TOPIC: Balsa Core Hull - replacement guide

Good Day:

I am planning a complete floor replacement on my 1959 Red Fish Shark Capri. I am having a heck of a time locating any specific guidance on how to replace a balsa core floor. Has anyone here had experience with this, or know of a reference that I could follow? My plan is to restore the boat as close to factory specifications as possible.
Appreciate any help you can offer.

For anyone who has done this, have you simply replaced the balsa, or have you substituted with another substrate? Where would one start looking for balsa in this quantity? I am interested in knowing which way the balsa would be layed up (bow to stern, port to starboard, endgrain up? Any thoughts would be appreciated.

Cheers.

Ok I will give it a go. This will be a very long post to cover everthing.
Start out you must remove the old glass that is on top of the old blasa. This usually brings you to some nasty looking black wet dust. Or maybe some resemblense of what the old balsa looked like. No matter chisel scrape vacumn all the old out. When you are done with that there will be a putty like substance on the floor this is resin and cabasill or a mixture of something to make a putty they used to install there balsa. Start sanding it smooth best to remove as much as you can. Not a nice job but grind down till you hit the glass in the floor. The smoother the better. You will now have a very weak floor becareful not to step thru or damage it.
Vacumun the old floor then clean the floor good with acetone. Now cut and lay out two layers of glass (I use 1.5 ounce mat.)on the floor. This will strenghten the old and will give you something good to lay your wood on. Let this cure over night. When this is cured it will have like a sticky to the touch finish on it. Rough this up with some forty grit. You will clog you paper as you are roughing up wax. Vac and wipe the glass with acetone.
Time for the wood. Balsa comes in many thickness try to use what was in the boat before. The wood will come in a two by four foot sheet with cheese cloth on one side. Cheese cloth up. Fit the area you want the wood to go.
Time to install. Mix cabasil and resin together to make a peanut butter like paste. This will push up into the wood and also level out what is needed. Mix up a gallon or more so it is ready to catalyze. Now put some in a quart or larger and add your MEKP. Mix it good Mix it good it is easy to not mix in the mekp enough. Now use a trowel or spatch with one eight to three sixteenth inch notch ya want it thick. Smear one sheet lay your wood in the paste. Now I use a two by four that is ten or so inches long to tap the wood into the paste. You can roll it too what ever make sure the wood gets into the paste good. Pick it up and check you coverage. So install all the wood. Let this cure over night.
Now you have a floor you can walk on. Cut a layer of glass that will cover all the areas of the wood. On top of this I put a layer of roving. Now glue this to your wood. If you do not like the look of the roving then after those two are cured add a light layer of cloth on top.
You can get all the products you need to do this job thru Express Compost's in Minneapolis Minnesota. They are an advertiser on this board.
Oh of course wear all the safty equipment you can.
Before you put in the floor are you sure your transom is good???????
A few pictures
A few pictures.

In the one pic with you Holding the grinder .. It looks like your just having a BLAST ..How long did you Itch after that ??? In the Body shop I worked at when we had to grind alot of glass we would take Vaseline and smear it where ever the fiberglass dust might hit on your skin . This keeps the glass from getting into the pores of your skin and causing itch ..When you wash up , make sure you use cold water first ..Hot water opens your skin pores up and youll get some in anyway .. This works good on House insulation as well ..Alot of you probaully know this but I just threw it out there for those who dont ...

Wow. That is exactly the information/tutorial I have been searching for. THANK YOU Herters. I guess I was having a bit of the pre-op jitters, not really knowing what I was going to be facing once I start to remove the old floor. My plan is to replace the floor/deck, and then address the transom afterwards if it turns out to be rotten. I figure the new floor with give the hull rigidity in the event that I have to separate the hull and deck. Does this seem like a reasonable plan? I did not realize the balsa comes in sheets like that. I figured I would be laying down strips. This makes it much easier.

Cheers,
Andrew

You'll may think about replacing the transom first and then the floor. I did a 1960 Redfish. I replaced the balsa wood core and transom. I found that removing the deck made the job easier. Before you remove the core think about supporting the hull. Once the core's removed the hull may sag out of shape.

Here's a few more pic's I used dry wall screws to join the deck back to the hull until the fiberglass cured.

Looks Great ... What Primer and paint did you use on there ??

That is awesome Billy-Mac. Just he sort of images I was looking for. Was your deck and hull glassed together? Mine is. I guess cutting it apart is the only way to separate. I am not so worried about the floor replacement job. It is the grinding down of gelcoat and refinishing the exterior that has me nervous.

Another question for redfish owners. I hate the replacement windshield that is on the boat. If I am unable to secure an original, I am thinkig about cutting this one down to the orignal height. Can someone tell me the original height of the windshield?

Cheers,
Andrew

Yes, the hull and the deck were glassed together on my boat. I used a saws-all to (carefully) cut them apart. I painted the boat with interlux Brightside Poly. This is the first boat I painted and if I do another I'd use different paint .