How I used expandable foam

[bostonhatteras]

The core in flying bridge supports and cockpit side decks was pretty much wasted. Took out all rod holders, deck fills etc from side decks. Cut away microscopically thin fiberglass layer that joined flying bridge support on outer house skin from inner cockpit side skin. Used fiberglass rod with threaded end electricians snake to hog out rotted balsa. Pretty much just kept rowing into the balsa with various things screwed to end of snake until I found solid balsa, or got rid of all of it in the side decks. Pics didnt attach Ill add them in next post

 

[bostonhatteras]

Unfortunately I didn’t take any pics of the underside, but the foam came out of any little area in the bottom skin that was light on resin. The bottom skin deformed a bit but the top skin stayed true. I added two layers of 1708 biaxis cloth on top but that was overkill One would have been plenty.

 

[bostonhatteras]

For the flying bridge supports I created braces so the section thickness would remain true. It was simple and can be clearly seen what I did in the pictures. Once the foam set, the top area of foam was cut back about 1.25 inch and the inside of the skins sanded out well. This resulting hollow was filled with thickened epoxy. A tool, or U shaped screed, was made to create the radiuses I wanted. The tool ran on the simple metal stud that was precisely placed and screwed to the inner skin. I filled and ran the screed a few times until I was happy with the shape and it was fully filled. If I took any pictures of the screed, I can’t find them but pretty much it’s how plaster crown mouldings are made. A trolley that rides on tracks and the trolley carries the profile of the crown Moulding. The trolley is run back and forth until the Moulding is done. This was just a much simplified version of that process.

 

[bostonhatteras]

A few more pics. In one can clearly be seen how empty of core the flying bridge supports were. They are very rigid now. I hope someone can use the info here.

 

[bostonhatteras]

Here’s what every deck fill or rod holder penetration looks like now. The foam was cut back and the area was epoxy filled, routed smooth, then deck fitting installed into a bed of butyl tape and bolted down. Very unlike the OEM precess with just brass screws into balsa and no bedding or caulking whatsoever.

 

[SKYCHENEY]

Good looking non-skid too

 

[Briankinley2004]

What brand and type of foam did you use?

 

[tgotch]

Did you do the non-skid? If so, how did you do it?

 

[bostonhatteras]

Did you do the non-skid? If so, how did you do it?

Yes I did the nonskid. It’s awlgrip alltex or whatever the name is I’ll look at the can I have left over and get a picture of the applicator box we applied the granules with. I experimented with a couple methods including mixing in an agitator pot and spraying. Even with my 16 cfm @ 90psi compressor and full set up with pressure pot hoses, correct tip, and full pressure regulation of fluid and air at the gun to overcome gravity when pot is well below the gun, it wasn’t happening. I believe spraying texture requires huge air consumption.
What we did do is spray a relatively heavy layer of flattened paint, then sifted the texture onto the wet paint. From there we used an air tool to blow non adhered texture off the deck. With a 9” mohair roller ‘candy stripe’ we rolled flattened paint over the texture for three coats. The flattened paint had to be mixed that way by the supply house, it’s a special base in the product I used anyway. A lot less pot life in a flattened state.

 

[bostonhatteras]

What brand and type of foam did you use?

It hilti Fire foam It needs an applicator gun. We have a relationship with hilti so it was a natural for us to use it but the hilti cans fit on the guns found at the big box stores. The quality of hilti is pretty high so despite the price we used itplus it appears by seat of the pants comparison to be a denser foam compared to Great stuff brand.

 

[bostonhatteras]

Speaking of foam, I was happy to discover that the cockpit coring is some form of foam panel. I know its heresy to some, but when I closed up the mounting hole for the long gone fighting chair it was readily evident that it was a foam core in a similar arrangement as baltec, small squares on a scrim. Tough to see from the pics as the deck is already wetted out with epoxy but the trash piece somewhat shows the foam. The transom has the same foam throughout.

 

[bostonhatteras]

The box that we devised to broadcast the nonskid. The two layers of screening are running in different directions so the effective mesh size is reduced. We tried a lot of methods and this one worked. The nonskid won’t flow through the screening without being vibrated. The box was half filled and tapped with the stick shown which enabled the nonskid to flow for that moment. When we were applying the nonskid we joked that Brendan’s hunched over posture and rhythmic tapping of the box was close enough to an Indian rain dance that he would ruin the weather for us. He did start in with the howling to the rain gods but he never managed to bring any rain.

 

[rsmith]

It appears the Hilti brand is waterproof also. I’ve seen people use great stuff on metal buildings and it holds water and causes rot

 

[Play'N Hooky Too]

For my non-skid I taped off a border around my deck surfaces, rolled on a layer of paint, then using one of those cheapo hopper-gun sandblaster things from Harbor Freight, I stood back a few feet and lofted non-skid media onto the wet paint surface. I wound up with a very uniform distribution of the non-skid media. After the paint dried, I blew off the excess media, removed the border tape and went over the deck surface with another layer of paint. Perfect!