass:

1 - probably nothing more than a face mask, unless doing alot of holes.

2 - if the holed area has wood core inside, you overdrill the hole size, put filled epoxy putty (easier to redrill than solid), and re drill the hole after that sets. For small bolts/screws, I just predrill the holes work epoxy paste inside (line the hole walls) using tiny brushes, toothpicks, pipecleaners, whatever, then put the screws in that IF NOT EXPOSED TO THE WEATHER.

3 - Passagemaker's last issue has a detailed breakdown of how to best install things into cored hulls.


Also, you can "hollow out" the sandwiched wood core by putting a bent hangar wire (small "L") thru the fiberglass hole in a hand drill. That undercutting removes damaged core and allows space to put the filled epoxy before redrilling. that way a leak thru the bolt would not be able to get into the wooden sandwiched area.
John
 
C-Brats All-

This discussion has yielded some interesting ideas on how to interface new wooden or composition modifications with molded fiberglass interiors, and Dr. John has done a creditable job to champion their cause!

However, it would appear that modifing a fiberglass interior is just fundamentally more difficult than a plywood one due to the hardness of the fiberglass, the very sharp and specialized tools needed, the hazardous waste produced, the difficulty in removing the waste, and the more difficult joinery usually required to attach the new wood material to the fiberglass.

Additionally, the molded fiberglass panels may be permanently bonded or otherwise difficult to remove, making working on them with more accurate stationary machines out in the shop difficult or impossible. This results in the use of, for the most part, hand power tools which are harder with which to do very accurate work.

Another aspect of this process is that fiberglass is more difficult in which to fabricate new parts when they or a composition material is required. Learning and practice can go a long ways in making one more comfortable with these building processes, but the combining of materials, the resin set-up and cure, and the mechanical bonding process during fabrication are simply more complicated to master.

Lastly, the wood to fiberglass joinery interface is asthetically somewhat more difficult to do, as dissimilar materials are being joined. The results, however, can be very beautiful and pleasing to the eye.

As an addendum, we have also seen that Iggy's original proposition that most of us are less familiar with working with glass than wood is a complicating factor that stymies the process of customization.

I'm not complaining here, just trying to summarize and bring together what we've found out together, adding a few thoughts in the process.

More ideas to consider?

Joe.
 
I love to work with wood--nothing more satifying than a hand chizzel. But Fiberglass is not all that bad either--I agree about the dust and itch--but try building a 38 foot boat! When doing serious fiberglass cutting or laminating, I wear a Tyvek suit. These are disposable and inexpensive. They are hooded. I also wear a good quality respirator, as well as googles. I also always wear nitrile gloves and put a barrier cream on the arms. Many of my friends who build composite boats use full suits with full displacement respirators.

However for drilling a hole, I just use a regular drill. I often use hole saws, and have from 5/8" up to 4" in my tool kit by about 1/8" sizes (some 1/16"). I also have sanding drums to enlarge holes. I use carbide tipped saws. For example a year ago I cut about 50 sections out of 20 wrecked boats for a project--all of this with a battery and 110 volt skill saws with carbide blades--the blades not the worse for the wear. (most had cores so the glass was not real thick). I also use bimetal saber and sawzall blades. They have to be changed regularly. Recently I have been using a rotozip--I tried one a few years ago--and the new ones are much better. (use a carbide blade). I also use a Dremel tool (own a number) with various carbide blades. Also a cutoff wheel and grider is used frequently. All are very agressive tools. Another tool is the Fein saws Not cheap, but can make fine cuts and are excellent tools.

As for building up; or adding, I prefer epoxy. Some are allergic to it so be cautious. Also one needs to be sure that the cloth used is compatable with epoxy (the sizing may be different than polyester resin compatable).
I often "stick" wooden blocks on glass surfaces to allow me to screw items to them. For example I was asked how I attatched the foreward window fans recently. I shaped a wooden block to the contour of the piller and after sanding the gelcoat, applied fast set epoxy and taped the block in place.

When cutting, I do remove upholustry, use tape and plastic to limit the dust. I often cover an area to be cut with duct tape to prevent scarring the edges.

I agree that most of what one modifies inside of a boat is to cut out areas and then put in wooden doors and shelves. However I would not put in a wooden shell to just screw to; this adds excess weight. It is easy to epoxy in cleats (wooden to fasten shelves to), or add "L" brackets to bolt or screw to.

When drilling a hole in gel coated area, start with the drill in reverse, or use a counter shink to cut the outer gel coat away and avoid cracks.

When cuttin holes in cored materials, always bore the hole oversize and coat the inside with epoxy (not polyester). The epoxy gives a much better secondary bond and prevents water intrusion into the core. You may have to use a small drum sander or drill to smooth and bring the hole up to the size you need.

I rarely vacuum bag items--this is more in using exotics or very compact laminates--it is a wonderful technique.

Fiberglass interiors have been around for along time--and I have owned both wooden and fiberglass interiors--either can be worked with and modifications made. I would not decline to buy a boat because of the glass molded interior. I have also done radical modifications of the exterior of boats--cutting a transom, putting in steps, putting in cockpit seats etc--all of this is fairly easily possiable--but there is a lot of detail work.

It is hard to know where to stop in discussion of techniques--but I am happy to attempt to answer any specific questions.
 
Back
Top